Tube Hybrid Amp Gain Calculation - Page 2

jmbee · 22nd November 2009, 11:25 AM

J. Broskie says about this amp:
"The triodes act as feedback resistors and they set the gain of the amplifier. So, is the gain of this amplifier 33, the mu of the 6DJ8? No, it is closer to 10 because the resistors in the input stage are not bypassed. " -- so near 20 dB.
imho, gain depends on transconductance of chosen Mosfets (and ev. the amount of nfb.)
For a Hafler P4000, page 8 , " in this connection, the output stage ( alone ) has its full voltage gain of typicaly 20 dB ..." but i dont know how to calculate it.

atiq19 · 22nd November 2009, 11:55 AM

Jmbee,

Many thanks.

I would still want to know the underlying formula so that I can choose devices for different gains.

Atiq

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22nd November 2009, 11:25 AM	#11
jmbee diyAudio Member Join Date: Sep 2008	J. Broskie says about this amp: "The triodes act as feedback resistors and they set the gain of the amplifier. So, is the gain of this amplifier 33, the mu of the 6DJ8? No, it is closer to 10 because the resistors in the input stage are not bypassed. " -- so near 20 dB. imho, gain depends on transconductance of chosen Mosfets (and ev. the amount of nfb.) For a Hafler P4000, page 8 , " in this connection, the output stage ( alone ) has its full voltage gain of typicaly 20 dB ..." but i dont know how to calculate it.

22nd November 2009, 11:55 AM	#12
atiq19 diyAudio Member Join Date: Jun 2007	Jmbee, Many thanks. I would still want to know the underlying formula so that I can choose devices for different gains. Atiq

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