On 27/01/2015 17:41, gareth wrote:
"Rambo" wrote in message
...
On Tue, 27 Jan 2015 14:49:49 +0000 (UTC), Custos Custodum
wrote:

"gareth" wrote in
:

The problems associated with replacing (or even obtaining) the HT
reservoir capacitors in valve projects might be replace with a series
/ parallel arrangement of those dinky 100uF 35V SMD ones?

There's still a significant market for valve-based guitar amplifiers, so
somebody must be making the HT capacitors for them.


Probably could be rolled up and placed inside the original aluminium
can, too!

Don't forget to include a suitable voltage divider chain.
Whats wrong with a 450volt rated cap?

Are they readily available?


All credit to you for posing the question Gareth, but real enthusiasts
know the answer as they take apart failed or obsolete equipment just out
of interest to see what is inside - and if anything is worth recovering.
Switch-mode PSUs - either as PSUs or as part of TVs, VDUs, printers
etc. etc. are a ready source of such capacitors. There's usually about
400v-worth of a couple of hundred microfarads of electrolytics in there.

Computer power supplies become dated so quickly - change of specs /
change of connector styles - that these caps are likely to have a fair
bit of life left in them - although they may over-smooth in a design
meant for the old combined 8+32uF - red spot for the 8 - that used to be
the bedrock of valve receiver PSUs.

PA