So I finished rebuilding a Fender Twin and enjoyed it. I bought a chassis and boards from Ceriatone to build a JM 50. Ceriatone lays out their filter caps in the JM out like their SSS, just with different dropping resistor values. 4 pairs of radial caps tied together after the big 220uFs.
The Tone Geek layout appears to be based on pics of a Two-Rock JM, with 4 axial caps after the big 220uFs.
Are there pros and cons using one approach versus the other? I have the Ceriatone power supply board and can build that, but would have no problem drilling holes and putting eyelets in a G10 board to follow the Two-Rock style if that is "better" for some reason.
Filter cap philosophy
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Filter cap philosophy
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Stevem
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Re: Filter cap philosophy
Modern bigger body filters will make for a punchier amp since there slower to sag .
Larger area to store a charge in other words and assuming that the two different filters have the same UF tolerance range as in that + or - thing.
Larger area to store a charge in other words and assuming that the two different filters have the same UF tolerance range as in that + or - thing.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Filter cap philosophy
I think it unnecessary to "over cap" the filters. 100uf is more than enough for a 50-watt tube amp. You could halve that and honestly, it wouldn't make audible difference with a guitar in my experience.
Opinions vary. That's my opinion.
On the physical size, you should look at the cap's spec. Bigger isn't better necessarily. The Sprague Atoms are physically large, but not amazingly great, especially since about 2010 or so when they seemed to change.
Modern radial caps usually are more compact, but have better overall ratings in every important parameter. They're also cheaper.
I'd probably skip axial caps in any new build in favor of good radials.
Opinions vary. That's my opinion.
On the physical size, you should look at the cap's spec. Bigger isn't better necessarily. The Sprague Atoms are physically large, but not amazingly great, especially since about 2010 or so when they seemed to change.
Modern radial caps usually are more compact, but have better overall ratings in every important parameter. They're also cheaper.
I'd probably skip axial caps in any new build in favor of good radials.
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Matthews Guitars
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Re: Filter cap philosophy
The industry is shifting toward radial capacitors as they make better use of limited circuit board space. Keep that in mind when building for future sustainability.
I like axials better. But radials are the future.
I like axials better. But radials are the future.
Re: Filter cap philosophy
During testing of the RI amps, Marshall found caps to be more important than transformers. I think it was Ritchie Flieger who is quoted on this in one of the ampbooks he contributed to.
Anyway, try to compare JJ caps with F&T, BC Vishay, Rifa, Spraque, TAD Audio and Gold caps, LCR, etc, and you should hear and feel a difference, esp. if you change the screens or a lot of caps at the same time.
What works best depends on the application. It is all about finding the right mix
Anyway, try to compare JJ caps with F&T, BC Vishay, Rifa, Spraque, TAD Audio and Gold caps, LCR, etc, and you should hear and feel a difference, esp. if you change the screens or a lot of caps at the same time.
What works best depends on the application. It is all about finding the right mix
Re: Filter cap philosophy
Radials from Nichicon, Rubicon, Panasonic, etc. typically outperform their axial counterparts from Sprague, F&T, MOD, JJ, etc.
Look for life ratings, temp. ratings and ripple current ratings in particular. As far as sound - brown caps sound best....YMMV
cheers,
Look for life ratings, temp. ratings and ripple current ratings in particular. As far as sound - brown caps sound best....YMMV
cheers,
Jack Briggs
Briggs Guitars
Briggs Guitars
Re: Filter cap philosophy
I have noticed the same thing. The larger body caps make for a punchier sound in a good way. Not larger uf rating but just physically larger.
Cheers
Guy
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Snicksound
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Re: Filter cap philosophy
One dirty secret is that some of those larger caps (that they sell mostly as replacement parts for older equipment) are hiding a smaller cap inside...
Re: Filter cap philosophy
Avoid slowly degrading and regularly replacing caps by switching from electrolytics to metalized film caps. They're larger so you may need to be creative in placement in existing builds. For new builds they should be incorporated in the planning process.
Tube junkie that aspires to become a tri-state bidirectional buss driver.
Re: Filter cap philosophy
jabguit wrote: ↑Wed Jun 03, 2026 10:44 am Radials from Nichicon, Rubicon, Panasonic, etc. typically outperform their axial counterparts from Sprague, F&T, MOD, JJ, etc.
Look for life ratings, temp. ratings and ripple current ratings in particular. As far as sound - brown caps sound best....YMMV
cheers,
LOL on the brown.
But yes, absolutely, modern radials are the way to go. Cheaper and better. Easy to pull up the parameterized search list on Digikey or Mouser and so on. Sort on values like ESR, ripple current, hours of life at 105c or 125c.
Kemet offers electrolytic caps (axial oddly enough) with 12,000 hours life at 105 or 125c. That's insane really. It will outlive a couple of generations of owners if it is used regularly.
Re: Filter cap philosophy
Thanks to those that responded. I'm still learning. I read this article....https://www.valvewizard.co.uk/smoothing.html
The article was very helpful but really prompted a lot of my questions because it seems like the Ceriatone layout would not be prompted by concerns about voltage. I could see it being parts availability, parts cost, chassis space or performance. I don't have enough experience to know. I was really trying to figure out if there's a performance benefit of one style versus another. I may be opening a can of worms but are the nichicon UBTs solid for 47uF/450v? (they aren't brown). Any preference on JJ vs F&T for a 50uF/50uF - 500v multisection can?
The article was very helpful but really prompted a lot of my questions because it seems like the Ceriatone layout would not be prompted by concerns about voltage. I could see it being parts availability, parts cost, chassis space or performance. I don't have enough experience to know. I was really trying to figure out if there's a performance benefit of one style versus another. I may be opening a can of worms but are the nichicon UBTs solid for 47uF/450v? (they aren't brown). Any preference on JJ vs F&T for a 50uF/50uF - 500v multisection can?
Re: Filter cap philosophy
The Nichicons are good.
F&T are good, though a bit expensive.
You should be fine with any reasonably good quality capacitor in this circuit that has the necessary voltage rating to withstand the fully-unloaded power supply in your amp. With silicon rectifiers, it's going to hit about 500v when you first turn it on before the tubes warm up and start drawing current. So the first "reservoir" filters and all the downstream capacitors need to be able to withstand that much.
The Ceriatone board does that by putting lower-voltage rated caps in series along with balancing resistors. So you get 2x the voltage withstanding rating, and half the capacitance (with equal value caps in series).
Saves a few bucks and works fine.
I'd just find parts of the same capacitance, and equal or higher voltage rating that fit the holes and don't put a big dent in your wallet. One of the things I've learned over the years is home-built amps are never done. It makes sense to build them up with correct, but cheaper parts and avoid the boutique parts. You can always upgrade them later, if that suits your fancy. But a any decent part is a decent part. Get it up and working, then make revisions later where you find them useful.
F&T are good, though a bit expensive.
You should be fine with any reasonably good quality capacitor in this circuit that has the necessary voltage rating to withstand the fully-unloaded power supply in your amp. With silicon rectifiers, it's going to hit about 500v when you first turn it on before the tubes warm up and start drawing current. So the first "reservoir" filters and all the downstream capacitors need to be able to withstand that much.
The Ceriatone board does that by putting lower-voltage rated caps in series along with balancing resistors. So you get 2x the voltage withstanding rating, and half the capacitance (with equal value caps in series).
Saves a few bucks and works fine.
I'd just find parts of the same capacitance, and equal or higher voltage rating that fit the holes and don't put a big dent in your wallet. One of the things I've learned over the years is home-built amps are never done. It makes sense to build them up with correct, but cheaper parts and avoid the boutique parts. You can always upgrade them later, if that suits your fancy. But a any decent part is a decent part. Get it up and working, then make revisions later where you find them useful.
Re: Filter cap philosophy
They did this specifically to appease vintage amp purists that want to see big ol' blue caps under the doghouse. Madness, but it makes them money.Snicksound wrote: ↑Wed Jun 03, 2026 2:16 pmOne dirty secret is that some of those larger caps (that they sell mostly as replacement parts for older equipment) are hiding a smaller cap inside...
Tube junkie that aspires to become a tri-state bidirectional buss driver.