Hi all,
I read everything I found about GU-50 tubes, here on the forum and on the net (I'm thinking to use them for my new amplifier).
The problem is that it is not clear to me the actual outrput impedance of such a tube: I found reference to a 10K, 5K, 2K transformers, and I don't know which is the right value.
The datasheet I found do not report any value for the output impedance, nor any graph for triode-strapped condition.
Can you help me?
Thanks in advance,
Giovanni
I read everything I found about GU-50 tubes, here on the forum and on the net (I'm thinking to use them for my new amplifier).
The problem is that it is not clear to me the actual outrput impedance of such a tube: I found reference to a 10K, 5K, 2K transformers, and I don't know which is the right value.
The datasheet I found do not report any value for the output impedance, nor any graph for triode-strapped condition.
Can you help me?
Thanks in advance,
Giovanni
Hi Giovanni!
For pentodes (regulated G2):
http://www.diyaudio.com/forums/showthread.php?s=&threadid=98678
For triodes with 400V plate voltage you'll probably need 2-3K CT
For pentodes (regulated G2):
http://www.diyaudio.com/forums/showthread.php?s=&threadid=98678
For triodes with 400V plate voltage you'll probably need 2-3K CT
Hi, thanks for the answer.
The topology will be a parafeed SE amplifier.
I would like to use two or more paralleled GU-50 as output tube, driven with a High Voltage CCS (not decided yet if use a solid state one or a tube one).
Output trafo will be a toroid (I found a good -and cheap- manufacturer here in Italy).
THIS is a draft of the idea I have.
The output tubes will have an idle voltage of about 300V (low, I know), while the CCS will work between 200 and 0V, with a current of 100mA.
I'm thinking to use two paralleled GU-50 tubes also for the upper CCS.
If I can keep the output impedance as low as 1K, I can have about 20W of RMS output power...
I don't know if use the GU-50 in pentode mode, triode-strapped mode, enhanced triode or whatever else comibnation of grid1, 2, 3 voltages...
My idea was to use them as triode as output tubes, and use pentode mode (if I will ever use tubes) for the CCS.
Ciao,
Giovanni
The topology will be a parafeed SE amplifier.
I would like to use two or more paralleled GU-50 as output tube, driven with a High Voltage CCS (not decided yet if use a solid state one or a tube one).
Output trafo will be a toroid (I found a good -and cheap- manufacturer here in Italy).
THIS is a draft of the idea I have.
The output tubes will have an idle voltage of about 300V (low, I know), while the CCS will work between 200 and 0V, with a current of 100mA.
I'm thinking to use two paralleled GU-50 tubes also for the upper CCS.
If I can keep the output impedance as low as 1K, I can have about 20W of RMS output power...
I don't know if use the GU-50 in pentode mode, triode-strapped mode, enhanced triode or whatever else comibnation of grid1, 2, 3 voltages...
My idea was to use them as triode as output tubes, and use pentode mode (if I will ever use tubes) for the CCS.
Ciao,
Giovanni
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