why replace capacotors?I

[cheeseface]

I've heard people discussing "recapping" thier amps. [relacing capacitors]
-What is the benifit if the thing seems to be working fine?
-How frequently should this be done?
-Do capcitors degenerate from amount of use or is it simply a matter of the passage of time?
I have and use a Traynor mono block B solid state bass amp, about 30 years old or more. Works good, but I'm all for optimising sound and performance.
would a recap benafit me?

 

[krankguitarist]

Re: why replace capacotors?I

Re-caps need to be done every 10 or 15 years or so on a tube amp's power section. Electrolytic capacitors tend to dry up over time, and especially when you got a lot of energy runnin though em, they can be a bit of a hazard when they get to be too old.

Some people will argue for or against re-capping the other electrlyics throughout the amp, but the important part is those filter caps. If one of those goes bad, your amp can be in for a world of troubles. I'm not sure how important re-caps are on solid state amps though, one of the more knowledgeable electronics gurus on here might be able to answer that one for ya.

 

[Rich_S]

Re: why replace capacotors?I

Well, one reason is it can improve the tone, tighten up the amp, remove noise and ghost notes. Electrolytic caps degrade over time, and replacing them can put the amp back where it should be.

The other reason is that when they do finally fail, it ain't pretty. It involves sizzling sounds, smoke, fire, a really really bad smell, and maybe other components getting burned up. Best to recap before it comes to that.

 

[Fresh_Start]

Re: why replace capacotors?I

One weird part of the answer to your question is that electrolytic capacitors degrade more the less they are used. IOW an amp that gets played every day runs less risk of electrolytics going bad than an amp which has been stashed in a closet for 10 years.

In tube amps, these caps are used as part of the power filtering ("power rail") and to shape the frequency response of preamp stages as cathode bypass caps. An old electrolytic may not be a danger in terms of catastrophic failure but may have drifted +50% or more in value. It may not make any difference in your particular circuit, but a cap which was 25uf when new may be 38uf or more after 30 years. That can make a noticeable difference in a tube amp's tone.

This probably doesn't apply to your solid state Traynor, but looking at the schematic might help.

Chip

 

[WhoFan]

Re: why replace capacotors?I

my 1982 Marshall is making distorted farting noises.... and not the good kind either... i assume it needs recaping.... one tech i spoke to wants to do a slight EQ mod to it and i assume it's caps he is changing... he said it will make the EQ controlls have a much wider range

 

[Gr8Scott]

Re: why replace capacotors?I

my 1982 Marshall is making distorted farting noises.... and not the good kind either... i assume it needs recaping.... one tech i spoke to wants to do a slight EQ mod to it and i assume it's caps he is changing... he said it will make the EQ controlls have a much wider range

Is the tech planning on doing a complete cap job including the filter caps or just the EQ caps? The EQ caps are not likely to be electrolytic IIRC. Changing them out won't cure the farty noises. New tubes and a new set of filter caps would do wonders I'll bet.