Chris Isbell wrote:
On Tue, 19 Jun 2007 13:31:00 GMT, (Don Pearce)
wrote:


I always found that for making low signal measurements on tubes it was
a good idea to supply the heater from a battery. Did away with all
sorts of mains hum nasties.

No good for a final design, of course - but that's another question.


Agreed. A lead-acid accumulator is much better. ;-)

This brings back fond memories of my Beethoven Portable radio. This
had valves to die for and was powered from batteries - one for the HT
and a 'grid bias' battery which supplied around five different
voltages.

The output valve had a terminal on the top (from memory, the anode) in
addition to the terminals at the base. It was around 15cm tall.


Thats annoying, I am now trying to find what the battery output valve
was with a top cap.

I am thinking of the likes of PT15 or 807, but neither of those are
"battery" valves.

--
Nick

"Nick Gorham"

Thats annoying, I am now trying to find what the battery output valve was
with a top cap.



** The 1B8-GT was popular in battery portables.

http://www.nj7p.org/Tube4.php?tube=1B8GT



........ Phil

"Chris Isbell" wrote in message
...
On Tue, 19 Jun 2007 13:31:00 GMT, (Don Pearce)
wrote:

I always found that for making low signal measurements on tubes it was
a good idea to supply the heater from a battery. Did away with all
sorts of mains hum nasties.

No good for a final design, of course - but that's another question.

Agreed. A lead-acid accumulator is much better. ;-)

This brings back fond memories of my Beethoven Portable radio. This
had valves to die for and was powered from batteries - one for the HT
and a 'grid bias' battery which supplied around five different
voltages.

The output valve had a terminal on the top (from memory, the anode) in
addition to the terminals at the base. It was around 15cm tall.

A colleague of mine has just such a radio (though not a Beethoven
portable) with two lead-acid accumulators.

It also has a three-position preset tone control marked
"Speech", "Music" and "Jazz" :-)

Iain

Phil Allison wrote:

"Nick Gorham"


Thats annoying, I am now trying to find what the battery output valve was
with a top cap.




** The 1B8-GT was popular in battery portables.

http://www.nj7p.org/Tube4.php?tube=1B8GT



....... Phil






Ah, yes, that would make sense, single ended pentode output stage.
Thanks Phil.

--
Nick

In article i,
Iain Churches wrote:
It also has a three-position preset tone control marked
"Speech", "Music" and "Jazz" :-)

My parents had a radiogram where the tone controls were labelled 'bass'
and 'brilliance' They were rotary switches rather than pots and appeared
to be high pass and low pass filters only - no boost. Wonder when Mr
Baxandall produced his near universal design?

(My spool cheeker didn't recognise Baxandall so knowing you picky lot I
did a Google on 'baxandall tone control'. And the first hit was pages
written by 'our own' Jim Lesurf...)

--
*Fax is stronger than fiction *

Dave Plowman London SW
To e-mail, change noise into sound.

On Jun 18, 3:30 pm, Ian Bell wrote:
Just got an email from Maplin to say they are out of stock of their one and
only type of mains transformer for tube supplies (250-0-259 @150mA and
6.3VAC secondaries).

Where else can I get something similar in the UK?

Cheers

ian

I bet any of a dozen wind houses there will wind you one but it's
probably cheaper to buy out of a catalog. Must be a bunch of vendors.

A PT for a Fender Deluxe is in that ballpark but 600 vct rather than
500.

Bret Ludwig wrote:

On Jun 18, 3:30 pm, Ian Bell wrote:
Just got an email from Maplin to say they are out of stock of their one
and only type of mains transformer for tube supplies (250-0-259 @150mA
and 6.3VAC secondaries).

Where else can I get something similar in the UK?

Cheers

ian

I bet any of a dozen wind houses there will wind you one but it's
probably cheaper to buy out of a catalog. Must be a bunch of vendors.


That's what I thought but Google doesn't seem to turn them up .

Ian

If you're going toroid have a custom wind done. It's not much more
expensive, whereas with EI types there's a big price difference.