For cathode biased power tube up to 100% is permissible, though 95% is preferred. Some amp designs with certain tube brands and/or tube tolerances can default to almost 120% and is one big reason why trained techs should do power tube changes.
For fixed bias amps the bias is manually adjustable to taste. Typically 65% being cool biased, 70% being moderate bias, and 75% being hot biased. There are many videos on YouTube where they say "set your EL34's to 30mA" or "set the 6L6 to 50mA" which in certain amps may work as a generic setting, however the gain of the specific tubes being used and variances between chassis may result in a way too cool or way too hot a setting. For my 2204 build with EL34's and to get 70% dissipation the setting worked out to be 44mA, yet in my JVM210c which also uses EL34's the same 70% dissipation setting came in at 35mA, so tube type alone does not dictate the idle current through the power tubes.
Either way a cooler setting adds to the longevity of the tube. Hotter settings burn through the tubes quicker.... case in point - Angus Young likes his amps biased as hot as possible at 75 to 80% or more... His power tubes on all his dozen or so Marshall heads get changed after 3 gigs, that's if they last that long...
Builds-
#18 PBG GSH-1R https://www.buildyourownguitar.com.a...ad.php?t=10236
#17 PBG PBA-4 https://www.buildyourownguitar.com.a...ead.php?t=9984
#16 PBG IB-1Q http://www.buildyourownguitar.com.au...ead.php?t=8754
#15 PBG TLA-12 http://www.buildyourownguitar.com.au...ead.php?t=8444
#14 PBG PRS-1H
#11 Scratch build AC15 clone headhttps://www.buildyourownguitar.com.a...ead.php?t=7686
#09 PBG ES-1TL
#07 partscaster Alder Denim Tele.
Some more tube theory Gold...
1523 pages of heavy going tube and basic electronics theory from circa 1954...
https://ia601602.us.archive.org/18/i...dbook_1954.pdf
Builds-
#18 PBG GSH-1R https://www.buildyourownguitar.com.a...ad.php?t=10236
#17 PBG PBA-4 https://www.buildyourownguitar.com.a...ead.php?t=9984
#16 PBG IB-1Q http://www.buildyourownguitar.com.au...ead.php?t=8754
#15 PBG TLA-12 http://www.buildyourownguitar.com.au...ead.php?t=8444
#14 PBG PRS-1H
#11 Scratch build AC15 clone headhttps://www.buildyourownguitar.com.a...ead.php?t=7686
#09 PBG ES-1TL
#07 partscaster Alder Denim Tele.
Success at last... I have got my DAW setup working and have made some files that I can upload to soundcloud.
I do like my crunch, and Seymour Duncan rails pick ups in this partscaster Alder Strat build into the hi gain input of the amp do make the first stage JJ 12AX7 work pretty hard. Nil pedals and "All the gain !!!" is just the ticket to hide my horrible playing really well (I am more a tech than a musician after all).
The vented cab is loaded with 16 ohm versions of a V30 and a G12H75 wired in parallel to give an 8 ohm load to the amp. The cab itself is made from 17mm form ply from the big Green shed and is a HiFi ported bass reflex design modified for guitar use which is the reason for the massive bass roll off on the amp. One SM57 into the Behringer USB interface to the i5 laptop running Reaper 5.6 ...
I intend to play with microphone options latter but just getting one track down of something was the first objective...
https://soundcloud.com/user-26130539...tscaster-build
Builds-
#18 PBG GSH-1R https://www.buildyourownguitar.com.a...ad.php?t=10236
#17 PBG PBA-4 https://www.buildyourownguitar.com.a...ead.php?t=9984
#16 PBG IB-1Q http://www.buildyourownguitar.com.au...ead.php?t=8754
#15 PBG TLA-12 http://www.buildyourownguitar.com.au...ead.php?t=8444
#14 PBG PRS-1H
#11 Scratch build AC15 clone headhttps://www.buildyourownguitar.com.a...ead.php?t=7686
#09 PBG ES-1TL
#07 partscaster Alder Denim Tele.
I can see it on SC but it's greyed out and won't play, have you got the settings right
I believe so Dave. It plays fine for me. What settings do I need to set right?
Builds-
#18 PBG GSH-1R https://www.buildyourownguitar.com.a...ad.php?t=10236
#17 PBG PBA-4 https://www.buildyourownguitar.com.a...ead.php?t=9984
#16 PBG IB-1Q http://www.buildyourownguitar.com.au...ead.php?t=8754
#15 PBG TLA-12 http://www.buildyourownguitar.com.au...ead.php?t=8444
#14 PBG PRS-1H
#11 Scratch build AC15 clone headhttps://www.buildyourownguitar.com.a...ead.php?t=7686
#09 PBG ES-1TL
#07 partscaster Alder Denim Tele.
I checked out the soundcloud demo and it played fine for me.
Builds-
#18 PBG GSH-1R https://www.buildyourownguitar.com.a...ad.php?t=10236
#17 PBG PBA-4 https://www.buildyourownguitar.com.a...ead.php?t=9984
#16 PBG IB-1Q http://www.buildyourownguitar.com.au...ead.php?t=8754
#15 PBG TLA-12 http://www.buildyourownguitar.com.au...ead.php?t=8444
#14 PBG PRS-1H
#11 Scratch build AC15 clone headhttps://www.buildyourownguitar.com.a...ead.php?t=7686
#09 PBG ES-1TL
#07 partscaster Alder Denim Tele.
It's now visible Marcel but it's late and the www seems to be slow ( one handed typists late at night bogging it down I guess ) will check it out in the morning and also do a screen shot of the settings I use which do have a lot of limitations for copywrite purposes which obviously don't apply here