Re-capping tube amps

Lynn Kasdorf · Post by **Lynn Kasdorf** » 26 Apr 2002 8:18 am

I'll be restoring a few tubes at some point soon, and could use some advice.

First, for the signal caps. I have a large collection of assorted caps- many sprague orange drops, which I hear are supposed to "sound" good (on the theory that the signal caps contribute to the sound). My question is, will a cap like this degrade in storage? Mine are probably 10 years or more old, and never used.

I really don't care to spend big bux on caps, especially since I have all these NOS ones that I've been hanging on to...

Also- what is the best/cheapest source for new filter caps?

BTW, the amps are (1) ampeg Gemeni II, (2) obscure "Sound" brand bass amp (size of a super reverb, 4 10's), and (3)a Leslie 147 amp

Brad Sarno · Post by **Brad Sarno** » 26 Apr 2002 1:20 pm

Check out www.angela.com for a good tube amp parts supply. They have your filter caps there at a fair price. As far as the orange drops or other signal caps, they last for a long long time. It's the electrolytic filter caps that go bad after 20-30 years. Signal caps dont have the corrosive chemicals that eventually leak and get nasty. Even the old blue signal caps from '60s fender amps are probably still fine to use. However, there are some newer signal caps that sound better.

Also in response to your comment that there is a "theory" that different caps effect your tone. Well it aint no theory at all. Just compare orange drops to the old fender caps. It doesn't take an audiophile to hear the difference, it's quiet obvious. However, some guys like the dark mellow sound of the old caps and think the Orange drops are too bright. For me the orange drops sound great for steel guitar as they really bring out the detail and upper harmonics.

Dont get shocked!

Brad Sarno
Angelfish Studios
St. Louis

Mullen U-12/'69 Fender Twin/Black Widow 15"

Bruce Derr · Post by **Bruce Derr** » 28 Apr 2002 7:07 pm

I have also used Angela.com and they are a great source for amp parts. But my favorite place for filter caps is Mouser Electronics (www.mouser.com). They have the best prices I've seen on the Vishay Sprague Atom electrolytics, which are good replacements for single-section axial-leaded filter caps. If you are looking for multi-section can-type caps, try Antique Electronic Supply (www.tubesandmore.com) or Vibroworld (www.vibroworld.com).

David Ip · Post by **David Ip** » 1 May 2002 7:16 pm

There should be no sound quality degradation at all with a Sprague Orange Drop after 10 years. These type of caps are basically plastic wrapped around two pieces of wire - there's nothing to dry out as with an electrolytic cap, which are basically two wires stuck inside a can of paste.)

However, after ten years, the plastic can become a little brittle, especially where the wires exit the main body of the cap. This introduces the possibility of moisture entering the cap (it's a longshot and will take a long time, but if you're covering all the bases, what the heck!)

Caps can sound different only 'cause they're made differently, and of different materials. You can rapidly enter the hifi tweako obsessive zone, so go with what you've got on hand and trust your ears.

Hope this helps!

Ken Fox · Post by **Ken Fox** » 1 May 2002 8:15 pm

I agree with Bruce. I recap and restore a lot of amps and Mouser can not be beat! For those 135 watt Fender amps, you won't find any caps big enough in the Vishay line. Filter caps (220 mfd) made by Illinois are avaiable from from Mojotone. Call them for best pricing on those caps.

Buck Dilly · Post by **Buck Dilly** » 2 May 2002 7:31 pm

Lynn- I have a sound amp with single 12" that I use for guitar and I love it. I bet the 4/10' model is amazing! I would die to find one. The Sound amp's tremelo is out of this world. A lot like Ampeg.