Hybrid Aikido-ish gain stage

[Fuling]

How about this circuit for driving a Mosfet power follower?
ECC86 is the european version of 6GM8, before anyone misreads and asks why I´m using ECC88 (6DJ8) at such low plate voltage.

A short explanation of the schematic:
The triode is of course the actual gain device, operating at 15V 2mA. The plate is loaded with a 2SK170-based CCS and direct coupled to a cascoded Jfet White follower.
This *should* give that whimpy little triode pretty much optimal circumstances to do it´s job as a voltage gain stage.
IME this tube is hardly capable of driving anything by itself, but this follower should be a very easy load.

 

[JoshK]

This circuit looks pretty cool to my newbish eyes. Have you built it yet?

 

[Fuling]

I´m working on it, will probably finish it tomorrow

 

[Fuling]

The circuit is built and tested and the results are very promising!
50kHz with a IRFP260-based follower on the output is no problem.
I´m planning to run much more tests on this one later, when I can borrow some better test equioment.

 

[kacernator]

Another hybrid idea

Hi,

I have come up with this Aikido hybrid preamp. In simulation distortion is same as with 6SN7 as cathode follower. I have not built it yet, so no comparison with all tube Aikido.

MJE350 is biased at 4mA and IRF610 at 10mA.

 

[ilimzn]

MOSFETs are not triodes, rather pentodes, and the influence of Vds to drain current is very small, hence no sense doing an Aikido style ripple nulling CCS for a MOSFET.

 

[kacernator]

Look here and scroll down to chapter "Variations".

Aikido Tube Amplifiers