So the tube is working well.
If you put 9mA (CCS) to anode and get 90V Ua, the grid voltage is 0V, not -3V!
Try to measure grid voltage (relative to cathode) with voltmeter.
If you put 9mA (CCS) to anode and get 90V Ua, the grid voltage is 0V, not -3V!
Try to measure grid voltage (relative to cathode) with voltmeter.
I measure anode voltage, one triode 146.25 and the other 144.12
SSHV2 CCS set to 40mA (9+9+20mA self consumption SSHV2 to work OK as per guide), Vout 232V
-2.7V both triodes grid.
SSHV2 CCS set to 40mA (9+9+20mA self consumption SSHV2 to work OK as per guide), Vout 232V
-2.7V both triodes grid.
I want to know once set the CCS (for example for 26 preamp 6mA each tube) exist a way to check if the tube is working at 6mA? of course not with the typical 1R or 10R of the CCS?
For IHT I measure the voltage across the cathode resistor but for 26 I use filament bias....
For IHT I measure the voltage across the cathode resistor but for 26 I use filament bias....
Wrong bias.
Bias voltage about filament resistor voltage + half of filament voltage.
If this and CCS current intersection doesn't match the datasheet's operating point voltage, the equipment inoperable (probably too low B+).
If the tube is worn, try to measure it with resistor loading: filament bias, appropriate resistor, higher B+.
R= (B+ minus desired operating point voltage)/desired operating point current.
If the real operating point (Ua, Ia) does not differ much from the desired point, the tube -more or less- working.
BTW the grid is grounded (with resistor)?
Bias voltage about filament resistor voltage + half of filament voltage.
If this and CCS current intersection doesn't match the datasheet's operating point voltage, the equipment inoperable (probably too low B+).
If the tube is worn, try to measure it with resistor loading: filament bias, appropriate resistor, higher B+.
R= (B+ minus desired operating point voltage)/desired operating point current.
If the real operating point (Ua, Ia) does not differ much from the desired point, the tube -more or less- working.
BTW the grid is grounded (with resistor)?
B+ both channels before the CCS +180VDC
CCS both channels 6mA
Anode Left channel +122VDC
Anode Right channel +115VDC
Ripple Left channel 1.7mVAC
Ripple Right channel 1.9mVAC
CCS both channels 6mA
Anode Left channel +122VDC
Anode Right channel +115VDC
Ripple Left channel 1.7mVAC
Ripple Right channel 1.9mVAC
Reading more carefully I understood what you said but mine filament bias is hybrid (resistor+Sic)?
With the rig you gave to match the 26 tubes, measurements were Right channel 4.79mA & Left Channel 4.81mA
With the rig you gave to match the 26 tubes, measurements were Right channel 4.79mA & Left Channel 4.81mA
