Choosing the "best" caps for a fuzz

[amptramp]

There is a D-Lab video here:

of the refurbishment of a Fender Bassman tube amp which shows how to use a plastic wand to check for microphonic components and that the 8:00 point of the video, he runs into a microphonic ceramic disc cap.  If the owner was using it as a bedroom practice amp, it may not be all that noticeable.  If he is using it at a gig, the volume levels will generate feedback and distortion.  Ceramic caps are not that different from ceramic microphone cartridges.  The higher the dielectric constant, the worse the effect.

Multilayer ceramic is not usually as sensitive.

Beware of assuming that if an amp or effects unit works at low audio level, it will work at high level.

[duck_arse]

I have an absolute crapload of vintage caps.  I'm pretty sure I even have the exact ones that are in your 3D PCB pic you posted earlier.  If your in the US shoot me a PM and I'll send ya a bunch to try out if you like.  Let YOUR ears be the judge!!

when those Siemens caps were new new stock, the production departement hated them because the end-plates often fell off. I never understood the construction - are they coated with something insulating? what stops them shorting on tracks run double-sided under them?

time passes. those stacked film caps have since been coated in epoxy, then put into a plastic jacket, and are now called box caps. does end-caps failing make for mojo?


edit for spelling.

[bowanderror]

I have an absolute crapload of vintage caps.  I'm pretty sure I even have the exact ones that are in your 3D PCB pic you posted earlier.  If your in the US shoot me a PM and I'll send ya a bunch to try out if you like.  Let YOUR ears be the judge!!

What kind of caps are those? Never seen anything like 'em.

[duck_arse]

https://pdf1.alldatasheet.com/datasheet-pdf/view/169368/SIEMENS/B32560/+0W84J-VPhEMGPU+hvvD.v+/datasheet.pdf

Siemens MKT. there is a TDK datasheet for box/poly caps somewhere, has a lot of how they are made info.

[Gus]

Don't dismiss a cap because of microphonics. IMO microphonics can be something to use

Think about this, tubes are microphonic(some can be too much) how much of the tube sound is a combo speaker shaking the chassis, caps and tubes or a head on top of a cab or tubes in a tube microphone.

I have told this story before I installed pickups in 70's strat for a friend and we tested it however tests were done at stage level in my basement we tried different caps (I checked the values) the stock? microphonic ceramic 1KV disk sounded the best when it was touching the body of the guitar in the electronics cavity.
FWIW and a little off topic if the effect you are adjusting building will be used on stage adjust it at stage volume often for guitar you will want to remove bass if using an open back combo.

Some(all at some level?) caps are microphonic and some good sounding fuzzes used disk ceramics. An old BMP like commercial built one before the boutique stuff had disk ceramics and sounded good I forget the brand I heard and there were others that used ceramic disks

Don't believe the stuff you read and see on the web(including this post) test it for yourself. Caps don't cost much.

[iainpunk]

Any comment on multi layer ceramic , these are 104 (0.1uF)

i used to use those axial ones a lot starting my pedal building ''career'' (when i only build opamp fuzzes), about 6 years ago.
it was all fine untill high volume levels were used with those fuzzes, and a nasty high pitched whistling came in to being, and i couldn't find out what was the problem.
fast forward to about 2 months ago
looking through my old perf board pile and found those opamp fuzzes, when i saw those tiny 104 caps, i immediately suspected where the whistle came from.

cheers, Iain

[WoundUp]

as long as you don't use ceramic disc caps your good - sound wise, they are microphonic, non-linear and fragile
i believe good looking components make stuff sound better through confirmation bias.
but there is no observable difference in sound between tropical fish, green foil or box caps, even the ultra mojo PAPER IN OIL caps are not different in electrical properties.

cheers

What's wrong with ceramic? I just ordered a delux cap kit and it comes with ceramic, mylar, electrolytic, and something else.

[iainpunk]

as long as you don't use ceramic disc caps your good - sound wise, they are microphonic, non-linear and fragile
i believe good looking components make stuff sound better through confirmation bias.
but there is no observable difference in sound between tropical fish, green foil or box caps, even the ultra mojo PAPER IN OIL caps are not different in electrical properties.

cheers

What's wrong with ceramic? I just ordered a delux cap kit and it comes with ceramic, mylar, electrolytic, and something else.

they have some ''nasty behavior''. they are microphonic (see post above yours), not really linear (lose capacitance under DC bias, and distort waveforms in a bad/ugly way), break under mechanical stress or to much heat, and they taste funny.

cheers

[ElectricDruid]

What's wrong with ceramic?

Nothing, if you use them for what they're good for. They work excellently for taking high frequencies to ground, for example, so all decoupling caps on logic boards and processors and similar jobs should be ceramic. Electrolytic caps are good at low frequencies, but not so hot once you get up into RF noise, which is why you sometimes see a 100n ceramic in parallel with a big electrolytic. Obviously such a little cap isn't going to do anything to the overall amount of capacitance, but it does help with high frequency stuff.

[Big Monk]

Frankly, I think much of the difference people "hear" is in the value used. For instance, I ordered about 20 0.22 uf Tropical Fish to sort for a Clyde Wah project. Tolerance was 20% based on the markings and old literature.

Not one of them was within spitting distance of 0.22 uf.

Careful, this is decending into the aforementioned DIYAudio territory. 


I test every component I put in a circuit - as far as the BMP stack goes, a 10% range can make a huge difference to fc and the crossover at the low end.

Have to agree with Iain, the majority of my 20% black band 10nf C280's measure consistently in the mid 9's; the larger value 10% white bands are typically <5%.
220nf's I have are mostly around 215nf - Genuine 60's Mullards with the slimmer bodies, crumbly split ends and flaking lacquer to boot!

ESR is about 1.5-2ohm on the fish, where the Vishay axials are around 6ohm or so.
Some of the Cornell Dubilier axials I have (same yellow package) are up around 30ohm 

There are some big differences there; both sonic and measured.


Similarly, every Pana FC I put in the power supply filtering/decoupling ends up sounding very industrial and pushed in the mids, so I tend to go with Nichicon KZ's which are much more relaxed but take a while to break in. Even the KZ and Fine Gold's are distinctly different, with the FG's having more of that mid, like the Pana, but still being musical about it.
All ESR's are around 200mOhm - 1ohm for these caps. I don't have the equipment to measure any other aspect but the differences are distinct and consistent enough to trust my ears implicitly. I really wanted to like the Pana FC's as well.

I know I can't speak for everybody here but I'd like to think the people who weigh in on this forum do so because they have real practical experience with such things. I'm only putting my neck on the line here claiming there's a difference because there actually is a difference.

Just to correct myself a bit here: I went back and measured all my little fishies and they were bang on for 0.22 uf.

I'm not sure why I remembered them being off so bad.

[Kevin Mitchell]

Man, this horse passed away a long time ago 
Usually it doesn't really matter. In the guitar world it's negligible more often than not. But here is my rule of thumb.

MLCC (multi layer ceramic capacitor) for power decoupling.
Polyester (like reds, greens or box film) for audio signals. These are my go-to in 95% of my projects.
Polystyrene or polypropylene for where stability counts in oscillators or sample/hold circuits (mostly for demultiplexing).

[mozz]

That may all be true from a textbook or RF perspective but not with music from a guitar point of view. Range master used a polystyrene cap, that sure wasn't from a cost saving measure.

[Kevin Mitchell]

That may all be true from a textbook or RF perspective but not with music from a guitar point of view. Range master used a polystyrene cap, that sure wasn't from a cost saving measure.

Not to be condescending, but those facts don't seem true. I'm all for learning something new.
I can't even find a photo of the original Range Master with any polystyrene caps. Just ceramic and polyester.

[garcho]

Range master used a polystyrene cap, that sure wasn't from a cost saving measure.

So what are you implying? I can't imagine a work-a-day engineer sat there testing out capacitor types, in 1965. These were not sophisticated audio electronics engineers working for Neve or Neumann, this was Dallas making amps trying to cash in on the British RnB/London Mod craze. The Rangemaster was probably just a preamp prototype that ended up in a box, made with whatever parts they bought a lot of. The engineer who designed it thought so highly of it he never even bothered to take credit. Why do you think they used that type of cap?

The reason this dead, rotten, stinking corpse of a horse is still being beaten is because those who make "golden ears" claims produce a lot of opinion but never any audio evidence. Occasionally a graph or two is thrown in to give the illusion of sophistication but somehow it's never accompanied by audio evidence of the actual sound.

That and it is really confusing figuring out what components to buy when you first start building. 

[Fancy Lime]

If it was a polystyrene cap, it was probably there for the same good reason that most part types and even values were chosen back then and still are by many outfits large and small today: we have a truckload of surplus (insert component type and value), let's use them in something. Some of the Russian Big Muffs (and many other designs) use two caps in series where one of half the value would suffice and be cheaper if bought new. But sometimes you gotta find a way to use those thousands of 1u caps you got for cheap when the Radio Shack around the corner went out of business.

[PRR]

> we have a truckload of surplus (insert component type and value), let's use them

+1.

There was the year I used 47r 2W in EVERYthing, because a box literally fell off the truck and spilled down the street. And there was a lot of Gold-plated surplus in the 1960s, between military and aerospace over-runs and design changes. Whole cartons of boards of fancy caps for the desoldering. (There was probably a higher class of surplus for caps which had not been soldered yet.)

[Big Monk]

> we have a truckload of surplus (insert component type and value), let's use them

+1.

There was the year I used 47r 2W in EVERYthing, because a box literally fell off the truck and spilled down the street. And there was a lot of Gold-plated surplus in the 1960s, between military and aerospace over-runs and design changes. Whole cartons of boards of fancy caps for the desoldering. (There was probably a higher class of surplus for caps which had not been soldered yet.)

A lot of people try to romanticize what was essentially people have milspec parts to use in fuzz circuits because that's what was going in the 60s.

[garcho]

a box literally fell off the truck and spilled down the street

the Chicagoan in me laughed at "literally"

A lot of people try to romanticize what was essentially people have milspec parts

It's also a lot easier to buy parts than talent or inspiration   Everyone wants a shortcut to sounding great, but it's mostly just the notes you play and how you play them. Same goes for these ancient pedal designs. Most, albeit not all, designs can sound just as good with obtainium.

[Big Monk]

a box literally fell off the truck and spilled down the street

the Chicagoan in me laughed at "literally"

A lot of people try to romanticize what was essentially people have milspec parts

It's also a lot easier to buy parts than talent or inspiration   Everyone wants a shortcut to sounding great, but it's mostly just the notes you play and how you play them. Same goes for these ancient pedal designs. Most, albeit not all, designs can sound just as good with obtainium.

The problem, as I see it, and this is way off topic and I apologize, is that for every Dave Main of D*A*M*, Stu Castledine, or Chris Vincent from R2R, there is an Isle of Tone and a dozen other trendy builders preying upon vintage mojo worship and the fact that people don't know any better.

[Kevin Mitchell]

I had once replaced the caps in my Deluxe Reverb amp from orange to mustard. I even went the extra mile to find the foil side of each capacitor to place them for "best performance" and also redid the entire ground routing by using a copper plate instead of flying wires. As a result it mitigated hum only. I can't credit the capacitor material as they're both "mojo" parts. It's the work around these parts that made the difference.

Don't lose yourself in the tangle of mojo vs facts. The parts and build quality altogether show how much you care for the circuit. If you hear a difference between one or the other, it's likely not due to polyester vs polypropylene.

Here's a little read from Mouser.
It explains the capacitor placebo effect as well as how most results are merely due to slight differences in capacitance alone. This jives with my prior research into mojo capacitors. If you're caught in the tangle, I encourage anyone to do the research since I'm sure they're only reciprocating a salesman's tale.