Capacitor selection

[scotto]

Here's an interesting article on the effect (or lack of) regarding different types of capacitors. The study is for guitars but the author concludes the same would apply for amps. Not suggesting I agree with this or not, just putting it out there as FYI. Given the fact that I've spent much time seeking the right caps and orienting them the right way, I want to say that the author is wrong regarding amps.

http://zerocapcable.com/?page_id=224.%C2%A0

[j0k3335]

Here's an interesting article on the effect (or lack of) regarding different types of capacitors. The study is for guitars but the author concludes the same would apply for amps. Not suggesting I agree with this or not, just putting it out there as FYI. Given the fact that I've spent much time seeking the right caps and orienting them the right way, I want to say that the author is wrong regarding amps.

http://zerocapcable.com/?page_id=224.%C2%A0

... wrong regarding amps

AND

indisputably this guy did a great job and highlights certain aspects BUT a musician can also do this, spend several hours with several capacitors... and use his EARS (in any case, for mine, it worked!!! ) ... he might be surprised

http://jose.kramp.free.fr/tone1.jpg

[10thTx]

A) One tone cap in one type of a guitar? VS. B) 19 capacitors in various stages of gain and position in a guitar amp with varying voltages on the caps.

Do you think one can take from "experiment" A and apply it to a tube amp like a Dumble? He is welcome to his opinion. My opinion is his reasoning is off.

Respectfully, 10thtx

[j0k3335]

A) One tone cap in one type of a guitar? VS. B) 19 capacitors in various stages of gain and position in a guitar amp with varying voltages on the caps.

Do you think one can take from "experiment" A and apply it to a tube amp like a Dumble? He is welcome to his opinion. My opinion is his reasoning is off.

Respectfully, 10thtx

... and you can add this , of course

[JD0x0]

Google 'Bateman cap notes'

https://proaudiodesignforum.com/images/ ... ound_1.pdf?

There are measurable differences in distortion of different cap compositions used in the signal path. Most notably, try a monolithic ceramic cap vs a decent quality film cap. The Monolithic cap will produce measurable odd order harmonics, while the film cap will have measurably less distortion. This may be why ceramic caps are often reported to be 'grainier' sounding while caps like Mica, will often be percieved as smoother or 'glassier' sounding when using caps of the same values in a given position. Apparently Dumble preferred the performance of the ceramics in most of his amps for treble caps in the tonestack, for example.

[erwin_ve]

Voltage stress on a (polyester) dielectric in a cap affects the tone. It is a proven thing.
Check this discussion with link to the Bateman files: https://ampgarage.com/forum/viewtopic.p ... 24#p399024

As for tonecaps in a guitar: I think every seasoned guitar player can tell you, when turning down the tone knob, there will be boost of mids at a certain point.
This is a resonance frequency. A befriended luthier showed me a cap he used and the mid bump with his chosen cap was the biggest I ever heard.

Erwin

[JD0x0]

This is a resonance frequency. A befriended luthier showed me a cap he used and the mid bump with his chosen cap was the biggest I ever heard.

This is the idea behind the Bill Lawrence microcoils. Very low inductance (1.6H-2H) pickups, which gives them a very wide frequency response. (For reference a vintage strat pickup tends to be around 2.6H) You can then use caps to shift the resonant frequency lower. With the right values you could mimic hotter single coils, P90s, and humbuckers by shifting the resonant frequency to mimic that of those pickups. If you have the cap(s) on a tone control, around '0' to '2' on the control can adjust the height of the new resonant peak, so if it gets a bit too midrangy, you can turn the knob from '0' to around '1' or '2' to tame the resonant peak. It's pretty versatile. With the right taper, around 4-5 will give you a fairly flat response, and 6-10 will adjust the original resonant peak of the pickups (Usually in the 6khz-10khz range on microcoils, depending on your cable capacitance)

[Aurora]

I¨ve been following these capacitor discussions off and on for several years now. While there are certainly differences between cap types, I wonder how much is really owed to the type rather than tolerance variations, - particulrly in vintage capacitors which are mostly 10% at best, - 20% being more common.
The cap test by Cyril Bateman, originally publishen in the old Wireless World mag back in the 80's, are certainly of interest among HiFi-nerds, I wonder how relevant it is to medium/high distortion amps for guitars... BTW - ceramic caps for signal are otherwise usually concidered useless in other audio applications...