The effects of old parts in a fuzz circuit

[Zork]

So, I was thinking about the effects of old parts in a fuzz circuit. Obviously the transistors are a thing here and as far as I know, germanium transistors are only available as nos parts anyway. But what about the caps and resistors? Does it really make a difference to use ancient carbon composition resistors to get the authentic sound of a Fuzz Face or Tone Bender? Or is it just about the "authentic looks"?
Does a ceramic disc capacitor sound any different to a film capacitor? Does physical size matter in a capacitor in a fuzz box?

[crochambeau]

Please note, I realize a lot of this is tongue in cheek, but I'm trying to embrace the root of the subject.

authentic sound

This is largely a figment of imagination.

Let's take a ride in the wayback machine, to an era in which a lot of electronic components had multiple stages of "human intervention" during their construction.

Part tolerances are all over the place. Whether it is a resistor, a capacitor, or a transistor...

Parts are built, and heaped into the QC department. Transistors are then tested, and stuff that tests to one level is stuck into a bin of similar parts, while stuff that tests to another level is stuck in a different bin. These different bins are allocated different part numbers, and ultimately different price points.

Does the manufacturing company have a government contract? If so, expect better tested components to just vaporize into the military industrial complex, where they will undergo another round of testing and the good parts will be used up and the fail/lesser parts will enjoy value markups decades later by optimistic junk dealers.

What are we doing, making amps sound like that? Jesus, the shit kids listen to these days, grab a bin of the cheapest junk and get to work.

Meanwhile in the resistor factory, a similar process unfolds. We have a batch of "100K" carbon comp resistors. Test them all. Is it within 1% of 100K? Oh good, I already have a buyer for those.. 5% get a gold band, 10% get a silver band, dump the rest out into this lot...

That lot which has had everything within 10% of an accurate value already filtered out.

Repeat at the capacitor factory, you know, in between bouts of pouring PCB contaminated oils down the sewer grate out front.

So, TL;DR a lot of the values packed into an old, build by hand fuzz box way back in the dawning of fuzz boxes is already all over the place. Germanium transistors are going to change their behaviour depending on how hot it happens to be that day, carbon comps are going to soak in humidity resulting in micro non-designated conductive paths, and capacitors are going to have shown up to the party a hot and sloppy mess.

So what is authentic sound then? Is it the sound in an air conditioned recording studio in 1967? Is it the sound in the same studio while the AC is broken in 1968? Is it the sound of some poor pedal suffering under noon day sun after having had the 16th beer spilled on it while it feeds a tube amp hanging off a suffering generator putting out 98 volts AC during an LSD soaked weekend?

Is it any of those after 40-50 years of component degradation?

I realize this may be an unpopular opinion, but I feel that, at this point - nothing is authentic where sound is concerned.

But yeah, it can still sound cool.

Does a ceramic disc capacitor sound any different to a film capacitor?

Typically, yes. Capacitors are a physical object, that impart their effect on an electrical field through the physical assembly of conductive elements and insulating elements. Ceramic disc plates are going to have different reactive characteristics to the array of internal and external influences than a rolled film suspended in a polymer. Different resonant modes, different damping, etc. Will you hear it? Depends on a WIDE array of things. What purpose is the cap serving? Sometimes that is pretty invisible.

Caps also have different inductive (you can often think of this as the OPPOSITE of capacitance) qualities depending on construction, and really big caps - rated for high voltages, are going to have heartier insulation which can affect the over all small signal transfer efficiency, meaning that a big fat 1kV cap might only be 0.01uf compared to a 50 volt 1uf of similar dimension - but meanwhile impedance has crept up which alters the character of the cap when compared to a 10 volt 0.01uf.

Sometimes this is microscopic, and the big parts are cool enough to overlook any treble bleed or whatever.

Sometimes decades worth of storage has infused carbon comp resistors with enough humidity/degradation to turn them into shot noise/popcorn generators.

Again, can be cool for some things, sucks for others.

No harm in trying them out, but I would advise against paying up for vintage parts as at this point the scarcity index far outweighs any imaginary authenticity they are supposed to endow. At least that's my take.

[Zork]

Please note, I realize a lot of this is tongue in cheek, but I'm trying to embrace the root of the subject.

Whoa, cool! Thank you for the very detailed answer. My post was actually not very tongue in cheek but I later realized this topic must have been beat to death in several forums and well, it is indeed. So, sorry for impulsive posting.

Let me explain: I stumbled upon the Vintage Technologies Orange Sunshine fuzz and thought it's cool. So I looked it up and was a little shocked by the prices so I thought I'd roll my own. I then saw a gutshot and they have these big ass ceramic discs inside and old resistors. To my understanding they were built in recent times, definitely no vintage fuzz boxes but with old parts all over. But why?

I've got a JH F1 Fuzz Face and it has NOS parts inside and it's fantastic. I built a Tone Bender with tropical fish caps for fun and it sounds amazing. People all over the internet enjoy building fuzz boxes with pio caps and whatnot and it's obviously something very special.

I understand that it's visually appealing and adds a certain vibe to the build especially when it's one of the early circuits. But I'm also aware about the issues with tolerances, shifting values and noise in old parts.

So it got me wondering because I don't have a lot of knowledge about sculpting tone with different special parts: would my homegrown Orange Sunshine sound any different than the original if I use simple film caps out of the box? Probably yes but probably ANY of the originals sounds a bit different then, right?

So, again, sorry for flogging a dead horse and thank you crochambeau for answering anyway.

[crochambeau]

Eh, the visual aspect cannot be denied - if you happen to have the circuit open and are looking at it - or if it's in a transparent case.

A lot of something sounding good has more to do with the electrical characteristics and "settings" than it does component selection (the two are intertwined, but hopefully you get my meaning)

There are lots of instances where measurable effect follows the mythical components - but most of those cases are not found inside of an effects pedal.

Example: carbon comp resistors can impart a fingerprint on the signal in circuit, but that hinges on dissipating wattage which is usually a side effect of dropping hundreds of volts.

The ceramic discs are probably going to be the cheapest/easiest to find. They are widely hated in audiophile circles (as opposed to the PIO caps you mention). They exhibit piezoelectric tendencies, which can affect stuff in the audio bandwidth. Often decent for fuzz, but I recall years ago a friend complaining about how sterile something using newer discs was sounding, and when the dirty, nasty bottom of the tool box discs were swapped in the build opened up.

Was this actual structure or materials? Was this just differences in the insulating coating on the outside? Hard to say, as parts differ. I'd suggest rolling your own build and finding a way to drive different caps and listen for what you like.

Everything effects everything, but there is an awful lot of homogenization going on. That is not a bad thing, mind you - as consistency is a nice attribute as well.

Have fun!

[moid]

One tip you might wish to try (if you don't breadboard all of these) is to place sockets on your PCB / vero / perfboard for the components you wish to check and then you can easily swap one capacitor out for another etc to see if you hear any difference.

[mictester]

Practically speaking, "capacitor sound" is (mostly) a myth. Similarly, I build the occasional fuzz for musician friends, and use silicon transistors. I add some small value capacitors from base to collector in each stage to filter off the "fizziness" imparted by the more modern semiconductors. In A / B blind tests of a "genuine" 1969 germanium fuzz against one of my modern ones, the onlt really noticeable difference is that mine tends to hiss less! When fed into a big guitar amp and played loud, NOBODY has been able to identify which is which - and that NOBODY includes big name musicians, recording engineers and producers!

The only real reason (these days) to use ancient components is aesthetic - what does it look like? Just for amusement, a friend of mine built a silicon Fuzz Face (with my additional capacitors) out of tiny surface-mounted parts. He built a bogus (non-working) "traditional" germanium Fuzz Face with big carbon resistors and axial electrolytics and polyester capacitors, and housed the whole thing in a perspex case, with copious amounts of clear epoxy resin inside to strengthen the case. The "real" working silicon circuit was concealed inside an emptied electrolytic capacitor case. Everyone who tried it was convinced that they were hearing the germanium Fuzz Face! It looks great, but provides an object lesson in "what you're seeing is not necessarily the real truth"!

[crochambeau]

I love it when a topic surfaces that I have opinions on, only to see that I've already replied and managed to not embarrass my future-self.

[Gone Fission]

I’ve seen varied opinions on whether old electrolytic caps having high ESR (equivalent series resistance) beyond the frequency-dependent resistance characteristics has an effect that could effectively be replicated with additional resistors in a circuit. Some of this came up in the FreeStompboxes threads on the Eric Johnson and Joe Boregasma signature Fuzz Faces. But that’s the only thing I’m particularly aware of with old components besides noise.

Unless leakage characteristics are substantially different on modern germanium transistors than on vintage—yes, China has responded to demand by producing them again, and I suppose there may be things about how the gain and leakage interact that could be interesting in an actual circuit. But I haven’t messed with germanium transistors so I don’t know.