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Low voltage V High voltage tone caps in Les Paul wiring loom.

Sol

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Oct 26, 2001
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544
Do high voltage capacitors sound any better than low voltage caps??
 
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Sol

Active member
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Oct 26, 2001
Messages
544
Were all familiar with the high voltage 'Bumblebee' caps in vintage Les Paul's. I'm interested to know if there are any comparison studies members might be familiar with using low voltage Mylar or Poly to compare with the traditional paper in oil 'Bumblebee' high voltage type ?

I'm slightly conflicted on this point as I would prefer my personal Les Paul's to have these high voltage paper in oil capacitors, while I've been using low voltage Green Mylar in guitars for some time.. Am I hypocritical for not using high voltage rated caps in all guitars and all circuits??
 

335Guy

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Feb 15, 2021
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the bigger the cap physically the better the sound... the bumblebee is the best example
 

335Guy

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Feb 15, 2021
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read about capacitor construction... engineers have been working for years to try and reduce ESR and self inductance ... by making caps smaller and the materials thinner ... what we want are big ole buick bumpers ... rolled foil caps ... not the compressed little chicklets ... find a real bumblebee and try it ...thank me later
 

Sol

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Oct 26, 2001
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544
No need to thank you just yet, as many of us are already familiar with with the cap types used in guitars, from the 50s to present day.

like forum member 'poor man's burst' I'd like to understand your thinking on, "the bigger the cap the better the sound" ?
I don't know the answer to this, so any light you bring will be appreciated.

Oh, by the way, a warm welcome to the forum!
 

335Guy

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Feb 15, 2021
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do some reading on something called a tank circuit... https://www.allaboutcircuits.com/te...rrent/chpt-6/parallel-tank-circuit-resonance/

when you have a pickup a capacitor and volume and tone pots set up as a circuit they behave like a tank circuit emphasizing certain frequencies.
the pots and bumble bee in an old Les Paul (or any guitar ) all have some unwanted inductance its a property of the old carbon paste used to make the old pots,
in a high voltage tubular cap the foil is physically thicker, and in the old designs wound somewhat looser ...so all things being equal (and they are not!) a larger cap has more inductive mass.
Cap companies tried to mitigate this by winding tighter caps, then later using mylar with metal sprayed onto the mylar instead of using foil ...later cap designs were crushed after they were rolled
which is why they are formed like chicklets or cubes ... all of these engineering changes were intended to reduce the natural inductance of an old school cap.
Thankfully Bumble bees were a terrible old design... which had very poor control of esr and self inductance ... the effect is highly noticeable
and explains why PRS removed the tiny ceramic disc caps from their guitars... and started using tubular rolled mylar caps about 10 years ago ...
if you disconnect the tone circuit in a guitar and build a tone control outside of the guitar on a workbench with an aligator clip to hook up various capacitors you will
hear some differences in modern caps with the tubulars sounding better and adding resonance ... test a bumble bee under these conditions and be prepared to say
HOLY CRAP ... whatever is going on is cool ... there are alternatives to bumble bees and my rule of thumb is if its physically larger and older it might have the older mojo ...
your mileage may vary ...
so yes its a terrible "rule of thumb" but no cap maker publishes their inductance numbers... but each NEW and Improved cap DATA sheet says "now with lower self inductance"
in other words ... our old version was terrible try our new cap ... read a few cap data sheets, understand a tank circuit and do some A to B testing and you will find I'm not as crazy as I let people believe
here's the real burn I have seen PIO caps offered specifically for guitars that say "fake Bee - low inductance wind" so yes they may be PIO but engineers cannot time travel backwards
its against their basic nature ... :)



Typically when I do explain it to fellow guitarists their eyes glaze over and and they don't follow then I hit them with "if you can't get a bumble bee try the physically bigger caps ..you will find something "

I don't own a burst ... a buddy does and when I got my poverty guitar sorted out he said "you have it 95%... " to which I responded given the budget "that will work"

if you really want a head scratcher we can talk about pickups copper plating and eddy currents ... guaranteed to make all the Girls gather round at a social event ... not


p
 
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Sol

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Oct 26, 2001
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544
335guy, I don't think your crazy, but you mention induction throughout your post without stating the effect induction has in a passive electrical guitar circuit that we could hear and replicate in order to confirm your claims. (Or not).
Providing links is okay, but you could summarise the inductive contrast between large and small capacitors, as they relate to guitar circuits in a way we can all get our heads around . I think this would be appreciated.
 
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335Guy

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Feb 15, 2021
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sure:
Induction is the opposite of capacitance. This has two direct effects: First any (unwanted but still present ) induction in a cap acts like a notch filter ... so while the purpose of the cap is to pass anything above the cutoff lower frequency the unintended inductance starts to limit the ultra high frequencies ability to pass ... so when you turn down your tone control the presence and articulation of the pickup are preserved and you have a wha wha filter effect aka "the woman tone"
The second effect is that these hidden inductances being in a tone cut circuit actually have a "reflective quality" just as you can see your reflection in a clean glass window due to light refraction... ie even on 10 some of the signal bounces off the cap ...
if you look at the link to a "tank circuit" diagram provided ... the harness is a tank circuit in disguise and helps perpetuate the signal ... its the electrical equivalent of an resonant acoustic chamber

which we hear as shimmer... sustain or whatever special qualities people will describe as properties of the Bumble Bee cap ...

If anyone doubts this there is a simple experiment to try
Grab your test guitar ...record some sound clips ... then grab two small inductors and add one before and one after the cap ... record a second set of sound clips ... more importantly while recording these clips...
even before you compare the recordings you should have a lot more fun playing the same guitar with the inductors in circuit with the cap...

if you can solder well try this and have fun and my ramblings will start to make sense
...if you can't and your eyes just glazed over you can just think I'm crazy I never take it personally

as for the larger cap rule of thumb ...it's simply a guide to help avoid wasting time trying the smaller modern caps which tend to be much lower inductance than a big old sprague, astron ect
FYI this is also the same effect that make Mullard mustard caps so desirable in a Marshall circuit ... while the inductance is tiny compared to a Bee ... it attenuates the RIZZ and FIZZ in a pass through circuit
just enough that your old Marshall sounds better at full clip... this applies to Blue Molded and Astron caps in Fender amps ...that ab763 low end Bounce comes from those guys in that tone circuit...

do some testing your ears won't lead you astray
some people get it ...others don't and that's ok too

have fun
 
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Sol

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Oct 26, 2001
Messages
544
Whilst I understand that as induction falls, resonant frequency will rise, and a capacitor within a Les Paul circuit for example may develop greater or lesser induction dependent upon its internal structure, aren't we in danger of discussing electrical values so small that our discourse become an exercise in the minutiae of component theory, but divorced from the real world experience of musicians ?
Respectfully,
Sol
 
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