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Hi there!!
I had adjust some fixed-bias amps in the last year, but last night was my first cathode-bias amp...
..
It was a Gibson Falcon. 2 6V6, GZ34, 6C4 and 3 6EU7...
Measurements are done using this information, http://www.diyguitarist.com/GuitarAmps/PT-Biasing.htm,
and those are my numbers...
Cathode Current = Cathode Voltage/Cathode Resistor Value
0,0537 = 25,8 / 480
Screen Current = Voltage Drop across Screen Resistor/Screen Resistor Value
0,0126= 10,5 / 833
Plate current = Cathode Voltage/Cathode Resistor Value - Screen Current
0,0411 = 25,8 / 480 - 0,0126
Plate Dissipation in Watts = (Plate Voltage - Cathode Voltage) x Plate Current
12,74 = 339 - 25,8 x 0,0411
I had read that in cathode bias amps is safe work hotter than in fixed bias amps, but... isnīt this value too hot?
The tubes are new TAD 6V6GTB-STR.
Them, i install the originals RCA 6V6 and the PLATE DISSIPATION dropp to 10,80 watts. Is this in the safer range?
Thaks everybody....
I had adjust some fixed-bias amps in the last year, but last night was my first cathode-bias amp...
..It was a Gibson Falcon. 2 6V6, GZ34, 6C4 and 3 6EU7...
Measurements are done using this information, http://www.diyguitarist.com/GuitarAmps/PT-Biasing.htm,
and those are my numbers...
Cathode Current = Cathode Voltage/Cathode Resistor Value
0,0537 = 25,8 / 480
Screen Current = Voltage Drop across Screen Resistor/Screen Resistor Value
0,0126= 10,5 / 833
Plate current = Cathode Voltage/Cathode Resistor Value - Screen Current
0,0411 = 25,8 / 480 - 0,0126
Plate Dissipation in Watts = (Plate Voltage - Cathode Voltage) x Plate Current
12,74 = 339 - 25,8 x 0,0411
I had read that in cathode bias amps is safe work hotter than in fixed bias amps, but... isnīt this value too hot?
The tubes are new TAD 6V6GTB-STR.
Them, i install the originals RCA 6V6 and the PLATE DISSIPATION dropp to 10,80 watts. Is this in the safer range?
Thaks everybody....
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