JJ 6L6GC's in my 5150: bias setting

[hellraiser85]

Hi! I've bought four matched JJ 6L6GC's to retube my 5150. A technician has installed a bias control in my amp and I would like to know how the bias must fit to obtain the best sound of my amp with these concrete power tubes. I want that it sounds tight, with percussive and punchy palm mutes (because I play metal with 7 string guitar and it tends to sound a bit muddy).

How must bias be fitted?

- cold setting (similar to the original bias setting in a stock 5150)
- medium setting
- hot setting

Thanks!

 

[Potshot]

somewhere around 32ma - 35ma, depends on the tube really, whatever it takes to get it out of crossover distortion and sounding sweet, not really something you can easily check without an oscilloscope I believe.

 

[Wolfeman]

The hotter, the better IMO...
But if you want your tubes to last, don't go to hot.
I'm not familiar with what the 5150 likes, but in my SLO I run the tubes hotter than shit(42mA), and they sound amazing. 6 months like that, being played every day, and they are still going strong.

But 35 would probably be safe and sufficient.

Remember, your range of bias may be limited, depending on the pot and resistor your tech put in.

 

[hellraiser85]

ok, thanks for the information!

 

[Metaltastic]

Bob on eurotubes recommends 36-40 mA, I have my JSX around 38, and the JJ KT77's in it are still going strong after semi-regular use for almost a year!