Discussion:
12V from 6.3V - Possible?
(too old to reply)
Ty Unes
2008-05-22 02:52:46 UTC
Permalink
I have a power transformer with 6.3VAC filament voltage I want to use in a
circuit. Is there a way to mix 6V and 12V tubes powered from this
transformer? In other words, can I power 2 6V tubes and then double the
voltage somehow to heat a single 12V tube? If so, I'm having trouble
visualizing how to do this.

Thanks.
Phil Allison
2008-05-22 02:57:37 UTC
Permalink
"Ty Unes"
Post by Ty Unes
I have a power transformer with 6.3VAC filament voltage I want to use in a
circuit. Is there a way to mix 6V and 12V tubes powered from this
transformer? In other words, can I power 2 6V tubes and then double the
voltage somehow to heat a single 12V tube?
** What 12 volt tubes are you dealing with ?

Most of them have split heaters for 6.3 or 12.6 volt operation.



... Phil
Marko
2008-05-22 05:35:32 UTC
Permalink
Voltage doubler circuit? Mark
Post by Phil Allison
"Ty Unes"
Post by Ty Unes
I have a power transformer with 6.3VAC filament voltage I want to use in a
circuit. Is there a way to mix 6V and 12V tubes powered from this
transformer? In other words, can I power 2 6V tubes and then double the
voltage somehow to heat a single 12V tube?
** What 12 volt tubes are you dealing with ?
Most of them have split heaters for 6.3 or 12.6 volt operation.
... Phil
Ty Unes
2008-05-22 04:06:12 UTC
Permalink
Post by Phil Allison
"Ty Unes"
Post by Ty Unes
I have a power transformer with 6.3VAC filament voltage I want to use in a
circuit. Is there a way to mix 6V and 12V tubes powered from this
transformer? In other words, can I power 2 6V tubes and then double the
voltage somehow to heat a single 12V tube?
** What 12 volt tubes are you dealing with ?
Most of them have split heaters for 6.3 or 12.6 volt operation.
... Phil
12SA7 / 6SA7
Phil Allison
2008-05-22 07:29:05 UTC
Permalink
"Ty Unes"
Post by Ty Unes
Post by Phil Allison
Post by Ty Unes
I have a power transformer with 6.3VAC filament voltage I want to use in a
circuit. Is there a way to mix 6V and 12V tubes powered from this
transformer? In other words, can I power 2 6V tubes and then double the
voltage somehow to heat a single 12V tube?
** What 12 volt tubes are you dealing with ?
Most of them have split heaters for 6.3 or 12.6 volt operation.
12SA7 / 6SA7
** Then try a voltage doubler:

http://hyperphysics.phy-astr.gsu.edu/Hbase/electronic/voldoub.html

You may wind up with a bit more than 12 volts - so add a low value resistor
in series with the tube heater.

The caps need to be about 220uF or 470 uF each, 16 volt.



...... Phil
Lou deGonzague
2008-06-03 21:06:49 UTC
Permalink
Post by Ty Unes
Post by Phil Allison
"Ty Unes"
Post by Ty Unes
I have a power transformer with 6.3VAC filament voltage I want to use in a
circuit. Is there a way to mix 6V and 12V tubes powered from this
transformer? In other words, can I power 2 6V tubes and then double the
voltage somehow to heat a single 12V tube?
** What 12 volt tubes are you dealing with ?
Most of them have split heaters for 6.3 or 12.6 volt operation.
... Phil
12SA7 / 6SA7
Why not just use three 6SA7's?

Alex
2008-05-22 12:04:19 UTC
Permalink
Post by Ty Unes
I have a power transformer with 6.3VAC filament voltage I want to use in a
circuit. Is there a way to mix 6V and 12V tubes powered from this
transformer? In other words, can I power 2 6V tubes and then double the
voltage somehow to heat a single 12V tube? If so, I'm having trouble
visualizing how to do this.
Thanks.
Voltage doubler of 2 diodes 1N400x and two capacitors: 1000uF/16V (input)
and 470uF/25V (output) will work. 25V rated cap is required for safe
operation if the valve is not plugged in. A dropping resistor will be
needed, most likely. It is better to connect it at the input to the doubler,
not the output. In this case voltage waveform will be less distorted and
less magnetic harmonic hum generated from the transformer. It is important
to connect return wires from one of the diodes and a capacitor to a terminal
of the transformer, not just to the chassis anywhere (if one end of the
transformer 6.3V winding is grounded). It will reduce conducted hum.

Regards,
Alex
Phil Allison
2008-05-22 13:03:51 UTC
Permalink
"Alexei the Fat Bastard "
Post by Alex
Voltage doubler of 2 diodes 1N400x and two capacitors: 1000uF/16V (input)
and 470uF/25V (output) will work. 25V rated cap is required for safe
operation if the valve is not plugged in. A dropping resistor will be
needed, most likely. It is better to connect it at the input to the doubler,
not the output. In this case voltage waveform will be less distorted and
less magnetic harmonic hum generated from the transformer. It is important
to connect return wires from one of the diodes and a capacitor to a terminal
of the transformer, not just to the chassis anywhere (if one end of the
transformer 6.3V winding is grounded). It will reduce conducted hum.
** Just ignore Alexei's incomprehensible ravings.

The ugly, fat bastard has never been the same since he got a big fat dose of
Gamma rays at Chernobyl.

They say he glows in the dark ......




..... Phil
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