Capacitor Brand Voodoo - Let's clear the air

Hmm, they don't seem to be available in "tube amp" voltage ratings. Too bad...

My line amp circuit uses a 22uF / 350V (or greater) for output coupling. I've been using a "general purpose" 'lytic but wouldn't mind trying something better as long as it's not huge or expensive.

oh geez, Im solid state guy, you should have known better! I wouldnt be suprised if they made larger voltages and digikey just doesnt carry them. I have a bad head cold so took the last few days off from mixing, got halfway through a QE project built up a marshall amp, I used those Sozo caps where I could, cant wait to fire it up and hear what those things sound like, or what they smell like in a puff of smoke, either way...

dave

I'm wondering whether the influence of caps couldn't simply be measured - at least some of the influences.

Like: the influence of brighter sounding caps is simply reflected in the frequency response graph of that piece of gear (ampl & phase).

Or are we talking about 'non-steady-sate' things like transient mechanisms here ?

Bye,

Peter

You can measure capacitance, tempco, ESR, parasitic inductance, dielectric absorption and a number of other quantities. But I haven't seen an instrument yet that can measure placebo effect :wink:

when i´ve recapped tube amps i´ve always let the condensers to load up slowly, a lightbulb in series with mains voltage for some hours. i read this is really important to do, somewhere, many years ago and it makes sense to me.

[quote author="cjenrick"]Cool Gus!
Whats a PET ?[/quote]

:green:

Polyethylene terephthalate, should be.

:thumb:

from NYDave:

You can measure capacitance, tempco, ESR, parasitic inductance, dielectric absorption and a number of other quantities. But I haven't seen an instrument yet that can measure placebo effect

Click to expand...

Right ! :wink:


Hmm, there are a lot of other possible influences there, but I guess at least a few of them simply translate to different freq-responses.

IIRIC several people here have multiple SSL-clones, stuffed with different caps and they're describing these as brighter than the other with this & that kind of cap etc. If different caps are the only differences between those units, a freq plot comparison would be informative.

Bye,

Peter

Maybe this sounds like vodoo, but I just replaced the reservoir PS caps in a stereo hi-fi amplifier, and the sound changed dramatically. The previous caps worked fine, were just different. To make sure I wasn't imagining things, I put the two sets of caps side by side and used alligator clips to switch between them. Totally changed the character of the music. Both sounded good, just very different. I was flabbergasted. That the PS caps could make any influence on the sound at all was astonishing.

A friend of mine has discovered the same thing and actually tested several different cap designs to see how it changed the sound. Each sounded different.

This isn't discussed often in pro audio circles where we are usually happy just to have a working PSU, but it is real, at least in this case, I've heard it. My friend explained it by saying that the amplifier audio circuitry exists to modulate the power supply. The power supply does the work. Therefore, the caps, rectifier and transformer will all contribute to the sonic signature.

Everything influences everything. That seems to be the philosophy that I keep returning to in audio, as in life.

Remember the power supply is part of the circuit. With guitar amps power supply caps make even a bigger difference because of the lower uf value often used. The way I like to setup the power supply in a guitar amp is a little different than what you see on schematics.

The title of this thread was "Time to clear the air". Still seems foggy to me.
Steve

well, since we can all agree that one cap sounds different from the next, in the end its going to come down to personal preference and really what you want the gear you are building to do. I suppose if you compiled a list of all the capps we've listed as faves, got a bunch, and did listening tests, you'll be able to see what works best for you, in your specific application, and the air will be clear, so to speak. Thats all I did. I would go on to mention though, that a cap that wasnt too cool in one circuit was really great in another, so Id stress the specific application part of the experiment pretty heavily.

dave

i think we still want more of a list with attributes. I see a meta in the future...

Polypro:
more expensive than polyester
clear highs

polyester
cheap
highs less clear than polypro

Teflon
expensive
best sound


blah
blah

get my drift?

we need to add the different 'lytics too and what the concensus is about different brands. we keep asking the same questions over and over because we don't have a list!

so if i want to parallel a film cap and a lytic to get a clear high end and good low end but a scooped midrange, what combo would i choose? if we had the list we could just pick them out.

just my .02$

[quote author="Svart"]i think we still want more of a list with attributes. I see a meta in the future...

...we need to add the different 'lytics too and what the concensus is about different brands. [/quote]

We mentioned some 'lytic caps in a recent thread. My experience was very similar to Dave's, and Butta's about the brown PW and black HE Nichichons and the Panasonic FCs and the blue BC axials.

I also mentioned Black Gates, which are made by Rubycon and are expensive. These all work "fine" with each having a definite character and "sound" of their own.

You might add that thread to the caps meta...

-t

Can anyone comment on the Russian Surplus caps that are for sale on ebay?

like these:  http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=200339684912

sold by kwtubes?


I'm curious if they function, are within tolerance, and sound good. 

I have heard good reports about them.