So all four tubes are biasing up in that zone?
FYI One needs to know the tube and the plate voltage to get an idea of where your idle bias is, even with the idle current/bias spec(s) figured out.
We know the amp, the tubes, and we know your voltages from what you've posted...
So, following, here's some of the info given by that bias calc I linked to before, with the voltage range you are getting on the plates.
Results: For 535 Volts
6L6GC (Max disapation 30 watts)
60% - 34ma
70% - 39ma
80% - 45ma
100% - 56ma
So 20ma of 56ma (20/56) is 36% max bias at idle.
26ma would be 46% max bias at idle.
50% of max bias at idle would be 28ma. I personally wouldn't go over that with most tubes.
[Now, some say the 7027s are 35w tubes. If someone is using NOS tubes, ok, go ahead and change the calc...I say, unless they're NOS, treat/bias them as what they probably are - 30w 6L6GCs at HV (~540v depending on the ampeg...)]
I bias for 1) tone and 2) longevity
Yes, in almost any other amp, this 36% bias zone would be cold. How's it sound to you?
I had a bias trim pot in there and dialed in everything from cut off (super low at idle) to 70%, at both low and turned up volume, and listened. I've done the same with Fenders. In the ampeg, I thought the cooler bias happened to sound best--cooler bias like you have offered HUGE lows, and no mid-range mush. Big, loud, clean, but not harsh. I put back the stock value resistor, and have left it ever since. Note: with blackface style fenders and 6L6GCs, , I tend to like the bias closer to 50- 70% to get more mids I suppose.
To me, the key is if one tube is drawing notably different current than the others. I think your bias is fine. This was just in response to your seeing glow on transients in some tubes more than others. If they all bias in the same zone, you're OK, it's just the tubes.
I'd suggest, leave it like this, and see how the tubes do over the course of a month or so, if anything develops. If all goes well, and you want to mess with the bias, THEN if you want to consider adjusting the bias, it makes more sense--AFTER you know the amp is good and stable at a decent bias point...in fact one or more tubes may drift in how they are biasing with some use, even in a month, at these voltages. You'll know more later.
I think the key info here and now:
1) It sounds OK, stable and it's holding up well after all the work you did on it?
2) Since we know where it's biasing at generally, is there much difference in bias from tube to tube?
FYI One needs to know the tube and the plate voltage to get an idea of where your idle bias is, even with the idle current/bias spec(s) figured out.
We know the amp, the tubes, and we know your voltages from what you've posted...
So, following, here's some of the info given by that bias calc I linked to before, with the voltage range you are getting on the plates.
Results: For 535 Volts
6L6GC (Max disapation 30 watts)
60% - 34ma
70% - 39ma
80% - 45ma
100% - 56ma
So 20ma of 56ma (20/56) is 36% max bias at idle.
26ma would be 46% max bias at idle.
50% of max bias at idle would be 28ma. I personally wouldn't go over that with most tubes.
[Now, some say the 7027s are 35w tubes. If someone is using NOS tubes, ok, go ahead and change the calc...I say, unless they're NOS, treat/bias them as what they probably are - 30w 6L6GCs at HV (~540v depending on the ampeg...)]
I bias for 1) tone and 2) longevity
Yes, in almost any other amp, this 36% bias zone would be cold. How's it sound to you?
I had a bias trim pot in there and dialed in everything from cut off (super low at idle) to 70%, at both low and turned up volume, and listened. I've done the same with Fenders. In the ampeg, I thought the cooler bias happened to sound best--cooler bias like you have offered HUGE lows, and no mid-range mush. Big, loud, clean, but not harsh. I put back the stock value resistor, and have left it ever since. Note: with blackface style fenders and 6L6GCs, , I tend to like the bias closer to 50- 70% to get more mids I suppose.
To me, the key is if one tube is drawing notably different current than the others. I think your bias is fine. This was just in response to your seeing glow on transients in some tubes more than others. If they all bias in the same zone, you're OK, it's just the tubes.
I'd suggest, leave it like this, and see how the tubes do over the course of a month or so, if anything develops. If all goes well, and you want to mess with the bias, THEN if you want to consider adjusting the bias, it makes more sense--AFTER you know the amp is good and stable at a decent bias point...in fact one or more tubes may drift in how they are biasing with some use, even in a month, at these voltages. You'll know more later.
I think the key info here and now:
1) It sounds OK, stable and it's holding up well after all the work you did on it?
2) Since we know where it's biasing at generally, is there much difference in bias from tube to tube?