[Gvt1911]

Looking into the Aikido preamps. Would like to try one , but need to build a "proper" power supply to get the best out of it from what I am reading on the web. Does anyone have a lead as to where such a power supply can be obtained? Can a complete power supply "kit" be purchased from someone? Anyone have one up and running ? Comments?
Thanks !!!

[Gordy]

Three or four of us have Aikido's up and running!  I'd love to try a Paul Hynes regulated supply link but, can't afford it as yet    .  I went with a tube power supply pcb from one of the HK dealers and then added power line choke's as per the Lynn Olsen blogs.  I'll post the HK dealer site as soon as I find it, my computer died since that time and I no longer have any of my old "favorites". Arg. 

I'll point a couple other builders this way as well....  oh, and the Aikido replaced my MW 9.0 quite nicely thank you! 

[denjo]

Gordy
The Paul Hynes PSU would be an excellent choice, IMHO. Although I have not tried a Paul Hynes PSU with an Akido preamp, I can only say that Paul's work has transformed my Altmann Attraction DAC and I can see no reason why any other equipment that will benefit from a quality PSU would not be transformed as well!

Best Regards
Dennis

[JoshK]

I'd build a Janus shunt regulator per Broskie's blog, but that is just me.   

[Gordy]

Cool Josh,  I didn't know you finished it!  Are they up and running? 

I heard an all 12v version of the Aikido built by Zacster at Occam's NY Rave back in May, he was using a commercial 12vdc power supply at that point.  Sounded great taking into account the unfamiliar room and equipment, though I did hear a Promi pre in the same basic setup IIRC....

Thanks Dennis, I'm still envious    Someday....

[CButterworth]

JoshK,

If you could post a schematic or details of your PSU, it would be really useful and interesting.  I assume that the Janus works.

As for my Aikido PSU it is:

1. 125-0-125 into a 1N4007 bridge rectifier
2. 0.68uF cap in parallel
3. 10H choke in series
4. 60uF cap in parallel
5. 10H choke in series
6. 60uF cap in parallel

Drawing around 20mA, I get 312VDC.

However, I have a very low level of hum, which maybe PSU related, or due to an annoying ground loop.  BUT....Bruce Anderson, one of the first Aikido constructors uses this PSU in his Aikido, although it is mounted in a separate chassis.

Charlie

[Gvt1911]

Thanks for all the info ! I guess I need to build one of these units, but need more help than the average Joe. I was thinking of going with the 9 pin stereo preamp and using 6922's since I have a few lying around. Maybe I am wrong and some other tubes sound better ? Also I guess I would need someone to point me to a complete PSU in kit form or ready made, as I see you fellows are way above me in your knowledge about PSU's,  etc. Thanks for all your help !

[JoshK]

No I haven't finished mine yet.     I said "I'd build" not I've built.  I did finish the design of what I am going to do first, but my shop is buried at the moment so I can't build the box for the line stage portion, but the power supply is 98% done and needs to be tested, maybe this weekend.

For the line stage box, I am building the wood frame and aluminum top plate style.  The top plate is done and has the stuff boards mounted.  I am just waiting to dig out my router station in the basement to finish the frame and then hook up the wiring.

My power supply looks a bit like this...  maybe tonight I'll post the Duncan PSUDII schematic

Tx (375-0-375) > dual 6AX4GT diodes > 10H triad choke >  98uf (oil caps in parrallel with poly caps) >  connector to line stage > (split channels) 320mH Triad chokes (1 for each channel) > 20uf > Resistance to drop to 300V, 100R maybe can't recall> 10uf on board. 

It models quite nicely with quick & smooth recovery, no ringing to step in load and pretty low ripple (<30mV iirc) and the ripple is "nice" looking.

The diode dampers are cheap and supposedly perform really well, better than the average tube rectifier.  The triad chokes are $10-15/each.  The 10H one is C-7X I think, and the other is C-14X iirc, both can be obtained from allied electric.  The caps I used is what I had on hand from Felicia testing, etc.  I got the motor run oil caps off ebay and I had some 10-20uf solens and jantzens left over from other projects.  I played with the values of the caps in the PSU using what caps I had on hand until I came up with the best simulating PSU.  Now I need to test whether the reality looks as good as the tests, but I have read that PSUD is generally confirmed with reality. 

The motor run caps you can generally find cheap on ebay from the HVAC guys that sell them to people replacing their caps on their furnace or A/C.  They cost a bit more than electrolytics of similar size but many say they are a huge upgrade to electrolytics in PSU's.  Also you will find through modeling in PSUD (and apparently in listening as well) that you don't need a huge amount of capacitance in the supply, and it can actually make your supply really "slow".  Too much capacitance and your supply take a long time to recharge after a large transient (but this is class A linestage so I don't know if you'll have too many large transients), too little and it'll ring and overshoot.  There is generally a range that I found (not super narrow) that looks best.

[JoshK]

I was thinking of going with the 9 pin stereo preamp and using 6922's since I have a few lying around.

That is a good reason to go with 6922's.  The only reason I see against it is that 6922's will provide quite high gain if used in the first section (17x).  That is a lot of gain for a preamp unless your amp is low gain.  Even my 6SN7 at 10x is too much gain IMO.  Its the big drawback of the aikido as a preamp IMO, most people don't need all the gain it provides.  For me, I plan to build some tube amps and I am going to specifically design the amps to take advantage of the Aikido's gain by not providing as much gain in the amp.

The average audiophile has too much gain in their system anyway, IMO, so it might sound normal to you.

[Gordy]

Here's the link to the (LSDY) tube PS I'm using... http://www.vt4c.com/shop/program/main.php?cat_id=1022&group_id=17&hit_cat=

If interested, I can list the mods I've done to both circuits and how to add the 75v reference (Thanks to Josh for the ref. schematic!).

[zacster]

I built the 24v version that John Broskie describes using 6GM8 tubes.  Since that is a common supply voltage, I just used a pre-built +/-24v supply from International Power.  It is probably a better supply than I could build myself and very steady on the voltage.  This is NOT a wall-wart.  The B+ and filaments run off the same supply at 6v x 4 in series = 24v.  I also built in a Creek phono pre-amp board that I had that runs off + and - 25v, but since there is an on-board regulator it didn't matter that it was slightly under voltage.