Hi guys . I have a few questions that haunts me for several years, because no one can give me a clear answer . It is believed that the normal plate voltage of VF14 in U47 should not be lower than 32 volts. Otherwise , the tube is considered to be spoiled . Klaus said absolutely incomprehensible things for me here:
http://repforums.prosoundweb.com/index.php?topic=35516.0
1. Why emission is considered bad if plate voltage is lower than 32VDC? Logically , if less plate voltage means more current - and therefore emissions contrary better!
2.Usually when the VF14 loses emissions, plate voltage increases above 34 volts , and not below, because the emission is less and the current is less. When performed revival of VF14 , the heating voltage for some time is maximized to ~55VDC , it leads to the purification of the cathode and improve emissions. As a consequence , there is a reduction in plate voltage at several volts, not increasing!. When I restored one of my tube, I had plate voltage 39 volts before recovery , and after recovery - 36 volts. Klaus says the opposite: after the recovery procedure voltage grows! Where is the truth?
3. Why is deemed unacceptable plate voltage lower 30-31VDC? I have a lamp that does not make noise, but has a plate voltage of 29 volts.
Thanks for answers and opinions!
http://repforums.prosoundweb.com/index.php?topic=35516.0
1. Why emission is considered bad if plate voltage is lower than 32VDC? Logically , if less plate voltage means more current - and therefore emissions contrary better!
2.Usually when the VF14 loses emissions, plate voltage increases above 34 volts , and not below, because the emission is less and the current is less. When performed revival of VF14 , the heating voltage for some time is maximized to ~55VDC , it leads to the purification of the cathode and improve emissions. As a consequence , there is a reduction in plate voltage at several volts, not increasing!. When I restored one of my tube, I had plate voltage 39 volts before recovery , and after recovery - 36 volts. Klaus says the opposite: after the recovery procedure voltage grows! Where is the truth?
3. Why is deemed unacceptable plate voltage lower 30-31VDC? I have a lamp that does not make noise, but has a plate voltage of 29 volts.
Thanks for answers and opinions!