Aikido 24V headamp - Page 38

Yes Mike, I did receive it and read it. Just haven't had the time to give you the fair reply that it deserves.

Well I've been enjoying my Aikido for a few days now, it really turned out well I think.

I wanted to wait before I posted again to make sure everything was working right, hehe. Its dead silent with absolutely zero hum which makes me happy, also no turn on/off popping stuff going on either.

I made some changes from how I first put it together, I had originally used some LD1085s for the output buffers but something just didn't seem right with them, my HD580s sounded "ok" but my other low impedance cans sounded really awful. I picked up some LM317s and used those instead and it totally changed the way it sounds, so so much better, now all my cans sound great with this amp.

I also was using some k42y-2 1uf caps at c12 and c13, I just so happened to stop by my local surplus store today and found a box of Wima MKP10 1uf 160v caps for $0.19 each so I grabbed all that they had and put those in c12 and c13 and noticed more improvement, everything sounds "faster" somehow. I can't wait until my Blackgates get here to see if I can get even more improvement, they should be here this week

For tubes I'm using an NOS quad of GE branded 6GM8's which I believe are rebranded amperex, seem to be pretty nice. I'm waiting on a quad of NOS Siemens tubes to come from England so I can try rolling those in too.

I also found some other interesting tubes at the surplus store today since I noticed they had a fresh box out on the shelf, found 2 nice 12BH7A, a Realistic 12BH7A GT with goldish looking pins, an RCA 6CG7 and an ECL84. Not bad for 2 bucks each.

Hard to believe a 24V hybrid with voltage regulators as output devices can sound so good, and capacitor coupled no less. Wait 'till you listen to the BG's, I left the leads long on mine so I could swop them out easily and try other stuff. What are you using for a source? What did you use for C11?

Damn, I wish I had a local surplus store like that! Nice finds!

Glad to hear you're enjoying the amp too! Any thoughts on putting MOSFETs in for the buffers after 10M45S? The IRF510 and IRF610 should work as well as the NPN FET from the standard MOSFET-MAX BOM...

The source is my modded Zero DAC with an Audio-GD OPA-Earth as the opamp in the DAC section.

I used a 1KuF 35v Nichicon PW for C11.

I'm also using a seperate heater power supply since I have 2 H-PS-1s and one was already built for 12.6v output, B+ is 25.2v

I got the Blackgates yesterday and put them in today.

I had .47uF Multicap PPFX in the bypass position but I pulled them for now to be able to hear the BGs by themself and they sound really nice so far, really clean. I may leave them unbypassed I don't know yet.

Let them burn in for at least 100 hours before you make that decision. Every single comment I've read is that the BGs definitely do improve with burn in. Most just argue how much improvement.

I am sure TCJ fans already know about this but for those who don't ...... a new all in one headphone / linestage amp from JB which runs at a higher B+ ..dB

Yeah, been looking out for the magical day when all eleven boards (total) will go on sale. They'll be gone quickly.

But manaox, you pre-ordered with JB via email, right?



I've been working on my chassis prep for my MAX and Aikido. I need to finish wire brush deburring all the holes, then test fit the boards. When I do, I'll take pics and post them up here...

Awww, no. oh well, I may have to skip over this sadly for now.

I'll be looking forward to it, I want to see what you do with the Nabu case.

I'll take in progress pics later and pics when I test fit everything again to make sure it lines up. The Aikido isn't nearly as packed as the V1.0 BJT MAX.

For anybody who built the 24V version of the Aikdio with the 6GM8 tubes and H-PS-1 power supply, what transformer reccommendation do you have? All I need to finish and test this amp.

I ended up using 2 H-PS-1 supplies for mine, with 2 transformers. I just used a standard 12.6v EI core one for the heaters, I don't remember the brand right now.

My B+ transformer is overkill, I already had it on hand though so I used it, it's a 160va 2x24vac toroid, I paralleled the secondaries and I am running 25.2v for B+.

If your going to run 1 supply I'm sure you will have good luck with a much smaller transformer, the H-PS-1 can only pass 2.5A max.

On mine the same PS is used for B+ and heaters. It's a simple matter of choosing the appropriate jumpers. You could go either way, seperate supplies with 6, 12 or 24v for heaters and 24v for B+ or use a 24v supply for both at the same time.

I think you will really enjoy this amp, and it's good to see another one will be built and listened to.