PIO (paper in oil) caps (capacitors)

oboylebass · #1 05-31-2010, 08:28 AM

Anyone try PIO caps in a passive bass? I see they have a pre-wired setup for J-Bass available (eBay), was thinking of snagging it for a bass I'm putting together.

Thanks!

See:

http://cgi.ebay.com/FENDER-STYLE-JAZ...#ht_2774wt_934

SurferJoe46 · #2 05-31-2010, 11:07 AM

The only trouble with paper-wax and paper-oil is that they change values during heat extremes and age. The wax or oil flows and migrates to the lowest gravitational location, leaving the upper layers drier and less capacitive. That's OK if they still AVERAGE-OUT close to the value you bought - but don't count on it.

There's a good reason why the industry went to poly or Mylar caps - they are more stable

But - all in all - they (the paper-style) are generally larger and you need to use a little more finesse when you solder them into a circuit as the heat can conduct into the connection point inside the cap and cause some off-value variances too.

Here's the funny part:: there's such a broad tolerance allowance in caps that you are prolly OK if they do wander off specs. They may be either 10-20% rated to be 'close' to spec right out of the box.

You can get some that are 0-1% tolerance rated, but they are NASA stuff and not something to worry about. You'd maybe have to sell your first born male child to even get to see them.

Bass tone isn't rocket surgery anyway.

M0ses · #3 05-31-2010, 11:13 AM

Quote:

Originally Posted by SurferJoe46

Bass tone isn't rocket surgery anyway.

Sigged.

Rick Auricchio · #4 05-31-2010, 12:42 PM

This thread should really be in Pickups and Electronics.

oboylebass · #5 06-01-2010, 02:44 PM

Quote:

Originally Posted by SurferJoe46

The only trouble with paper-wax and paper-oil is that they change values during heat extremes and age. The wax or oil flows and migrates to the lowest gravitational location, leaving the upper layers drier and less capacitive. That's OK if they still AVERAGE-OUT close to the value you bought - but don't count on it.

There's a good reason why the industry went to poly or Mylar caps - they are more stable

But - all in all - they (the paper-style) are generally larger and you need to use a little more finesse when you solder them into a circuit as the heat can conduct into the connection point inside the cap and cause some off-value variances too.

Here's the funny part:: there's such a broad tolerance allowance in caps that you are prolly OK if they do wander off specs. They may be either 10-20% rated to be 'close' to spec right out of the box.

You can get some that are 0-1% tolerance rated, but they are NASA stuff and not something to worry about. You'd maybe have to sell your first born male child to even get to see them.

Bass tone isn't rocket surgery anyway.

Cool info. Wonder if what they're claiming in the eBay aution is true though, tone-wise.

SurferJoe46 · #6 06-01-2010, 02:54 PM

Quote:

Originally Posted by oboylebass

Cool info. Wonder if what they're claiming in the eBay aution is true though, tone-wise.

Here's what works::

Go to Radio Shack and buy a couple of packs of the Mylar-Wafer styles. They are very low voltage, but you're never gonna get to anywhere near enough voltage in the pups, active OR passive to punch through a very small cap anyway.

This is a .1uF cap:::

Those giant pills and things they sell are 'way overkill! You don't need anything like them at all.

I think I got a 2-pack for $1.19+tax.

These come in all sorts of values and you can just piggy-back them onto the existing caps that you already have on the tone pot.

You will get a tonal change if you add more capacitance. It's a lot of fun to try different qualities of tone out by swapping caps in and out of the circuit.

**line6man** · #7 06-01-2010, 03:04 PM

Another one of these "Does this capacitor sound better" topics...

My usual sentiments on the matter:
Ajax Blue .027 tone capacitor???...

SurferJoe46 · #8 06-01-2010, 03:09 PM

Quote:

Originally Posted by line6man

Another one of these "Does this capacitor sound better" topics...

My usual sentiments on the matter:
Ajax Blue .027 tone capacitor???...

Sure - if that's the question.

Try it this way: "Will this capacitor change the tone of my bass to something I want more or less?"

That works for me. I DID work for me on a formerly hated and disgusting-sounding Fender that sat in the closet for almost 13 years. I added the .1uF cap on top of the existing cap and it's a front-line player now.

I guess it's also fair to say that you cannot hear the pots, the wires or the wax job on the bass either. But then what do you have?

To quote my favorite Vulcan, Mr. Spock: "The sum of the parts must equal the whole".

bongomania · #9 06-01-2010, 03:23 PM

Right, but by your own description you changed the total capacitance, you didn't just change types of cap at the same value. Of course changing the capacitance will change the tone.

And you can hear the pots--just look at the threads about wiring direct to the jack!

SurferJoe46 · #10 06-01-2010, 04:19 PM

Quote:

Originally Posted by bongomania

Right, but by your own description you changed the total capacitance, you didn't just change types of cap at the same value. Of course changing the capacitance will change the tone.

And you can hear the pots--just look at the threads about wiring direct to the jack!

Yeah - the original cap is tubular-Mylar, and I was just a' thunking it's not the only design that's acceptable for this application.

Those green drops, or whatever they are called are 'way overboard for what they are required to do. We ain't NEVER gonna see voltages enough to blow the dielectric out on a wafer or disc style either.

The OE cap was prolly .047uF - I never looked; I just added another .1uF piggyback on top of it and soldered it to the same locations.

I also guess that a pot that is too resistive will cause all sorts of tone or volume changes too - I totally discounted that, but I was being snide about the idea that a cap could be heard and was belaboring the point to be silly.

testing1two · #11 06-01-2010, 04:35 PM

Here's some food for thought since this is a subject that gets vastly oversimplified or prematurely branded as snake oil:

http://www.thegearpage.net/board/sho...ight=capacitor

In the long run, it's just another pebble in the pond on tone.

i_got_a_mohawk · #12 06-01-2010, 04:57 PM

Quote:

Originally Posted by SurferJoe46

Sure - if that's the question.

Try it this way: "Will this capacitor change the tone of my bass to something I want more or less?"

That works for me. I DID work for me on a formerly hated and disgusting-sounding Fender that sat in the closet for almost 13 years. I added the .1uF cap on top of the existing cap and it's a front-line player now.

I guess it's also fair to say that you cannot hear the pots, the wires or the wax job on the bass either. But then what do you have?

To quote my favorite Vulcan, Mr. Spock: "The sum of the parts must equal the whole".

I had a black car with a 2 litre engine and a red car with a 5 litre engine. Red cars are faster than black ones.

Spencer! · #13 06-01-2010, 05:02 PM

Your bass will sound like crap unless you buy one of these: http://www.alessandro-products.com/main.php?p=parts

**line6man** · #14 06-01-2010, 05:08 PM

Quote:

Originally Posted by SurferJoe46

I also guess that a pot that is too resistive will cause all sorts of tone or volume changes too

Why would a pot that's too resistive cause volume/tone changes?
"Too resistive" is relative to what, exactly?

The more resistance you have between the signal and the capacitor, the less signal is getting cut.
For reference, infinity ohms is the equivalent of no tone control, and 0 ohms is the equivalent of putting the capacitor directly into the circuit with no pot.

OTOH, if the capacitor has a high leakage resistance, (Honestly, I don't know off hand what the leakage resistance is of various types of capacitors. I need to look at a spec sheet.

) that could cause the tone control to behave more like a volume control, as the capacitor would be shunting a lot of the signal to ground.

Completely unrelated, but for the record, I'm not worried at all with the ESR and ESL of tone caps.

The ESL should be low, and given the relatively low frequencies found in audio applications, the inductive reactance should be pretty insignificant.

The ESR pretty much means nothing, as you are already putting so much resistance between the capacitor and the signal with the tone pot, that a few fractions of an ohm more won't matter.

bongomania · #15 06-01-2010, 05:10 PM

Quote:

Originally Posted by testing1two

Here's some food for thought since this is a subject that gets vastly oversimplified or prematurely branded as snake oil:
http://www.thegearpage.net/board/sho...d.php?t=656811

Responding to the paper referenced in that link (i.e. not assuming your opinion on it), the major fault there is that the cap in a tone pot circuit is not in series in the audio path. It drains signal to the ground path. So there is no doubt that if we were listening to the ground path, we might hear the subtle variances in tone between different types of caps. But we don't--we listen to the signal path, which does not pass through the capacitor.

It could be argued that tone is subtractive, and that the way the cap drains signal off from the main line reciprocally affects tone on the main line... but that's a stretch IMO.

**line6man** · #16 06-01-2010, 05:13 PM

Quote:

Originally Posted by SurferJoe46

Those green drops, or whatever they are called

Polyester film?

bongomania · #17 06-01-2010, 05:15 PM

Most of the green drops I've gotten from Mouser have been mylar, FWIW. I don't know if the color has any correlation though.

**line6man** · #18 06-01-2010, 05:23 PM

Quote:

Originally Posted by bongomania

Most of the green drops I've gotten from Mouser have been mylar, FWIW. I don't know if the color has any correlation though.

Ok, maybe it's mylar then.

Passinwind · #19 06-01-2010, 05:25 PM

Quote:

Originally Posted by bongomania

Most of the green drops I've gotten from Mouser have been mylar, FWIW.

Mylar is a form of polyester film.

testing1two · #20 06-01-2010, 05:46 PM

Quote:

Originally Posted by bongomania

Responding to the paper referenced in that link (i.e. not assuming your opinion on it), the major fault there is that the cap in a tone pot circuit is not in series in the audio path. It drains signal to the ground path. So there is no doubt that if we were listening to the ground path, we might hear the subtle variances in tone between different types of caps. But we don't--we listen to the signal path, which does not pass through the capacitor.

It could be argued that tone is subtractive, and that the way the cap drains signal off from the main line reciprocally affects tone on the main line... but that's a stretch IMO.

I agree that the white paper presented in that link is not directly related to a guitar circuit for a number of reasons but the rest of the thread raises interesting points about the guitar circuit as a whole and how capacitors of different constructions may or may not behave differently in this context. It's also interesting to read about potential testing of this theory.

I think my point is that in theory we often treat capacitors in guitars like simple shelving filters when in practice the capacitor/tone-pot network causes a variable resonant peak in the pickup's output that doesn't necessarily adhere to such a simple definition.

Again, it's just food for thought. I'm not selling PIO over Silver Mica over Polyester Film over Ceramic over anything else. I continue to advocate experimentation until one's ears are happy.