matguy

I feel the same about most aftermarket head units. I don't want whiz-bang flashy, I want classy and simple to use. Interestingly enough, as you noticed, a lot of the simple and easy to use systems are also lower quality.

As opposed to the theories mentioned by others in the linked thread that I was also involved in, the Pioneer system does also send the signal as standard line level to the factory amp.

Basically you do the opposite of what's mentioned in this thread: https://www.clublexus.com/forums/lex...b-working.html

Now, the Pioneer sub is either 1 or 2 ohms. This poses a slight problem as currently available amps that can handle 1 ohm well are usually higher powered and more expensive.

You have 4 main options for the sub:

• Deal with an over-powered and likely more expensive amp that can drive your Pioneer sub, make sure to keep the gain low, and hope for the best.
  
  
• Replace the stock Pioneer sub with an aftermarket sub that's 4 ohms; usually requires some fabrication to get it to mount and make sure the sub isn't so deep that it hits the gas tank.
  
  
• Use the factory sub amp, it does appear to be possible to wire it in without the factory main amp.
  
  
• Replace the factory Pioneer sub with a factory Nakamichi sub. It should drop right in, it's better quality, and it's 5 ohms, so won't over stress a standard aftermarket amp

Then there's the amp options: A single 5 channel amp, a 4 channel and a small mono sub amp, a pair of 2 channel amps and a mono sub amp, or a trio of 2 channel amps and bridge one for the sub (Ok, you could also do mixes of 2 channel and 4 channel amps or all sorts of bridging of multi channel amps.) There is the "tri-power" option of running the sub off the same 2 channel amp as the rear speakers, but then you lose the ability to adjust the gain for the sub separate from the rears.

Personally, I'd say to do a single 5 channel amp and put the factory Nakamichi in place of the Pioneer sub or if you really don't want to replace the 10" Pioneer sub you could just put in a 4 channel amp and continue to use the factory sub amp (if it's an 8" I would certainly replace both.)

Here's what you'd do, as main points:

Pull factory amps (or just the one if you're keeping the Pioneer sub and sub amp.)

Isolate the line level wires. The diagrams show each channel having its own positive wire, but they all connect to a common signal ground (not chassis ground.)

Connector A
Front Right Line Level + : Red
Front Left Line Level + : Blue
Rear Right Line Level + : Brown
Rear Left Line Level + : White
Signal ground (- on all main line level connections) : Brown

On the sub Amp connector
Sub Line Level + : Black
Sub Line Level - : White
(Yes, backwards of what I would expect.)

Once you find them all, splice those in to separate RCA connections. If you're keeping your factory sub amp, don't splice the sub wire. You can either just get RCA ends and terminate the factory wires to them and use RCA extension cables to stretch to where you're mounting your amp or splice shielded wires that are pre-terminated with RCA connectors that are long enough to get to your amp. The signal ground will go to the - or shield on the new main speaker connections. On the Sub, + to center, - to shield; again, only if you're replacing the sub amp.

The mute function (from the phone option?) won't work on aftermarket amps, neither will the "beep", ignore these.

Now, I'm not sure how the factory Pioneer system does its crossover, or if it even does. If its done in the head unit, then you just hook everything up and it's easy. If not you should do at least some filtering to keep the main speakers from over-working trying to reproduce bass they can't as well as blocking the high frequencies from the subwoofer that it can't reproduce. Some amps will have a crossover built in, otherwise you'd be looking at either line level crossovers or speaker level.

If you don't replace the sub but want to replace the sub amp you'll have to select an amp that can drive it at the 1 or 2 ohms that it is. Or, as motioned earlier, you could replace the sub (aftermarket or factory Nakamichi) and have way more amp options.

Then you'll need to isolate the speaker wires coming from the factory amp and wire them in to your new amp(s.)

Connector B
Front Right + : Light Green (B1)
Front Right - : Blue (B5)
Front Left + : Pink (B2)
Front Left - :Violet (B6)
Rear Right + : Red (B3)
Rear Right - : White (B4)
Rear Left + : Black (B8)
Rear Left - : Yellow (B9)

Sub (if you're replacing it)
Connector on Sub Amp
Red/White +
Black/White -
(not backwards from one would expect, go figure.)

Oh, and power. Most amps are going to need more amperage than the factory power wires should be expected to deliver (I think the little Alpine Power Pack amps might be fine, though, for the main amp; look in to those...) There are plenty of threads on how to run power.

For most amps you'll also need to isolate the remote turn on lead that goes to the factory amp (the Alpine amp I mentioned senses input, so no remote lead needed.)

On the main amp connector A it's Pink/Blue on pin 6 (also pin 6 on the sub amp.)

I've also attached a wiring diagram.

Now, I started on this last night and have also been on baby duty on and off, please afford the appropriate slack for any mess-ups.

KahnBB6

iTrader: (5)

Small update to this. Other things have gotten ahead of tearing into it and for a while it was intermittent enough that I just lived with it.

I should have recorded this initially as a companion to the other strange sound in the previous attachment. Here's a sound file (about 4min) showing what the high pitched frequency noise is like 99% of the time. That previous sound file demonstrates the more uncommon version of this sound issue.

Car is started from cold. I began recording after the sound began shortly after turning on the factory head unit. At 20sec in I point the microphone directly at the rear subwoofer from the driver's seat-- there was no sudden change in volume, just a change in the microphone's direction.

Notice the first manifestation has the frequency starting from high and going to low before dying out. After a few seconds of pause, it reverses and goes from low frequency to high.

At 56sec it fizzles out and at 1min,11sec it starts up again and keeps on climbing steadily in frequency until about 1600Hz or so. After about 3min,10sec I demonstrate the engine revs NOT affecting the sound issue at all. This is normal behavior.

As mentioned earlier in the thread, volume level adjustment from the **** doesn't affect it until you take it all the way to zero, at which point it (and all sound) just stops. Turn the volume above zero and the sound resumes already in progress.

Now, what's funny is that sometimes the issue doesn't happen at all and the stereo sound is perfectly clean.

.....

From everyone's suggestions I've been convinced this is the factory Pioneer amp or possibly the Pioneer sub amplifier, since it doesn't originate from the front-- only the back.

KahnBB6

iTrader: (5)

Matguy, you have gone above and beyond. Thank you for your very thorough breakdown!

That is a lot I need to consider and really to go through step by step as I diagnose this. And the diagram is very helpful, thanks!

In looking at the four options you listed I am very curious about something I don't think you specifically addressed:

Since the Pioneer system has a main amplifier for the entire system and a separate amplifier for the factory 1-2 ohm sub... is it possible that what is going out is not the main amplifier but the sub-amp?

And if so, would swapping in a factory Nakamichi sub be possible while wiring it into the factory amp? My guess would be that the sub-out as designed from the factory amp (Pioneer) doesn't have enough driver power for this.

First order of business, I think, is to locate the separate Pioneer sub-amp and disconnect it to see if the problem disappears. If so, that would pinpoint the source of the issue.

If not... then I'll need to start exploring the options you outlined.

Also, we're definitely on the same page about most aftermarket head units. I swear, old Nakamichi, old McIntosh and old Blaupunkt were among the only ones that really caught my attention for aftermarket units. Aside from those, I like t2d2's approach.

Though I did like those Parrot 1-DIN units that were available for a time. Only they proved to be completely unreliable.

.....

For those interested I have posted a new sound file into my original thread meant to identify this issue. If you listen to it (post #9 in that thread) you can accurately hear how this high pitched sound malfunction is acting and how it seems to be going on while isolated from any engine or wireless interference.

https://www.clublexus.com/forums/per...ml#post9253744

t2d2

iTrader: (8)

When you remove the parcel shelf, it's sitting next to the sub on the passenger side. You can see it from the trunk, but it's bolted in from above and the connectors are on top, as I recall. It looks like a little sardine can.

If that turns out to be the problem, you can have mine for the cost of shipping. It's untested, since my system was a mess when I got it, with only one working speaker, and I replaced everything but the head unit. I think the P.O. had it bypassed with all the speaker amp/CD changer wiring intercepted and an amp power cable run to the trunk, and just never hooked it back up when removing the aftermarket amp. I mounted a small amp in its spot to power a new sub, rather than try to sort it out.

matguy

Hey, no problem. I enjoy figuring this stuff out. My wife has no interest in hearing about it, so someone has to.

Sure, it's totally possible the sound is coming from the sub amp. But, is the sound coming from the front speakers, too? If it is it's not coming from the sub amp.

It's probably the switching power supply in the amp that's not getting filtered any more, likely due to dying capacitors. In theory, you could probably find some kind of repair shop to replace the caps. But I wouldn't quite be sure how to go about finding such a shop or figuring out if you should trust them. Or look on Ebay for a replacement, though you might end up with the same problem down the road, or right out of the box.

But, yeah, you're right about trying to connect the Nakamichi sub to the Pioneer amp, it'll drop it to putting out only 16 watts. Not nearly enough (at one point I had that in the earlier post, I guess it didn't make the final cut.)

When the impedance rises the sub pulls less amperage from the amps, so you get less wattage. So, if the stock Pioneer amp puts out 40 watts at 2 ohms (80 watts at 1 ohm) you can take the 40 x 2 / 5 and come to 16 watts (or 80 / 5.) I have a feeling that the Pioneer amp may be the same between the 2 different Pioneer systems and just relying on the impedance change to raise the wattage, but that's just a wild theory.

matguy

I just finally read the other thread. It sounds like it's probably the sub amp, but it still could be the main amp. I'm not sure of the design of the main Pioneer amp, but there could easily be an issue that affects one pair of channels and not the other. But there's a good chance it's the sub amp. The sub, itself, can easily reproduce up through 1600hz, probably up over 5000hz, maybe up to 10khz, and it could easily sound like it's coming from all 3 channels and be hard to isolate since they're all so close.

KahnBB6

iTrader: (5)

t2d2 -- If I do learn that it's the sub-amp causing the issue I will definitely take you up on that offer. I'd be fine with a simple (if still temporary) factory replacement fix for the time being. Have to identify it first though.

matguy -- I understand well that position you're in when it comes to this stuff in the home

Glad you agree with the hypothesis. I'm going to get in there and verify it myself tonight.

You're right, it is hard to be 100% certain if it's not also coming through the front speakers but I am 99% sure what I am hearing is coming from the rear only and especially from that center sub speaker. If you listen to the most recent audio clip I posted you can also hear the sound seem to increase in volume at 20 seconds in. That was entirely due to my changing direction of the recorder microphone from the front of the car directly to the rear.

I'm disappointed about the Nakamichi sub incompatibility but damn if doesn't seem like a good part to snag for the future, since it's factory bolt-in. How long do normal subs like those last?

On repairs... I've been looking into capacitor repair but like you I am also wary of trusting just anyone. I guess I could learn to do it myself too since I'm no stranger to soldering but I know it takes some precision. Tanin Auto has already confirmed to me that they don't service factory Lexus amplifiers.

I also think you're probably right about the filter for the amp's power supply having failed. To me these sounds have not appeared to be interference or due to a bad ground but rather some internal electrical phenomena that isn't being masked. It sounds too similar each and every time.

And thanks for the math lesson on how subwoofer amplification is calculated. I've never been into that stuff as much as other hobbies and it's good to know, finally.

I will let you guys know what I discover later. Worst case if the factory amp is bad I may actually have to make this thread live up to its title

matguy

Also, you could get the replacement amp and still try to fix your original amp for a spare (or swap in and keep the replacement amp as a spare.)

It's hard to say how long a sub will last. Some speakers run for half a century or more, some die in 10 years or so. Depends on conditions, how they're treated, and how they're made. The foam is what usually dies on ours. Foam surrounds just don't last. Rubber and accordion folded fabric or paper are common alternatives that generally last longer. You can usually replace the foam on many speakers with various degrees of success. That success is determined by a mix of what kind of speaker it is, whether or not the new foam kit fits correctly (being a universal kit or a kit specifically for that speaker), the skill of whoever is doing it, and luck.

I was just playing around with mine with my wife in the car. Played some old-school D.J. Magic Mike. She was impressed.

KahnBB6

iTrader: (5)

^^ That's good to know. I think... I am inclined to look into picking up a spare factory Nakamichi sub in that case... for a rainy day. I just got into the Pioneer sub and with as tight as it is, I'd rather try to stay mostly factory in that spot.

Nothing sells a sound system like the classics

That said, I got the brakelight cover off and disconnected the sub. Tried the stereo a few times and the verdict is...

A bad sub-amp.

The bass channel being removed I found all the other speakers have nice, clear sound!

The label on the underside of the amp in the trunk reads:

Toyota 86280-24151
GM-9161ZT-02
Pioneer Electronic Corp

And what looks like a 1 Ohm symbol on the far right after the "Load Impedance".

Cheapest I see them for new (if they are even available) is $428. Most common is $720+. I think I'll go used

matguy

I'd be surprised there are any new, still.

KahnBB6

iTrader: (5)

^^ I would be also. When I called a Lexus dealer the other day to confirm the part number of the main Pioneer amplifier I was informed they don't even have remanufactured units left. I assume it's the same for this one.

I think this will be my fix for now-- to replace the Pioneer sub-amp with another. I'll leave real modifications for another time. Though it may also be time to pick up another set of the 4" Polks to have on standby for the front doors.

Tomorrow I think I will merge my earlier thread with this one since the main amp hasn't turned out to be the issue.

t2d2

iTrader: (8)

Same here. It took me a while to figure out the brilliant place I hid it in the garage... At least now I remember exactly how many spares of every part I have.

KahnBB6

iTrader: (5)

t2d2,

Thank you very much for finding that amplifier... but I'm too late to call off your extra trouble then, sorry :/

Last night on a whim I looked on ebay and found what is supposed to be a new out of box, never installed Toyota remanufactured sub-amp. Bit the bullet and grabbed it. I know Toyota used to recondition these parts for a while. Price was reasonable and hopefully it's legitimate. I was going to contact you today about your old one but saw that just before konking out last night. And I came here to let you know and just saw your post.

I wish I'd left a quick message last night for you to hold off and save yourself the trouble of digging out your old one. It sounds like you found a lot of your other spare parts though?

t2d2

iTrader: (8)

No worries, it's not like I was falling over stuff in the over-crowded garage while on crutches or anything.

Glad you found one that should work well for years to come, though.

KahnBB6

iTrader: (5)

Ha! Fair enough

Yeah, that's what I hope I've found. The subwoofer still looks to be in good condition, though there was a tiny bit of rust on the plastic connector mount point so I'll clean that up once the part comes in.