NAD: 50w SLO clone

[viking]

Great tone  :D! Well done !

[Transcend]

Thanks!

[teepants]

Nice job and awesome sound! What biasing values do you use in power tubes?

I own the original SLO100 and I'm swapping the power tubes from factory Sovteks to TAD 6L6GC's and I think they're re-labelled JJ's... Soldano recommends cold biasing values like 25-30 mA with 6L6's. Did you test any different values with JJ's?

Thanks!

[Transcend]

I currently have them biased a bit cold at 33.3ma per valve.

what i use to figure it out is the plate dissipation of the tube divided by the plate voltage multiplied by .7

[Dmoney]

I wouldn't say any of those numbers are really cold, more like on the cool side.
It's not like the 5150 I had that was idling at 14mA before a bias adjust mod.
I know Soldano recommend ~26mA for EL34's.

When I put that 50watt transformer into my 6V6 build and moved up to EL34, I made sure the EL34's were biased as cold as possible when I fired them up... the amp sounded bad. that was 11mA per valve. Once I cranked that up to 30-40mA it sounded much much better, but not a huge difference in that range of 10mA I'd say. Not as much difference as 11mA and 40mA a side. The amp I'm on about has an SLO lead channel but approx 30watt about. 390v on the plates as opposed to the 495v or whatever is in the SLO.

[Transcend]

I wouldn't say any of those numbers are really cold, more like on the cool side.
It's not like the 5150 I had that was idling at 14mA before a bias adjust mod.
I know Soldano recommend ~26mA for EL34's.

When I put that 50watt transformer into my 6V6 build and moved up to EL34, I made sure the EL34's were biased as cold as possible when I fired them up... the amp sounded bad. that was 11mA per valve. Once I cranked that up to 30-40mA it sounded much much better, but not a huge difference in that range of 10mA I'd say. Not as much difference as 11mA and 40mA a side. The amp I'm on about has an SLO lead channel but approx 30watt about. 390v on the plates as opposed to the 495v or whatever is in the SLO.

Mine is a touch high at 527v but everything is working fine and i havent noticed any stability issues but i am keeping an eye on it.

the 5150 bias is a bit peculiar.

i guess the tubes last ages though

[Dmoney]

yeah I guess. I think the other main advantage is that it's probably hard to get a set of 5881's or whatever that will draw enough current to get that bias up to anything near dangerous, so people can change the valves at home easier without going to a tech. Peavey also sell (or used to sell) plastic tubes of matched valves. JJ's. I bought a couple once.
The other theory is that in the 5150, the output valves are biased so cold that it brings on cross over distortion which is 'part of the 5150 sound', or what EVH wanted or whatever.

527vDC is a good little voltage eh? you're in the plus 500 club.