What caps should you use to replace filter caps?

[GuitarStv]

The original schematic calls for four 40 uF 450V capacitors. That's what the big silver cans have written on them as well.

Just checking through mouser.com I notice that there's a pretty huge price difference between various 450V electrolytic capacitors.

Like, what makes this capacitor worth 16.20$ vs wiring up two of these in parallel for about 7$? There are ripple current and temperature measurements in the data sheets, but does any of this really matter for an old tube amp or would I just be blowing money getting the more expensive capacitors?

 

[crusty philtrum]

Re: What caps should you use to replace filter caps?

Do you mean the current (no pun intended) configuration is four separate silver cans, or one big one that incorporates four 40uF caps ? Are these big silver cans standing up on the outside of the chasis, like the tubes, or are they inside the chasis ?

Regardless, these caps will be in the power supply. To me, that dictates buying something of a reasonable quality ... not necessarily the most costly, but certainly not the cheapest either.

 

[GuitarStv]

Re: What caps should you use to replace filter caps?

Two silver cans, with two tabs on each . . . the cans are marked 40 uF 450 V for each tab.

I'm trying to determine what tells you that a capacitor is of reasonable quality. Like do you just go entirely by price? What measurements are important for a filter cap in a tube amp?

 

[BrianS.]

Re: What caps should you use to replace filter caps?

Steve,

This guy has what you need: http://hoffmanamps.com/MyStore/perlshop.cgi?action=template&thispage=Capacitors&ORDER_ID=295419005

Edit: 47uf @500v should work for you. Illinois brand

I spoke with a boutique amp builder who's been around a while and he said they use Illinois caps in their builds and they are fine. I've used them, but only once. They are a lot cheaper than Sprague.

 

[GuitarStv]

Re: What caps should you use to replace filter caps?

Steve,

This guy has what you need: http://hoffmanamps.com/MyStore/perlshop.cgi?action=template&thispage=Capacitors&ORDER_ID=295419005

Edit: 47uf @500v should work for you. Illinois brand

I spoke with a boutique amp builder who's been around a while and he said they use Illinois caps in their builds and they are fine. I've used them, but only once. They are a lot cheaper than Sprague.

Any chance that you know what electrical measurements make these Illinois caps more suitable for use in a guitar amp than any other electrolytic? They don't have data sheets up on that site.

Edit - OK, so the Illinois 47/500 caps have a leakage current of 670mA, an operating range of -25 to 105 C, and a 2000 hour working life. That seems to be comparable to any of the cheap 450v caps I can pick up at mouser, no?

 

[BrianS.]

Re: What caps should you use to replace filter caps?

Couldn't tell ya, I just trust the experts...

 

[VanDerchuck]

Re: What caps should you use to replace filter caps?

I find Illinois caps in a lot of amps. I've only used a few for odd sizes. F&T, JJ, Sprague are all quality caps. If your amp has a rectifier tube I wouldn't stray to far old rom the original first cap in the line. Other than that keep the same voltage rating and experiment with them. Have fun and stay safe.

 

[BrianS.]

Re: What caps should you use to replace filter caps?

FYI, here's a pic of an expensive Sprague Atom capacitor that has the insides exposed. The blue can is just a big blue can that holds the actual, much smaller capacitor:

 

[LReese]

Re: What caps should you use to replace filter caps?

I used F&T and TAD in the last 3 I recapped. No issues.

 

[MetalManiac]

Re: What caps should you use to replace filter caps?

All modern caps, even the premium ones are a joke when it comes to being within tolerance. They dont make em the old Mallorys to Mil spec anymore The Spragues actually are designed so that the gasses expand withing the shell, so its not a gimmick.
Filter E-lytics don;lt contribute to tone like other cpacitors in the circuit - the 'tone caps", that are made by Sozo, Jupiter, CDE, Mojo, and others. There are diffrent caps favored for difefrent amps in the tone circuit- usually Mallorys or Mojo Dijon Mustard cap copies for Marshall, and Sprague Orange drops or teh Jupiter Astron copy and Sozo Blue Molded copy for Fender.
Just get IC filter caps . Thats what Peavy uses and they are very trustworthy. No, I'm no expert, but I do like talking about this.

 

[GuitarStv]

Re: What caps should you use to replace filter caps?

I would think that the filter caps have the potential for a pretty huge effect on tone . . . seeing that all the power in your amp goes through them all the time.


So . . . . nobody knows if I should be aiming for a particular ripple current or leakage current amount from the capacitors, or why the expensive caps cost more?

 

[STRATDELUXER97]

Re: What caps should you use to replace filter caps?

All modern caps, even the premium ones are a joke when it comes to being within tolerance. They dont make em the old Mallorys to Mil spec anymore The Spragues actually are designed so that the gasses expand withing the shell, so its not a gimmick.
Filter E-lytics don;lt contribute to tone like other cpacitors in the circuit - the 'tone caps", that are made by Sozo, Jupiter, CDE, Mojo, and others. There are diffrent caps favored for difefrent amps in the tone circuit- usually Mallorys or Mojo Dijon Mustard cap copies for Marshall, and Sprague Orange drops or teh Jupiter Astron copy and Sozo Blue Molded copy for Fender.
Just get IC filter caps . Thats what Peavy uses and they are very trustworthy. No, I'm no expert, but I do like talking about this.

You're still looking at a plus or minus 20% tolerence on can caps...I still like the blue Sprague Atoms in my Fender amps.

 

[STRATDELUXER97]

Re: What caps should you use to replace filter caps?

I would think that the filter caps have the potential for a pretty huge effect on tone . . . seeing that all the power in your amp goes through them all the time.


So . . . . nobody knows if I should be aiming for a particular ripple current or leakage current amount from the capacitors, or why the expensive caps cost more?

They aren't tone caps in a sense(that's what the preamp does)..They filter out the ripple and 60 cycle hum in the power supply.Try to keep the MFD rating at it's stock rating.

 

[Edgecrusher]

Re: What caps should you use to replace filter caps?

All modern caps, even the premium ones are a joke when it comes to being within tolerance. They dont make em the old Mallorys to Mil spec anymore The Spragues actually are designed so that the gasses expand withing the shell, so its not a gimmick.
Filter E-lytics don;lt contribute to tone like other cpacitors in the circuit - the 'tone caps", that are made by Sozo, Jupiter, CDE, Mojo, and others. There are diffrent caps favored for difefrent amps in the tone circuit- usually Mallorys or Mojo Dijon Mustard cap copies for Marshall, and Sprague Orange drops or teh Jupiter Astron copy and Sozo Blue Molded copy for Fender.
Just get IC filter caps . Thats what Peavy uses and they are very trustworthy. No, I'm no expert, but I do like talking about this.

Mil spec doesnt mean what you think it does. Its just a specification it can be tight on some things or pretty damn loose on others. If you look at what the military demands for electronic parts there is a range of consistency that is called for. Ruggedness is usually prized over consistency most military electronics arent so sensitive that caps that are within a 20 percent range arent acceptable.

You would be scared of most military firearms if you knew what the "Mil Spec" tolerances on head space and throat erosion are.

 

[zzmoore]

Re: What caps should you use to replace filter caps?

The caps you linked to are fine.
Illinois
Xicon
Panasonic
F&T
Nichicon
etc etc
They are all perfectly fine for our purpose.
Just be aware you are buying Radials...nothing wrong with that, as long as the configuration works for you.
What amp is this.?
best