StatguyKT88
New Member
This message is directed to anyone out there and in particular to dcgillespie if you can see this post that can answer a couple of question(s) I have which make reference to the attached schematic of the Beveridge 2SW-1 amplifier and the attached schematic of a proposed balanced I/O tube driver circuit (attached below) which I am considering substituting for the current transistor driver circuit in the 2SW-1 schematic. This circuit substitution would be between the input and up to resistors, R1,2,3 & 4. Referring to the schematic, I want to know if I can use my DVM to measure the AC voltage (audio) at the input side of these four resistors. The asterik note shown on the schematic at the outputs of R2 and R4, shows the normal operating DC bias voltage is -30Vdc when wire lead #11 (+1650V) from the secondary of power xformer is connected and -70Vdc when lead #11 is disconnected. Would I be able to take an accurate AC voltage measurement at R2 and R4, with a 100-200 mVrms signal of 1kHz input to the circuit with this lead disconnected?
Also, referring to the attached schematic of the 2/28/21 post showing a tubed balanced I/O mu stage circuit taken in part from an old white paper by Alan Kimmel. The schematic shows R2 and R4, NFB resistors (7.5M) which are connected from the cathodes and Grid3's of V201 and V204 of the Bev 2SW-1 amp schematic to the plates of V2A and V2B in the attached tubed balanced I/O circuit. My question is, is this the appropriate point in the circuit to apply the NFB?
Thanks to anyone who can reply to these two questions.
Guy (Statguy)
Also, referring to the attached schematic of the 2/28/21 post showing a tubed balanced I/O mu stage circuit taken in part from an old white paper by Alan Kimmel. The schematic shows R2 and R4, NFB resistors (7.5M) which are connected from the cathodes and Grid3's of V201 and V204 of the Bev 2SW-1 amp schematic to the plates of V2A and V2B in the attached tubed balanced I/O circuit. My question is, is this the appropriate point in the circuit to apply the NFB?
Thanks to anyone who can reply to these two questions.
Guy (Statguy)
