se 6v6 ?

[tim614]

Im trying to get a winter project going and i decided to build another RH84 amp but with 6v6. My question is, what needs to change on the rh84 schematic for 6v6 (beside changing bias point)? or any good se 6v6 schematic i should be looking at.
Thanks
TIM

 

[cubby01]

Out of curiosity what benefit are you looking to achieve with the 6v6 over the EL84?

 

[Tom Bavis]

Raise the cathode resistor for 6V6 vs. 6BQ5 - that's it. Exact value will depend on the B+ that you use. I'd also add a screen bypass cap for either tube - at least 10 uF @350 V.

 

[tim614]

Raise the cathode resistor for 6V6 vs. 6BQ5 - that's it. Exact value will depend on the B+ that you use. I'd also add a screen bypass cap for either tube - at least 10 uF @350 V.

Hi Tom
Thanks for the replied. I still dont under stand the part about ("I'd also add a screen bypass cap for either tube - at least 10 uF @350 V")
you mean both 6v6? or 6v6 and the 12AT7?
Sorry i can build anything according to direction but my tube knowledge are still very slow. please let me know if this is correct (SCHEMATIC)?

 

[tim614]

Out of curiosity what benefit are you looking to achieve with the 6v6 over the EL84?

Well i love the RH84 i've built and i have a pair edcor 5k se optx, 2 console pulled 275ct ptx and bunch of 6v6 so i figure its time to get the solder going
and build 2 monos.

 

[Kegger]

What kind of outputs do you have, if you have ones with UL taps you can
experiment with that, if so raise the 100k feedback resistor to say 300K or
experiment with doing away with it altogether.

I believe what Tom is saying is the 2.2k resistor on the screen to turn that
into an RC stage and run a cap to ground, I usually do the same thing and
power the driver stage from there as well.

 

[tim614]

What kind of outputs do you have, if you have ones with UL taps you can
experiment with that, if so raise the 100k feedback resistor to say 300K or
experiment with doing away with it altogether.

I believe what Tom is saying is the 2.2k resistor on the screen to turn that
into an RC stage and run a cap to ground, I usually do the same thing and
power the driver stage from there as well.

KEGGER i was hopping you chime in.
Yes the output does have UL taps.
Kegger do you have a schematic i can use for 6v6 se?
the reason i chose the RH was that im familiar with it i've built two so far

 

[Kegger]

I believe this is what Tom was saying..
(I usually take the B+ for the driver from that same 2.2k/cap position
an do away with 10K and cap up top to the driver when I do UL amps)

And the cathode resistor on the 6V6 take that to say oh 300ohm as well.

 

[Kegger]

If going UL, this is along the lines of what I'd do for that change.

 

[tim614]

Thanks Kegger!
Thanks Tom!
i might try both but the UL seem more intersting atleast im not building another RH

 

[thefragger]

Interesting... :scratch2:

 

[Kegger]

Thanks Kegger!
Thanks Tom!
I might try both but the UL seem more interesting at least I'm not building another RH

Looking to experiment a little more try another driver even.

6DJ8, 5965, (6BK7, 6BZ7, 6BQ7).. would work well here to...:yes:

 

[tim614]

Thanks guys!
I will start a thread when i get started.

 

[Dave C]

Kegger, What happens if I build this amp and slip a 7591 into that 6V6 position? Maybe drive it with a 6sn7 ?? You can PM me if you think this is a hijack.

 

[Kegger]

Sure PM me, I'd use this same basic circuit but you can either use more voltage
on the base amp or just run more current in the output, I'd suggest more voltage.

 

[tim614]

Kegger, What happens if I build this amp and slip a 7591 into that 6V6 position? Maybe drive it with a 6sn7 ?? You can PM me if you think this is a hijack.

Let's put it on the table please I would like to know how in detail if I can, 6sn7 was on my mind also

 

[Kegger]

Alright, when I get time then I'll post it up.

BUT, gunna need/want more voltage for both 7591 an the 6SN7, say like 375v B+ area.
(LED biasing on the 6SN7 is my suggestion as well for all the 6SN7's gain)

 

[tim614]

oooh!

 

[CharleyW]

A 6SL7 would be a better match to the 12AT7 than the 6SN7.