More 6AU6 p/p amp ideas

[tubenit]

one 100ohm, two 200ohm resistors, or four 400ohm

I don't understand what that means?  Not saying it's incorrect, just not sure what it means?


I may be approaching this completely wrong since I am not that knowledgeable about this stuff? 

For a SE 6V6, I would use 470R      Like in the Fender Champ 

http://www.el34world.com/charts/Schematics/files/fender/champ_5f1_schem.pdf

And for a P/P 6V6, I would use 250R   Like in a Fender 5E3

http://www.el34world.com/charts/Schematics/files/fender/DELUXE_5E3.pdf


So I was thinking when you double the number of tubes, that you half the cathode resistor value? 

Is that accurate or incorrect, please?   I may be way off on this?

With respect, Tubenit

[DummyLoad]

one 100ohm, two 200ohm resistors, or four 400ohm

allow me clarify.

one 100ohm if you have 4 tubes sharing one cathode resistor.
two 200ohm if you have 4 tubes with one 200ohm under each pair
four 400ohm if you have 4 tubes each with it's own cathode resistor.

double the current halve the resistance. halve the current double the resistance.

--DL

[zambo]

It makes so much sense when you put it like that. Thanks!

[zambo]

ok here is the latest updated schematic. I cant get my puter to make this a jpeg or gif. will do asap. Thanks again for the help.









Zambo,  you need to edit it to a bitmap (BMP) then save to a GIF ...... then "shrink" it down to a postable size by hitting "stretch"
feature (under windows "PAINT")  and stretching smaller to 45%    Tubenit

[TIMBO]

Hi guy's,All very interesting stuff and it seems that this idea may apply to other preamp tubes http://www.ampbooks.com/home/amp-technology/EF86-power-amp/bes .

[DummyLoad]

ok trying to post schematic.

zambo, either the schematic is drawn wrong or the NFB ckt. is basically ineffective. as drawn the 100K NFB resistor has a direct path to ground and the 5K pot and 100nF cap are shorted to ground.

peace.

--DL

[tubenit]

zambo, either the schematic is drawn wrong or the NFB ckt. is basically ineffective. as drawn the 100K NFB resistor has a direct path to ground and the 5K pot and 100nF cap are shorted to ground.

Good catch!

This would be an option and something I've done on some of my amps.

Tubenit

[arjepsen]

Hmm... aren't the 2k2's going to the screens shown wrong?
It looks like there's a 2k2 going from "B" to the screen on the "bottom" tubes, and then another 2k2 going from the screen to the screen on the "top" tubes....
should these resistors both go from "B"?

EDIT:  corrected schematic above post  Tubenit