I'm hunting a replacement power supply capacitor for a Fourier OTL
amplifier. Its a Rubycon 1200uF 360v with radial 10mm spaced connection,
width 35mm, height 85m but amp could accommodate higher.. This cap has been
discontinued by Rubycon, (I think it was originally designed for photo flash
work ) Any one know where I can source an equivalent?

TIA,

Mike

Mike Gilmour wrote:

I'm hunting a replacement power supply capacitor for a Fourier OTL
amplifier. Its a Rubycon 1200uF 360v with radial 10mm spaced connection,
width 35mm, height 85m but amp could accommodate higher.. This cap has been
discontinued by Rubycon, (I think it was originally designed for photo flash
work ) Any one know where I can source an equivalent?

One problem is that 1200 uF is not a 'preferred value' nor is 360V. You may have
to settle for 1000uF or 1500uF @ 250V.

It's unlikely to be a photo cap btw nor would that benefit an amplifier.

Graham

"Mike Gilmour" wrote in message
...
I'm hunting a replacement power supply capacitor for a Fourier OTL
amplifier. Its a Rubycon 1200uF 360v with radial 10mm spaced connection,
width 35mm, height 85m but amp could accommodate higher.. This cap has
been discontinued by Rubycon, (I think it was originally designed for
photo flash work ) Any one know where I can source an equivalent?

Hello Mike,

It might be worth your while to contact Jensen capacitors in Denmark.
http://www.jensencapacitors.com/audio/contact/

They make a huge range of caps not found in standard
catalogues.

Cheers
Iain

Pooh Bear wrote:

Mike Gilmour wrote:

I'm hunting a replacement power supply capacitor for a Fourier OTL
amplifier. Its a Rubycon 1200uF 360v with radial 10mm spaced connection,
width 35mm, height 85m but amp could accommodate higher.. This cap has been
discontinued by Rubycon, (I think it was originally designed for photo flash
work ) Any one know where I can source an equivalent?

One problem is that 1200 uF is not a 'preferred value' nor is 360V. You may have
to settle for 1000uF or 1500uF @ 250V.

***** sorry I meant 350V ( or 400V ) ***** - 250V is also a 'prefered voltage'
though.

Graham

"Iain Churches" wrote in message
...

"Mike Gilmour" wrote in message
...
I'm hunting a replacement power supply capacitor for a Fourier OTL
amplifier. Its a Rubycon 1200uF 360v with radial 10mm spaced connection,
width 35mm, height 85m but amp could accommodate higher.. This cap has
been discontinued by Rubycon, (I think it was originally designed for
photo flash work ) Any one know where I can source an equivalent?

Hello Mike,

It might be worth your while to contact Jensen capacitors in Denmark.
http://www.jensencapacitors.com/audio/contact/

They make a huge range of caps not found in standard
catalogues.

Cheers
Iain



Thanks Iain and Graham,

I'll go for 1000uF 400v to get the amp up & running again and may later swap
it if Jensens have a nearer value, though electrolytic tolerances are quite
wide anyway. The failed cap exploded violently, splitting it's can wide
open, three people in the room were temporarily deafened!

Cheers,

Mike

Mike Gilmour wrote:

"Iain Churches" wrote in message
...

"Mike Gilmour" wrote in message
...
I'm hunting a replacement power supply capacitor for a Fourier OTL
amplifier. Its a Rubycon 1200uF 360v with radial 10mm spaced connection,
width 35mm, height 85m but amp could accommodate higher.. This cap has
been discontinued by Rubycon, (I think it was originally designed for
photo flash work ) Any one know where I can source an equivalent?

Hello Mike,

It might be worth your while to contact Jensen capacitors in Denmark.
http://www.jensencapacitors.com/audio/contact/

They make a huge range of caps not found in standard
catalogues.

Cheers
Iain

Thanks Iain and Graham,

I'll go for 1000uF 400v to get the amp up & running again and may later swap
it if Jensens have a nearer value, though electrolytic tolerances are quite
wide anyway. The failed cap exploded violently, splitting it's can wide
open, three people in the room were temporarily deafened!

Do check the circuitry. An exploding psu cap indicates a possible problem ( ok I
know it sounds obvious - but it normally means it boiled the electrolyte and
that happens due to excessive current draw ).

Graham

"Pooh Bear" wrote in message
...


Mike Gilmour wrote:

"Iain Churches" wrote in message
...
[clip]

I'll go for 1000uF 400v to get the amp up & running again and may later
swap
it if Jensens have a nearer value, though electrolytic tolerances are
quite
wide anyway. The failed cap exploded violently, splitting it's can wide
open, three people in the room were temporarily deafened!

Do check the circuitry. An exploding psu cap indicates a possible problem
( ok I
know it sounds obvious - but it normally means it boiled the electrolyte
and
that happens due to excessive current draw ).

Graham


Thanks, will do, though it's one cap out of many, I feel it may have been
just an isolated, albeit dramatic, failure, see schematic:

http://www.one-electron.com/Fourier/FC_SPmk3.pdf

Mike

Mike Gilmour wrote

I'm hunting a replacement power supply capacitor for a Fourier OTL amplifier.
Its a Rubycon 1200uF 360v with radial 10mm spaced connection, width 35mm,
height 85m but amp could accommodate higher.. This cap has been discontinued
by Rubycon, (I think it was originally designed for photo flash work ) Any one
know where I can source an equivalent?

Panasonic ECET2GP122FA

In stock at RS

http://rswww.com

It's not high temp, and its 40mm dia. Perhaps there are others in the catalogue.

cheers, Ian

On Mon, 12 Jun 2006 23:08:01 +0100, "Mike Gilmour"
wrote:

http://www.one-electron.com/Fourier/FC_SPmk3.pdf

Note that the B+ supply is choke-input from 340 VAC
using capacitors rated at 360 VDC. Exceptionally bad
idea without time delay.

All good fortune,

Chris Hornbeck

"Ian Iveson" wrote in message
.uk...
Mike Gilmour wrote

I'm hunting a replacement power supply capacitor for a Fourier OTL
amplifier. Its a Rubycon 1200uF 360v with radial 10mm spaced connection,
width 35mm, height 85m but amp could accommodate higher.. This cap has
been discontinued by Rubycon, (I think it was originally designed for
photo flash work ) Any one know where I can source an equivalent?

Panasonic ECET2GP122FA

In stock at RS

http://rswww.com

It's not high temp, and its 40mm dia. Perhaps there are others in the
catalogue.

cheers, Ian


Thanks Ian, that's perfect. The amp is fan cooled so temperature rating
should be okay.

Mike

"Chris Hornbeck" wrote in message
...
On Mon, 12 Jun 2006 23:08:01 +0100, "Mike Gilmour"
wrote:

http://www.one-electron.com/Fourier/FC_SPmk3.pdf

Note that the B+ supply is choke-input from 340 VAC
using capacitors rated at 360 VDC. Exceptionally bad
idea without time delay.

All good fortune,

Chris Hornbeck


Agreed its very close to rated value, though the surge limiter board
provides some protection, the relay has approx 6 secs delay.

Mike

Mike Gilmour wrote:

"Pooh Bear" wrote in message
...

Do check the circuitry. An exploding psu cap indicates a possible problem
( ok I
know it sounds obvious - but it normally means it boiled the electrolyte
and
that happens due to excessive current draw ).

Graham

Thanks, will do, though it's one cap out of many, I feel it may have been
just an isolated, albeit dramatic, failure, see schematic:

http://www.one-electron.com/Fourier/FC_SPmk3.pdf

I only see one of those 1200uF on the HT supply.

Graham

Chris Hornbeck wrote:

On Mon, 12 Jun 2006 23:08:01 +0100, "Mike Gilmour"
wrote:

http://www.one-electron.com/Fourier/FC_SPmk3.pdf

Note that the B+ supply is choke-input from 340 VAC
using capacitors rated at 360 VDC. Exceptionally bad
idea without time delay.

A 400V cap will help there.

Graham

yeah if you have access to some caps to test and a Z meter, you could
probably find one stamped 1000uf thats exactly what you need.

Thanks Iain and Graham,

I'll go for 1000uF 400v to get the amp up & running again and may later
swap it if Jensens have a nearer value, though electrolytic tolerances are
quite wide anyway. The failed cap exploded violently, splitting it's can
wide open, three people in the room were temporarily deafened!

Cheers,

Mike

On Tue, 13 Jun 2006 00:49:49 +0100, "Mike Gilmour"
wrote:

Note that the B+ supply is choke-input from 340 VAC
using capacitors rated at 360 VDC. Exceptionally bad
idea without time delay.

Agreed its very close to rated value, though the surge limiter board
provides some protection, the relay has approx 6 secs delay.

Without load a choke-input supply soars to the same voltage
as if cap-input, and the transformer's output is slightly
higher too. 500 volts DC is not overly conservative here.

The primary delay relay also affects heater voltage, so
also slows valve warmup. Assuming otherwise is a recipe
for the kind of problem you've already experienced.

FWIW, the last generation of ordinary production valves
were designed with a warmup time of 11 seconds with full
heater voltage.

All good fortune,

Chris Hornbeck

On Tue, 13 Jun 2006 00:51:55 +0100, Pooh Bear
wrote:

I only see one of those 1200uF on the HT supply.

Perhaps you're concentrating on C1 fed by DB4? This
seems to actually be a bootstrapped pre-regulator
screen supply for the "upper" valves.

There's a fatal typo in C1's polarity in the diagram;
doubtless the source of much confusion.

Not as bad as the under-rating of the main B+ caps
though...

All good fortune,

Chris Hornbeck

Chris Hornbeck wrote:

On Tue, 13 Jun 2006 00:51:55 +0100, Pooh Bear
wrote:

I only see one of those 1200uF on the HT supply.

Perhaps you're concentrating on C1 fed by DB4?

I was.

This
seems to actually be a bootstrapped pre-regulator
screen supply for the "upper" valves.

There's a fatal typo in C1's polarity in the diagram;
doubtless the source of much confusion.

LOL ! Now you mention it....

Not as bad as the under-rating of the main B+ caps
though...

That schematic's a bit naughty. You shouldn't draw primary and secondary
windings on the same 'side' of the core.

Graahm