PX25

[gianis]

I found 4 tubes PX25 [VR40] NOS Osram Marconi brand, any proposal of designing something around these tubes?

[EC8010]

You could make a glorious PP 15W amplifier with those. Mind you, as you'd probably never be able to afford to replace the output valves when they failed, I expect you'd prefer to send them them to me for proper disposal. I'd even refund the postage!

[gianis]

Please any data for px25 tube?? thanks,

[croat47]

Here's one source:

http://www3.osk.3web.ne.jp/~euvalve/data/px25.html

And another:

http://www.ginko.de/user/franz.hambe...xrefp.html#TOC

Google = good.

[gianis]

Ok thanks again ..gianis

[EC8010]

Here's the mother and father of all valve data sites:

http://www.tubedata.info/

It has the Osram PX25 data sheet. Note that PX25 requires a British 4-pin base.

[kevinkr]

Both KR Enterprises and TJ make the PX25 in the original British 4 pin base and UX-4 U.S. style base with 4V/2A filaments.

Note that TJ also makes the PX25 in a UX-4 base with a 5V/1.6A filament for those wanting to sub it in an existing amp with say 300B.
Some other changes may be required depending on amplifier design.

So - there shouldn't be a problem getting good quality replacements for worn out PX25 for the forseeable future. (I would get some new ones fairly quickly and use the classics for critical listening.)

I would do an SE amplifier and keep the other pair as spares if it were me.

Plenty of Japanese designs out there using this tube incidentally, many of which will be found on otherwise incomprehensible Japanese language websites.