-grid supply, 7809 or 7808 '~=''?

[petemoore]

  6sn7 as best I can find info for wants a -8v grid supply.
  290v plate supply...6.3 spot on for heaters, I just need the -8 [very DC-like] to bias the grid with instead of the battery [chuckles.
  I have an amplifier working, sounds extrodinarily nice, the simple easy [less than reliable] way to bias grid, a weak battery !
  I tried and debugged pretty good I think the 2w PP poweramp at ax84 but got -3 volts out of that. I don't understand how it works exactly to debug it...kind of just a couple diodes from 1/2 of a secondary tap...a string of resistors and filter caps..pretty simple, I though of 'adjusting' it but decided to either figure that, or an alternative out.
   For now the battery is on a switch, and the low gate current...not too worried...just don't try it at home without measuring the battery...my tube was redplating with a 3v grid bias.

[Gus]

I am not understanding your post there is not enough information

Are you using the 6sn7 as a dual triode output in a push pull amp?

The 6.3 volts AC or DC?

You don't want to cathode bias but you want fixed bias?

[petemoore]

   It's the AX84 2w Push Pull amplifier schematic, in Building Blocks section
  Are you using the 6sn7 as a dual triode output in a push pull amp?
  Yes, it sounds very good.
  The 6.3 volts AC or DC?
  AC..from secondary tap for the heaters.
You don't want to cathode bias but you want fixed bias?
  Yes, I'd like to try one, I have an LM317 here, there's room for another small transformer/rectifier/filter also...I was thinking just get 11 [or so] AC volts going then 'bend it down' to the 8volts I want for the fixed negative bias using the regulator [or string of diodes].
   I've only tried this once, this time, using a battery for it's floating ~8.5v to
-bias the PP output grids.
  The amp has 3x 6sn7 in it. One for preamp stages, one for phase inverter, The -bias is only for the grids on the PP output.

[merlinb]

  Yes, I'd like to try one, I have an LM317 here, there's room for another small transformer/rectifier/filter also...I was thinking just get 11 [or so] AC volts going then 'bend it down' to the 8volts I want for the fixed negative bias using the regulator [or string of diodes].

That bias supply in the schematic does exactly that- it takes the AC voltage of the transformer and half-wave rectifies it to make a negative DC voltage. Why on earth would you want to add another transformer/rectifier/regulator when you already have a system that does the same thing, and just needs to be trouble shooted??? It's only got one diode, a couple of resistors and a couple of capacitors, it can't be that hard to find what you've wired wrong!

[petemoore]

  OT:
That bias supply in the schematic does exactly that- it takes the AC voltage of the transformer and half-wave rectifies it to make a negative DC voltage.
 
 Why on earth would you want to add another transformer/rectifier/regulator when you already have a system that does the same thing, and just needs to be trouble shooted???
 Incorrect, I don't already have a system that does the same thing.
  I have an already crowded PS Section, I don't intend to attempt re-threads of added circuitry, much less debugs in that area, I have strong preference for 2 disconnected primary connections debugged [ie make sure the primary is good, test the secondary/isolate connections to AC120plug], then nice low tension voltage via Stancor w/LV secondary, outside the powersection and amplifier entirely, to debug and measure to hearts content...and as a way to defy the prevailing logic, having a cute little Stancor Iron, a 317 variable regulator, a 5k pot that could provide more lug/stays for the grid bias circuit + allow me to alter grid bias [for personal reasons such as why not, easier than askin' exactly what does grid bias drift sounds like]. BTW sounded pretty bad @3v.
 Yea, figure break it down, work with it at low voltage is asking for less trouble.
  It's only got one diode, a couple of resistors and a couple of capacitors, it can't be that hard to find what you've wired wrong!
 Yep, I can count the nodes connections on that circuit by now, even without the cheat sheet.
  In the meantime with the battery it works great.

[merlinb]

 Incorrect, I don't already have a system that does the same thing.

Sorry, I have trouble understanding your posts, I assume English is not your native language. You said
"I tried and debugged pretty good I think the 2w PP poweramp at ax84 but got -3 volts out of that."
So did you not build the whole circuit shown here?
http://ax84.com/static/corepoweramps/2W_PP/AX84_2W_PP_Poweramp_Schematic.pdf

  I have an already crowded PS Section, I don't intend to attempt re-threads of added circuitry,

But adding another transformer and PSU circuit will make it even more crowded and complicated...

+ allow me to alter grid bias [for personal reasons such as why not, easier than askin' exactly what does grid bias drift sounds like.]

But the original AX84 circuit already has an adjustment pot (VR1) so you can alter the grid bias. If you build it correctly, it will give you much more than -3V

[petemoore]

  I know better than to be so hasty...but sometimes I still am.
   Anyway, I thought it over again and decided I can do a proportional voltage.   
  Build the little circuit rectifier/filter/filter divider adj./10k>Gnd. ...bias divider string outside the box, test it at say 4v, do math for a minute, then another, place that in the open spot inside the chassis, connect it to the PT...test it in there.

[merlinb]

 

Instead of going OT in my threads:
 If you want to discuss your problems start your own thread, plain enough english for ya ?
 If you feel the need to urge others to cram circuits into already crowded HV sections of 'expensive' [cost me like 30 buxx, 3 days @ 8 hours a day], amplification, start your own thread to do it.
 Even if you want to praise the design of the 2w PP amplifiers grid bais section, I don't care about it...start your own thread for that too.

Now I'm plain bewildered.

[petemoore]

  Now I'm plain bewildered.
   Perhaps you can open your own threads for english grading, bewilderment training and advanced thread hijacking techniques.
   You've done a real wiz-bang job here, your skills, by the book that doesn't work and hostility toward experimentation are no longer wanted or needed here.