# PIO Capacitors



## Lincoln (Jun 2, 2008)

What is the general opinion on Russian paper in oil capacitors? 

Is there any reason to use them other than their rugged good looks? Are they "as good" as an Orange Drop in guitar amps?


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## Granny Gremlin (Jun 3, 2016)

unpopular opinion: snake oil.

PIO caps are old and have all inevitably degraded by now; they leak (messy) and the value drifts over time (their tolerance was shit to begin with).

Also they are larger than they need to be (first off bc old tech, second because they are usually designed for much higher voltage handling than is required in a guitar - e.g. the caps in a pedal are usually 63v box films.... even an orange drop is overkill at 400-600 volts, but at least you can get new production relatively cheaply).

Lastly, since tone caps are used to bleed treble to ground, they are not actually in the signal path at all, so ....

A quality modern prod (5% tolerance) polyester or polypropylene cap (like orange drops, but there are other more appropriate for guitar brands/sizes) will do fine and you won't hear a difference in a blind test (I think it was @jbealsmusic who posted such a test a year or 2 ago). Just don't use electrolytics (or tantalums) or ceramic disc types and that's about as good as it gets.

Now if you are going to get Orange Drops (or Mallorys) don't get them on ebay - fakes abound (could be the same, or could be something else, in terms of dialectic type used, entirely; tolerance could also be abysmal).


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## DavidP (Mar 7, 2006)

What GG said... Get a DMM that measures capacitance -- value matters more than material IMHO...
Ok, now that I've contributed my $.02 CAD, I'm making some popcorn and sit back to watch this one unfold!


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## knight_yyz (Mar 14, 2015)

Post edited, I thought we were talking about pot caps....


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## KapnKrunch (Jul 13, 2016)

Gar Gillies wouldn't use them. 😛


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## DavidP (Mar 7, 2006)

My comments generally apply to amp caps as well. 
Also, there are a lot of different versions of 'Orange Drops' made by CDE (formerly SBE/Sprague) out there (225P, 715P, 716P), as well as generics... 
FWIW, I like the 225P the best of the 'brand' ODs, but prefer Mallory M150s or MojoTone Dijon for amp coupling caps. Honestly, there's not a huge difference among them to my ears.
Again, popcorn ready!!


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## Latole (Aug 11, 2020)

For same value, cap material make a difference. Can you always hear it ? 
I never have a chance to use PIO cap


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## Lincoln (Jun 2, 2008)

knight_yyz said:


> Post edited, I thought we were talking about pot caps....


I've noticed you use a lot of them in your guitar wiring kits. I'd like to hear what you have to say about it. If a capacitor type is going to make a difference, I think inside a guitar would be the place.


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## Latole (Aug 11, 2020)

More difference in a amp than a guitar.


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## nonreverb (Sep 19, 2006)

In the end, the speaker has the final word. 😁


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## gtone (Nov 1, 2009)

I inherited a large number of old Black Beauties and Bumblebees, but let me tell ya, there's a lot of duds in that lot. For those seeking PIO caps, I'd imagine you might have better luck with later production yrs of Russian caps than those old Spragues from the 50's/60's. I could be wrong though as I don't have much experience in this subject other than selecting caps for own instrument acquisitions and builds.


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## Latole (Aug 11, 2020)

nonreverb said:


> In the end, the speaker has the final word. 😁



100% right


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## dtsaudio (Apr 15, 2009)

Those Russian PIO caps are all the rage over Audio Asylum (simply cause they're cheap). I've seen a few stereo tube amps with them, and that was almost always the problem. Either leaking or shorted. At best off spec by 20%. They don't like being run near their voltage limit either. Whatever the rating, cut it in half.
If you must use PIO, then buy newer ones, but i usually avoid that particular cap technology.
Mostly junk.
For the record, I don't like Orange Drops either, but for other reasons.


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## greco (Jul 15, 2007)

dtsaudio said:


> I don't like Orange Drops either, but for other reasons.


Overpriced? (just a guess)


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## nonreverb (Sep 19, 2006)

I lump PIO caps in with old wax caps. Old, outdated technology that's ripe for replacement whenever I see them.


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## knight_yyz (Mar 14, 2015)

Lincoln said:


> I've noticed you use a lot of them in your guitar wiring kits. I'd like to hear what you have to say about it. If a capacitor type is going to make a difference, I think inside a guitar would be the place.


Honestly, the only reason I use them in my harnesses is I have a ton of them. They cost almost nothing compared to an orange drop at 6 bucks for a 200v cap rated at .022 or .047. And the odd values are easier to find. I'm not sure where to find say a .006uf orange drop rated at 100 or 200v. In a guitar it doesn't matter what you use as long as it s not a metal can. But I have found that 90% of the people who contact me for a harness want something other than the 20 cent panasonic chicklet in their guitar even though it dos the exact same thing as any cap will do. It feeds the highs to ground and that's it. I will put any cap you want in a harness but I tell all my potential customers the exact same thing. If you want an a pair of orange drops you have to add 25 bucks to the price because that is how much it costs to ship a pair from next gen. The only thing that is important about your cap is the value you choose. How much of the highs do you want to cut off with the tone at 0. A .033 will have a more gradual roll off than a .047 and sound a lot better at 0 as well.


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## dtsaudio (Apr 15, 2009)

greco said:


> Overpriced? (just a guess)


Price is part of it, but size, tolerance, materials used, specifications are all bettered by more modern capacitors. Some at much lower prices.
These aren't the most expensive capacitors I've ever used though.


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## Markus 1 (Feb 1, 2019)

Latole said:


> For same value, cap material make a difference. Can you always hear it ?
> I never have a chance to use PIO cap



I have used Polystyrene caps and compared them with ceramic in amps. Especially in signal circuits for coupling purposes. There is a difference. (Just one example)
I have no idea how old the Russian PIO is and how it held up. Try it- and keep a modern alternative handy- my 2 cents


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## Markus 1 (Feb 1, 2019)

knight_yyz said:


> Honestly, the only reason I use them in my harnesses is I have a ton of them. They cost almost nothing compared to an orange drop at 6 bucks for a 200v cap rated at .022 or .047. And the odd values are easier to find. I'm not sure where to find say a .006uf orange drop rated at 100 or 200v. In a guitar it doesn't matter what you use as long as it s not a metal can. But I have found that 90% of the people who contact me for a harness want something other than the 20 cent panasonic chicklet in their guitar even though it dos the exact same thing as any cap will do. It feeds the highs to ground and that's it. I will put any cap you want in a harness but I tell all my potential customers the exact same thing. If you want an a pair of orange drops you have to add 25 bucks to the price because that is how much it costs to ship a pair from next gen. The only thing that is important about your cap is the value you choose. How much of the highs do you want to cut off with the tone at 0. A .033 will have a more gradual roll off than a .047 and sound a lot better at 0 as well.


@knight_yyz , I am curious about this. Honestly
This has been my contention in guitar harnesses as well. If you have a cap feeding signal to ground- how would a high quality PIO or Orange drop for instance, make a difference? I say it won't make any difference- correct? 
I'm sincerely asking


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## knight_yyz (Mar 14, 2015)

It makes absolutely no difference. Aesthetics is the only reason, In a guitar. I'm sure it makes a huge difference in an amp. The only expensive cap I would buy is if I had a 50s LP and it didn't have a stock bumblebee. But again, not for tone, for historical accuracy. 

And you can tell customers until you are blue in the face, but hype says put an orange drop, or a vitamin q, or a tropical fish... 

On another note there is an ebay seller selling Nos tropical fish @.022 for about 2.50 each if you buy a sealed 10pack.


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## Markus 1 (Feb 1, 2019)

knight_yyz said:


> It makes absolutely no difference. Aesthetics is the only reason, In a guitar. I'm sure it makes a huge difference in an amp. The only expensive cap I would buy is if I had a 50s LP and it didn't have a stock bumblebee. But again, not for tone, for historical accuracy.
> 
> And you can tell customers until you are blue in the face, but hype says put an orange drop, or a vitamin q, or a tropical fish...
> 
> On another note there is an ebay seller selling Nos tropical fish @.022 for about 2.50 each if you buy a sealed 10pack.


Thanks for this.
Agreed, in _amp_ circuits it makes a difference when signal toward output flows through. That said, not necessarily always better or worse, instead just different. 
Ceramic caps are a bit grittier for instance in a treble boost application, whereas a polystyrene cap may be more hi fi. Those green japanese poly caps actually sound great ( neutral to my ears) if you can get them in a 400 volt rating.
I hear more difference with caps BTW, than between resistor types 

I find this stuff fascinating 
Markus


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## Granny Gremlin (Jun 3, 2016)

Lincoln said:


> I've noticed you use a lot of them in your guitar wiring kits. I'd like to hear what you have to say about it. If a capacitor type is going to make a difference, I think inside a guitar would be the place.


No - guitar tone caps are NOT in the signal path. A coupling cap in an amp is in the signal path.



Markus 1 said:


> I have used Polystyrene caps and compared them with ceramic in amps. Especially in signal circuits for coupling purposes. There is a difference. (Just one example)


Polystyrene has its fans (me included) but are expensive and only good for small values; not sure if they're easy to find in the guitar tone cap range (too $ for something not in the signal path so never even thought to look) but maybe. Also usually overkill for voltage handling. I have used them in pedals, and IIRC an amp tone circuit.

ANYTHING sounds better than ceramic disc. That's the shittiest of the shit - replace those with whatever else anywhere you find them (which includes guitar tone circuits - usually cheap/offbrand imports from the 70s/80s). One reason is that the value drifts (often a lot) with temperature as well as voltage (in addition to time in general) - as the amp warms up it changes value. In pedals for super small value caps (picofarad range where you often see ceramics in vintage pedals - even back then they avoided them when they could) I will use (among other things) MLCCs (multilayer ceramic capacitors) but only ones with C0G or NP0 dielectric - the other (cheaper) types have the same temp/voltage drift issues as cheap ceramic discs. Def only buy these from a proper shop (Digikey etc) where you can be sure what the dialectric is because they provide a spec sheet.


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## GuitarPix (Jan 11, 2007)

Sent from my iPhone using Tapatalk


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## jb welder (Sep 14, 2010)

Not trying to stir things up but a couple things should be mentioned (I'm not one who fusses over cap types).
The 'not in the signal path' is a bit of semantics. A tone cap provides a signal path to ground for highs. If it makes a difference for amps, it should also make a difference in guitars. Maybe the extent of the impact is not as much, but it is not like 'apples and oranges'. More like 'what's good for the goose should be good for the gander as well'? 
If the type of cap can affect how signal flows through it in series, then it also can affect how signal flows through it to ground. And those highs are then removed from the main signal.

If we are talking about voltage dependant coefficients, that is a valid point, but there are other coefficients that have to be considered also.


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## knight_yyz (Mar 14, 2015)

It won't make a difference for guitars... See if I can make it more clear. Let's say a cap takes 10 percent of your signal at value X capacitor. (instead of saying the highs. Pretend that the highs constitute 10 percent of your signal) In an amp 100 percent of the signal goes through the cap to next component. In a guitar harness that "10 percent" is redirected to the material inside the pot which is grounded, while the original 90 percent goes to the next component in the chain. So the main part of your sound does not travel through the cap... Only the highs go through the cap. So your signal is not flavoured, but it is altered


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## Markus 1 (Feb 1, 2019)

jb welder said:


> Not trying to stir things up but a couple things should be mentioned (I'm not one who fusses over cap types).
> The 'not in the signal path' is a bit of semantics. A tone cap provides a signal path to ground for highs. If it makes a difference for amps, it should also make a difference in guitars. Maybe the extent of the impact is not as much, but it is not like 'apples and oranges'. More like 'what's good for the goose should be good for the gander as well'?
> If the type of cap can affect how signal flows through it in series, then it also can affect how signal flows through it to ground. And those highs are then removed from the main signal.
> 
> If we are talking about voltage dependant coefficients, that is a valid point, but there are other coefficients that have to be considered also.


I have heard the argument above, and frankly because I tend to err on the side of "I can always learn", I keep asking opinions.
I have not tried this in the amps I've built but maybe next time for any tone stack caps to ground I should put my money where my mouth is and a/b cheap caps vs the exotic stuff. Then just listen.

I strongly suspect that where anything goes to ground the effect will be negligible. Because what goes through the cap by design never shows up in the signal chain downstream

As always, I'm more interested in being convinced than being right

Markus


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## jb welder (Sep 14, 2010)

Markus 1 said:


> I strongly suspect that where anything goes to ground the effect will be negligible. Because what goes through the cap by design never shows up in the signal chain downstream


It never shows up, but it is removed from the signal. So if there are indeed differences, you should have more or less of the highs affected.
I personally don't think the difference is significant enough in either guitars or amps to worry about. But all I'm saying is whatever you believe for one, must also be true for the other. Maybe not to the same degree, but the same electronic principles apply to both scenarios.


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## Paul Running (Apr 12, 2020)

Markus 1 said:


> I have not tried this in the amps I've built but maybe next time for any tone stack caps to ground I should put my money where my mouth is and a/b cheap caps vs the exotic stuff. Then just listen.


A good experiment. Also, if you probe around with your scope, you will be amazed at the attenuation at different frequencies, they are level controls for specific frequencies...bypass the complete tone stack and listen to the sound level, with a certain design and selection of components, you can build an amp with very few capacitors and obtain the sound you wish. The simple-design amps provide raw sounds and this is where your fingers on the fretboard and other hand have a lot to play with...tone controls are restrictive circuits.


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## Markus 1 (Feb 1, 2019)

Paul Running said:


> A good experiment. Also, if you probe around with your scope, you will be amazed at the attenuation at different frequencies, they are level controls for specific frequencies...bypass the complete tone stack and listen to the sound level, with a certain design and selection of components, you can build an amp with very few capacitors and obtain the sound you wish. The simple-design amps provide raw sounds and this is where your fingers on the fretboard and other hand have a lot to play with...tone controls are restrictive circuits.



Precisely why I have built numerous Trainwreck clones. 
Very little in the circuit. Quite minimalistic. 
Of course that causes a level of unforgivingness to the player. My playing is not really up to that level. But what the hell. I can, so I do

Cheers 
Markus


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## greco (Jul 15, 2007)

Paul Running said:


> A good experiment. Also, if you probe around with your scope, you will be amazed at the attenuation at different frequencies, they are level controls for specific frequencies...bypass the complete tone stack and listen to the sound level, with a certain design and selection of components, you can build an amp with very few capacitors and obtain the sound you wish. *The simple-design amps provide raw sounds and this is where your fingers on the fretboard and other hand have a lot to play with.*..tone controls are restrictive circuits.





Markus 1 said:


> Precisely why I have built numerous Trainwreck clones.
> *Very little in the circuit. Quite minimalistic.*
> Of course that causes a level of unforgivingness to the player. My playing is not really up to that level. But what the hell. I can, so I do
> Cheers
> Markus


This really fascinates me. Thanks for the posts.


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## nonreverb (Sep 19, 2006)

jb welder said:


> Not trying to stir things up but a couple things should be mentioned (I'm not one who fusses over cap types).
> The 'not in the signal path' is a bit of semantics. A tone cap provides a signal path to ground for highs. If it makes a difference for amps, it should also make a difference in guitars. Maybe the extent of the impact is not as much, but it is not like 'apples and oranges'. More like 'what's good for the goose should be good for the gander as well'?
> If the type of cap can affect how signal flows through it in series, then it also can affect how signal flows through it to ground. And those highs are then removed from the main signal.
> 
> If we are talking about voltage dependant coefficients, that is a valid point, but there are other coefficients that have to be considered also.


+1...I sometimes feel the cap type/brand debate is akin to the tube debate (let the flaming begin). That said, my concern with any coupling caps is leakage, drift related to temperature coefficients and also loose tolerances which are ultimately component quality considerations. As previously posted here, there are plenty of options if you know what you're looking for.


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## Frenchy99 (Oct 15, 2016)

I say these vintage caps are the best for guitar or amps !


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