Carbon Black Fuzz - To Vintage or Not to Vintage...

[manfesto]

I have a friend that designs capacitors for the military for things she can't even tell me about. The shape and material of the capacitor are used for various applications she can't tell me about. If there were no difference between them she wouldn't not have a job that she can't tell me about.

But those are clearly not the sorts of capacitors being used in audio circuits, much less bandwidth-limited audio circuits like guitar amps or pedals.

And again, she's doing *science* - she has a set of design requirements that she has to meet that are *way* stricter than anything anyone on this forum will ever dream of touching in a pedal. But I'm sure if she built a 4.7nF capacitor out of 100% unobtamnium and shaped like a donut, as long as it was within tolerance and you dropped it in a pedal, it'd sound the same.

 

[manfesto]

One of the 5E3's that I built was getting run away oscillation when I would turn the volume up.

When chop sticking it, hooked to an oscilloscope, I watched that wave form go from a box full of squiggly lines to a perfect wave when I moved one wire. I could actually change the breakup on the amp by moving this one wire to different positions. Which is probably why no two 5e3's have the same sound (and also since they don't have a NFB circuit.) You can see the position of the blue wire that I settled on for the frequency response to my ears.

This is another thing about "mojo" stuff - it isn't a *good* thing that no two products from the same production run sound the same, at least not to the engineer who designed it.

If Leo Fender could have found a cheap and repeatable solution to make sure nobody had to ever-so-slightly move a blue wire to stop oscillation, he obviously would have (and clearly did, given subsequent designs not requiring that specific sort of tuning).

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There are artists, and there are artisans.

Artists make unique beautiful things. Artisans make beautiful things, consistently and en masse (anything from bread to microprocessors).

Engineers are artisans - to the degree that there is an "art" to their work, it is in the functionality of their design, the elegance with which they achieved it, and the repeatability with which they can continue to make it.

Leo Fender's "art" was the mass-producible bolt-on neck guitar, and years worth of tube amp designs that were hugely influential and that are still produced in some form today.

His "art" was *not* the blue wire you could shift around and basically break his design. That's the errant brush stroke on an early painting that he'd rather not be remembered by.

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Ivor Arbiter's "art" was unique distortion design he created using a 2-stage transistor amplifier with feedback.

His "art" was not the hours we hobbyists spend measuring germanium transistors and throwing them on breadboards trying to recreate the sweet spot of what he did.

We know this because, when given the chance, he did what any good engineer would do and switched to silicon transistors from germanium. Why? For their consistency.

 

[HamishR]

When I build old-style amps like a 5E3 or a '68 Plexi clone I'm not interested in using out-of-spec NOS mojo parts like CC resistors. I use Carbon film resistors (metal film and wire-wound for the higher wattages), F+T electrolytics etc to build a great sounding long lasting amp with minimal need for repair.

But I do often use Sozo caps and haven't found any problems with them. In fact my recent builds with them have been whisper-quiet. I am starting to use Mallory 150s a bit more, especially given how expensive Sozos are becoming! I like the Sozos mainly for the aesthetics - the do look good IMHO! I pay a lot of attention to lead dress and in the past few years as I learn more I have been more attentive to things like capacitor outside foil direction so perhaps that is why my most recent builds have been quieter than ever? There have been a few times when I have accidentally left my latest 5E3 on overnight because it makes so little noise or hum that it's difficult to tell if it's on until you play something. It's something I'm quite proud of.

 

[andare]

I thought Arbiter ripped off the Tone Bender 1.5!

I've been using carbon comp and carbon film resistors for my latest builds on turret board because they look cool and have thick, sturdy leads.
I'm under no illusion that they sound better or different. If anything, they probably raise the noise floor.

 

[HamishR]

Carbon comps are likely to increase noise, if not at first then as the amp ages. But I've not had any noise issues with carbon films, despite what the experts say. I like carbon film for the regular resistors on the board. For anything which should be more than 1W I'll use metal film or wirewound but carbon films are fine. I guess I don't build super high gain amps, so it's not a thing for me. Maybe if I started building Soldano style amps I would need to move to all metal film?

 

[RetiredUnit1]

Exactly, which makes the rationale of using CC resistors in guitar pedals snake oil.



"extensive double blind tests for their tone" IS science. Like, almost the definition of.

(and the odds are *very* high that once values were settled on, a *lot* of A/B testing was done between brand A and slightly-cheaper-brand B to determine if going with A made enough difference that going with it over B would be worth it. Because a solid chunk of engineering is building to cost.)

(and of course that's how modern amps and pedals are designed too, just with parts with significantly tighter tolerances leading to less variation when produced in high quantity.)

Science is attempting to disprove your hypothesis by every means imaginable. When you cannot disprove it, then it becomes theory. Double blind testing is still subjective in that we humans are all the same and all different at the same time!

 

[Chuck D. Bones]

Whatever EQD does, I question.
Mojo parts sell pedals, which on its own is reason enough for pedal builders to use them.

 

[Nostradoomus]

Oh hey old builds of mine, I made a pedal like that exactly once. Won’t bother again