I also thought this way in the eighties and completely ruined the sound of a Leak Stereo 20 by going overboard with the metal films. Apparently perceptions change and the sizzling highs of generic metal films excite me no more.
These days, if i really must poke around inside a nice classic amp i start with a selection of ABs, Kiwame and Riken. And most importantly - listen after each and every change. Very often i go back to the original resitor. Don't know if some parts were just better 40 years ago or extended burn-in made them sound this way.
Anyways, it's hard to find every values in CC.
Both the Xicon Metal Oxide and the BC Metal Films handle around 500V from the datasheets. It seems I'll go with that!
Then I have the problem to find what I'll use to replace the multicap. I need 20µF x1 and 40µF x2... Both values are hard to find except with the 5$ each Sprague Atoms...
What's more suitable to replace 40µF? 47 or 33?
Both the Xicon Metal Oxide and the BC Metal Films handle around 500V from the datasheets. It seems I'll go with that!
Then I have the problem to find what I'll use to replace the multicap. I need 20µF x1 and 40µF x2... Both values are hard to find except with the 5$ each Sprague Atoms...
What's more suitable to replace 40µF? 47 or 33?
Hi DragonMaster,
You can go either way. Cap tolerances are very wide, if it were me I might use the 33uF. You can pad it up with a 10uF unit to keep in a safer zone.
-Chris
Edit: Your 33 uF could easily be 39uF, or a similar value. You'd have to measure it.
You can go either way. Cap tolerances are very wide, if it were me I might use the 33uF. You can pad it up with a 10uF unit to keep in a safer zone.
-Chris
Edit: Your 33 uF could easily be 39uF, or a similar value. You'd have to measure it.
Too much warmth in an amp is not necessarily a good thing. I think you need to do what sounds best for you.
Carbon comps are noisy and unstable. It is considered to be their poor temperature coefficient that is responsible for their warmth (assymetrical distortion). They are unsuitable for the earliest stages in a high gain amp.
That said though, I once noticed a great improvement when I replaced my sand cast crossover resistors with generic carbon films.
Carbon comps are noisy and unstable. It is considered to be their poor temperature coefficient that is responsible for their warmth (assymetrical distortion). They are unsuitable for the earliest stages in a high gain amp.
That said though, I once noticed a great improvement when I replaced my sand cast crossover resistors with generic carbon films.
Oh, carbon -film- could be an option : Every values can be found with this type.
But here, I'm with Metal Oxide -- and a bit of Metal Film.
But here, I'm with Metal Oxide -- and a bit of Metal Film.
lndm said:
Nup....can't quite agree on this one.....I come across quite a few early amps for MI repair which use cracked carbon r's in the 1st/2nd stages.....most early amps used them right through and I've never found them far out of 10% tol so left them in place. It is well known that the resistance of carbon resistors varies dramatically with high voltages.
Replacing the old caps is far more responsive on the sound quality....the esr has come a magnitude downward compared to the early electrolytics.
Wer'e back to the old arguement that with 15dB nfb the noise created by those old components is simply reduced to an inaudible level..
richj
I'll try the metal oxide and metal films, since there's a part I'm ordering for someone else who's getting impatient -- I would have to do an other parts list....
I'll mod one amp first, do the other and see!
I'll mod one amp first, do the other and see!
richwalters said:
I agree that the noise from carbon comps is largely inaudible except, for example, when used at the input to a phono amp where gain is great.
By the way, I don't chose to use global nfb.
I do agree that capacitors affect sonics more than resistors due to their parasitic tank effects, but this is different to resistors and noise.
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