Sound differences between cap brands? Test results?

[guitician]

That's funny because I select most of my best sounding caps from discarded junk. :O

[kleuck]

Not necessarily funny or strange, Tonemaster amps get their unique sound from mainly two things : grid-leak bias everywhere (or almost everywhere) and cheap ceramic caps everywhere (or almost. ....) Best Hi-Fi solutions are not necessarily the best solutions for guitar amps ( and imo, most of the times, are not), I'm always shocked when guitarists thinks that ceramic caps are crap, because I think they are really useful to us -except if you are after the cleanest sound ever. I'm not.

[defaced]

Did Steve ever post the answer to the clips he posted?

[guitician]

If you think about it, what makes an acoustic guitars tone has to do with how it alters the vibrations of a piece of tensioned wire.
With electrics, this continues with how the alternating voltages/currents are changed by the signal path, and speaker.
For electric guitar non-linearities are welcomed because it adds to that vibrating wires tone, as the wood of an acoustic does.

[Mark Hammer]

What you never really hear about in such comparisons, is the the specific tonal goals and circumstances. Only a small handful of players will aim for pristine clean sound, and often those that do are NOT using combo amps, but rather plugging into high-end preamps and an audiophile-quality power amp, or else going straight into the mixer and PA. If it's a combo amp or head and cab, chances are pretty good that the user intends to achieve at least a modicum of coloration, and probably has no plans for how to keep all that stuff above 8khz.

One of the heavy auditory tasks humans have to achieve with those two puny ears is to take the entire sound-field and perceptually assign this harmonic content to that fundamental, and that reflected staggered sound to this sound source. Light and touch does us a great service by having different sources land on different parts of the retina or skin, but all sound comes in through two little apertures, and the brain has to figure out what goes with what. One of my former profs - Al Bregman - has described this as "auditory scene analysis". Auditory scene analysis - Wikipedia, the free encyclopedia

The micro-timing of auditory events is a component of how what comes in those two holes is organized by the nervous system. When there are many concurrent sound sources, that micro-timing , and "diagnostic" spectral content (i.e., this goes with that because only that has that harmonic content/pattern), can become especially important in assisting analysis of the "auditory scene".

Why am I telling you this? Because if I was working a mixing board, and processing multiple signal sources that were all going to come out two speakers and go into two ear holes, assuring that all harmonic content be present as it was generated, and line up perfectly with all fundamentals, would be important in assisting the listener to make sense of all that signal, and being able to "hear" the multiple sound sources being reproduced, the same way you can see these words on the screen and it's not just a chaotic mess of pixels. Is that stuff at 10khz supposed to "go with" the cymbal, the violin, the synth, the banjo, or the audience rustling?

As such, I will maintain to my last breath that, when it comes to sound reproduction involving multiple sources, cap type will very likely matter, simply because caps are critical in the timing of signal properties, and timing is fundamental to making perceptual sense out of all that concurrent sound. When the caps are components in a circuit devised to process a single sound source, and most especially when that circuit will likely be used to degrade the accuracy and fidelity of the signal, the likelihood of cap type mattering drops dramatically.

I won't rule out type from mattering at all, but the likelihood is very low. If I had a combo amp for playing an acoustic guitar equipped with an internal condenser mic and a piezo bridge, and that amp was intended to capture the acoustic properties of my instrument clear on out to 15khz, then cap properties might matter somewhat. But that's the rare case. If I was running my guitar through a chorus, then fuggedaboudit.

As always, context is important. Never forget that.

[Steve Conner]

Thanks for the reminder Mike Here are the answers:

Mallory150 = 3
NOSMustard = 1
SozoStandard = 4
SozoVintage = 2
NOSMustardNOSPreampTubes = 5

I'm not sure I buy Mark's "timing" explanation either. A coupling capacitor appears like a short circuit to high frequencies. It passes transients through with essentially the same propagation delay as a piece of wire of the same length as the capacitor's body. And if it's big enough, it should also pass the fundamentals without phase shifting them. So, coupling capacitors shouldn't mess with the timing of a signal.

This explanation doesn't hold for capacitors used in filter circuits. We want those to mess with the phases of all our frequencies. Well, we don't want it as such, but Bode's law says that if we want to use analog filters to change the amplitudes of different frequencies, we have to accept some phase shifts. (Digital filters are exempt from Bode's Law.)

But audiophiles don't use tone controls. Well, apart from RIAA networks in their vinyl preamps. OK, so capacitor tone might be an issue with those. I personally don't use vinyl so I haven't thought about it.

[loudthud]

It passes transients through with essentially the same propagation delay as a piece of wire of the same length as the capacitor's body.

I have the equipment to measure that, but the edge speed that would be required would be well past the capacitors self resonant frequency.

A place I used to work had an Agilent 4194A. You could plot the impedance graph of a capacitor and it would derive ESR, ESL and other losses. Remember, don't drink and derive

[guitician]

If I had a combo amp for playing an acoustic guitar equipped with an internal condenser mic and a piezo bridge, and that amp was intended to capture the acoustic properties of my instrument clear on out to 15khz, then cap properties might matter somewhat. But that's the rare case. If I was running my guitar through a chorus, then fuggedaboudit.

As always, context is important. Never forget that.

When amplifying an acoustic guitar, the combo amp becomes part of the instrument. How about playing into a line driver connecting the exact signal coming from the piezo/condenser to everyone in the audience with headphones? Rare?...listening seems to be getting there... I've never attended one of these, but the idea is intriguing.

http://en.wikipedia.org/wiki/Headphone_concert