Biasing Ruby 6L6GCMSTR in Laney VH100R

[Emetal]

Hey guys I got new tubes and wanna bias them, just wanna check my numbers here with you because I found on the internet that maximum dissipation wattage for these Ruby tubes is 30 W ? So my numbers for biasing at 60% with plate voltage of 415 V comes up like this:

30W*600/415 V = 43.3 mA

Does this looks OK to everybody?

[JazzGuitarGimp]

Yes, 415V * 0.0433A = 17.97W - and 18W is 60% of 30W. So you nailed it!

[xtian]

Yes.

Here's a nice bias calculator to confirm your work:

http://www.ax84.com/biascalc.html?Bvolt ... ction=calc

[Emetal]

Thanks guys PS bias is currently only 20 mA which is SERIOUSLY low and the amp still sounds OK, can't wait to hear it with proper bias

[JazzGuitarGimp]

Keep in mind that when you go up from 20mA per tube to 43mA per tube, your B+ will go down to something lower than 415V, so you'll need to recalculate for the new current to achieve 60%.

[Emetal]

Yeap, B+ went down to 392 volts, gotta chase around a little with calculations, not a problem Love doing stuff with the amp.