Where do you like to bias a Deluxe Reverb?

[Randall]

Where do you like to set bias on the 6V6's in a Deluxe Reverb, and why?

[Leo_Gnardo]

Generally 20 to 25 mA. Just a smidge past where the crossover notch disappears. Of course not all Deluxe Rev's are created exactly alike, the B+ varies somewhat, from the high 300's to 450V or so, and less bias current needed with higher voltages. I generally use JJ 6V6, one of their more reliable tubes.

Psst, big secret, I sometimes install 6L6's in Deluxes. Oh that'll melt the filament winding won't it? With 20-30+ amps done like that in the field, and used often by gigging musicians for 10-15 years or more, hasn't happened yet. Gets a tad more power, generally @ 25W, and increased tube lifetime. Bias current @ 30 mA, again dependent on B+. Princeton reverbs too, oh horrors me, what sacrilege, shame the devil! The pro muso's ain't complainin'! Good tone and reliability are where it's at.

[Chuck H]

+1 on the 6L6's. You can use lower power 6L6's like the "G" and 5881's. As to current with 6V6's I'll side with Leo. You need to keep the current consistent with the plate voltage for -75% dissipation at idle. This applies to new production 6V6's. NOS 6V6 were apparently more robust WRT current but more sensitive to high voltage because one popular suggestion for biasing was to increase current until the plate voltage dropped below 420Vp. I've only read about this and would never personally try it. But maybe someone here has some experience on this. I'd like some clarity too if there is any truth to it.

[Leo_Gnardo]

NOS 6V6 were apparently more robust WRT current but more sensitive to high voltage because one popular suggestion for biasing was to increase current until the plate voltage dropped below 420Vp. I've only read about this and would never personally try it. But maybe someone here has some experience on this. I'd like some clarity too if there is any truth to it.

I've found my old RCA 6V6 "pulls" seem to withstand high voltages and 100% plate power situations well. Others, not so much. I have a handful of vintage Visseaux which cost me plenty but wilt like hothouse flowers when the voltage goes past 325, also pass way too much current in self bias mode. I put a pair of $$ Mazda 6V6 shoulder tubes in a friend's brown Princeton (fairly low B+) and they have lasted him over 12 years so far, no sign of trouble. So NOS can be way different, brand to brand. Nothing new about that.

Got to ask Jim Kelley what about his amps that put nearly 500V on the plates of a quad of 6V6 - the JJ seem to resemble Sylvania STR's, another tough as nails 6V6.

I've found the EH (aka TungSol) 6V6 don't hold up too well. Use only in sub-400V amps if you expect them to last.

For a long time I've learned to distrust the "black painted" 6V6 from either Russia or China, ALTHOUGH on occasion I find a pair which have lasted in high-voltage situations in spite of their reputations for breaking down. For a while in the 90's these were just about the only new-manufacture 6V6's available, and they went up like firecrackers in the Kelleys. Also not happy in higher voltage Deluxes & Princetons so that's when I started swapping in 6L6's.

[JoeM]

Leo,

On the DRs you're putting 6L6s in, does that include the Re-Issues too? Wondering how the PT compares to the earlier BF or SF Fenders.

[Leo_Gnardo]

On the DRs you're putting 6L6s in, does that include the Re-Issues too? Wondering how the PT compares to the earlier BF or SF Fenders.

I avoided for years putting 6L6 into RI Deluxe Reverbs, expecting their PT's were probably not as tough as the original item. But within the last 2 years I have - and no meltdowns yet. So far so good.

[bob p]

By any chance would you know the impedance ratio for the vintage Fender DR OT? I know that I've got a repro BFDR OT from MM sitting around here in a box somewhere, but I just can't find it. It'd be interesting to compare.

I've always wondered what the Z ratio is for the original OT, and thought it'd be interesting to look at how the operating conditions for the tubes change if the load impedance is intentionally "mismatched" when you swap tube types. I've heard a lot of magical stories about running 6L6 on a BFDR type of OT and it'd be interesting to look into why this combination seems to be so popular.

[JoeM]

Bob,

Dont know if this applies to 'vintage' DRs. But a Mag Components DR OT I bought as an upgrade for my Princeton is 6600ohms for an 8 ohm load. And I've always heard that's what DRs are. (VS 8000 to 8 for a PR OT)