Hello!
I need a piece of advice for what capacitor value should I put in A-602R stereo amplifier from Pioneer!
Originals are 18000uf, 53V.
The sound is a little harsh at this value!
I am thinking a lower value of the capacitors would be better for this amplifier so that it sounds smoother?
Thanx!
I need a piece of advice for what capacitor value should I put in A-602R stereo amplifier from Pioneer!
Originals are 18000uf, 53V.
The sound is a little harsh at this value!
I am thinking a lower value of the capacitors would be better for this amplifier so that it sounds smoother?
Thanx!
The big PSU caps may not be to blame
Couple of points.
The preamp section will have its own caps, and what that puts out the power amp sections adds current to, tinkering with the preamp section will cost a fraction the amount that a new set of PSU caps would. Don't tinker without the service manual and knowing what you're doing.
Is the amp the issue - definitely not source or speakers? Decent source components can put out some pretty harsh sounding signals.
Couple of points.
The preamp section will have its own caps, and what that puts out the power amp sections adds current to, tinkering with the preamp section will cost a fraction the amount that a new set of PSU caps would. Don't tinker without the service manual and knowing what you're doing.
Is the amp the issue - definitely not source or speakers? Decent source components can put out some pretty harsh sounding signals.
I guess you are talking about the power supply caps right? Well, it is not as that simple. sometimes you can achieve an improvement when you change some parts., but if the design is not so good...even with the best and most expensive parts that you can buy, you will never make it sound good.
But, if you want to give it a shot...go ahead!.
You can try Panasonic caps 18000uf/20000uf 63v or higher, They are very good caps.
in my diy amplifier I use Mundorf audio grade caps 6800ufx4 but again that is another story 😉
PS: Good point there dry joint!!! it can also be the speakers!!! So you should try with different speakers before you try replacing those power supply caps.
But, if you want to give it a shot...go ahead!.
You can try Panasonic caps 18000uf/20000uf 63v or higher, They are very good caps.
in my diy amplifier I use Mundorf audio grade caps 6800ufx4 but again that is another story 😉
PS: Good point there dry joint!!! it can also be the speakers!!! So you should try with different speakers before you try replacing those power supply caps.
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I didn't know we had Random Component Blaming Day.
Connecting (subjectively) bad sound to the big power supply buffer caps seems a bit far-fetched, certainly so in an amplifier that is only about 20 years old and would be expected to use quality components. If it's been seriously abused, yeah, then the caps may be dead. (Hot climate takes its toll as well.) In normal home use at moderate temperatures, rather not. There would be far more likely candidates then.
How exactly did you arrive at the conclusion that "sound is a little harsh"? Do you actually have the slightest idea of what it takes to even compare two amplifiers properly without introducing all kinds of bias? You have to take great care in order to avoid fooling yourself. (Exact level matching to <0.1 dB, quick A/B switching ability, blind testing, yadda yadda.)
Compared to a proper listening test, measurements almost seem piece o' cake territory. I mean, you "only" have to wire up a loudspeaker dummy load with level attenuator (~30 dB), grab some half-decent soundcard and RMAA or ARTA or whatnot, run its output to a high-level output and the attenuated signal to its input, tweak settings a little, et voilà, something that should give some sort of half-decent basic amplifier measurements, like THD up to a few kHz and SMPTE IMD and all that fun stuff. (Though I would prefer a separate source in practice so as to avoid ground loop issues - those independent floating inputs and outputs on dedicated audio measurement gear have to be good for something. And note that while tying the R and L output grounds together is OK for many amps, it is a big no-no for bridged / BTL type configurations.) It can still be arbitrarily fiddly, but basically it's not rocket science and has been done many times before, and once you get the hang of intepreting the results, the results tend to be an awful lot more reliable than evaluation by ear.
Now coming back to the "somewhat harsh" sound, this could be caused by any of the following (all reasonably likely):
1. Sighted bias / expectation bias on part of the listener.
2. Significantly better damping factor than in the amplifier it is being compared to (Pioneer gear in general seems to hold up pretty well, protection relays included, so its contacts might still be good where another amp's no longer are). Subpar DF (overly high output impedance) often results in more bassy sound as many speakers have impedance peaks down there, and people tend to like that.
3. Absence of noise (hiss). No kidding, audible noise tends to make sound "softer" subjectively.
4. Idle current that is far too low, e.g. because of contact issues in adjustment pots (sanely designed circuits drop bias then, many older ones do the opposite and possibly blow up the amp). Again, the amp is a bit too young for that, but you never know.
Note how only one option actually needs to assume something being wrong with the amp, and even then it would be a pretty standard problem that could be resolved with a careful check and adjustment (and I do mean careful, for you can easily blow something up bigtime if you aren't).
I would not expect a ~1990 Japanese mass-market upper middle-class integrated amp to have any severe, plainly audible construction problem. Standards were too high for this sort of device.
Connecting (subjectively) bad sound to the big power supply buffer caps seems a bit far-fetched, certainly so in an amplifier that is only about 20 years old and would be expected to use quality components. If it's been seriously abused, yeah, then the caps may be dead. (Hot climate takes its toll as well.) In normal home use at moderate temperatures, rather not. There would be far more likely candidates then.
How exactly did you arrive at the conclusion that "sound is a little harsh"? Do you actually have the slightest idea of what it takes to even compare two amplifiers properly without introducing all kinds of bias? You have to take great care in order to avoid fooling yourself. (Exact level matching to <0.1 dB, quick A/B switching ability, blind testing, yadda yadda.)
Compared to a proper listening test, measurements almost seem piece o' cake territory. I mean, you "only" have to wire up a loudspeaker dummy load with level attenuator (~30 dB), grab some half-decent soundcard and RMAA or ARTA or whatnot, run its output to a high-level output and the attenuated signal to its input, tweak settings a little, et voilà, something that should give some sort of half-decent basic amplifier measurements, like THD up to a few kHz and SMPTE IMD and all that fun stuff. (Though I would prefer a separate source in practice so as to avoid ground loop issues - those independent floating inputs and outputs on dedicated audio measurement gear have to be good for something. And note that while tying the R and L output grounds together is OK for many amps, it is a big no-no for bridged / BTL type configurations.) It can still be arbitrarily fiddly, but basically it's not rocket science and has been done many times before, and once you get the hang of intepreting the results, the results tend to be an awful lot more reliable than evaluation by ear.
Now coming back to the "somewhat harsh" sound, this could be caused by any of the following (all reasonably likely):
1. Sighted bias / expectation bias on part of the listener.
2. Significantly better damping factor than in the amplifier it is being compared to (Pioneer gear in general seems to hold up pretty well, protection relays included, so its contacts might still be good where another amp's no longer are). Subpar DF (overly high output impedance) often results in more bassy sound as many speakers have impedance peaks down there, and people tend to like that.
3. Absence of noise (hiss). No kidding, audible noise tends to make sound "softer" subjectively.
4. Idle current that is far too low, e.g. because of contact issues in adjustment pots (sanely designed circuits drop bias then, many older ones do the opposite and possibly blow up the amp). Again, the amp is a bit too young for that, but you never know.
Note how only one option actually needs to assume something being wrong with the amp, and even then it would be a pretty standard problem that could be resolved with a careful check and adjustment (and I do mean careful, for you can easily blow something up bigtime if you aren't).
I would not expect a ~1990 Japanese mass-market upper middle-class integrated amp to have any severe, plainly audible construction problem. Standards were too high for this sort of device.
I agree
Also banks are to supply current ... you cannot blame them for harsh sound there is going to be other things in the amplifier producing that, together with topology design aspects and materials used
Also banks are to supply current ... you cannot blame them for harsh sound there is going to be other things in the amplifier producing that, together with topology design aspects and materials used
The amplifier sounds like it has sounded when it came out the factory, but I am saying that it could do better with some other taylored to already-made design components and mainly are caps. so that is what I am searching to make!
deep knowledge of the circuit is required and laying your hands in any of the parts will eventually alter the character of the amplifier ...for the best or the worst is for you to decide
Kind regards
Sakis
Kind regards
Sakis
That is right! I have interpreted it as cap replacement in speakers crossovers! Can't wait to give it another personality, with caps. replacement!
Why not go for a stepped attenuator instead of the volume pot? It would make more difference than the PSU caps and avoid messing with anything sensitive.
If you have your heart set on component changes - tantalum resistor in the feedback and signal entry spots would warm the sound if metal film are currently used. If they have carbon resistors already the issue might just be that the design just sounds harsh, I recall a Pioneer designer not liking one of his own amps of that era very much due to harshness. A better PSU will just make the amp be itself only more so.
If you have your heart set on component changes - tantalum resistor in the feedback and signal entry spots would warm the sound if metal film are currently used. If they have carbon resistors already the issue might just be that the design just sounds harsh, I recall a Pioneer designer not liking one of his own amps of that era very much due to harshness. A better PSU will just make the amp be itself only more so.
the ones on the side vertical board, arent tantalum? Thought I've seen orange samll tantalum but they are film, that is so
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Tant resistors not caps. They have are warmer and softer sounding than metal film and way more detailed than carbon, and cost way more than both. The old stock being Japanese Shinkoh, whilst Audio Note are reponsible for the recent output. You need the service manual to find the details and see how easy the amp is to disassemble.
An alternative might be a tube buffer between a digital source and the amp.
An alternative might be a tube buffer between a digital source and the amp.
I think that I am going to keep this amplifier till next years end and buy a Denon PMA-1500 to make a change for my hi-fi component choice!
Anyhow thank you very much for all the support! I think I won't change anything inside of it and leave it as it is! For better understanding what I posted here, is that the amplifier itself does not have any damaged part inside to cause it sound bad, but is how it sounds out of the factory! What I was asking was what could I have replaced in it to make sound reproduction more contoured! I think I might go for Panasonic or ELNA caps the big ones for 63V and 18000uf guess I will just listen to it a little bit more!
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