66 DR Bias and plate V

[blackguard1135]

I've just been reading Gerald Weber's book Hip Vintage Guitar Amps and he says that DR's 6V6 plate voltage should not exceed 425V.He also says that that if the bias is adjusted for greater current (he suggests 30mA per tube) that the plate voltage will decrease. I, in my limited knowledge, thought that plate voltage was determined by the rectifier tube independent of anything else.
Does it actually move up or down depending on the tube current draw?

With my (Ted) Weber Bias Rite I get a reading of 26.5 mA current draw and 434V on the plates which I've been told is fairly "hot". If I adjust the bias so that the tubes draw 30mVs each and the plate V drops, will that still be considered "hot?"

The amp sounds incredible right where it is, but according to G. Weber, I'm running the plate V too high.

any thoughts?

[Bluesbob]

it is good! Don't worry about 9 volts. I don't ever bias a 6V6 at 30mA. Enjoy your amp.

[Tremo]

Originally Posted by blackguard1135

I've just been reading Gerald Weber's book Hip Vintage Guitar Amps and he says that DR's 6V6 plate voltage should not exceed 425V.He also says that that if the bias is adjusted for greater current (he suggests 30mA per tube) that the plate voltage will decrease. I, in my limited knowledge, thought that plate voltage was determined by the rectifier tube independent of anything else.
Does it actually move up or down depending on the tube current draw?

With my (Ted) Weber Bias Rite I get a reading of 26.5 mA current draw and 434V on the plates which I've been told is fairly "hot". If I adjust the bias so that the tubes draw 30mVs each and the plate V drops, will that still be considered "hot?"

The amp sounds incredible right where it is, but according to G. Weber, I'm running the plate V too high.

any thoughts?

Yes. Take these pages of MISINFORMATION, tear them out of the book, and use them for what they're worth, wipe in the restroom. Old Gerrie is totally WRONG on this one. The LAST thing you want to do is use tube idle current to load down the power supply to cause it to sag to some predetermined level. All you will do is overstress the tube (over-dissipation) in both the plate and screen, possibly leading to meltdown and catastrophic failure. No tech with even half a clue would suggest doing that.

NOS 6V6s can generally take the overvoltage of the DR. The current production JJ 6V6 can as well. I would not trust ANY of the current manufacture Chinese or Russian 6V6s however. 435 on the plates isn't so bad, just use a quality 6V6 and bias normally, you should be fine.

I personally own a 64 BFDR and run the JJ 6V6s in it. I biased it to 25 mA, and let the plate voltage fall where it may. That was well over 2 years ago. since then I've pounded the livin hell outta it, and those tubes just keep on tickin. Sounds good as well.

Don't fall for the hype and BS that you read in some high-profile BS-meister's books and magazine articles.

[krashjones]

I tend to prefer the tone of the EH tubes (Russian tube bashing aside) but they are rated at 450V IIRC and I know the JJ's are rated at 500V.

In my friend's Super Reverb converted for 6V6s it has about 450V on the plates and biased at about 30mA it sounds great, but does go through tubes relatively fast even with JJs. Maybe a set every six months of gigging. With 420V and 25mA in my Princeton Reverb 6V6EH's last many years.

[Wally]

Most folks like what 6V6's do in the 22-25ma range. Running them at a higher current draw is hotter and does lower the plate voltage. Would I run a tube way hot just to get plate voltage down? I doubt it. would I take note of plate voltage on a DR with the current draw set where I want it. Yes. Will a JJ handle what a DR has to throw at it? yes. Do other current manufacture
6V6's have the ability to handle those voltages? I don't know because I never took the chance. Before JJ's, I would run NOS or 6L6's in DR's to insure that the tube would work at the voltages that DR's develop. Post JJ's, no worry. What tubes are you running?

[11 Gauge]

Heck, I dropped a pair in my 50 watt Marshall, and that amp only has 388 on the plates!

I was so impressed with Lord Valve's conclusion on the bulletproof nature of the JJ 6V6S that I just had to try out a pair.

I dropped 'em in and biased it at a hair over 25 mA. Even with the low plate voltages, they sound fantastic for a current production tube.

[blackguard1135]

I'm running NOS JAN GE 6V6 coin base.
Great tube (I think 1970s military). Clear and strong clean and nice breakup at around 6.

This DR is not my main gigging amp so these GEs have been in there a long time. They were in there 10 yrs ago when I bought the amp. And when I bought it. Since then I've used the amp only in small clubs, but usually cranked. Those tubes are certainly still strong. The others are V1= JAN GE 12AX7WA, V2=RCA 12AX7, V3=Mullard CV 4024, V4=JAN GE 12 AX7WA, V5=I'm not sure, V6=Mullard CV 4024. The GZ34 is a new JJ.

I do have a matched pair of RCA blackplates but want to learn a bit more about setting the bias correctly before I put those in.

My other amp is a Bruno Cowtipper 35—yeah, I know—I had to starve for a while after buying that one. And it's everything they say about it: like the holy grail, but there's something about the DR, it's got that vibe—it's just about perfect for all situations. I just wish that damned drummer wouldn't hit em so hard—I'd use it all the time!

[jjmantele]

Originally Posted by blackguard1135

..............With my (Ted) Weber Bias Rite I get a reading of 26.5 mA current draw and 434V on the plates which I've been told is fairly "hot". If I adjust the bias so that the tubes draw 30mVs each and the plate V drops, will that still be considered "hot?"
.............

"Hot" means high wattage, not plate voltage. You get more watts by increasing (milli) amps. Even though the plate voltage goes down when you increase current, the wattage goes up. voltsxamps=watts

High plate voltage and "hot" are not refering to the same thing. Both matter.