Do Amplifiers Wear Out?

[Fubar0715]

What’s involved in removing the door panels to replace the speakers? Any special tools needed?

pretty simple actually, couple screws, a few snap ins, and a wire connector adapter. I bought the adapter brackets to mount the 6.5" speakers since the factory units are part of the housing.

 

[Scott in AZ]

What’s involved in removing the door panels to replace the speakers? Any special tools needed?

It’s really easy. Front and rear are both held in place by 2X 7mm hex screws, and some clips. I find it easier to remove the door panel courtesy lights before starting. While they are out replace them with Amazon LEDs. Best to watch the YouTube videos but pics below give a good overview. Rear door is a little easier for first attempt because it’s a coaxial speaker not a component (woofer and tweeter) speaker. I used Polk Audio 6.5” (approx $100 / pair) in the rear and didn’t even need to drill new holes. I used Genuine GM OEM replacements (approx $200 /pair) in the front in order to utilize the “clip-in” front speaker design but if doing again I’d use Polk Audio in front also, with Metra 82-3002 5.25” /6.5” speaker adapter. If you use aftermarket speakers absolutely be sure to use the Metra or Red Wolf wire harnesses for GM vehicles so you don’t need to cut or splice the OEM wires.

 

[Scott in AZ]

What’s involved in removing the door panels to replace the speakers? Any special tools needed?

It’s really easy. Front and rear are both held in place by 2X 7mm hex screws, and some clips. I find it easier to remove the door panel courtesy lights before starting. While they are out replace them with Amazon LEDs. Best to watch the YouTube videos but pics below give a good overview. Even better to buy your gear from Crutchfield and get their step by step instructions and super-helpful tech support.

Rear door is a little easier for first attempt because it’s a coaxial speaker not a component (woofer and tweeter) speaker. I used Polk Audio 6.5” (approx $100 / pair) in the rear and didn’t even need to drill new holes. I used Genuine GM OEM replacements (approx $200 /pair) in the front in order to utilize the “clip-in” front speaker design but if doing again I’d use Polk Audio in front also, with Metra 82-3002 5.25” /6.5” speaker adapter. If you use aftermarket speakers absolutely be sure to use the Metra or Red Wolf wire harnesses for GM vehicles so you don’t need to cut or splice the OEM wires.

 

[2591tdj]

It’s really easy. Front and rear are both held in place by 2X 7mm hex screws, and some clips. I find it easier to remove the door panel courtesy lights before starting. While they are out replace them with Amazon LEDs. Best to watch the YouTube videos but pics below give a good overview. Rear door is a little easier for first attempt because it’s a coaxial speaker not a component (woofer and tweeter) speaker. I used Polk Audio 6.5” (approx $100 / pair) in the rear and didn’t even need to drill new holes. I used Genuine GM OEM replacements (approx $200 /pair) in the front in order to utilize the “clip-in” front speaker design but if doing again I’d use Polk Audio in front also, with Metra 82-3002 5.25” /6.5” speaker adapter. If you use aftermarket speakers absolutely be sure to use the Metra or Red Wolf wire harnesses for GM vehicles so you don’t need to cut or splice the OEM wires.

Thanks!

 

[abrasumente]

@swathdiver amps can and do degrade over time. As others have said it's usually the caps, although these dudes have Nichicon caps in em which are pretty highly regarded. There is a possibility that the nav radio in your '13 has a higher baseline output voltage (think 5v preout on an old school Alpine HU vs 2v on a barebones Sony from walmart), or a different crossover frequency which results in less distortion as the speakers wouldn't be playing frequencies they can't handle, and thus will sound better.

I suppose there could be a difference between the 2012/2013 UQA amps. When I was doing research for my UQS upgrade project I definitely remember seeing different part numbers for the UQA amps. The only way that could be determined would be removing the amp, pulling it apart, and looking up the numbers on the amplifier chips to find their cutsheets, which will tell you what their output is per channel and at what voltage/THD.

Or, if the truck wasn't new to you off the showroom floor, someone could've upgraded the amp in the past.

Here's the guts of my UQA for reference.

 

[swathdiver]

Well, I was wrong about the amps being the same in my three trucks. The pick ups run 20811235 and mine runs a 20811234. They are both "dumb" amps and of course mine has 2 more speakers.

Could it be that the lack of 2 extra speakers left more power to give to the speakers in the pickups?

 

[abrasumente]

Well, I was wrong about the amps being the same in my three trucks. The pick ups run 20811235 and mine runs a 20811234. They are both "dumb" amps and of course mine has 2 more speakers.

Could it be that the lack of 2 extra speakers left more power to give to the speakers in the pickups?

The d pillar speakers are wired in parallel with the rear door speakers in the SUV's without the uplevel amp. This effectively splits the audio signal between them, but only on the rear "stage". If all other things are equal (same internal guts) with these amps, not having the d pillar speakers would result in the ones in the rear doors being louder.

 

[swathdiver]

The d pillar speakers are wired in parallel with the rear door speakers in the SUV's without the uplevel amp. This effectively splits the audio signal between them, but only on the rear "stage". If all other things are equal (same internal guts) with these amps, not having the d pillar speakers would result in the ones in the rear doors being louder.

That makes a lot of sense, thanks!

I drove the lifted Sierra tonight to Grandma's for dinner and there was no bass unless I really cranked it up to where it was uncomfortable. The kids put two 12" subs in it with a 1500 watt amplifier under the rear seats. Did not like it.

 

[abrasumente]

That makes a lot of sense, thanks!

I drove the lifted Sierra tonight to Grandma's for dinner and there was no bass unless I really cranked it up to where it was uncomfortable. The kids put two 12" subs in it with a 1500 watt amplifier under the rear seats. Did not like it.

You're welcome!

I used to be all about loud subs. Honestly after doing the UQS amp upgrade it's enough to satisfy my desire for full range sound without making my tinnitus worse. The original UQA amp really is wimpy.

The only way you could improve on your sound without actually replacing the amplifier would be to find speakers that are both really close to the impedance of the Bose jobs AND have a higher sensitivity. Bose uses weird impedances, like 1.9 ohms for the front door speakers, and 3.2 for the d pillars. 2 ohm aftermarkets for the fronts would be a rounding error to the amp, but putting a 2 ohm speaker in place of a 3.2 in the D pillar will likely fry something, and using a 4 ohm will result in less audible sound from that particular channel if all other specs of the replacement speaker are the same as the old one.

But if you're going into the center console to drop a new sub in the Bose box, might as well find a NOS or known good Y91 amp and drop it in too. I think I'm going to swap the speakers out myself eventually, so if I get to it first I'll let you know how it goes.

 

[iamdub]

The only way you could improve on your sound without actually replacing the amplifier would be to find speakers that are both really close to the impedance of the Bose jobs AND have a higher sensitivity.

Or improve the signal going to it with an aftermarket HU that can be fine-tuned to your particular tastes.

 

[swathdiver]

But if you're going into the center console to drop a new sub in the Bose box, might as well find a NOS or known good Y91 amp and drop it in too. I think I'm going to swap the speakers out myself eventually, so if I get to it first I'll let you know how it goes.

I looked into that about six years or so ago when the guys on here were doing those swaps. Different connectors and wiring harnesses. I'd rather play with the engine! Keep me posted though!

 

[swathdiver]

Or improve the signal going to it with an aftermarket HU that can be fine-tuned to your particular tastes.

A long time ago, I had my factory radio overhauled and they put new and improved parts in it that made it sound so much better. Is there anyone doing that today?

 

[iamdub]

A long time ago, I had my factory radio overhauled and they put new and improved parts in it that made it sound so much better. Is there anyone doing that today?

How long ago?! I've never heard of that being done to these. I can see the really old school stuff having room for improvement with fresh caps, etc. (as was outlined earlier). But these things are too digital. The HU doesn't have much of an amp in it at all, it's more of just a line level signal generator and the amplifier does the rest. The amplifier does process some, but it's mostly still just a musical transformer to ramp up the voltage to the speakers. "Garbage in = garbage out", as it were. Just louder garbage.

 

[swathdiver]

How long ago?! I've never heard of that being done to these.

Early 1990s in one of my Buick GNs.

 

[ccole]

I run a pretty high end competition level system in My 07. I’m running the factory head unit and pull the RCA signal directly from the head. The signal is extremely clean from 20Hz to 20khz when viewed on an oscilloscope. The Bose amp handles all the crossover points to the various speakers. This is where the bass limiter is active and any other sound manipulation occurs. Replacing the factory head unit isn’t required for better sound if you pull the RCA signal before the amp.

I would recommend looking into CDT Audio for 2 Ohm speaker options. They offer around a dozen 2 Ohm options in various configurations and price points. I run a set of their coaxial speakers in the rear doors for the kids. I have a switch that kills the rears and factory sub for critical listening sessions. The CDT’s do sound louder and clearer than the factory option. Also they’ve never caused issues on the factory Bose amp with the lower impedance.

In our trucks GM offered a more powerful optional Bose “Luxury” amp. These were mainly in the Escalades and Denali’s but we’re available in LTZ’s. This may account for the better sound quality and bass output.
I believe you may have already figured this out. I recall reading about guys swapping their Tahoe Bose amp with the “Luxury” model as an upgrade. I don’t remember the outcome???

 

[Charlie207]

Per Rock Auto, it looks like the smaller Bose amp is: GM GENUINE 20811234

The larger amp is: ACDELCO 84943755

 

[George B]

I run a pretty high end competition level system in My 07. I’m running the factory head unit and pull the RCA signal directly from the head. The signal is extremely clean from 20Hz to 20khz when viewed on an oscilloscope. The Bose amp handles all the crossover points to the various speakers. This is where the bass limiter is active and any other sound manipulation occurs. Replacing the factory head unit isn’t required for better sound if you pull the RCA signal before the amp.

I would recommend looking into CDT Audio for 2 Ohm speaker options. They offer around a dozen 2 Ohm options in various configurations and price points. I run a set of their coaxial speakers in the rear doors for the kids. I have a switch that kills the rears and factory sub for critical listening sessions. The CDT’s do sound louder and clearer than the factory option. Also they’ve never caused issues on the factory Bose amp with the lower impedance.

In our trucks GM offered a more powerful optional Bose “Luxury” amp. These were mainly in the Escalades and Denali’s but we’re available in LTZ’s. This may account for the better sound quality and bass output.
I believe you may have already figured this out. I recall reading about guys swapping their Tahoe Bose amp with the “Luxury” model as an upgrade. I don’t remember the outcome???

I believe my ‘13 LTZ has the LUX amp and I am very happy with the sound and bass.

 

[kbuskill]

I believe my ‘13 LTZ has the LUX amp and I am very happy with the sound and bass.

If it has the center dash speaker then it should be the "LUX" amp.

This was not an option on my '08 LTZ Burb.