Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Bantam on April 24, 2020, 01:40:07 pm
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I want to replace the originals in my bantam Bass. I know the values aren't exact and possibly even more so with the Illinois, but in my experiences with older/other amps I'm not that fond of 50uf (2x100 in series) in power supplies like when I've had to change over in super reverbs. Considering in-Rush it doesn't seem like the two at 700 volts is a bad idea, but it seems like I'm only left with 32 at 500. Am I missing something or is there somewhere besides here to order from that would get me closer. I just looked again and maybe I should just do the 40 20 20 20 it's only a few dollars more then separates, although then I'm left with either the fast and dirty silicone or another mounting ring for another 3.50, any thoughts/experience would be gladly appreciated. Also thinking of going ef86 on one of the nine pins in there but maybe that's for another post.
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> maybe I should just do the 40 20 20 20
Is that rated 500V on the 40u section? While the working voltage at OT is noted as 400VDC, in Standby it will rise and maybe to over 450V, the usual limit on e-caps. A 10 minute beer-break at 460V won't kill a 450V cap, but if you stand-by for an hour of speeches/toasts it may poof by the time you need to play again. Yes, there are 500V caps suitable but I have not been shopping recently. (OK, I just shopped and came back with cheesecake....)
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ha, I came back with pizza rolls :icon_biggrin:
seems like I'm only left with 32 at 500. Am I missing something
32V :dontknow:
My understanding of a Bass amp, PS sag isn't a thing
the rectifier tube has a max cap value it can "feed". I'd find that value to "set" how big caps should be.
anything past those caps can be as big as you want, surf up electrolytic caps 450vdc, should find them from smaller than thumb to bigger than fist
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JJ Electronics, 500V, 40/20/20/20µF seems like a good choice for that amp. Price is right too.
https://www.tubesandmore.com/products/capacitor-jj-electronics-500v-40202020-f-electrolytic
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Very much appreciate the quick replies as I would like to get these ordered and over with sap. Shooter the 32 at 5 I was talking about was 32Uf @ 500 volts that is sold on this site I think it's F+T. PRR, yes it's more than a good chance that the amp can stay on standby 4 a good long time, sure although I could change habits and try to remember to turn it off it's a good chance that doing casuals as I used to do a lot I'd rather not have to think about it. Is it a general consensus that the 500 volt cap would be okay in here, I think I've only been end it once before and I seem to remember the voltage is running 10% higher than the postage schematic. Thinking of running that large cap and by the way Slukey thanks for that link that's a good deal cheaper like $7 I think... I'm on a very tight end of life stipend. In the Spirit of non alteration I was thinking if it came to mounting the large multi-cap maybe keeping it in the doghouse and just adding some spacers to the cover.
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PS cheesecake sounds great and smaller than a thumb and no bigger than the fist wasn't that the old sizing for what you could whack a lady with.... or that wife is no lady or something like that?