Has anyone simulated an "Aikido" amplifier?

[G]

I thinking about trying to build a integrated Aikido amp using 6sl7s in the gain stage, 6sn7s in the CF stage and SE triode connected EL34s on the output. I'm wondering if anyone has a model for this circuit in general. I think I would need to change the 1M resistors in the first stage to 470K to bring down the gain in the first stage so I don't clip the EL34s. Thoughts? Here is a similar circuit using a 300B:

http://www.tubecad.com/2006/05/blog0064.htm

Go to the bottom of the page for the circuit in question. Obviously a EL34 does not need nearly the drive that a 300B does. If anyone has the software with the model schematic already there maybe they could plug in the different tubes and see what happens? I think I could run the 6sl7s at around 1mA and the 6sn7s at around 5mA and have no problems driving the EL34 but as I said before I would like be able to crank it without clipping the output stage. Any help would be appreciated. Thanks.

[Tubes4e4]

Hi Gavin,

did you consider to apply, say, 6dB of gNFB? This would half the sensitivity at input and double the DF of the power stage.

Tom

[Andypairo]

Since the gain is half of the mu of the first tube... you could pick up a lower mu tube as well without spoiling the circuit, that relies on its simmetry to achieve such good results without overall NFB.

Just my 2cents

Andrea

[James D.]

Whynot just use 6sn7s for both stages? Gain of 10 seems about right for driving an El34 in triode...

[G]

Originally posted by James D.
Whynot just use 6sn7s for both stages? Gain of 10 seems about right for driving an El34 in triode...

What I'm wanting to do is use this as a stand alone component and forgo a preamp. I didn't think a 6SN7 would have enough gain to drive a EL34 to full output for a given plate voltage and bias. My DAC puts out around 2 volt rms so I think I need a gain of 20. I'll be running the EL34 in triode at 55mA (as much as my transformers will allow) with about 22 volts sitting on the cathode so I would need about 40v PP to drive it to the edge of clipping. I suppose I could just build the thing and then play around with the biasing until I get it where I want it.

[Giaime]

With 22Vgk on the EL34, and 2Vrms output of the DAC, you need a gain of 7.77 So use 6SN7 with a gain of 10 and you'll be fine.

[James D.]

To be explicit:

Your DAC has 2Vrms out and that is +/- 2.8V or 5.6Vpp ouput

and you want 44Vpp to drive the EL34 into cutoff so a gain of 10 is perfect for your front end.

James

[G]

Thank you both for correcting me. 6SN7 it is.