Lee Jackson Metaltronix Amplifiers

[beamish]

Hi Lee,
Did your Fender Concert Mod recently, which now sounds great. I have also replaced the tubes, EH Pre amp and Svetlana 6L6GC Power tubes.
The problem I have now is the power tubes are running to hot ( the plates start to glow). They were sovtek 5881WXT before I changed them and if I put the sovteks back in everything seems to be fine, but of course these are old tubes and sound abit lifeless. There seems to be about 50Ma running through the Svetlana`s which I believe should be between 35-37Mamps. Does this mean that the spec for Svetlana`s may be different than the Sovteks which also means I need to change the 470 1 watt resistors to get the voltage down. Am I thinking on the right lines or is it not that simple.
Thanks John

[LeeJackson]

Hi John

If the 5881's bias and the new tubes don't I would be concerned with the new tubes.

New Tube Production is not very good, I get bad new tubes all the time.
And if one of them is bad it will pull the bias down and burn the others.

I would try a new set before I changed the bias,

I would check the 470 ohm resistors to make sure they are the same value, if one is drastically different then the other, that causes biasing problems too.

[craiga23]

Hi Lohn

Just wondering about your thoughts on the upgrade?
how much difference is there than before to the drive
chanel & reverb, slight or great.

Regards, Craig.