Yamaha C-4. Capacitor types on the main board.
- Thread starter Hifibythekg
- Start date
Sparkplug
Super Member
UDB series cover a somewhat different range as they are primarily for hi-fi speaker networks, but if you can find the value you need (I did for C-6, 4.7uF and 10uF), you can’t beat the sound. Physically they’re over twice the size of UES caps …For NP or BP caps use UES( MUSE),UEP (high temp) there is a much larger available selection of voltage and µf values to choose from than the UDB..
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Hifibythekg
Super Member
Thanks for the continuing contributions guys.
I now know so much more than I did.
…the essence of this forum…
I now know so much more than I did.
…the essence of this forum…
Sparkplug
Super Member
I came across them by accident, was trying to upgrade my C-6 non-polar caps but anything I found (UES, etc.) we’re half the size of the originals and just left me unsure (I know size alone isn’t a scientific reason). The UDBs are sizable, of the same order as the originals. For me the audio quality was what sealed the deal because I felt there was no impact that I could hear to the original sound. LOL, I have on many occasions changed a bunch of caps and changed back again because I couldn’t stand the new sound. Any departure from that flat Yamaha sound is a no-no for me.
I’d be very interested to hear what you think of them.
Size has very very little to do with performace, and modern caps are smaller simply due to the better etching of the foil to allow greater capacitance per area of the foil. Probably better electrolyte too.
Film caps have far less THD than electrolytic caps and less leakage too, so are preferable IF they fit. Bad choice if they do not fit down flat or very close to the board, the very last thing you want in the signal path is an audio range radio antenna mascarading as long capacitor leads.
Outside of the signal path caps have very little (if any) effect on the sound quality unless they are the wrong value (poor engineering) or defective. The vast majority of them in audio circuits are there to either filter unwanted signals out (high and low pass filters), suppress oscillation, or remove noise from power rails. Only filter and coupling caps need to be "audio grade" -- the others send all the "signal" they see to ground. Power conditioning caps need to be low impedance to supply current on demand without heating, but unless really undersized (or dead) they have no effect on signal. Undersized or dead will result in voltage sag on transients, i.e. weak bass or cause early clipping on transients.
Film caps have far less THD than electrolytic caps and less leakage too, so are preferable IF they fit. Bad choice if they do not fit down flat or very close to the board, the very last thing you want in the signal path is an audio range radio antenna mascarading as long capacitor leads.
Outside of the signal path caps have very little (if any) effect on the sound quality unless they are the wrong value (poor engineering) or defective. The vast majority of them in audio circuits are there to either filter unwanted signals out (high and low pass filters), suppress oscillation, or remove noise from power rails. Only filter and coupling caps need to be "audio grade" -- the others send all the "signal" they see to ground. Power conditioning caps need to be low impedance to supply current on demand without heating, but unless really undersized (or dead) they have no effect on signal. Undersized or dead will result in voltage sag on transients, i.e. weak bass or cause early clipping on transients.
Hifibythekg
Super Member
Terrific posts, very helpful for this and future projects.
Sparkplug
Super Member
Even for caps sitting on the supply rails cleaning the noise, I use audio grade caps, because small signal circuit analysis shows clearly that most of these caps are actually seen by the audio (ac) signal and sit in parallel with the equivalent impedance of the circuits they’re part of at the point of insertion. In addition to getting rid of noise, they’re made as large as possible in practice (within cost, space, etc. constraints) to prevent any fluctuations in the DC bias voltages due to fluctuations in the ac audio signals, as that would directly but subtly affect the active devices they govern and hence the audio quality. This is easier to analyze and see in simple Op-Amp circuits than multistage class AB amplifiers though the principles are the same.
The difference may not be as audible as in the case of coupling or filter circuits, but it is there.
The difference may not be as audible as in the case of coupling or filter circuits, but it is there.
And that is precisely why I use low impedance caps in those positions. Audio caps are low noise and distortion, at the expense of higher impedance. Filter caps won't have the signal running through them, any effect they have signal is due to either DC supply (hence the low impedance) or some sort of resonance, and that will be so small it won't be detectable.
Most likely the vast majority of listeners wouldn't be able to tell if you used low impedance caps in the signal path except maybe coupling in a phono amp. Modern caps are pretty low noise and distortion.
Most likely the vast majority of listeners wouldn't be able to tell if you used low impedance caps in the signal path except maybe coupling in a phono amp. Modern caps are pretty low noise and distortion.
Sparkplug
Super Member
No, audio signals do not run through the filter caps. But … somehow the choice of filter caps affects the audio quality, I can not quantify how or why through equations but can hear it clearly. I think construction, material used, dimensions, all play a role. For example take Nichicon KZ series, they exaggerate the sound in a very attractive way, but use too many of them in the circuit and you’ll end up with a rather wild and edgy sound, this from personal experience. I’ll give low impedance caps a try one of these days and at some point will report back. For now, my go to caps are Toshin UTSJ audio caps, Yamaha of caps … I think they’re pretty low impedance as well.
Whether or not a listener would be able to tell if you used a low impedance cap in the signal path, totally depends on the listener. If you know what to listen for or have the right instrument sounds to test with (piano or violin), it’s not so hard to tell.
Whether or not a listener would be able to tell if you used a low impedance cap in the signal path, totally depends on the listener. If you know what to listen for or have the right instrument sounds to test with (piano or violin), it’s not so hard to tell.
Sparkplug
Super Member
LOL … I only wish …
Small signal analysis refers to ac (in this case, audio signal) analysis of the circuit. By contrast, large signal analysis refers to the DC circuit analysis (bias, etc.). In small signal analysis, the coupling caps are generally assumed to be shorts and power supplies ground. That simplification allows for the calculation of equivalent impedances, circuit gains and much more, especially in multi stage amplifiers.
Your best bet to understand this thoroughly would be to pick up a basic electronic circuit theory book or better yet, register for a college level circuit theory course. Hope this helped.
Yamaha5000
Never settle for 2nd best
Any recommendation on a Online College offering such courses?
Yamaha5000
Never settle for 2nd best
I am growing very depressed that all I seem to do is step on land mines with my far below average circuit theory knowledge
Sparkplug
Super Member
[URL]https://www.coursera.org/learn/linear-circuits-dcanalysis[/URL]
https://www.coursera.org/learn/linear-circuits-ac-analysis#syllabus
There are too many options online these days, one needs to look around and pick what suits their objective best. Coursera is usually pretty good …
Please make sure you meet the prerequisites if there are any otherwise you might end up struggling to follow the material presented.