Hey all,
I am going to do a build in my 05 Volvo xc90 with some vintage amplifiers. I like their sound!
I am debating using a couple of the following, Set of Two A/D/S PQ10, or Sony XM-7557, and maybe a Kenwood KAC-4285...
That being said, I want to keep this system rolling as long as possible. I have some basic amplifier repair (for home and automotive) and am wondering what your opinions on PREVENTATIVE maintenance for these puppies..
I am thinking capacitor replacement for the ADS?
Also, what other forums could also be a resource?
Thanks guys!
I am going to do a build in my 05 Volvo xc90 with some vintage amplifiers. I like their sound!
I am debating using a couple of the following, Set of Two A/D/S PQ10, or Sony XM-7557, and maybe a Kenwood KAC-4285...
That being said, I want to keep this system rolling as long as possible. I have some basic amplifier repair (for home and automotive) and am wondering what your opinions on PREVENTATIVE maintenance for these puppies..
I am thinking capacitor replacement for the ADS?
Also, what other forums could also be a resource?
Thanks guys!
Attachments
If the amp has more than 10 years and/or unused by more than 5, then a recap is very recommendable. If you will do it, I suggest to replace one or two at a time between functionality tests. If something goes wrong, it is easy to go back and discover the error.
Also, replace the thermal grease, usually it dries and becomes useless.
Also, in some instances, when components are glued, the glue becomes carbonized by heat and voltage, and (rarely) becomes conductive.
Also, replace the thermal grease, usually it dries and becomes useless.
Also, in some instances, when components are glued, the glue becomes carbonized by heat and voltage, and (rarely) becomes conductive.
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Are the caps in the ADS known to leak?
In some of the similar Sony amps, the low-voltage transformer transistors caused some problems from overheating. You should, at least, check to see if there is any damage in that area. The transistors are SMD parts on the bottom of the board near T701.
And I'm sorry but I've tested MANY electrolytic caps that were as old as 20 years old and they were OK. Not all but most. Unless the caps are known to leak, replacing them is mainly useless.
In some of the similar Sony amps, the low-voltage transformer transistors caused some problems from overheating. You should, at least, check to see if there is any damage in that area. The transistors are SMD parts on the bottom of the board near T701.
And I'm sorry but I've tested MANY electrolytic caps that were as old as 20 years old and they were OK. Not all but most. Unless the caps are known to leak, replacing them is mainly useless.
My best advice that I give to people still using or want to use older amps is don’t mount them to a box and make sure they have good air circulation. The legs on the mosfets become brittle from years of heating and cooling and vibration countermeasures inside the amp may be minimal, compromised, or non existent.
I would pop the lid and look for obvious signs of caps leaking onto the board or bulging. Check the mosfets and transistors with a DMM. Do some voltage checks while inside. Look for signs of heat damage to the board and check for bad solder connections. I’d also check screws and connections for tightness. If no problems are found, I’d leave well enough alone.
Just my two cents,
David
I would pop the lid and look for obvious signs of caps leaking onto the board or bulging. Check the mosfets and transistors with a DMM. Do some voltage checks while inside. Look for signs of heat damage to the board and check for bad solder connections. I’d also check screws and connections for tightness. If no problems are found, I’d leave well enough alone.
Just my two cents,
David
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I'm agree with Perry Babin and jkrokemberger.
Twenty years minimum for caps generally, but it's necessary look at the board for see if all ok, and about cleaning, the screws, and terminals, cables..
So, a small check.
Before mounting you can to listen the amps some hours at test bench for to understand if there are some issues like old weldings or similar.
That is some precaution only, old school amps more resist than chinese tin cans normally, and sounds better especially, i think.
Twenty years minimum for caps generally, but it's necessary look at the board for see if all ok, and about cleaning, the screws, and terminals, cables..
So, a small check.
Before mounting you can to listen the amps some hours at test bench for to understand if there are some issues like old weldings or similar.
That is some precaution only, old school amps more resist than chinese tin cans normally, and sounds better especially, i think.
Thanks all,
So it sounds like I am just a bit paranoid on the caps... I have been watching vintage mac repair, those caps scare me. One guy even put the motherboard into the dish washer...
I will toss them on the bench, open them up and see if anything is leaky or bulging.
As far as the amplifiers themselvs, has anyone heard them before and have any opinions on them? I will let me ear guide me, probably listen to them on the bench for a week or so each. I do value the forum's opinion though.
So it sounds like I am just a bit paranoid on the caps... I have been watching vintage mac repair, those caps scare me. One guy even put the motherboard into the dish washer...
I will toss them on the bench, open them up and see if anything is leaky or bulging.
As far as the amplifiers themselvs, has anyone heard them before and have any opinions on them? I will let me ear guide me, probably listen to them on the bench for a week or so each. I do value the forum's opinion though.
The A/D/S are good quality amps, highly regarded in their time, better reputation than the others. 4x40W from around 1987-1991, I installed quite a few of them and their brethren. Clean was the typical word used to describe their sound. Gain controls are accessable through holes in the heatsink, you'll want a tiny plastic screwdriver to adjust them.
The Kenwoods of that era were not quite in the same league, yours is a little newer than the A/D/S. I'm clueless about the Sony.
The Kenwoods of that era were not quite in the same league, yours is a little newer than the A/D/S. I'm clueless about the Sony.
The plot thickens...
I powered up the Sony because, it's big and it's red... It worked when I bought it, now no sound out of front left. I though, well let's check it out.
Rail voltage is +- 5% between them, so skipping the power section.
Checked the outputs in board and no dice.
Then went to the bias adjust point and I get nothing between tp6 and tp7..
I have really only had experience in output and power supply stuff. I am thinking a problem would cause a short in the voltage stage or differential amp to get me no idle current. I will do some reading in the service manual to see if I can get some learning in.
Well the ADS sound fantastic! Hooked up to some EV sl10-2v, they sound as uncolored as I had hoped for.
I powered up the Sony because, it's big and it's red... It worked when I bought it, now no sound out of front left. I though, well let's check it out.
Rail voltage is +- 5% between them, so skipping the power section.
Checked the outputs in board and no dice.
Then went to the bias adjust point and I get nothing between tp6 and tp7..
I have really only had experience in output and power supply stuff. I am thinking a problem would cause a short in the voltage stage or differential amp to get me no idle current. I will do some reading in the service manual to see if I can get some learning in.
Well the ADS sound fantastic! Hooked up to some EV sl10-2v, they sound as uncolored as I had hoped for.
I think this is the best solution.
But i agree with tsmith, PQ10 a more high step.
Perry, fist of all I forgot to say I appreciate your work.
I will start a new thread if I can't figure it out in a month or so. I want to see if I can try my hand at it.
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