Got a vintage Marshall? Change those can caps!

R

Racerxrated

Well-known member
I've always avoided changing the filter caps in older Marshalls, simply because the amps have always sounded good to great and the caps haven't been leaking, or bulging. No need, it ain't broke so why fix?
Well, recently I grabbed an 87 2210, I had a magical 2205 a few years back and have regretted selling it. Looking to find another, this 2210 is clean and came with nice vintage Siemens 34s and Telefunken pres. Under 1K, and it sounds really good. Surprisingly takes boost pedals well, which other channel switchers haven't. Really screams at volume...but sometimes it wouldn't sound as good as the day before. Thought it was my power, so I plugged straight to the wall instead of my power strip. Still had that inconsistent thing going. Caps looked good, original LCRs...but I thought why not, I'll buy 3 ARS can caps and change them out. I can always put the LCRs back in. It's only 35 bucks and some of my time. Well hot damn. Changed them out and it is a freakin monster now. Easily as good or better than ANY 2203 I've had, and I've had plenty from 78-88. I wonder how great those older Marshalls could have sounded if I would have changed them also.
If you have an older Marshall, consider changing those filter caps. The tone is the same but the thump it has is almost twice what it was. More articulation, and the Bass is tighter too.
:rock:
 
Do you think these caps would work just as well in a iic+, vintage black face, Wizard or any amp really? I haven’t really thought much about caps before
 
braintheory":2mlq96nk said:
Do you think these caps would work just as well in a iic+, vintage black face, Wizard or any amp really? I haven’t really thought much about caps before
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As long as you're using caps of the same voltage (or higher) and capacitance, you can use whatever brand you want. ARS are good caps, though. I like them more than F&T, JJ, etc. However modern snap-in and PCB mount caps are definitely better spec-wise. I just wish companies making these caps would make multi-section cans. Sadly, nobody uses those anymore except for tube audio.
 
You need to form caps before putting them in amps...or at least you should. Bringing the voltage up slowly.

I’ve changed caps in an amp only for the amp to sound like absolute shit. I was smart enough to mark the old caps and was able to put them back in. The amp was sold a little while after for fear of the originals not lasting much longer. Thing is, it was a friends amp and he was floored how bad the amp sounded with the new caps. For reference, the new caps were F&T 50/50 typical blue ones.
 
It shouldn't be necessary to form new electrolytic unless they've been sitting on a shelf for years.
If you buy direct from ARS, you can ask for date of manufacturer based on the batch number.

Doesn't hurt to form them. But it's a waste of time IMO. I don't think any major amp companies bother, it would take too long to slowly form filter caps for 24 hours on thousands and thousands of amps... I dunno... maybe big companies have a device that pre-forms all their caps before they're installed? I know caps are pre-formed during the manufacturing process. So why form them again if they're new and fresh?
 
FourT6and2":17b8f3ke said:
It shouldn't be necessary to form new electrolytic unless they've been sitting on a shelf for years.
If you buy direct from ARS, you can ask for date of manufacturer based on the batch number.

Doesn't hurt to form them. But it's a waste of time IMO. I don't think any major amp companies bother, it would take too long to slowly form filter caps for 24 hours on thousands and thousands of amps... I dunno... maybe big companies have a device that pre-forms all their caps before they're installed? I know caps are pre-formed during the manufacturing process. So why form them again if they're new and fresh?
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I have no way to check and don’t like to rely on chance when it’s pretty easy to do for my own projects. Just my way of thinking. :)
 
psychodave":e2xnx7e9 said:
You need to form caps before putting them in amps...or at least you should. Bringing the voltage up slowly.

I’ve changed caps in an amp only for the amp to sound like absolute shit. I was smart enough to mark the old caps and was able to put them back in. The amp was sold a little while after for fear of the originals not lasting much longer. Thing is, it was a friends amp and he was floored how bad the amp sounded with the new caps. For reference, the new caps were F&T 50/50 typical blue ones.
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I bought these ARS from Valvestorm, they advertise as formed and ready to go. The date is etched on the plastic top of the cap, these are from last year. The only change in tone was for the better, as it has a bit more clarity but a lot more punch. Which after reading about cap changes, I was hoping for or at least some consistency in the day to day tone.
 
braintheory":tmyjelzt said:
Do you think these caps would work just as well in a iic+, vintage black face, Wizard or any amp really? I haven’t really thought much about caps before
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It's my first cap change, I'd only do it if the original caps are 15 yrs old or more, or show signs of drying like leaks or bulging. The stock LCRs had neither but thought I'd give it a shot, worse thing is I'd just put the old ones back in. It shouldn't change the tone but will increase the punch and tighten the bass. I did have an older Jubilee that had new F&T caps, that amp had a grainy nature to the tone that I'd never heard out of a Jubilee before, and I've owned a bunch. Not bad but not the normal smooth nature of the Jubilee tone that I'd been used to. I've read that ARS are the most similar to the LCRs that came stock in vintage 800s. I agree.
 
As long a you play the amps regularly the electrolyte can remain good for many years well into the 15 to 30 year or more range longevity is affected many factors including luck. Keep an eye on them and listen for signs of 60 cycle hum or ghosting and/or bulging as stated above.

I agree with Racer the ARS are the best caps that seem as well built as LCR's, The Black CE ones made in Taiwan are pretty good too and are well made I would say equal to the ARS but they are bit shorter..

The caps the tend to go bad more often are your Bias Supply 8uf/10uf caps. If they have 15-30 years you might want to change them. They make a mess when they go.
 
harddriver":1zjpfnwu said:
As long a you play the amps regularly the electrolyte can remain good for many years well into the 15 to 30 year or more range longevity is affected many factors including luck. Keep an eye on them and listen for signs of 60 cycle hum or ghosting and/or bulging as stated above.

I agree with Racer the ARS are the best caps that seem as well built as LCR's, The Black CE ones made in Taiwan are pretty good too and are well made I would say equal to the ARS but they are bit shorter..

The caps the tend to go bad more often are your Bias Supply 8uf/10uf caps. If they have 15-30 years you might want to change them. They make a mess when they go.
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I'd bet that my 2210 sat for a while, when I first fired it up it didn't sound very good. Checked the bias and the tubes were a little hot but not too bad, put the amp back together and fired it up and let it sit for a bit warming up. Sounded much better after. I wonder if it was a closet queen for a time. I'd bet those caps were drying up.
 
Hmmmmm. I have a 78 2204 and a '71 Superlead that have the original caps - both amps sound damn good, and the caps show no sign of bulging, etc.

Maybe I'll give it a try.
 
reverymike":3amorxm3 said:
Hmmmmm. I have a 78 2204 and a '71 Superlead that have the original caps - both amps sound damn good, and the caps show no sign of bulging, etc.

Maybe I'll give it a try.
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I'd leave them be.
If you're not noticing a detrimental change, they're good.
 
I have never regretted changing the electrolytic caps. I also use a variac to bring up the voltage on them slowly as Psychodave mentioned.

For any amp that is built in the 70's or before I change electrolytic caps if they are original. For 80's amps, its where I recommend, but do not insist. I recently changed the large electrolytic caps on my 2553 Silver jubilee, I did not change the small Electrolytic caps on the board. I didn't really notice a difference in performance, but I figured it was time.

My 1990 Mesa Mark IVA is about due for a cap job and I am not looking forward to doing the caps on that amp, as its going to be a pain. The Marshall's are super easy, at least for the large caps in the power supply.
 
Glad to hear you benefitted from the change!

I had a bad experience with a can cap change to a JMP 100 watter.. didn't need the change at all as there was nothing wrong with the caps (1980jmp). If a tech checks the caps to make sure they are operating according to spec there is no need to change them- this takes the guess work of merely eyeballing for bulges etc out of the equation.
 
psychodave":afoyme6j said:
You need to form caps before putting them in amps...or at least you should. Bringing the voltage up slowly.

I’ve changed caps in an amp only for the amp to sound like absolute shit. I was smart enough to mark the old caps and was able to put them back in. The amp was sold a little while after for fear of the originals not lasting much longer. Thing is, it was a friends amp and he was floored how bad the amp sounded with the new caps. For reference, the new caps were F&T 50/50 typical blue ones.
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Dave no need to form new caps. This is only necessary on NOS

Also F&T caps don't sound that great in the first place, that's probably why the amp sounded bad.

But yes, you might change caps and like the way it sounded better with the originals. It's a crapshoot. Best to mark, and save them like you said.
 
blackba":38wdi8na said:
I have never regretted changing the electrolytic caps. I also use a variac to bring up the voltage on them slowly as Psychodave mentioned.
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That isn't how you (properly) form filter caps.

For 100-watt Marshall, you need to remove all tubes, run a resistor between the rectifier and the first filter cap, remove the bleeder resistors, and unsolder the center tap from the PT secondary. Then monitor the voltage drop across the resistor over the course of 24 hours until the voltage drop is reduced to 5v or so. Then the caps are formed and you can hook everything back up the way it was.

Using a variac limits the voltage to the entire amp. That isn't what you want to do to form caps. You need full voltage but have to limit current. That's why a resistor works better.
 
I recapped my '78 100w NMV last weekend with F&Ts and Sprague Atom for the bias caps. It still had the original Dalys and they were long in the tooth. Amp sounds fantastic now and I can play it loud without worry. I've used F&Ts for all my recap jobs or clone builds. They sound fine to me.
 
lespaul6":k7xsvg12 said:
Glad to hear you benefitted from the change!

I had a bad experience with a can cap change to a JMP 100 watter.. didn't need the change at all as there was nothing wrong with the caps (1980jmp). If a tech checks the caps to make sure they are operating according to spec there is no need to change them- this takes the guess work of merely eyeballing for bulges etc out of the equation.
Click to expand...
It really did add some oomph to the output and tightened the low end. I've never bothered to do this before, and was prepared to put the originals back in if it sounded worse. I've read about that happening before. If it sounded worse, then I'm out 30 bucks.
 
reverymike":2qo6cvuh said:
Hmmmmm. I have a 78 2204 and a '71 Superlead that have the original caps - both amps sound damn good, and the caps show no sign of bulging, etc.

Maybe I'll give it a try.
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One thing I noticed about the LCRs I pulled, there is a small bulge in the middle of the bottom of 2 caps. Definitely a tell. Have to look closely though, I didn't even see them when I pulled the caps out.
 
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