Aikido 9pin with 6n1p and 6n6p as Headphone

[eeyore]

I recently bought the Aikido All in One 9 pin kit a few months back, and now collating the parts to build. This is for a headphone build version

The concept was for a 6n1p input and 6n6p output tube. The B+ would be somewhere in the 150-200V range, as I have a 0-115V dual secondary transformer.

I was thinking for the cathode resistors as 250r for the 6n1p and 400r for the 6n6p, would that be sensible? Which I think, gives a bias current of around 8mA for the 1p and 15mA for the 6p?

Your thoughts appreciated!

[eeyore]

Looking at the Russian datasheet curves, if I wanted to run the 6n6p at 27.5 mA, -4V on the grid and 150V on the plates, would necessitate a B+ of 308V on the Aikido (is it because each triode sees only half the B+, and thus, to get 150V on each plate, would be 150+150+4+4V). That would mean a cathode resistor of 145R.

Would this be the correct assumption?

[DualTriode]

Hello,
You look to be on track or at least it makes sense to me so far.
How do the headphones connect? What impedance headphones? What is the impedance output? Are you going to use an output transformer?
DT
All just for fun!

[eeyore]

Senn HD650, and in future either HD800 or Beyer T1. All 300R plus headphones.

No output transformer, just using the standard kit. However, I do have a paid of Hammond 119DA that are not being used, so a transformer output could be relevant.

[DualTriode]

Hello,
I have used Senn HD 600’s with the Aikido with and without a Para Transformer. The output tube you are using looks to have the current to drive your headphones. The connected active load line will be steep and the output impedance will be high. Some people have a preference for a lower (less than 20 ohm) output impedance and feel the Bass end of response from the Senns is a little flabby due to the absent dampening factor using the OTL Aikido.
I have used this Trans former,
EDCOR Electronics Corporation. WSM600/15K
and the Hammond 119D. Both tighten up the output impedance and dampening ratio well.
Using the transformer allows you to use a smaller metalized poly Pro capacitor at the output.
Plug it in try it with and without the transformer and let us know what you think.
DT
All just for Fun!

[eeyore]

Will try the transformer. Basically it just gets connected to the output between the normal Aikido output and the headphone terminals right?

The other question was potentially using 5670 as the first tube instead of the 6n1p. Lots of substitution options, etc, might be a fun tube to roll, but about its sonic signature?

[Stixx]

Basically it just gets connected to the output between the normal Aikido output and the headphone terminals right?

Yes, see pic.
Am using that for over a year now, my Aikido still being on the breadboard.
But casing up is making progress, and parafeed transformers will be upgraded to custom trannies from AE in Holland.

[DualTriode]

Originally Posted by eeyore

The other question was potentially using 5670 as the first tube instead of the 6n1p. Lots of substitution options, etc, might be a fun tube to roll, but about its sonic signature?

Hello eeyore,
I would also roll in some other tubes just to mix it up a little. Check the user’s manual for a long list to consider. The 5670 is a nice little tube; I don’t think that you will find it on the list. It has a different pin out,
DT
All just for Fun!