current bias for 6L6

[sergio]

What is the range value for the 6L6 tubes?

more of 35mA?

Thanks

[tele_player]

It depends on the plate voltage, but in most cases, way less than that is appropriate - more like 20-25ma.

You should check the plate voltage, and calculate plate dissipation, and probably bias it so plate dissipation is 60-70% of maximum.

[greiswig]

I'm not sure I agree...for 6L6's, 35ma would be relatively "cold" (low current) for an amp with 430V on the plates. 20-25ma is more like what you would expect for 6V6's. Unless he has a much higher plate voltage than that, 35ma should be fine.

But yes, the plate voltage is another necessary thing to know for figuring out what your power dissipation is. Sergio, take a look at http://www.webervst.com/tubes/calcbias.htm
for some useful insight.

[v00d00blues79]

I've run mine at 38-40mA with 450-470v on the plates and not had problems...


Andy

[Johnhenry]

you need to look at a Tube data sheet for the type of 6L6 tube you want to bais to get the proper dissapation, there's a lot of Diff in the spec's when you look at a 6L6 to a 6L6 GT tube, Close will get you in the ballpark but if you check for your tube's rating it'll get you closer to max. power
Johnhenry

[odourboy]

I recall Dogears recommended a relatively cool 35mA for D amps.

[sergio]

Thanks all for help me

Sergio

[Structo]

I recall Dogears recommended a relatively cool 35mA for D amps.

Depends what your plate voltage is doesn't it?
Mine is around 430v and according to that chart that is pretty low.

[odourboy]

I recall Dogears recommended a relatively cool 35mA for D amps.

Depends what your plate voltage is doesn't it?
Mine is around 430v and according to that chart that is pretty low.

I don't think he qualified it, but a fair assumption is with Twin iron, so that would be about 440-450V typically. So, yes, that's low, thus the 'relatively cool' qualification. I biased my 6L6 HRM build to 35mA. Sounds good to me. In other amps I go higher.