Hey I have a questions about biasing an amp with NOS 6L6GC's
Need some input
Plate votage is 410V with NOS 6L6GC's which on the weber bias calculator come to 51.2ma for Class AB 70%. Now my question is the percentage range from 51.2ma based of the plate voltage would be the low and high I would want to be within.
I never noticed but are most amps designed around the AB 70% figure or are they set slightly lower, more like 60%. I'm Just curious where others perfer to run there 6L6GC's and a nice range to find the tubes sweet spot.
NOS 6L6GC at 70%
Moderators: pompeiisneaks, Colossal
Re: NOS 6L6GC at 70%
I guess at 21 watts for the 6L6GC rated for max spec 30 watts/500v is not really pushing the tube limits but is optimum max
Am I correct ? This does not include crossover distortion considerations and what sounds the best within the range of the baising.
Am I correct ? This does not include crossover distortion considerations and what sounds the best within the range of the baising.
Re: NOS 6L6GC at 70%
yep 21W for a 30W tube is the nominal Class AB1 mode in PP. However they will run just as okay at 17W or anywhere in between - its really a matter of personal taste at this point.
Re: NOS 6L6GC at 70%
Some amps sound better with a colder bias while others sound best hotter.
So you have to experiment and as long as you are below 70% you are fine.
Usually when I bias an amp I try it with several bias settings between 60 and 70% and leave it set where it sounds best.
Keep in mind that the plate voltage will fluctuate a bit with different bias settings.
So you have to experiment and as long as you are below 70% you are fine.
Usually when I bias an amp I try it with several bias settings between 60 and 70% and leave it set where it sounds best.
Keep in mind that the plate voltage will fluctuate a bit with different bias settings.
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: NOS 6L6GC at 70%
I suggest you test at gig volumes. On my amps I have found that running more volume does change how they sound and react.
My 6L6 amp I started off at 30mV and played it loud for several minutes then raised the bias in increments of 5mV and play on again until I got it up to a point that scared me.
I found that (on my amp that is) that a low bias caused my amp to sound treble high and thin. As I raised the bias I could hear a punchy dynamic tone coming in with much added response to pick pressure and guitar volume. I must say I chickened out before I hit the end of the bias pot adjustments but that little bias test of mine taught me a lot about my amp and also about my supposed playing style. I know now that I like a pretty hot bias and I also know my personal preferred style requires a pretty hot bias but I'm not so sure my pocket book can afford my perfect setup amp, nor my perfect supposed playing style.
Personal taste, tube quality, amp setup, $$$ I'm willing to spend on replacement tubes, etc ... only in my personal opinion of course, will determine the best (maybe even the needed) bias point for any amp.
But then again..... all of this might, and probably will, change tomorrow. lol
good luck man
My 6L6 amp I started off at 30mV and played it loud for several minutes then raised the bias in increments of 5mV and play on again until I got it up to a point that scared me.
I found that (on my amp that is) that a low bias caused my amp to sound treble high and thin. As I raised the bias I could hear a punchy dynamic tone coming in with much added response to pick pressure and guitar volume. I must say I chickened out before I hit the end of the bias pot adjustments but that little bias test of mine taught me a lot about my amp and also about my supposed playing style. I know now that I like a pretty hot bias and I also know my personal preferred style requires a pretty hot bias but I'm not so sure my pocket book can afford my perfect setup amp, nor my perfect supposed playing style. Personal taste, tube quality, amp setup, $$$ I'm willing to spend on replacement tubes, etc
... only in my personal opinion of course, will determine the best (maybe even the needed) bias point for any amp.But then again..... all of this might, and probably will, change tomorrow. lol
good luck man