[Escott1377]

I just bought a new tube based piece of equipment over the weekend.

Aside from upgrading the tubes, I have been reading about upgrading capacitors.

I have been using the Jupiter Condenser site as a guide for budget pricing, but as you can see from the attached, none of the values match.  Also, I am assuming the values not shown in pico farad are micro farad and these are extremely high when converted to the smaller pico.

Also, should I match all caps from the same source, mix them up on input / output?  I have never gone down this road and any help is greatly appreciated.

[sfox7076]

You should use microfarad as most caps are sold that way.  Is this vintage tube gear or new?  What caps are in it now?  I am going to say vintage based on a 25 volt cap.  That's not a common value these days.  You can always go up in voltage.  I then try to be within 5-10% of the original uf rating on a cap if I am replacing it.  Also, well this is me, I would not recap anything in the power supply unless it was old.  I would just stick to things in the signal path.

[Escott1377]

What am I looking at here as the division on the farad?  I am trying to convert the mico farad so I can price.

Thanks.

http://jupitercondenser.com/product/round-beeswax-audio-capacitor/

[sfox7076]

It will be much easier to discuss if you send me the name of what you bought or a schematic.  And this is a good conversion tool: http://www.convertunits.com/from/microfarad/to/picofarad  But you look to be dealing with power supply caps if it is 8200uf...

[randytsuch]

What am I looking at here as the division on the farad?  I am trying to convert the mico farad so I can price.

Thanks.

http://jupitercondenser.com/product/round-beeswax-audio-capacitor/

You don't need to convert.
The 220pf is smaller than anything in the Jupiter list.

And you will NEVER see a 220pf cap listed in uf.

Off the top of my head, 1 pf is 0.000001 uf

EDIT:  Also, the lower voltage, larger value caps are electrolytics, you won't find Jupiter or any film cap equivalent.  You can upgrade to a better electrolytic for those.

Randy

[sfox7076]

I agree Randy, but the list is confusing so I was trying to make sure that the data is all right.  8200uf at 10v is an oddish value (not the 8200uf, but the 10v).  Clearly an electrolytic cap and likely in the power supply.  Nichicon has those in the 50-100v range you can buy and use, but I am not sure it would need an upgrade.  But, well, I would like to know more before having a discussion. 

[Escott1377]

Built from a kit, so I really do not feel comfortable sharing the schematic.

From what I can tell, these are the caps in the signal chain...

1.0mf, 250 V x 2
220pf, 500V x 2
1000mf, 35V x 2
1000mf, 35V x 2
0.1mf, 400V x 2
0.1 mf, 250V x 2
100mf, 160V x 2
3.3mf, 250V x2

This is a pre amp using 2 x 12AU7's and 2 x 300B's.

Thanks!

[richidoo]

With an electrolytic cap, it is safe to swap in a higher voltage rating. The only issue is that the higher voltage rated cap might have larger size can and (wider lead spacing) than the original cap. So make sure bigger cap will fit your PCB.

pF value caps are often used to stabilize circuits to prevent very high frequency oscillation. They are rarely "in" the signal path alone, often paralleling a resistor that is in the signal path to form a filter or provide damping. Their affect on sound quality in audio band is much less significant than larger caps, imo.

Also, in your last post you mixed up mF and uF. mF = millifarad, uF= microfarad, 1000uF = 1mF. mF is often used to describe large storage caps, like your 8200uF cap could be called 8.2mF.

Rich

Edit: You can mix and match from different brands, types etc. Some mfgs make power supplies with film caps. Some vintage speaker mfgs used electrolytic caps in crossovers. As long as the voltage rating is adequate for the signal, you can use whatever you want. Film usually sound a little more refined than electrolitics, but not always. Electrolytics have  a lifespan, films last forever if voltage rating is not exceeded. blablabla... you'll pick it up. Welcome to DIY!

[randytsuch]

I agree Randy, but the list is confusing so I was trying to make sure that the data is all right.  8200uf at 10v is an oddish value (not the 8200uf, but the 10v).  Clearly an electrolytic cap and likely in the power supply.  Nichicon has those in the 50-100v range you can buy and use, but I am not sure it would need an upgrade.  But, well, I would like to know more before having a discussion.

My guess is that the 8200uf 10v cap is for the heater circuit.  Heaters are usually 5-6v from what I remember.  A large value, low voltage cap would make sense to me for the heater.

BTW, for heaters, you also need to worry about the ripple current rating of the cap, depending on how much current the heaters use.  I was building a dht amp at some point, but never finished .  DHTs pull significant heater current, so it was a factor there.

Also, I agree there is not enough information here to provide good guidance. 

Randy

[avahifi]

My suggestion when starting "capacitor rolling" is to first buy a low cost capacitor meter, or a multimeter with a useful capacitor measurement function built in.

Then note that the value of a capacitor IS NOT THE VALUE PRINTED ON THE CASE!!!

The value is what it actually measures.  The actual value should measure within the plus or minus range of the value printed on the case, within its rated tolerance limits, but this does not always happen.

If you (for example) replace a 10 percent tolerance 10 microfarad capacitor with another supposedly identical value capacitor of the same tolerance, you may be replacing an 11 microfarad capacitor with a 9 microfarad one without knowing this.  You have now changed the value by 20 percent.  Depending upon the circuit design function, you may certainly hear this as a musical difference and it will have nothing to do with the "goodness" of the capacitor, just because you changed the value and the "goodness" will just be random.

With a capacitor meter you can replace capacitors in the same circuits of both channels with parts of the same measured values (unless you want a 20 percent difference between your two channels or thereabouts.) 

You can measure the value of the capacitor you are removing and replace it with a new one of the same measured value and then wonder why this did not change the music.  Its no fun at all actually trying to use good engineering practices.

Frank Van Alstine

[Mark Korda]

Hi Escott, go to Google and type in Just Radios. They are a little company that sells resistors and caps for tube people. The main page has a little lesson called Tips an Caps. It even has a beginners tips on ordering. I had the same question you had and viewing what I told you will put you light years ahead of where you are. I ordered caps from them and they couldn't have been nicer. Listen to AVA, Franks the man!.........P.S.  I'm having trouble forwarding with my Windows 8. Thats why you should Google it. You won't regret your effort......take care...Mark Korda

[Speedskater]

And if you are changing types of caps anyplace but in crossovers & signal coupling caps, get a high speed O-scope. Even in power supplies, you may create an oscillator.