I don't want to use anode resistors for each tube: I prefer connect direct the Salas HV reg also I have only one Bartolucci transformer 150VAC secondary & one 10H Bartolucci choke (both are expensive: best quality), the RIAA is for a friend who has spent a lot of money & I don't want to ask more money.
What about if I reduce E88CC to 80V with a anode resistor? could you tell me the value if OK?
What about if I reduce E88CC to 80V with a anode resistor? could you tell me the value if OK?
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Just received Guy answer:
"The internal resistance of an 83 is about 70Kohm which is in parallel with the 120K load resistor giving 44Kohm. This is added to the 330K and the result works in parallel with the 1M0 to ground giving 272K which is the net value used in the Eq calculation. The Miller capacitance of the 88 is 40pF which must be added to the 2n2 and 560pF to get the eq calculation spot on.
rgs
Guy"
"The internal resistance of an 83 is about 70Kohm which is in parallel with the 120K load resistor giving 44Kohm. This is added to the 330K and the result works in parallel with the 1M0 to ground giving 272K which is the net value used in the Eq calculation. The Miller capacitance of the 88 is 40pF which must be added to the 2n2 and 560pF to get the eq calculation spot on.
rgs
Guy"
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This is not really a low noise design. The 22 Ohm resistors plus R2 and two Fet`s are in series. S/N against 5mV is -85dB but against 0.5mV what is more common in MC carts it is only -65dB. That is 15dB less then it could be. It should have tremendoes speed though.
It's only a MC pre-pre max 26dBs so needs a MM, I mesured Idss NJFET & all are aprox 14mA, if you know any way to upgrade without changing the SMD NJFETS please be so kind to let me know. Yes have speed, body, resolution, etc that will be perfect combo with a MM tube far better than a step-up tx.
Just received Guy answer:
"The internal resistance of an 83 is about 70Kohm which is in parallel with the 120K load resistor giving 44Kohm. This is added to the 330K and the result works in parallel with the 1M0 to ground giving 272K which is the net value used in the Eq calculation. The Miller capacitance of the 88 is 40pF which must be added to the 2n2 and 560pF to get the eq calculation spot on.
rgs
Guy"
Now this completely changes my previsions.
I will need some time to digest and soon will post my best bet.
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