Deluxe Reverb 6l6/5881 BIAS question

ChrisCox1994

Correct me if I'm about to blow my amp up but...... in the quest for clean headroom, I have a local tech who does biasing, some tung-sol 5881s and a Deluxe Reverb with a 75 watt creamback in it.

Is it realy just a case of re-biasing the amp as the fenderguru website would suggest? 

If so what number should I tell the tech to bias to? 

Am I likely to prematurely wear any transformers, caps, etc whatever by doing this? 

Cheers. 

ESchap

What does the Fenderguru site suggest?  raising the bias?   If so, the amp should be OK unless you change the cap / resistor values to go higher than design.  With higher bias you'll wear out the output valves quicker and depending on how high, they may be more prone to failure. 

ICBM

On the reissues there's just enough range on the trimmer to bias them correctly with 6L6s. With an original you might have to reduce the feed resistor value. Also make sure the amp is set for 240V and not 230 as they come stock - you'll get a bit more bias voltage.

For absolute maximum clean headroom, you also want to fit a solid-state rectifier plug-in - not a valve-emulating one, just a straight diode pair. The cap ratings are high enough in the reissue that it's also safe to do this with no other mod.

It won't cause increased wear or other harm.

roberty

Hey, bumping an old thread here but I bought @ChrisCox1994 's DRRI off him the other day and would like to swap the recto for solid state. Would this thing from Thomann do it, or is there something else anyone can recommend?

https://www.thomann.de/gb/tad_rectifier_rt515_gleichrichter.htm?

Cheers

ICBM

Yes, that will work fine. It's the same as the TAD one, although the shipping appears to be cheaper.

james

I'd like to try a solid state rectifier in mine. Does it require anything else, such as rebiasing?

ChrisCox1994

I personally liked the squash of the valve recto with the added overall power of the 5881s, that was the point... SS recto makes it more like a blues deluxe etc - but a fancy one at that.

ICBM

james said:

I'd like to try a solid state rectifier in mine. Does it require anything else, such as rebiasing?

It probably will - the plate voltage will go up quite a lot, so the bias will need adjusting or the valves will be running a bit hot.