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Need help choosing right caps for amp
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Author:  Yungman [ 15 Dec 2018, 22:18 ]
Post subject:  Re: Need help choosing right caps for amp

Try to identify the problem channels and go from there.

Author:  Yungman [ 16 Dec 2018, 05:09 ]
Post subject:  Re: Need help choosing right caps for amp

Another thing you can try, since this is a complete 5 individual amp with it's own power supply module and amp module. If you identify one good channel for sure, mark the amp module, switch the good amp module with a bad one. Now see whether the problem follows the amp module. OR if the problem stay with the same channel regardless you have a good amp module. I want to identify whether the problem is in the amp module or the power supply module.

Author:  mtosh [ 17 Dec 2018, 13:14 ]
Post subject:  Re: Need help choosing right caps for amp

Hi guys, thanks again!

I spent some more time with it today, and it may be something that in the end would expose me as a moron :|

I have been using random interconnects to route the receiver signal/power to the amp. Never been an issue before, but today I noticed that when I heard the static problem on a channel I was testing, I swapped the cable out with a good quality audio specific interconnect and it sounded fine. 4 out of 5 channels sounded fine, one of them is dead. I will go pick up some decent audio interconnects and test in my full set up. If it is just a matter of good shielded audio cables, I will feel like an idiot for this whole fiasco.

Author:  kitchi [ 17 Dec 2018, 16:20 ]
Post subject:  Re: Need help choosing right caps for amp

We all have been there once or twice.
Once I had a short on an modular amp and it took me 2 days to realize it wasn't on the power distribution board, It was actually on a different board all together.

Not my finest moment.

Author:  mtosh [ 17 Dec 2018, 17:44 ]
Post subject:  Re: Need help choosing right caps for amp

I'm 2 seconds from losing my mind on this. I realized I had a few nice Audioquest analog cables running from my CD player to the receiver, so I used those to test this out. Same damn problem. I moved the amp back into the theater setup to try it out and sometimes I get non stop audio drop outs and crackling sound, other times it works perfectly for a few minutes before dropping out.

Absolutely inconsistent and impossible to reproduce the same outcome more than once.

I'm beginning to think it may be a bad solder or circuit board component in the power line? I don't think the issue is related to any particular channel(s) and the one thing they all share is the power distribution?

Either way, I'm close to abandoning this thing as it has been a thorn in my side for a long time now. What frustrates me the most is that you are all trying to offer opinions and suggestions, but I can't even isolate the actual problem due to the wildly inconsistent nature of the results. It's like mixing two chemicals in a lab and getting different results each time regardless of your process.

Author:  Yungman [ 17 Dec 2018, 21:18 ]
Post subject:  Re: Need help choosing right caps for amp

You need to calm down and go step by step. Read my last post, try to identify which channel has a problem, whether the problem follows the amp module or stay with the power supply module.

Stay with one set up as long as you can make it fail often, don't switch between the theater and the other room. If it fails in the theater, stay with it and go from there.

If you suspect the power distribution, use a wood stick to poke and move the power wires to see whether you can make the noise.

As long as it is happening this often, it's not hard to find the problem. Just go step by step.

Author:  kitchi [ 18 Dec 2018, 07:08 ]
Post subject:  Re: Need help choosing right caps for amp

You are adding variables to the problem when you switch rooms
I agree with Yungman's advice.
Stay in the theater room get a chopstick and poke aground ONE channel that is giving you problems.
When I train new service techs they are always overwhelmed with the big picture and my advice to them is grab a coffee and visually break the machine into sections and go from there.
In your case
1. pick one channel and location only... don't jump around.
2. if you think the problem is in the power dist. poke around there
3. if that dosn't show anything go to the preamp
4. tone section
5. output
6. wire to the speaker terminals
7. and finally speaker terminals

It is amazing what you will find by wiggling wires poking at components and gently flexing the pcb with a stick
You will find the problem It may take time but you will find it and when you do you will get feeling of accomplishment.

Author:  mtosh [ 18 Dec 2018, 09:19 ]
Post subject:  Re: Need help choosing right caps for amp

Very wise words!

I will slow down and simplify.

Author:  mtosh [ 22 Dec 2018, 11:23 ]
Post subject:  Re: Need help choosing right caps for amp

OK, I followed your advice and found a few odd things:

1- I opened the amp and tested out a bad channel by using a wooden stick to jiggle wires around in various areas of the amp. This didn't seem to make any difference or allow me to identify a probable cause. Some channels would sound fine and the next time I test it they barely work, even when all variables are constant. I was unable to change the sound signature by jiggling wires in any area of the amp, for all channels tested.

2- I started to feel as though it may be the rca terminals on the amp so I cleaned them with detoxit and tried the next day. This seemed to make a difference as I was able to get good sound from all but 1 terminal. I hooked up two speakers and played music for a while and it was working perfectly so I shut everything down and walked away without making any changes.

3- I fired the system up this morning and only one speaker was remotely audible, with only occasional sound coming through. It was crackling and full of "static" sound with very low volume but I could tell the signal was coming through as it was playing music. The other speaker was absolutely silent. Here's where it get's odd. I did nothing but wait and as time went on the both speakers eventually cleared up and started to sound fine again. All without doing anything to the receiver, wires, amp, cords etc. I didn't even change the volume on the receiver, it just began to improve on it's own. Just as it starts to degrade on it's own as it has done in the past.

4- It seems as though running the same test/variables on different days gives different results which is making it very difficult to narrow down. Hence my frustration.

5- I have not found a single channel that either works, or does not work consistently. Thus, I am unable to swap the good/bad channel as was suggested in order to identify whether or not the problem follows the channel or is with the main components of the amp which all channels share.

6- Most repair shops at this point would need to start replacing components in order to identify the problem/solution. It must be frustrating on your end to attempt to help when everything seems so inconsistent. I would (if I were you) be believing that I am missing something very obvious or, not approaching this with a step by step, almost scientific approach. Perhaps this is true. However, running the exact same test with wildly different results on different days makes this logical approach produce illogical results, at least to my untrained eye.

Author:  laurie54 [ 22 Dec 2018, 15:51 ]
Post subject:  Re: Need help choosing right caps for amp

I have been watching this thread as it has been said "we have all been there". At this point I to suspect a faulty wiring problem (soldering). Especially when it comes to many channels all the same. A mistake made on one channel is easily duplicated over and over. Reading #3 in the above it sounds like after a bit of time and a bit of warmth from the channels being powered has changed the problem. This really points to a bad solder joint. I would start looking in the signal input area first due to explanation again #3. Just a gut instinct.
It could be a bad batch of res or caps which are problematic but start with solder joints. Don't second guess which joints to solder just do them all from start to finish on one channel and try it on off over the coarse of days. If all is good do the same with the others.

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