Reading up on this a bit, it seems it's unclear what this "Vloss" parameter means: main 10000uf power caps exceeding V-loss having 1,5% V-loss
Other maybe useful links: How to Pick Audio Capacitors
ESR Values for Electrolytic Caps - Page 1
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I see I contributed in one of those threads 🙂
I would say unless you remove the caps to test them then you can not judge this vloss thing that seems to have become a current 'buzzword'. If the term means the voltage decay across the cap vs time then any parallel parts will alter that figure massively.
All these component testers, although ingenious and clever in what they do, often fill me with mistrust on the results they display and how they achieve them, and also the interpretation of them.
The ESR will only be measured at a low test value, you have to ask whether that value is maintained as the cap passes more ripple current, and it may actually be better rather than worse if that could be done. ESR is also temperature dependent and dependent on the frequency of the test signal used.
ESR is really just a measure of resistive losses in series with what we would otherwise describe a a 'perfect cap'.
I would say unless you remove the caps to test them then you can not judge this vloss thing that seems to have become a current 'buzzword'. If the term means the voltage decay across the cap vs time then any parallel parts will alter that figure massively.
All these component testers, although ingenious and clever in what they do, often fill me with mistrust on the results they display and how they achieve them, and also the interpretation of them.
The ESR will only be measured at a low test value, you have to ask whether that value is maintained as the cap passes more ripple current, and it may actually be better rather than worse if that could be done. ESR is also temperature dependent and dependent on the frequency of the test signal used.
ESR is really just a measure of resistive losses in series with what we would otherwise describe a a 'perfect cap'.
Thanks, yes, definitely tricky to determine this. I suppose the capacitance reading close to 12000 uF is a good sign.
I'll put the amp back together for now, but will probably also order some replacement caps.
Because of the more reasonable shipping rate, I could order straight from Nichicon it looks like, either:
- two 12000 uF 63V : Nichicon KS 12000uf – 63v Snap In (but I'll have to work with the larger diameter, 35mm)
- or four 6800 uF 63V :Nichicon KW Series 6800uf - 63v
No idea yet what the difference is between all those "series" (see "product categories" at the right of the page).
I'll put the amp back together for now, but will probably also order some replacement caps.
Because of the more reasonable shipping rate, I could order straight from Nichicon it looks like, either:
- two 12000 uF 63V : Nichicon KS 12000uf – 63v Snap In (but I'll have to work with the larger diameter, 35mm)
- or four 6800 uF 63V :Nichicon KW Series 6800uf - 63v
No idea yet what the difference is between all those "series" (see "product categories" at the right of the page).
Capacitance is often the one thing that doesn't change much as a cap deteriorates and so I wouldn't take that alone as measure they are OK.
If you have a scope you could look at the ripple component directly on the cap pins and get a baseline starting point. Ideally you would add a known load across the cap to draw current (a mains filament bulb might work OK at these rail voltages).
You could add another cap in parallel and see if the ripple reduces or not. It would have to be mounted using its pins though, adding any wire would increase any low ESR a cap alone might have.
If you have a scope you could look at the ripple component directly on the cap pins and get a baseline starting point. Ideally you would add a known load across the cap to draw current (a mains filament bulb might work OK at these rail voltages).
You could add another cap in parallel and see if the ripple reduces or not. It would have to be mounted using its pins though, adding any wire would increase any low ESR a cap alone might have.
Now sure what to make of that site. It seems connected to an audio store in Bulgaria (?!).
I got a request for a scan of the schematic from the service manual from diyaudio user Karl vd Berg (since the only online manual seems to be a German one).
I decided to put together a simple site dedicated to the PMA 560, scan the manual, and provide it as a download: Denon PMA-560 fan site 😀
He has big plans for his 560 (replacing the relays, filter caps, all other caps, replace the opamp..).
I decided to put together a simple site dedicated to the PMA 560, scan the manual, and provide it as a download: Denon PMA-560 fan site 😀
He has big plans for his 560 (replacing the relays, filter caps, all other caps, replace the opamp..).
I'm thinking I'm going through all the "standard 90's amp problems": now the right channel is faint/cutting out sometimes.
Diagnosing was easy: wiggling the input selector "fixes" it. So that's another switch to clean..
