![[-]](https://theultimatetone.com/images/collapse.png "[-]")
Hi everyone.
The idle current I set it to was around 27mV per tube with the MV at zero. I'm still new to using the oscilloscope and realized I set the signal amplitude to about 2V. I think that was too much signal being fed into the amp and hence the significant increase in dissapation on the tubes. I set it to about 150mV I guess in range of a typical guitar signal?
Only issue I have with the digital oscilloscope is I have some trouble triggering the signal at that low of a signal.
From there if i remember correctly with increasing volume and constant signal applied i saw the current go from 27mV to as high as 78mV for the EL84s which i think is above the max operating range. I would say in reality the signal wouldn't be constantly and consistently fed in like that when playing. The current draw would jump around. But would it ok for the tubes to pass their typical tube rating when high amplitude signal is breifly applied? Maybe this is normal and not unsafe for the tubes?
Apart from all that I see what you are saying Kevin. It would be more efficient to reserve that high voltage rating and use a smaller voltage rating with a higher capacitance? And hence the higher the capacitance the better the stability in the output section if I read that correctly?
I currently finished a liverpool trainwreck build and increased the 50R cathode bias bypass capacitor at the power section from 22uf to 220uf. Also increased the main power filter cap from 47uf to 80uf. From my ears at least it tightened up the bass response and I liked what it did. Would it be safe to say that using high capacitance for those parts of the circuit be overall beneficial in that at least it improves bias stability in a cathode bias amp? As well as tighten the bass response a bit?(if that is what is wanted).
I agree that the 450V is way too high of a rating as the voltage drop is only about 45 times less than that in that portion of the circuit and wild be better to use a higher capacitance and lower voltage rating.
The idle current I set it to was around 27mV per tube with the MV at zero. I'm still new to using the oscilloscope and realized I set the signal amplitude to about 2V. I think that was too much signal being fed into the amp and hence the significant increase in dissapation on the tubes. I set it to about 150mV I guess in range of a typical guitar signal?
Only issue I have with the digital oscilloscope is I have some trouble triggering the signal at that low of a signal.
From there if i remember correctly with increasing volume and constant signal applied i saw the current go from 27mV to as high as 78mV for the EL84s which i think is above the max operating range. I would say in reality the signal wouldn't be constantly and consistently fed in like that when playing. The current draw would jump around. But would it ok for the tubes to pass their typical tube rating when high amplitude signal is breifly applied? Maybe this is normal and not unsafe for the tubes?
Apart from all that I see what you are saying Kevin. It would be more efficient to reserve that high voltage rating and use a smaller voltage rating with a higher capacitance? And hence the higher the capacitance the better the stability in the output section if I read that correctly?
I currently finished a liverpool trainwreck build and increased the 50R cathode bias bypass capacitor at the power section from 22uf to 220uf. Also increased the main power filter cap from 47uf to 80uf. From my ears at least it tightened up the bass response and I liked what it did. Would it be safe to say that using high capacitance for those parts of the circuit be overall beneficial in that at least it improves bias stability in a cathode bias amp? As well as tighten the bass response a bit?(if that is what is wanted).
I agree that the 450V is way too high of a rating as the voltage drop is only about 45 times less than that in that portion of the circuit and wild be better to use a higher capacitance and lower voltage rating.
