When to change Filter Capacitors?

[Jofipe]

Alright, so I just got this Friedman KS modded '80 JMP. I'v heard mod ppl talk about changing the filter capacitors on those old Marshalls.
How do you know if they need to be changed? The amp doesnt noise very much, which is a good sign... anything else? Can your overall tone be affected by old filter caps?

I'm super-noob on this technical stuff... sry.

 

[Shask]

They usually say about 15-20 years.

 

[LP Freak]

It's a dead give away if the top of the caps start to have a bubble instead of being flat.

 

[Jofipe]

Alright, thanks allot

What typical audial signs will there be?
Would changing them make the amp sound better/more open ?

 

[LP Freak]

Alright, thanks allot

What typical audial signs will there be?
Would changing them make the amp sound better/more open ?

The amp will get looser over time. Not something that happens over night. If they're bad, you'll definately hear a difference after you change them. If they're over 10 years old it's good to change them as normal maintenance.

 

[Jofipe]

Ok, cool. My Friedman modded JMP 2203 still has the original DALY's. It sounds great tho! But maybe it could even be improved more... My KK++ with brand new filter caps sound a bit more open, maybe thats just the nature of the mod.

Which filter filter caps is suggested for this type of amp?

Thanks again for the answers! Rig-Talk rules.

 

[MississippiMetal]

Depleted tube amp supply capacitors typically present in, as stated before, looser lowend, but also lack of lowend. You would be surprised how an amp can grow its balls back after changing out worn, tired 'lytics. Increased hum is also a common symptom. I've got a box FULL of old LCR's and Daly's I've replaced in old Marshalls.

And let's not forget outright capacitor failure, which can range from inert to catastrophic. Oscillating, pops, etc. Catastrophic failure occurs when the capacitor incurs acute physical breakdown, which can turn it into a firecracker in some cases, and can cause all kinds of hell inside the amp.

 

[LukeCurd]

Ok, cool. My Friedman modded JMP 2203 still has the original DALY's. It sounds great tho! But maybe it could even be improved more... My KK++ with brand new filter caps sound a bit more open, maybe thats just the nature of the mod.

Which filter filter caps is suggested for this type of amp?

Thanks again for the answers! Rig-Talk rules.

F&T and Ruby are some good choices.
50uF+50uF 500V Radial Capacitor

 

[blackba]

I find when exactly to change tubes and when to change caps equally challenging. Its easy for caps when the amp is from the 70's or before.

I probably need to change the electrolytics on Marshall Silver Jubilee (1988) and Mesa mark IVA (1990). Hopefully I can get to that this year.

 

[Jofipe]

Awesome! Cheers for the answers. My amp isnt cracking, popping, have allot of noise and the bottom end isnt floppy either.. at all.

But since it's the originals, I just might try to get the changed.

My amp guys has JJ and F&T. Are these any good?

 

[MississippiMetal]

I would personally go with the F&Ts over the JJ's.

 

[Jofipe]

Awesome!

 

[D-Rock]

My 2001 Soldano needed some changed out last year. One was leaking and a few others were begining to bulge.
Can't speak to the tonal results afterwards, because the amp got new tubes and a proper bias afterwards too so there were too many variables.

 

[MrDan666]

Ok, cool. My Friedman modded JMP 2203 still has the original DALY's. It sounds great tho! But maybe it could even be improved more... My KK++ with brand new filter caps sound a bit more open, maybe thats just the nature of the mod.

The KK++ is definitely a bit more open in the mids compared to Dave Friedman's Mods, so that's probably what you're hearing.

If the Friedman still has the original filter caps in there, you will hear a difference when you replace them. The low end will sound more punchy and tight. Also in my experience, a re-cap will also make the amp sound bigger and wider overall. You really can't go wrong

I used JJ filter caps in your KK++ Mod. You could use JJ's or F&T's or ARS caps. They're all decent choices!

 

[VC4Ever]

Anyone ever change the filter caps on a mesa mark iii? The ones under the board are hard to get at. You need to completely remove the power supply board or something.

 

[charveldan]

Do it and get rid of those shitty ohms plugs too ...

 

[Jofipe]

Ok, cool. My Friedman modded JMP 2203 still has the original DALY's. It sounds great tho! But maybe it could even be improved more... My KK++ with brand new filter caps sound a bit more open, maybe thats just the nature of the mod.

The KK++ is definitely a bit more open in the mids compared to Dave Friedman's Mods, so that's probably what you're hearing.

If the Friedman still has the original filter caps in there, you will hear a difference when you replace them. The low end will sound more punchy and tight. Also in my experience, a re-cap will also make the amp sound bigger and wider overall. You really can't go wrong

I used JJ filter caps in your KK++ Mod. You could use JJ's or F&T's or ARS caps. They're all decent choices!

Great info right there Dan! Yeah, I realized your amp is slightly bigger sounding

Ill go for it then.. cheers!

 

[Jofipe]

Do it and get rid of those shitty ohms plugs too ...

This? http://store.acradiosupplyinc.com/bogentl600.aspx

 

[charveldan]

Do it and get rid of those shitty ohms plugs too ...

This? http://store.acradiosupplyinc.com/bogentl600.aspx

No ... This : https://www.ebay.com/itm/IMPEDANCE-SELEC ... 23223bfa13

It's an easy fix for a good tech, they have to slightly widen the hole.

 

[Anonymous]

Just get a Kemper.

Steve