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Aikido 9pin with 6n1p and 6n6p as Headphone

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!
 
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?
 
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!
 
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. ;)
 

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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!
 

kodabmx

Member
Paid Member
2011-10-31 1:00 am
Toronto
Included is a design I was given by John Broskie of tubecad.com

"It offers excellent balance and a gain of slightly over 2 with the 32-ohm load. With a 300-ohm load, the current-sense resistor value must be increased from 200 ohms to 255 ohms. (A toggle switch could be used which would short the 255-ohm resistor with a 931-ohm resistor for use with 32-ohm HPs.)"

I've built this for use with 470R headphones (ATH R70X) and subbed the 12AU7 for a 6CG7, a 6N1P, a 6DJ8, and (what I'm using now) another 6N6P

It's being powered off a DC-DC boost converter (12V to 265VDC) decoupled through 4.5H chokes/47u caps.

It's honestly the best sounding amp I've ever heard let alone built myself.

Because it's running off of switched power the current sense resistor doesn't need a switch but if you're running a linear supply it's useful for improving PSRR. You could also put a 200R resistor in series with a 55R resistor and have the switch short the 55R resistor instead.

Koda
 

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kodabmx

Member
Paid Member
2011-10-31 1:00 am
Toronto
Included is a design I was given by John Broskie of tubecad.com

"It offers excellent balance and a gain of slightly over 2 with the 32-ohm load. With a 300-ohm load, the current-sense resistor value must be increased from 200 ohms to 255 ohms. (A toggle switch could be used which would short the 255-ohm resistor with a 931-ohm resistor for use with 32-ohm HPs.)"

I've built this for use with 470R headphones (ATH R70X) and subbed the 12AU7 for a 6CG7, a 6N1P, a 6DJ8, and (what I'm using now) another 6N6P

It's being powered off a DC-DC boost converter (12V to 265VDC) decoupled through 4.5H chokes/47u caps.

It's honestly the best sounding amp I've ever heard let alone built myself.

*The 100u cap should infact be closer to 0.68u*
 
Sorry if I'm a bit late to the party but eeyore you might be interested in the following Aikido info from the tubecad web site:

Aikido Push-Pull

New LV-Regulator scroll down a bit in this blog you'll see a version that of the Aikido HPA that uses a 6N1P and an ECC99. It might be a good starting point for you as the 6N6P is (I think?) fairly close to the ECC99 in characteristics.

In my experience the Aikido really works well with high impedance HPs. I use mine with Senn 600s, a buddy uses his with Senn 650s and yet another pal from work uses his Aikido with high impedance Beyers. All of us are of the opinion that the Aikido has something special.

See my earlier post regarding my experience with tube rolling:
http://www.diyaudio.com/forums/tubes-valves/268193-adventures-aikido.html

My only hesitation with using the 6N1P and the 6N6P is that you'll likely have few tube rolling choices

Cheers, Steve