The voltage on the collector of TIP41 is 335Vdc. On the emitter of the TIP41 it's 327Vdc. They may vary a bit but the 8Vdc difference voltage should be the same. If it isn't, the buffer has issues. If you are unfamiliar with measuring high voltages, do not attempt this. Sometimes the probes can load the buffer down. It is not necessary to have the output tubes in the amp when you measure the buffer voltages, but you will need a variac to drop the line voltage to 115Vac if you remove the output tubes as a load will not be on the main filter cap bank and they may see an over voltage.
Audio Research D70 mark1 + schematic
Hallo ! I´m trying to repair a D70 from 1983 . It has a 6DJ8
which determine the "workingpoint" for itself and the following two 6FQ7 tubes for each channel . This poweramp has no solid state parts and the cathodes of the 6DJ8 have two 1,5k resistors connected to each cathode ...... not 110 ohm and 511 ohm as mark 2 . I would very much like to find a schematic for this version of the D70 . ( The two 6FQ7 tube
in each channel have just two 6K powerresistors from their cathodes to earth ...... no other resistors as in version mark2 ) Regards Stewen
which determine the "workingpoint" for itself and the following two 6FQ7 tubes for each channel . This poweramp has no solid state parts and the cathodes of the 6DJ8 have two 1,5k resistors connected to each cathode ...... not 110 ohm and 511 ohm as mark 2 . I would very much like to find a schematic for this version of the D70 . ( The two 6FQ7 tube
in each channel have just two 6K powerresistors from their cathodes to earth ...... no other resistors as in version mark2 ) Regards Stewen
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- 24 posts total
- 24 posts total