OTL amplifiers come to mind.
They can use a couple 1000uF easily.
e.g.: The Atma-Sphere M60 has 3 x 1500 uF per phase per mono-block in the P.S.
That is no less than 12 x 1500 uF caps for a complete stereo set.
They can use a couple 1000uF easily.
e.g.: The Atma-Sphere M60 has 3 x 1500 uF per phase per mono-block in the P.S.
That is no less than 12 x 1500 uF caps for a complete stereo set.
actually big caps and tube power traffo can go together well, why? because the impedance of tube power traffos are such that charging currents are not that extreme....but if you choose to go this way, then tube rectifiers are out of the equation....
the VTL 6L6gc pp amps used 1000ufd/300vdc in series....other stateside manufacturers are doing it...
but of course, if you do not understand the implications and the hazards that goes with big caps, then do not do it....simple as that...
as long as the cans are not dented, and the rubbers seals are intact, they should reform well, i have done a lot of reforming in my 40+ years of dealing with caps....
My "super picky" audiophile friend, from a group of Vietnamese "audio nuts" got his Harman Kardon Citation II back the other day.
On another thread, I discussed having to overhaul the amp..
Mind you, it is now powered by an almost stock B+ supply, which I "upped" to 90uF (multi-can of 3x30uF) from the original 40uF.
The bias supply is "upped" to a pair of 100uF, from a pair of 20uF.
No biggie capacitors like 1000uF's involved there..... no obsessive banks of cans like I see in these photos.....
The amp's KT88's run on the "cool side" and only a barely audible-if-you-put-your-ear-against-the-speaker hiss.
His,and his friends, reply to me at a group listening session today..... "simply beautiful!..fantastic job!"
By the way, the speakers used in their "test" were a pair of Altec Lansing Valencia's.
On another thread, I discussed having to overhaul the amp..
Mind you, it is now powered by an almost stock B+ supply, which I "upped" to 90uF (multi-can of 3x30uF) from the original 40uF.
The bias supply is "upped" to a pair of 100uF, from a pair of 20uF.
No biggie capacitors like 1000uF's involved there..... no obsessive banks of cans like I see in these photos.....
The amp's KT88's run on the "cool side" and only a barely audible-if-you-put-your-ear-against-the-speaker hiss.
His,and his friends, reply to me at a group listening session today..... "simply beautiful!..fantastic job!"
By the way, the speakers used in their "test" were a pair of Altec Lansing Valencia's.
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I have to admit I have a pair of 9100 uf 250 volt caps in series for my 845 amp. It has a 1,5 H choke between the 1n4007 rectifiers and the cap. It has been my generic tube amp power supply for quite a few years. The high capacitance is probably not necessary but they were free from a retired UPS.
I was under the impression that 1000u was needed per 1A of current for PSU's, so for a 120w that draws 0.6A at full power I used that much capacitance. An amp sounds better with a hefty PSU on the transients, I'd love access to a box full of these.
Also where they come into their own is when used with high HT ; two or three in a 6/700v PSU or even 10 in series for a 3.5kv sounds about right. Therefore these are very nifty caps to have.
Also where they come into their own is when used with high HT ; two or three in a 6/700v PSU or even 10 in series for a 3.5kv sounds about right. Therefore these are very nifty caps to have.
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I agree I have had good results reforming Rifa PEG 3300uF 350V electrolytics.
I managed to get leakage down to about 50uA or less, as good as new spec (these are from 1995).
i am very sure that if the designers of old were alive today, they would be jumping up and down with joy with today's available e-cap quality and quantity...and with a good price to boot...😎
Funny, I use 3300uF in my monoblocs and they are perfectly suitable... Funny enough, they ARE pulls from UPS systems, too.
Add a power stage and they will be more useful though...
Here's what I use for my monoblocs, but as other have stated, the capacitor is overkill for a preamp.
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I used a 2x3 stack of 470uFd, 705uFd@800V, to up-rate my my Bogen 300/400W amplifiers.
That made sense for large outdoor concerts. I never tried it at home.
well it seems many are doing it and not telling the world....
but of course, the usual caveats follow.....
but of course, the usual caveats follow.....
i once reformed a nichicon 56000ufd/63 vdc cap, the voltage went up to 75volts and leakage current was only a few micro amps....talk about cap quality eh....
If you power up old caps in an amp build using a light bulb limiter or variac for the first time you *are* re-forming them. Just mot necessarily in a controlled manner. If they don’t form they’ll heat up quickly and die. You might have been lucky and not had one *die* in a spectacular manner.
The more in need of reforming they are, the slower you have to do it in order to be successful. Also the bigger bang that it could potentially cause, the slower you *should* do it.
The more in need of reforming they are, the slower you have to do it in order to be successful. Also the bigger bang that it could potentially cause, the slower you *should* do it.
people in the west will just toss those caps in the rubbish bin, we in the third world have no such luxury....so we make things count for as long as possible....
I can’t see throwing perfectly useable amplifier capacitors in the trash, even when I have more than enough money to buy a brand new one from Mouser. That won’t always be the case.
If you saw my parts sash you’d say I was crazy. I’m retiring in a year, perhaps two, and then the days of spending big bucks on electronics will be over - for good. The idea is to have enough inventory to keep working on this stuff for decades, with a reasonable budget for shop supplies (resistors/caps, wire, solder, hardware, etc). I have many many many unused computer grade caps, most purchased surplus, that were formed and stored in air conditioning. I’m counting on being able to use these, rather than spend $27 on one or two from Mouser on every project.
If you saw my parts sash you’d say I was crazy. I’m retiring in a year, perhaps two, and then the days of spending big bucks on electronics will be over - for good. The idea is to have enough inventory to keep working on this stuff for decades, with a reasonable budget for shop supplies (resistors/caps, wire, solder, hardware, etc). I have many many many unused computer grade caps, most purchased surplus, that were formed and stored in air conditioning. I’m counting on being able to use these, rather than spend $27 on one or two from Mouser on every project.