OR:Nuvistor plate(anode) voltage
 

While I have been active in electroincs since 1962 I
managed to miss Nuvistors. Started wtih regular tubes
(valves) and went on the bipolar and FETs. Is it reasonable
to find a plate voltage of about +30V?

I was recently given a RCA multiset coupler that uses Nuvistors.
The primary in the power is open. I disasembled the transformer,
but the open is not in the first few layers. A friend is going
to rewind it, he rebuilds vintage tube guitar and HiFi amps.

Whne I inspected the rest of the circuitry I found the power
supply caps rated at 50V. the faded and amost unreadiable schematic
on the inside cover give the plate voltage as 30V +/-5. I owned a
R392 which used special tubes with plate volatage of 26.5V, but
I have never seen "normal" tubes operated at this low a voltage.
Heck I can power the unit with 3 9V in series for testing.

My wife has scanned the image and is using photshop to "enhnace"
it. Almost like a CSI program.

Anyone in the group ever work with Nuvistors and can offer any
information on the usual plate voltages?

I will be away from the net until saturday morning.

Terry

I forgot to give the tube number:
They are 8056.
I did just find a listing showing the plate voltage to be 50V.
So maybe 30 isn't too far out of line.

Terry

) writes:
While I have been active in electroincs since 1962 I
managed to miss Nuvistors. Started wtih regular tubes
(valves) and went on the bipolar and FETs. Is it reasonable
to find a plate voltage of about +30V?

Nuvistors came along right at about the time of the hybrid car
radios. I'm quite certain there was a Nuvistor or two designed to
run on low voltage, because there were converters described in
various publications that ran off 12volts.

From the 1968 editiion of the ARRL's "The Radio Amateur's VHF Manual:
"The Nuvistor is now available in a model that works very well
at low plate voltages. The 8056 is very similar to the 6CW4,
except that it has a transconductance almost as high when working
at 12 to 24V on the plate."


Micahel

I was recently given a RCA multiset coupler that uses Nuvistors.
The primary in the power is open. I disasembled the transformer,
but the open is not in the first few layers. A friend is going
to rewind it, he rebuilds vintage tube guitar and HiFi amps.

Whne I inspected the rest of the circuitry I found the power
supply caps rated at 50V. the faded and amost unreadiable schematic
on the inside cover give the plate voltage as 30V +/-5. I owned a
R392 which used special tubes with plate volatage of 26.5V, but
I have never seen "normal" tubes operated at this low a voltage.
Heck I can power the unit with 3 9V in series for testing.

My wife has scanned the image and is using photshop to "enhnace"
it. Almost like a CSI program.

Anyone in the group ever work with Nuvistors and can offer any
information on the usual plate voltages?

I will be away from the net until saturday morning.

Terry

On 28 Apr 2005 10:08:05 -0700, wrote:

While I have been active in electroincs since 1962 I
managed to miss Nuvistors. Started wtih regular tubes
(valves) and went on the bipolar and FETs. Is it reasonable
to find a plate voltage of about +30V?
My recollection is 30V is probably on the high side, I remember
running one at 22V. It is planar UHF triode with very small
dimensions. It didn't take much.

I was recently given a RCA multiset coupler that uses Nuvistors.
The primary in the power is open. I disasembled the transformer,
but the open is not in the first few layers. A friend is going
to rewind it, he rebuilds vintage tube guitar and HiFi amps.

Whne I inspected the rest of the circuitry I found the power
supply caps rated at 50V. the faded and amost unreadiable schematic
on the inside cover give the plate voltage as 30V +/-5. I owned a
R392 which used special tubes with plate volatage of 26.5V, but
I have never seen "normal" tubes operated at this low a voltage.
Normal tubes have MUCH MUCH larger inter-electrode dimensions. What
counts in a tube is the e-field, and the if the distance between the
cathode and the plate is 1 cm, and you have 400v, that is 4000v/mm.
On a nuvistor, the cathode to plate distance is measured in mm, and it
isn't many mm either, so you can hefyt e-fields without much voltage.

Nuvistors were typically operated a microwatt/milliwatt output levels.

In article . com,
wrote:

I forgot to give the tube number:
They are 8056.
I did just find a listing showing the plate voltage to be 50V.
So maybe 30 isn't too far out of line.

Those tube used relatively low voltages.

Check this out...
http://hereford.ampr.org/cgi-bin/tube?tube=8056

Here is a pdf

http://www.drtube.com/datasheets/8056sie64.pdf

--
Telamon
Ventura, California

In article

,
Telamon wrote:

In article . com,
wrote:

I forgot to give the tube number:
They are 8056.
I did just find a listing showing the plate voltage to be 50V.
So maybe 30 isn't too far out of line.

Those tube used relatively low voltages.

Check this out...
http://hereford.ampr.org/cgi-bin/tube?tube=8056

Here is a pdf

http://www.drtube.com/datasheets/8056sie64.pdf

Here is a nice RCA pdf data sheet that says the plate voltage is 24V.

http://mapage.noos.fr/dom.mafrand/8056.pdf

--
Telamon
Ventura, California