So I noticed the other day that my front tubes seem to be glowing less "Bright" then the rear tubes, I felt that was odd so I decided to measure some voltages and see what's going on if anythning
All measurements were taken with speakers connected and shorting plugs across the inputs, also the amp was allowed to warm up for 5 min before taking measurements
Here is what i see
Input Voltage from wall 118V AC
Rectifier (Russian Mullard GZ34)
Pin 4 -398V AC*
Pin 6 - 398V AC *
Pin 2 - 455V DC
Pin 8 - 457V DC
(Note, 4 and 6 are hit via yellow sheet mod diode)
*The power transformer going into the rectifier is putting out 398v ac on pins 4 and 6 BEFORE the yellow sheet mod diodes, on ACTUAL pins 4 and 6 I see 48v AC I assume this has to do with the diode only letting half the wave through
Output Tube (Sovtec 6550
If I am looking at the amp from the front, clockwise starting from lower left
Lower Left
Pin 3 - 453V DC
Pin 4 - 455V DC
Pin 5 - -57V DC
Pin 6 - -57V DC
Pin 8 - .448 V DC
Upper Left
Pin 3 - 455V DC
Pin 4 - 455V DC
Pin 5 - -58V DC
Pin 6 - -58V DC
Pin 8 - .441V DC
Upper Right
Pin 3 - 455V DC
Pin 4 - 456V DC
Pin 5 - -59V DC
Pin 6 - -59V DC
Pin 8 - .441V DC
Lower Right
Pin 3 - 455V DC
Pin 4 - 456V DC
Pin 5 - -55V DC
Pin 6 - -55V DC
Pin 8 - .430V DC
The filament voltages are all good at the 6550's (within 0.05 of each other) and around 6.5 volts
These are slightly lower then the manual states I should have (Plate and screen for example on the outputs should be between 470 - 520)
For the rectifier, the plate2 and cathode (Pins 2 and 8 ) should be between 490 and 530v)
Is this something I screwed up or is this normal for 118v Input?
All measurements were taken with speakers connected and shorting plugs across the inputs, also the amp was allowed to warm up for 5 min before taking measurements
Here is what i see
Input Voltage from wall 118V AC
Rectifier (Russian Mullard GZ34)
Pin 4 -398V AC*
Pin 6 - 398V AC *
Pin 2 - 455V DC
Pin 8 - 457V DC
(Note, 4 and 6 are hit via yellow sheet mod diode)
*The power transformer going into the rectifier is putting out 398v ac on pins 4 and 6 BEFORE the yellow sheet mod diodes, on ACTUAL pins 4 and 6 I see 48v AC I assume this has to do with the diode only letting half the wave through
Output Tube (Sovtec 6550
If I am looking at the amp from the front, clockwise starting from lower left
Lower Left
Pin 3 - 453V DC
Pin 4 - 455V DC
Pin 5 - -57V DC
Pin 6 - -57V DC
Pin 8 - .448 V DC
Upper Left
Pin 3 - 455V DC
Pin 4 - 455V DC
Pin 5 - -58V DC
Pin 6 - -58V DC
Pin 8 - .441V DC
Upper Right
Pin 3 - 455V DC
Pin 4 - 456V DC
Pin 5 - -59V DC
Pin 6 - -59V DC
Pin 8 - .441V DC
Lower Right
Pin 3 - 455V DC
Pin 4 - 456V DC
Pin 5 - -55V DC
Pin 6 - -55V DC
Pin 8 - .430V DC
The filament voltages are all good at the 6550's (within 0.05 of each other) and around 6.5 volts
These are slightly lower then the manual states I should have (Plate and screen for example on the outputs should be between 470 - 520)
For the rectifier, the plate2 and cathode (Pins 2 and 8 ) should be between 490 and 530v)
Is this something I screwed up or is this normal for 118v Input?