View Full Version : Vp=480V on new-production 6L6es; OK?
MikeMcK
08-26-2008, 12:16 PM
I have a Ceriatone Overtone Special with 6L6es. The closest schematic I can find shows 440V on the plates, but I'm measuring 480 on mine.
The 6L6 data sheets I've found show Vp(max) = 500V, but I've also heard that newer 6L6es (these are SED Winged C) are a lot less robust. I'm wondering if there needs to be some adjustment or if the 480 V is OK.
I'm biasing each tube to dissipate < 21W, so Ip=40 mA.
scottl
08-26-2008, 12:45 PM
I'd set at 32-32ma. Also, I'd raise the 1st dropping string resistor to something in the 6.8K to 8.2K range. Otherwise, you preamp voltages are going to be highe than Dumble had them. Just sayin'.... Assuming you have 480v....
MikeMcK
08-26-2008, 03:20 PM
I'd set at 32-32ma. Also, I'd raise the 1st dropping string resistor to something in the 6.8K to 8.2K range. Otherwise, you preamp voltages are going to be highe than Dumble had them. Just sayin'.... Assuming you have 480v....
Thanks Scott... normally I'd take this with a big grain of salt, but I have heard your clips. Appreciate it.
MikeMcK
08-26-2008, 07:50 PM
Okay, here comes my ignorance...
I'm assuming that the "1st string dropping resistor" is the first leg of the dc signal out of the rectifier/bridge and filter. If the circuit has a choke, should the added resistance be in series with the choke, or additional resistance in the next leg off the power supply?
RussB
08-26-2008, 08:26 PM
Does the amp more awesome biased at 40mA as opposed to say, 32mA?
MikeMcK
08-26-2008, 08:55 PM
Does the amp more awesome biased at 40mA as opposed to say, 32mA?
Hard to say until I really crank it... maybe in a day or two. I don't use a ton of gainy distortion, though.
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