Little OT. Building a Tube Power Amp.

[SISKO]

Hi.
Im building a tube power amp on a JCM800 like chassis. The first tube its gonna be the pashe splitter. The othres two socket from the preamp are gonna be for two EL84, and the octal sockets for the EL34, so one would have the chance to play with one pair, or the other.
Now, my question is this, Would i have problem/s running in parallel the chords from the octals to the novals? Kind of oscilations or somethin alike?

[soulsonic]

Using both EL34s and EL84s would require two different power supply setups and two different output transformers. Basically, you'd likely have to build two separate amps in the same chassis. Those two tube types are so totally different, it's not really practical to mix them in one circuit.

[SISKO]

The change in supply and bias its already done. I was hopping to get something like the THD Univalve (if i remeber correctly the model). Since my OT its overdimensioned, i hope to have no problem with that

[snoof]

check here for some answers...

http://www.ppwatt.com/

[soulsonic]

If you have the power issues all sorted out, then I guess you don't have to worry about anything. As long as the unused section is muted, there shouldn't be any issues with interaction.

The way the Univalve works is it's setup to be able to have many different types of tubes plugged into it - but what your describing sounds different. Are you only going to have one set plugged in at a time, or is it going to switch between the two different outputs?

[SISKO]

Hey that was what a ment. On pair (set) at a time. My question was concerned on the problem that may have if you run the powers chord from one pair of socket (octals) to the others (novals) in paralel. Crosstalking, or oscillation.

[R.G.]

If by "powers chord" you meant "heater wiring", sure, that's fine.

But you probably need to have separate grid coupling capacitors to each tube, not paralleling the grids of the novals and octals. They'll have very different bias voltages.

[SISKO]

Thanks guys for your patience on traiyng to undestand my words. I tend to be not so clear when i write.

My idea its to have a class AB1 tube power amp. Whit its own phase splitter and 4 sockets for the power tubes (2 novals and 2 octals), where you can plug one set of novals power tubes (el84) or another set of octals power tubes (el34). But no boths set at the same time.

Now my question is this (i hope to be clear this time ). Would i have any problem if i ran the grid (and the cathode, anode and screen grid) wire from both tubes sockets (the octals) in paralel to the other two sockets (the novals)?
Let me know of a picture would be more helpfull.
Thanks for your patience, again

[morcey2]

I would suggest drawing up a schematic and re-asking this at ppwatt.com or ax84.com.  Lots of us are at both here and the other places, but there are many extremely knowledgable people that can help and may have done something really close to what you're doing.    A schem and pictures would be extremely helpful. 

Matt