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Old 08-11-2003, 02:03 AM   #1
PacificBlue
 
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Scosche TA-03 Wiring Kit Noise Mod


Left: Original Scosche TA-03 (came w/BlueBox) <------> Middle: Scosche TA-03HB (harness only/no BlueBox) <------> Right: Best Kits BHA8113 identical to orig TA-03 (search eBay)
Note: orig harness (left) doesn't have a shell covering the pins so it's easy to mod, newer harness (middle) has the extended shell covering the pins making it difficult to mod, and BHA8113 harness (right) is identical to the original TA-03 so GET THIS ONE!

20-Pin Toyota Wiring Harness w/RCA for 2K & Up Premium 8-spkr w/FactoryAmp Mod for:

The Scosche TA-03A & TA-03B Harness
and BestKits.com BHA8113 Harness


(update 1/05: This mod fits 2000 & up GT's & GTS's w/optional Premium 3-in-1 AM/FM ETR/Cassette/CD w/8 spkrs & separate amp)
= click to jump to post about which GT's this will fit & about TA-02 harness vrs. TA-03 =


(update 7/07: Latest notes on the new TA-03B Harness, BestKits.com BHA8113 harness, Metra TYTO01 harness)
1) Some time ago the original Scosche TA-03 was superceded by a newer TA-03B harness which uses a different connector that has an extended shell covering the pins, making it more difficult to mod.

2) When selecting resistor values from the Termination Resistor Table for the newer TA-03B, add +16% to the value from the table, or use the following calculator to find the exact value, substituting 2200 ohms for R1 (the TA-03A uses 1900 phms for R1): Voltage Divider Calculator

3) There are many wiring harnesses out there which claim to be compatible with the 00-02 / 03-05 Celica's but members have discovered are not compatible. We know the original TA-03 was the easiest to modify and absolutely works, as well as the newer TA-03B, even though it's a bit more difficult to mod. We also know the BestKits.com BHA8113 Harness also works, and may still have the original Scosche TA-03 style connector that's easier to work with.

4) Recently members have been asking me about a new "compatible" harness called the Metra TYTO01. At this time all I can say is that it looks like it might work with later JBL-equipped vehicles which use the Toyota databus to control Turn-On. Other than that, I don't know yet whether it needs the mod or not. Note: Metra does not list any Celica's in their TYTO01 compatibility table.

(update 8/07: )
1) Confirming: the BestKits.com BHA8113 Harness is identical to the discontinued original TA-03 harness, including long pins making it easy to modify compared with the newer Scosche, so I'd recommend you use the BHA8113 instead of the Scosche TA-03B.

2) If your HU only has two RCA outs (L&R) you can use an RCA Y-Cable to connect to the StockAmp's Rear RCA's, but you'll need to roughly double the value of the termination resistors to avoid double-terminating the signals. For example if the table says use 600 ohms, use 1000-1200 ohms instead.


PacificBlue
--------------------------------------------------------------------------

You might think installing an aftermarket head-unit and hooking it up to the existing FactoryAmp would be a piece of cake, esp. using Scosche's TA-03 wiring harness and matching Toyota connector. Not so, and like just about everyone else here who's tried it I got loads of ECU noise, power-window buzz, dimmer buzz, and the worst: alternator whine. After installing and removing my HU about a dozen times trying things, I was about ready to throw that fancy HU out the window and put the stock unit back in, until...

I love my Celica like most everyone here does, and cuz I got so much help from reading the posts on this board, I'm posting this to give a little back. So I hope I do this right...

I'm an electronics engineer, but after re-checking everything it all looked like it was hooked up ok, aw crap. Like everyone else I thought it must be a grounding problem. Well, yes & no. And what's with the blue box Scosche gives you with the switch on the side? I wasn't about to give up because I know how good the stock GTS Premium Stereo can sound, so that FactoryAmp can't be all that bad... so I kept going.

In a nutshell... I found out our GTS Premium 4-channel FactoryAmp has high-impedance inputs with virtually no input termination. This means when you hookup most head-unit's PreAmp Outs (which have virtually no output termination) the RCA cables and the Celica's own HU-to-FactoryAmp wiring harness act like radio antennas picking up every little electrical noise generated by the car. Have you ever stuck your finger on the end of a guitar cable with the amp cranked up? Same thing.

On top of that, the TA-03 has a 1.9k resistor in series with every RCA cable. If you feel the heatshrink, you can feel the resistor inside each cable.

Solution... Terminate the inputs of the FactoryAmp to match the output impedance of the head-unit being installed. Doing this effectively dumps most of the electrical noise picked-up by the RCA's & wires to ground while allowing the higher-level audio signals to pass on to the FactoryAmp's inputs.

Click Here: If you don't see pics (goes to Tripod clone site) (updated link: 3/06)


Remove heatshrink from audio pins (notice hidden resistors in black shrink, also 4 new resistors in front



Back of TA-03 showing 4 audio pins - (Red Wire is Right Channel & Top Row is Front)



Unsolder the 4 RCA wires from the connector pins and twist termination resistors onto them before soldering


Add heatshrink tubing (yel) to prevent shorts & add structural support, then tin the ends and solder
them back to the pins

["tin the ends" means melt some solder into each twist first, then when you solder them back to the pins they've
already got plenty of solder so you don't need 3-hands to add more. Use one hand to hold the twist onto the pin
then touch the soldering iron just long enough to make the connection melt back to the pin.]




Add more heatshrink (blu) then twist the ends of the resistors together and tin with solder



Add larger heatshrink to Analog GND wire & solder it to the twisted end of the resistors



After applying heatgun to shrink tubing - (Top Row is FRONT Left & Right)



Completed Mod - tie-wrap all power leads together, then separately tie-wrap all audio & gnd's together



Scosche TA-03 FactoryAmp Noise Fix Mod - Basic Pictorial Diagram & Notes


The output impedance of my head unit is 60ohms at 5vrms, so the 1.9k (1900 ohm) series resistors don't hardly reduce any level and it's easier to leave em in. Basically what you're doing is adding a terminating resistor from each signal wire to ground, closest to the FactoryAmp's inputs. (Ideally you would do this right inside the amp, but this won't be necessary unless you plan on listening to your stereo while driving thru an MRI Scanner or past some military radar dish)


----------------------------------------------------------------------------------------------------------
|__________________SCOSCHE SLC-4 "BLUEBOX" SPECS
|____________( comes w/TA-03 Kit - features & notes below )
|
| * 4-channel HV LINE LEVEL to 4-channel LINE-LEVEL converter
|__( don't need SLC-4 for HU's w/Preamp Outs - Only use TA-03 Conn w/Mod )
|
| * 4-channel SPEAKER LEVEL to 4-channel LINE LEVEL converter
|__( up to 80 watts max per channel )
|__( use SLC-4 together with TA-03 Conn w/Mod - adjust trimpots on SLC-4 to match levels )
|
| * Transformer circuit for noise cancellation.
|
| * Common ground adapter.
|
----------------------------------------------------------------------------------------------------------


So what's with the blue box Scosche provides? Well in an ideal noise-free world you would set the switch to "Line" and plug your RCA's into it and wire the other end into your amp, but if you don't have a HU with high-level preamp outs you can connect your HU's speaker outputs into it (thru the screw terminals) and it will drop speaker-level down to line-level to feed the FactoryAmp. Will you still need to do this mod? Uhm, yeah probably... it's because inside the SLC-4 BlueBox are 4 level-dropping circuits and impedance matching/isolation transformers. What's great about transformers is that they can match the impedance of one circuit to another almost perfectly, plus they can isolate DC path between two devices and only pass the audio signal, but what's not so great is that they can also act like guitar pickups when designed to be connected to high input-impedance amps like ours.

Ever hookup a Scosche SLC-4 BlueBox and wave it around the inside of the dash with the ignition on? Acts like a Theremin doesn't it? That's cuz its transformers are picking up the noise from the data bus running all thru the Celica wiring harness. Ever play with a telephone pickup coil? Almost the same thing.

Notice the TA-03 has 3-ground wires coming out of it. Make sure you connect the ends of the 4 resistors (tied together) to the wire labeled Analog GND in the photos & diagram. The other two GND wires can be tied together and connected to your HU's GND wire. Believe it or not, once you terminate with resistors, your grounding problems will pretty much disappear.

I forgot to mention that when you terminate audio lines with the matching impedance of your HU, your frequency response will probably be restored more closely to what it's supposed to be too. In otherwords if it sounded too bright & tinny before, your bottom end (bass & lows) should come back to life again and you won't have to subtract your treble & max your bass eq settings anymore.

thanks for the help on the board & enjoy your FactoryAmp, I hope it helps...


ps ~ i want to give some credit to EvilED who posted a msg way back in 10-12-2002 about a mod for the factory amp. I found it while searching to make sure the TA-03 Noise wasn't a topic already covered. It just goes to show that doing thorough research pays off if you bother to do it (and no, I didn't find it until it was too late cuz I was lazy too... crap!)

Click Here: EvilED's factory amp mod

Click Here: If you don't see pics (goes to Tripod clone site)

Click Here: For a table of Termination Resistor Values and Final Test Results

Click Here: To jump to post about which GT's this will fit & about TA-02 harness vrs. TA-03

Click Here: Wanna hear a simulation of what the Scosche TA-03 Harness sounds like -without- the mod? [updated 4/2017: sample mp3 file moved to Tripod]
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Old 08-11-2003, 06:22 AM   #2
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cool write up, i was actually about to buy an amp to get rid of the noise, but i guess i'll try this mod....
is there any way you can make the pics show?
so far, are there any drawbacks to this mod?
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Old 08-11-2003, 07:41 AM   #3
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Yeah, host your pics somewhere else besides image station.

I just got rid of my whine, but I did something different. I cut the speaker leads away from the stock amp and hardwired them to my HU, running the front speakers in a series. Unfortunately this destroyed the power in the front speakers, they were really weak and sounded terrible, so then I got an idea... I reconnected the larger front speakers to the stock amp (my HU has both pre-outs and speaker leads) and left the front tweeters and rear speakers connected straight to the HU. This way I keep my power and almost completely remove any whine or humm. If you listen really close there is a slight whine, but the speakers are mid-range only so it's not noticable over any other normal cabin noise. I'm very pleased with the way it's turned out.
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Old 08-11-2003, 08:18 AM   #4
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Sweet write up. Try taking the .orig out of the link. Oh, and you've got a PM.

Curt
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Old 08-12-2003, 06:35 AM   #5
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Thanks everyone.

01blkgts, nope no drawbacks so far. Before the mod I could tell my bass was missing and the mids & highs were way too loud & out of proportion when my volume control was barely cranked up. Now it's nice & loud while the volume sits right in the middle of its range with plenty left to go plus now the "Loudness" button works like it's supposed to. Just make sure the termination resistors match the HU's output impedance: My HU's high voltage preamp outs are 5v @ 60 ohms, some HU's are 2.5v @ 200 ohms, in that case you'd substitute 200 ohm resistors in place of the 60's that I used.

Sorry about the Imagestation thing, I know it can be a pain. I used to not be able to see stuff on the boards until I finally gave-in & registered. Ever since then I guess it set a cookie in my browser so I automatically get access to pics from their site. I thought about moving them over to a Yahoo account but I'm not sure what their policies are about inactivity & traffic loads.

The pics were originally shot in 1600x1200 by an Exilim w/closeup adapter lens but I didn't want to offend the board by posting Jurrasic-sized pics in the thread so I shrunk them down to 640x480. If there's enough interest maybe I'll upload the monsters to an album on Imagestation and post a link in the thread.

SQ GT-S thanks, I sent you a PM. I tried dropping the ".orig.jpg" but the pics shrank even smaller so I put em back the way they were.
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Old 08-12-2003, 06:28 PM   #6
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i would really apppreciate it if you can post the pics somehow...
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Old 08-12-2003, 06:34 PM   #7
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Or just post the links to the pics for those who can't access them...
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Old 08-13-2003, 07:46 AM   #8
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just make them links...
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Old 08-15-2003, 09:53 AM   #9
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The Imagestation thing is weird, on some computers the post comes up w/empty Imagestation boxes instead of pics and on others it comes up with pics even tho those computers have never been registered on Imagestation (no previous cookie).

Anyway, I copied the post to Tripod and put a link to it near the top & bottom of the original post, or you can just click the same thing here:

Click Here: If you see Imagestation boxes instead of pics

(let me know if the empty Imagestation thing is still happening in the original post and if you like, maybe I'll just hook the pics directly to Tripod instead)
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Old 08-16-2003, 08:19 AM   #10
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I'm still new at this and plan on installing my system next week. Anways, if I have an aftermarket amp and HU, will I still hear a whine when I install it. Which is a better method? Hardwiring it to the stock harness or buy a new one that is an adapter made specifically for the Alpine(where can I get one that is good).
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Old 08-16-2003, 11:40 AM   #11
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this should be stickied
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Old 08-18-2003, 12:20 PM   #12
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Does anyone know how many wire harness there is for the stock radio? Also, is the stock wire harness connected to another wires then goes to the fuse? I'm asking this because my lights dont' work anymore for the stock radio but it still play music though. I might be the grounding because my cig light and my ac control grounding is burn/shorted out.
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Old 08-18-2003, 10:28 PM   #13
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tripnotic - I don't know if your Alpine HU is terminated inside, but from reading the posts of others on the board likely not. You'll just have to get a Scosche TA-03 kit and try it out. If you get noise you'll definitely need to do the mod.

(please note: this mod is only for the Scosche TA-03 which mates w/Toyota's 8-speaker 4CH premium stereo HU connector)

Technically, if you buy a HU that comes with high-voltage preamp outs (2.5 - 8.0 volts) plus a built-in or external power-amp, the best way to hook it up is to use the HU's own amp which is designed to match it. Of course this means bypassing the factory amp by disconnecting the speaker wires from the amp and splicing into them or running new wires to every speaker. (don't wire your HU's speaker outs across the factory amp's speaker outs - disconnect em from the factory amp)

If you're happy with how the premium factory amp sounds (w/stock or upgraded speakers) but just want to install a different HU, then get the Scosche TA-03 and mod it if necessary.

The last thing you want to do with any decent sound system is to drive a power amp off another power amp. I mention this only because there are products out there like some of the OEM Interface Adapters (aka speaker-to-line level converters including the bluebox that came with the TA-03) which take speaker level from your aftermarket's HU and drop it to line-level to feed the inputs of another power amp. Sounds innocent, but all power amps add some distortion & noise to the output signal. This is because they switch large amounts of voltage & current thru power transistors, coils, and transformers which in turn overshoot, undershoot, hiss, and throw spikes into the output. Why add that into the signal you're going to feed your power amp esp. when your HU's manufacturer gave you 4-clean HV preamp outs to use?

To answer your question about whether the 8-speaker 4CH Toyota HU connector & harness has a wire going to the fuse: Yes it does, and GND too. I keep reading about people losing their radio & cigarette lighter lights. This may be a little late but...

(Warning: Never use the ground of any illumination lights to ground your HU or (anything else)! This includes the following lights: Cigarette Lighter, A/C Switch, Hazard Switch, a/t Shift Lever)

This is because their brightness is adjusted by varying their connection to ground by a dimmer circuit on the Combination Meter. If you fry it, you'll lose all those lights but your gauges will still work cuz they're on a separate dimmer circuit.

Don't know if it's a replaceable part, maybe someone can tell us this, otherwise you may have to get a new Combination Meter.

There's a dirty fix for this but I don't think this is the place to post it, maybe in a new thread if there's interest.
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Old 09-05-2003, 01:27 PM   #14
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has anyone found a cheap place to get this online?
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Old 10-01-2003, 12:33 PM   #15
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ur a smart dude for figuring that out, not learn how to host pics!
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Old 11-24-2003, 02:12 AM   #16
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Noise Mod for those without HU Connectors

The Scosche TA-03 Wiring Harness Kit is great if you want to do a clean install that's pre-wired to the right pins & right grounds, already has built-in attenuators for HV outs, is easy to hookup, & easy to remove. To keep it that way I stuck the 4 terminating resistors inside the TA-03 harness for the Mod. Later if you want, you can remove your HU in its original condition, disconnect the TA-03 and replace the stock radio, or connect the same TA-03 to a new HU and drop it in. Clean, simple.

But if you've already cut off the Toyota HU connector there's still hope. You can order a replacement R4 connector from your Toyota dealer (I've never ordered one so I'm not sure if comes with pins in it, if not I think they sell pins w/pigtails in small packs of 10 for repairs, see below). Or you might drop by a junkyard and cut the connector off of some GT-S or Lexus. For R4 Pinouts & Color Code see below.

Again this is a little long, but then it's for everybody else who's ever wanted to get rid of that noise but already hacked-off their Toyota HU connector, so here goes...

1) You'll need to find each audio line coming from your HU: FrtL, FrtR, RrL, RrR.

2) You'll need to find the ANALOG GROUND wire in the Toyota harness and free it up from any other ground wire it may be twisted together with.

3) You'll need to find the Output Impedance of your HU (specified in ohms).

4) You'll need 4 terminating resistors (1/8 watt to 1/2watt size) that match your output impedance, 20" of small hookup wire, some heatshrink tubing (or electrical tape), and some solder and a soldering iron.

5) You want to add some wire to the ends of the terminating resistors, so twist a short 4" wire onto the end of each resistor & solder it. Leave the other end of each resistor exposed for a 1/2" and slip some heatshrink over it and shrink it. Strip the end of the 4" wire and set it aside.

6) Find the centerwire of one of the 4 audio lines from the HU. Twist the centerwire onto the exposed end of one of the terminating resistors and solder it. Do this for all 4-lines. Go ahead and heatshrink or tape-up the exposed connections.

7) You should now have 4 short wires from the terminating resistors hanging loose. Twist all 4 wires together then connect them to the ANALOG GROUND wire you separated from the Toyota harness earlier.

8) Now take all 4 braided shield wires (from each audio line) twist them together, and connect them to the ANALOG GROUND wire too.

Which one's the ANALOG GROUND wire? It's been awhile since I had my dash apart so I'm trusting the manual which sez: SOLID BLACK (You'll know if you use the wrong one: it'll still be noisy)

Double-check your work, turn key to IGNITION, power-up your HU, listen for ECU noise, run your power-windows up/down, then start the Celi and listen for alternator whine. If you still get noise check you work again: make sure you're using the correct wire for ANALOG GROUND, make sure only the 4 short wires from the terminating resistors & the shields from the audio lines are connected to it, nothing else. --> don't connect the ANALOG GROUND wire to the car's ground, radio's ground lead, or radio's chassis <-- Connect the radio's ground lead to a ground bolt on the car.

If you don't have a soldering iron you can find inexpensive soldering irons at Radio Shack good enough to do the job, some RS's stock heatshrink.

Since each manufacturer designs their HU & Amp specifications differently (some have 2V, 4V, 5V, 8V PreampOuts with output impedances like 60ohm, 200ohm, 330ohm, 10Kohm, and 47kohm outs) matching them to the Toyota Premium Stereo Amp ideally means selecting the right values for the attenuating resistors (already in the stock TA-03 harness) and terminating resistors (added by the Mod).

Generally, the terminating resistors should match the output impedance of the HU, so that's easy. The only reason why you might want to add series antenuating resistors in each audio line (or replace the ones Scosche already put in their TA-03 harness) is if the sound gets too-loud & distorts when barely cranked up, or isn't not loud enough. Compare it to how loud your stock radio radio got. The stock amp won't go much beyond that, so your new HU should at least be able to match it if everything's right.


Wiring Harness Color Codes & Pinout for Toyota HU 20-pin R4 Connector:

1 BATT = BLU w/Yel Stripe*
2 ILLUM = GRN*
3 AMP ON = RED*
7 Mute = Brown
8 FrtR = Red
9 FrtL = White
10 Shield (drain wire)
11 ACC = Gray*
12 FACTORY RADIO ONLY = WHT w/Grn Stripe* (Don't use! Cover w/tape!)
16 SGND = Black (ANALOG GROUND)
17 Beep = Green
18 RrR = Blue
19 RrL = Yel
20 GND (car chassis) = BROWN*

*1, 2, 3, 11, 12, & 20 (in caps) are individual wires, the rest are shielded together (pin 10)

(I think I got the pinouts right, lemme know if I screwed anything up)


'00-'02 Celica GT-S R4 connector: PN 90980-12038

Note: I'm not sure if these are the right pins for our R4 connector, but give your dealer the PN to point him in the right direction and maybe he can tell. Toyota calls them "Terminal, Repair":

Pack of 10 Prewired Female Pins w/6" Pigtails:
Terminal, Repair PN: 82998-12340
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Old 12-17-2003, 07:09 PM   #17
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Hey everybody,

Well, this is my first official post. I'd like to thank PacificBlue for the Mod. It works to about 95%.

I did everything like Blue said and the stereo works way better than it used to with that awful whine. However, the "whine" is still faintly there. I was wondering if anyone else still hears the faint whine and if so how (if possible) can I take care of it. My girlfriend can't hear it; but I can, I guess I am making a huge deal out of something so tiny. The slight whine is alternator whine, because when accelerating the pitch jumps. Like I said, it is so slight, it is almost not even worth bothering about but if there is an easy way to fix it, I'd like to know.

The stereo settings are perfect now. Without the mod I would play the volume on about 5 (out of 40) and the audio would be blasting. The resistors really helped tune down the sound. Now, I can jam at a comfortable 15-20.

Thanks Again PacificBlue and everyone else who has been posting car audio help,

Kevin
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Old 12-18-2003, 02:10 PM   #18
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Sweet...I got everything fixed...COMPLETELY!!!

If you have your head unit completely pulled out of the dash and held far from the center console, there is absolutely no whine. The closer you move the unit, the louder the whine gets.

After doing the mod, the noise was dramatically reduced but not eliminated. What I did to rid myself of this final noise is mount the harness and the SC-4 box just behind the HU and above on the crossing piece of plastic.

No noise now.
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Old 12-20-2003, 05:54 PM   #19
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Okay so where do I get these termination resistors so I can get the ball rolling?

About to buy the Schoche TA03 & SLC-4.
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Old 12-22-2003, 02:29 AM   #20
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Nice feeling to be rid of that god awful noise isn't it?

Don't use the SLC-4 BlueBox Level Converter if you're going to connect your HU Preamp Line Outs directly to the Toyota Factory Amp, you don't need it - like I said, hang it on the wall and turn it into a dart board. The TA-03 wiring harness connector emulates the one on the back of the stock radio and mates directly with the connector in the Toyota GT-S harness. Use the SLC-4 only if your HU doesn't have PreOuts or LineOuts and you're forced to use the speaker outputs. The SLC-4 has transformers in it that unfortunately tend to pickup the electrical noise around it (that's why it's sensitive to careful placement behind the dash).

If you do the direct Mod without the SLC-4 BlueBox and crank your headunit up to max (during silence), all you should hear is some HU & amp hiss and very little else. There should be -zero- alternator whine, power window motor buzz, or ECU hash.

If you're in a hurry, you can try your local Radio Trash Store for resistors, or ask them where there's a decent electronic parts supply store. I used tiny 1/8 watt 5% tolerance carbon-film resistors so they'd fit neatly inside the heat shrink tubing and keep things tight. You can use 1/4 watt resistors which are a little bigger if you like. Here's a link to Radio Trash if you want to get 'em right away: 1/4 watt Carbon Film Resistors. (8/07 updated link -PB)

"...dude, what'cher hearin' now is 1.21 gigawatts of silence"

PacificBlue
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Old 12-22-2003, 08:53 AM   #21
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Okay, so as long as I don't use the SLC-4, & just use the TA03 I won't have any problems with noise from the alternator coming through my speakers?

GREAT!

Amer Q.
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Old 12-25-2003, 07:15 AM   #22
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Troubleshooting Grounds

Checklist:

1) Plug the 4 Male RCA's directly from the TA-03's harness into the HU's 4 Female RCA's. (Unless your HU only has SPKR Out's, in which case you'll have to use the BlueBox and mount it carefully behind the dash so it doesn't pickup noise, but also do #6 below).

2) Connect your HU's GND (-) wire to the 2 BLK (Digital & Chassis) GND wires in the TA-03 harness. Don't connect anything else to them.

3) Connect your HU's +12v wire to to the TA-03's own +12v wire. Don't connect anything else to this wire.

4) Make sure your HU's GND wire is not conected to something else's GND, sharing it. Only connect it only to the 2 BLK wires in the TA-03.

5) Check any crimp or butt connectors you may have added to any of the wires. Check for loose crimps making poor connections.

6) Run a separate GND wire from the HU's chassis (case) to a GND bolt on the Celica's frame. On many HU's you'll find a GND lug sticking out the back of the chassis for this. Don't rely on the tin mounting brackets to do your grounding for you, use real copper.

I ran a length of #16 guage heavy-duty flexible copper wire (GRN) bolted to the frame behind the Celica's dash to the back of my HU (hard to see in the pic, but follow alongside the green line drawn-in, or click on the link below the pic to view the ShockWave animatic). On one end I crimped a heavy-duty spade lug which slips under the Celica's top-left bracket bolt (see left arrow). On the other end I crimped a smaller eye lug and screwed it to the back of my HU. (You can see the HU's GND lug sticking out of the back in the pic (right arrow), but I didn't use it cuz i wanted it bolted-down instead)


Added: #16 guage heavy-duty flexible copper wire (GRN) from Celica's dash to back of HU.
[ Click here to view an SWF animatic following the GRN ground wire added in the pic ] [ Don't use the BlueBox! ]


Note: I didn't want use this pic in the original post cuz it shows the Scosche BlueBox (which wasn't used in the final mod). Yes I hooked it up, yes I made-up 4 nice extra RCA cables to go between the HU and the box, and no it doesnt work very well in the Celica, so don't use it.

The only time the SLC-4 BlueBox should be used is if your HU only has SPKR LVL Out's (no PreOuts) and then you'll have to do the mod anyways because the transformers inside it will pickup noise inside the dash. You'll have to be careful about where you stick it and try to find a quiet place for it to live.

Anyway sorry, me bad for not mentioning this in the original post... without this chassis-to-frame ground wire you're almost sure to get some residual noise. I know cuz during testing I could hear the ECU buzz leaking thru until I cinched the bolt down tight.

I hope this solves any remaining noise problems for you.

(edited 12.30.05: add Red HL's)
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Old 12-28-2003, 09:40 PM   #23
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pacificblue,
I haven't tried the ground yet, but everything is finally hooked up, subs, changer, etc.. i still need to remove the deck again to ground the body of the deck to the chasis.

another question for you is after your install, did you experienced any engine noise or turn on/power up "pop"? i have this turn on pop right not and i think it only on the stock speakers.
please let me know.
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Old 12-29-2003, 04:30 AM   #24
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No noise, but I get a "pop" if the ignition's already ON and I turn the HU OFF manually, but I never hear it cuz I always leave the HU on and turn everything on/off with the ignition key: When I put the key in and start the car, everything turns on and comes up smoothly. When I turn the key OFF, same thing... everything shuts down smoothly, no pop - ever.

I forgot all about the HU PowerOFF pop until your post and had to run out to the Celi to check it out. Right after I did the mod I remember trying to figure out what was causing the pop whenever I turned the HU off but not the key. I never took the time to look into it, then forgot all about it cuz I always leave it ON.

The two common causes of PowerON/PowerOFF "pops" are:

1) HU's preamp outputs have DC transients on them during power-up or shutdown.

2) Power amp's outputs have DC transients on them during power-up.

Most head units have an AMP CONTROL wire which connects to the Remote Input on the external amp to turn it on/off by the power button on the HU (including the stock radio). But how elegantly they control the remote PowerON/PowerOFF timing of the external amp may be different from manufacturer to manufacturer (like from nil to maybe a one-second delay). Interesting thing is, the stock radio never popped no matter what.

Some external power amps have built-in muting relays to keep the speakers from getting connected to the output stage until the amps have stabilized (ever hear that delayed "click" coming from the inside of a high-end high-power amp, EQ, or crossover?)

Head unit PowerOFF pops are harder to fix than PowerON pops. If you turn your HU OFF and its preamp outputs have transients on them during the shutdown and the external amp is still ON, there'll be a pop in the speakers. But how do you turn OFF the external amp before the HU if the OFF button you're pushing is on the HU? Ideally the remote AMP CONTROL wire should turn OFF first, then the HU should turn itself OFF a second later.

PowerON pops are easier to fix because you can connect a delay relay between the AMP CONTROL wire and the Amp to turn it on a second later after the HU's preamps have stabilized. If you've got a PowerON pop you can try a STINGER "SGN21" which supersedes their older "SPSON" module to see if it fixes the problem:


"SGN21: Stinger PopStopper"
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Old 12-31-2003, 11:10 AM   #25
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This thread is exactly what I have been looking for, but I was hoping someone might be able to answer a few questions.

I just ordered a Sony CDX-MP80, it should be here soon and I wan't to install it asap. After reading this post I also ordered the Scosche TA-03 adapter kit from sound domain. From what I understand, I DO NOT need the SLC-4 blue box because I have rca pre-amp outputs. All I need to do is the noise reduction mod to the TA-03, right? Now I am not sure on what kind of resistors I need to purchase for my head unit. I was hoping someone here could help me figure this out.

Here is detailed info on the Head Unit http://www.crutchfield.com/cgi-bin/S...s&i=158CDXMP80
I am having a hard time finding out the ohms on the deck, all I can find is 2 4volt preamp outs with high pass and 1 4volt sub out with low pass. So what kind of resistors do I need? Do I need to modify the resistors already inside the TA-03 or can I leave them? Any help would be greatly appreciated. thanks in advance.
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Old 12-31-2003, 05:45 PM   #26
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TA-03 Mod Termination Resistor Values for HV HU's

This post goes out to dchan8 & Tryan77 who've been brave enough to try this mod and to keep me on toes searching for the math to resolve the termination value question. Reverse-engineering is like hacking, you don't give up until you've got it all figured out and then you're a little smarter and grin a whole lot:

I knew the series resistors that Scosche put in the RCA cables of the TA-03 were part of an "L"-pad attenuator network, used to drop higher-level audio to lower-level audio. But what was their intended design spec? My best guess was that it was originally meant to be a 50% voltage divider into a 2k input load for some Toyota factory amp (500mv in = 250mv out, etc), but not ours.

Our factory amp has practically no input termination, so it puts no load on the TA-03 & HU and the series resistors basically don't do anything except pass pretty much the full voltage from the HU to the amp (which in turn makes it sound too loud & the volume dial way too sensitive).

I searched the internet looking for some old audio equations I knew were out there and yep, it's true - the Truth is out there somewhere... I'll give you a range of resistor values first, then leave you with a couple of links if you want to learn more about this sort of stuff:

8v : 36 ohms = 150mv / 48 ohms = 200mv

5v : 60 ohms = 150mv / 79 ohms = 200mv

4v : 74 ohms = 150mv / 100 ohms = 200mv

2v : 154 ohms = 150mv / 211 ohms = 200mv

(this table is updated in a later post: Final test Results)

Assuming the factory amp wants to see 150-200mv of signal at its inputs w/termination, and using the existing series resistors in the TA-03 harness, these values should work.

In my setup I used 60ohms so the factory amp is theoretically getting 150mv. It sounds & works great, but I'd probably try using a higher value resistor next time to get me closer to 200mv so I'd have more volume range to crank up the quieter tunes.

Don't forget, these numbers are based on using the existing series resistors Scosche put in the harness. If you want to build a "by-the-book" perfect "L"-pad, you may have to replace them with other values. Here's a couple links explaining attenutation and voltage-dividers:

"Line level signal to microphone input adapter"

"The Voltage Divider Rule" - Resistive Dividers

"Voltage Divider Calculator"

If you want to follow dchan8 & Tryan77's troubleshooting thread click here:
"Termination Resistor" - dchan8 & Tryan77 (for Alpine 10k 4volt PreOuts)
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Old 12-31-2003, 06:35 PM   #27
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does this mean that i should try for my alpine(4v preouts) a resistor from 74-100 ohms?
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Old 12-31-2003, 06:55 PM   #28
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Yes.

In audio, 10k impedance is still considered a "high-impedance" and prone to picking up some noise unless well-shielded.

I'd try the 100 ohm, it should kill any remaining stray noises you've been tackling, give you plenty volume, and leave your volume control set so you don't have to max it out to hear the softer tunes.
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Old 01-01-2004, 11:09 AM   #29
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sorry to be a nag but,

So if my pre-amps are pumping out 4 volts, then you suggest doing this mod using 100 ohm resistors?

This is my virgin electronics experience and I don't want to mess anything up when my HU gets here next week.

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Old 01-01-2004, 07:39 PM   #30
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lowendfrequency - Yep it looks that way so far, least on paper. We're waiting for dchan8 & Tryan77 to finish tuning their Alpine 4volt HU installs to find out if the math works.

It's kinda difficult trying to figure this out by "remote" cuz I'm not there in front of your rides where I can help you test & tune them. That's why in the TA-03 Noise Mod post I said the 60 ohm terminators's worked for my HU, but the values might be different for yours (if it's got different output voltages & impedances than mine).

According to the math there are many ways to accomplish the same goal (match levels, impedance, signal transfer, minimize or eliminate noise). But which one to use depends on the gear's specs, type of power source, grounds, electrical envoironment (noise), shielding, etc.

For us, with our super high-tech, muchly-electronic, almost fly-by-wire 7th Gen Celica's, there are computers communicating with & controlling everything everywhere, talking over wire harnesses that rival ones used in 747's, we share power to everything off of one poor little 12 volt battery, we share the same ground which floats on rubber insulators (tires) that keep us from using a "real" ground (mother earth), we generate high-voltage sparks to startup our HID's, more sparks to fire-off the sparkplugs that make us go & give us Lift, we generate mega-pulses of power to recharge our battery (alternator), and we generate more noise everytime we switch-on or roll a window, sunroof, or cabin air blower, and we expect our super-sensitive high-end audio gear to be noise-free in all this soup?

Yep. So, based on collecting the 411 from mod'ing mine & others trying to mod their's, then applying the formulas used for calculating the resistors for building an "L"-pad attenuator (with a little rule-bending), it looks like the resistor values in the last post (above) will probably work ok in this hostile environment. Just find your HU's PreampOut voltage in the left column and pick a resistor value between the two values listed in the chart.

You're right about the Sony CDX-MP80 output impedance specs being difficult to find. But that's okay, the math has already been done for you and the termination resistor values in the last post should work fine for the PreampOut voltages shown. So if your CDX-MP80 has 4volt PreampOuts, you'd use a 100 ohm termination resistor on each audio pin on the TA-03 harness connector just like the 4volt Alpines.

But, you might wanna hang out for the results from dchan8 & Tryan77 first, or go ahead and be real brave and join their "Alpha test" team. The more 411 we get the better and the sooner we'll know what works best.
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Old 01-02-2004, 07:06 AM   #31
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Thanks for getting back to me man,

I should be getting my HU on monday, and the TA-03 sometime soon after, so I'll hold off till then. After that I think I will become an alpha tester as well.... gonna pick up some 100ohm resistors today and go over everything to make sure I know what I'm doing.

So, just to make me feel better, humor me real quick. Worst case scenario....The noise mod doesn't work, I get loads of alternator whine and electrical buzz, and am forced to bypass the factory amp to get rid of it, right?
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Old 01-02-2004, 08:17 AM   #32
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Don't worry there's no question the mod works, you just have to pick the right value termination resistors for your particular HU and you're done.

Personally, I tried the TA-03 just to see if I'd be happy with a new HU powering the existing amp & speakers. Answer? I'm very pleased. Plus, I always knew I could install an aftermarket setup later if I wanted to. In fact I went ahead and added a sub because the Celica's sound system really lacks bass (it doesn't have a trunk or airtight enclosed compartment that can support a decent low-end bass setup). Now, it kicks ass.

How much sub, bass, midrange, highs and SPL (sound pressure level) you want is a personal choice. Take a look at the "Pics of trunk setups here!" thread and you'll see what I mean.

You can always bypass the factory amp if you want to, but it's a little bit more work than mod'ing the harness. You'll have to locate a place to mount your new amp, disconnect the old one, patch into the wiring harness for power, IGN, and GND, and splice into existing speaker wires. You'll find instructions on this board and others complete with color codes.

Try your new HU with the TA-03 & Noise Mod for now. You can always add aftermarket gear later if you want to.
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Old 01-02-2004, 11:48 AM   #33
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pacificblue,
i just tried the 100ohm resistor, and there is pretty much no ecu or engine noise, but i have to max my volume to get it to be pretty loud(kind of normal for me) but it's not loud enough, what size should i try next?
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Old 01-02-2004, 02:20 PM   #34
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Quote:
Originally posted by dchan8
pacificblue,
i just tried the 100ohm resistor, and there is pretty much no ecu or engine noise, but i have to max my volume to get it to be pretty loud(kind of normal for me) but it's not loud enough, what size should i try next?
dchan8
Are you running 4volt preamps? I just purchased some 100 ohm resistors to do this mod but it sounds like I might have to take them back. How loud is it compared to what it was stock? I usually listen at a medium level but I like to crank it now and then and I don't want to lose any power.

Also, what should the wattage be on these resistors. I bought the ones that looked most similar to the ones in the pictures that pacific blue posted, they are QW110 100ohm 1/4Watt Flameproof resistors w/ metal film. Does that sounds right?
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Old 01-02-2004, 03:36 PM   #35
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according to pacificblue,
1/4 to 1/2 watt is fine for the resistors.
i have 4v preouts too. i suggest to use 470ohm resistors. i think this is the boundary for engine nose and not. keep in mind that you probably won't be able to hear any engine noise when the car is running and you have some volume with the stereo.
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Old 01-06-2004, 01:02 PM   #36
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got this mod workin in my car with 300ohm resistors, works like a charm :thumup: A+ work here pacificblue
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Old 01-07-2004, 06:42 AM   #37
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TA-03 Mod Termination Resistor Values for HV HU's - Final Test Results

Wow!, looks like everyone finished tuning their mods... Excellent! This is my first chance to catch-up with the board since returning to work after vacation. You guys just made my day.

So it looks like feeding the factory amp about 500mv signal is the magic number. Here's a list of the termination resistor values each of us ended up using w/comments about the results:

150mv / 5v 60 ohms "It's plenty loud but the dial is spread out, so I may try it with 211 ohms later so I don't have to max it just to hear the softer tunes." - PacificBlue

432mv / 4v 230 ohms "If I changed anything I would try a "slightly" lower resistor. I think something between my 230 and the next lower size of 150 might eliminate virtually all the noise and still give people similar to me, enough volume." - Tryan77

546mv / 4v 300 ohms "The 300ohm resistor was the perfect match for me, I can't even detect a hint of ecu/alternator noise but I can still crank it as loud as I dare and have room left to go." - lowendfrequency

793mv / 4v 470 ohms "i settled on 470... this has a little/faint ecu noise when the car was off, but on start. no ecu noise when the key was in the on/acc position" - dchan8

So 333.3 ohms was the average of the three Alpine 4v setups.


Here's the updated termination resistor selection table. Don't forget, these numbers are based on using the existing series resistors Scosche put in the harness:

(update 7/07: Instructions for Calculating Values for newer TA-03B harness)
Note: The TA-03A harness uses 1900 ohm series resistors while the newer TA-03B uses 2200 ohm resistors, so if you're using the newer TA-03B and want to be precise, add +16% to the value found in the table below for your termination resistors, or follow the instructions on how to use the Voltage Divider Calculator linked further below. Resistors are usually rated with a +/-10% tolerance, so it's really no big deal if you want to stick with the table.


(update 8/07: Termination Resistor Values for HU's with only 2-RCA Outs)
Note: If your HU only has two RCA outs (L&R) you can use an RCA Y-Cable to connect to the StockAmp's Rear RCA's, but you'll need to roughly double the value of the termination resistors to avoid double-terminating the signals and losing level. For example if the table says use 600 ohms, use 1000-1200 ohms instead.



Just find your Preamp-Out Voltage on the left, then use the resistor value shown in BOLD for your mod.

8v: 36 ohms =150mv / 48 ohms =200mv / 61 ohms =250mv / 126 ohms =500mv / 271 ohms =1volt

5v: 60 ohms =150mv / 79 ohms =200mv / 100 ohms =250mv / 211 ohms =500mv / 475 ohms =1volt

4v: 74 ohms =150mv / 100 ohms =200mv / 127 ohms =250mv / 271 ohms =500mv / 634ohm =1volt

2v: 154 ohms =150mv / 211 ohms =200mv / 271 ohms =250mv / 633 ohms =500mv / 1.9k =1volt

1.8v: 173 ohms =150mv / 237 ohms =200mv / 306 ohms =250mv / 731 ohms =500mv / 2.4k =1volt

The resistor values in BOLD to produce 500mv are highly-recommended, the values for producing 1volt out are for reference only and definitely not recommended. If you want to put more spread on the volume dial use a lower value resistor, if you want more guts on the dial use a higher one.

If you want to build a "by-the-book" perfect "L"-pad, you can do the math and replace the series-attenuator resistors Scosche built into the TA-03 harness and the mod's termination resistors with custom values. Here's a couple links explaining attenuation and voltage-dividers:

"Line level signal to microphone input adapter"

"The Voltage Divider Rule" - Resistive Dividers

"Voltage Divider Calculator #2" {added 12/30/06 to replace dead link}
(update 7/07: Instructions for Calculating Values for newer TA-03B harness)
Note: Input R1=1900 for TA-03. Input R1=2200 for the TA-03B to get the correct termination resistor value.


If you want to follow dchan8 & Tryan77's troubleshooting thread click here:
"Termination Resistor" - dchan8 & Tryan77 (for Alpine 10k 4volt PreOuts)


And here's a review & summary of all the 411 we gathered from reverse-engineering, mod'ing, testing, and tuning:

High-end aftermarket head-units equipped with high-voltage (2v, 4v, 5v, 8v) preamp outputs place the audio signals way above the noise found in our cars, but are too hot to directly drive the factory amp used in the 2000-2002 GT-S w/Premium 8-Speaker Stereo system without sounding too loud in the midrange and picking up all sorts of electrical noises from the car.

Because the stock amp has a very high input sensitivity, the aftermarket HU's PreOuts need to be attenuated from 2v, 4v, 5v, or 8v to approx. 500mv (.500v) in order to drive it to full output without distortion. Also, because the amp has a very high input impedance of 1-meg or higher, it needs to be properly terminated in order to drain the electrical noise picked up by the audio lines to ground before they reach the amp. Among the potential sources of noise in the Celica are its multiple ECU's, cabin light dimmer, power windows, power sunroof, power doorlocks, front & rear windshield wipers, HID's, ignition system, alternator, and any aftermarket gear like neons, inverters, guages, etc.

Using the inexpensive Scosche TA-03 wiring harness you can connect an aftermarket HU with the Celica GT-S' wiring harness without cutting the connector off or splicing wires, but it must first be modified with the addition of 4 termination resistors to accomplish two things: 1) to attenuate the HU's signal level down to 500mv's and 2) to terminate the audio lines between the HU and factory amp so that any noise they pick up will be drained to ground thru the resistors before entering the amp. By adding the 4 termination resistors in a bridging configuration and using the existing series attenuating resistors already built into the TA-03 harness, we form an "L"-pad attenuator which reduces the level and drains the noise at the same time. The factory amp can then be driven to full output without loss of low-end (over-bearing midrange), distortion at high levels, or picking up surrounding electrical noise.


btw: If you don't feel comfortable doing an audio install by yourself after studying these boards, I highly recommend you find a professional installer in your area by posting a question in the Audio & Electrical Forum and asking for one; some are better & more familiar with the Celica than others and this is probably one of the best ways to find one. You could also ask if any nc.org member in your area would be interested in helping you or doing it for you, can't hurt.


Thanks again to everyone who posted their questions, comments, suggestions, & results. Like I said, I'm real pleased with how the Celica sounds now with the stock amp & speakers w/new head-unit & sub, and even more pleased to be rid of that god-awful noise.

Now the rest of you Celi lovers out there that have been dyin' to stick a better head-unit in the dash and were worried about how to do it, can do it.


"Bill?" "What is it Ted?

"...the next sound you hear will be 1.21 gigawatts of most excellent silence!"
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Old 03-29-2004, 04:46 PM   #38
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So if I have a preout out impedance = 2.2v/1k Ohms (I think)

here is a link to my manual
http://www.pioneerelectronics.com/pi...1325447930.pdf

what type of teminating resitors do I need give the results for a 2.2v
154 ohms = 150mv / 211 ohms = 200mv / 271 ohms = 250mv / 633 = 500mv

154?
211?
271?
633?
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Old 03-30-2004, 01:39 AM   #39
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Because the stock amp has a very high input sensitivity, the aftermarket HU's PreOuts need to be attenuated from 2v, 4v, 5v, or 8v to approx. 500mv (.500v) in order to drive it to full output without distortion.

...according to the chart 633 ohms is what you'd use, but since that's not a standard off-the-shelf value buy the next closest value: 620 ohms.
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Old 04-12-2004, 08:18 PM   #40
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i have this HU http://www.hookedontronics.com/show_...s.jsp?cid=4394

so which resistors should i get?

thanx
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Old 04-12-2004, 09:53 PM   #41
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Looks like the Pioneer DEH-P750MP CD WMA MP3 Player has 6 volt PreOuts. So 172 ohms would give you 500mv, but again that's not a common off-the-shelf value so use 150 ohms (or 180 ohms) instead.
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Old 04-13-2004, 07:30 PM   #42
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thanks pacific,
i have a few more ?'s though
what do you mean by "unsoldering" at the beginning steps of this mod? i'll be buying a soldering gun this weekend, never actually used one...
right now, i'm planning to install this unit temporarily until i get my jdm console http://www.wholesaleaudio.com/ALPINE/IVA-C800.htm would it be alright if i just leave the resistors which were for the pioneer, and just plug and play with the alpine, or do i have to get new resistors?
also, the last step requires a ground from the hu chassis to the celica frame, is this really necessary? i don't really know where or how to do this part

thanx
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Old 04-13-2004, 09:21 PM   #43
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The 2-RED and 2-YEL wires in the pics are the center wires of the RCA audio cables in the Scosche TA-03 Harness. Scosche slips a short piece of black heat shrink over them, solders 'em to the Toyota connector, then slides the shrink tubing over the solder joint & pins and heats them to shrink tight so nothing can short out across any exposed pins.

I used an exacto knife to slit & remove the black heatshrink so I could expose the wires and unsolder them from the pins (hold the soldering iron on the pin until the solder melts so you can pull the wire free).

Once the wires are free it's easy to twist the resistors onto the exposed ends. After that, "tin" the ends by touching the soldering iron to each end and apply a tiny bit of solder until it flows into the wires, then immediately pull the soldering iron away so you don't melt the RED or YEL jacket. After the ends are cool slip a short piece of heatshrink over them.

If you tinned the ends enough you should be able to rest each wire on a pin, press the soldering iron on top of the wire and it should melt the solder and flow onto the pin. Lift the iron as soon as the solder melts. Hold the wire still - don't move it or else you'll make a cold solder joint which is mechanically weak and electrically "iffy". If it looks shiny, it's good. If it looks matte finish it can't be trusted, reheat & try it again.

After the pins cool, slide the heatshrink over each pin and heat with a heatgun or hair dryer until it shrinks. Don't overheat 'em or they may burn & curl.

The Alpine IVA-C800 has 4volt PreAmp Outs and would ideally need 271 ohm resistors in the harness, but you probably won't notice too much of a difference. You'll still be able to crank it up and it'll still be loud, but you may have to turn up the dial more than your Pioneer. I'd mod the harness for the Pioneer and not worry about the Alpine levels.

In answer to your question about the extra GND... I installed it while troubleshooting the original TA-03 noise problem. After figuiring it out I began wondering if the extra heavy-duty ground was still really necessary. With the key turned to accessory, engine OFF, and HU ON, I could hear a faint tiny bit of noise from the ECU. When I connected the heavy-duty GND wire to the Celi's frame and cinched the bolt down - the noise disappeared.

If you use metal brackets bolted to the sides of your HU, then bolt the brackets to the Celi's frame, this should take care of all the grounding you need, but the best of the best will tell you that it never hurts to run an external heavy-duty GND Strap or GND Wire because "brackets & bolts" have a tendency to work themselves loose over time thru vibration.

I hope this helps.
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Old 04-14-2004, 06:53 AM   #44
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that really helped alot, thanks
i will try and do this mod this weekend

thanks again
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Old 05-06-2004, 11:40 AM   #45
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I just got fed up and rewired the pre-amp. No Noise. Took 15 minutes start to finish :-)
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Old 05-12-2004, 08:00 PM   #46
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Thanks PacificBlue for the install info and everyone for their ohmage (is that a word) feedback.

I used the 620 ohm and it sounds pretty close to when I had it in my other car. I do hear the pop when turning it off but that is something I generally never do.

Thanks again all
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Old 01-09-2005, 08:41 PM   #47
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this thread rocks
i havent even messed with my radio yet but this is what i have gathered from this thread and all the links that deal with it
\/
this only deals with the premuim sound in the gt-s
i take it the jbl factory sound thats in my 03 gts is premuim

the head deck i have to put in is my alpine 9813

this has 3 sets of pre outs
front rear and sub
these are 4 volt pre outs
( so i would be shooting for 271 ohms@500mv?)
found here 270ohms 1/2 w resistor
http://www.radioshack.com/product.as...Fid=271%2D1112

am i forgetting some thing besides the long deck to chassis ground?
oh and where can i get a din mount w/ the little pocket underneath?

thanks in advance
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Old 01-10-2005, 10:32 PM   #48
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I'm glad the thread is still helping out. It was written for 2k-2k2 Celi GTS owners with the 8-Speaker Premium Sound System (not for GT's). Scosche still specs the TA-03 for 2k & up Celica's, so it should work on your 2k3.

Yes, 270 ohms is the magic number for your Alpine. Keep in mind resistors get physically bigger the higher the wattage rating, so although you can use anything from 1/8 watt thru 1/2 watt at 270 ohms, I'd try to stick with 1/8 or 1/4 watt resistors as they fit inside the shrink much better.

As far as the single DIN mounting kit w/pocket goes, probably the most popular one is the SCOSCHE TA2045 with small pocket underneath. You can check it out here: Scosche TA2045 Single DIN w/Pocket

Larry Dougherty did an awesome job custom mounting his HU in a Single DIN mounting kit available from the UK. have a look here: Single DIN mounting kit

It can sometimes be a little difficult holding two heavy pieces of HU gear stable in a double DIN mount, but when Chiznarles still had his 2k Celi, he installed a Double DIN mounting kit and finished it off with a pair of Toyota OEM side fillers to make it look nice and smooth. You can check that out here: Double DIN Installation Kit

The heavy-duty ground is something I did cuz I just don't like depending on the mounting brackets for grounds, especially if they're going to conduct power to ground and double as a pathway for noise to ground. I'd rather trust a nice hunk of copper wire anyday over Japanesium brackets that were never designed to serve as grounds in the first place.

Have fun doing the mod and enjoy the Alpine!
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Old 01-12-2005, 06:17 AM   #49
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Quote:
Originally posted by PacificBlue
It was written for 2k-2k2 Celi GTS owners with the 8-Speaker Premium Sound System (not for GT's).
Well I guess i'm one of the few GT owners that has a premium sound system and has benefited from your posts.

Has anyone tried the BHA8113 from best kits and harnesses a.k.a. stinger-aamp. I spoke with them and their harness uses 2k ohm resistors on the rca leads.
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Old 01-12-2005, 07:48 AM   #50
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Yes you are...

According to the 2000 brochure the GT comes standard with: "Deluxe 3-in-1 AM/FM ETR/Cassette/CD with 6 speakers". But you could order the "Upgrade Package" (Upgrade Package - includes power windows and door locks, and cruise control) and then add the "Premium 3-in-1 AM/FM ETR/Cassette/CD with 8 speakers" to the order.

According to the Toyota Schematics, the standard "Deluxe" system (without separate amplifier) uses a 10-pin R2 & 6-pin R3 connector (Scosche TA-02 harness works here), and the "Premium" system (w/separate amplifier) uses a 20-pin R4 connector (Scosche TA-03 harness w/mod works here).

I'll update the top of the thread later when I have more time, thanks for the 411. (01/12/05: done -pb)


The BHA8113 from bestkits.com in the pic below looks identical to the TA-03, and 1.9k/2.0k is essentially the same value (within 10% tolerance). I didn't want to slit the heatshrink open on my TA-03 to find out, so I measured the them with an ohmeter and each one read about 1.9k. So like I said, the BHA8113 kit is probably the same harness as the TA-03 kit. You can compare them for yourself:



BestKits.com BHA8113 - "20 Pin Premium Toyota Harness w/RCA"
(If anyone actually tries the BHA8113, PM me or post here to share your results)


Scosche.com - TA-03 "2000-Up Toyota Amplifier Harness"

Reminder to those "speed-reading" this thread, yes these harnesses will work, but you've gotta mod them first. So don't go ordering one and think it'll work straight out of the package.
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