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Aikido LV ordered! Will be a fun project!

post #1 of 20
12/20/10 at 2:01pm
Thread Starter 

They are FINALLY back in stock! Will be a fun project / amp for my office listening. Will first be pared with my PXC-350's and then with the HD650's after tax time :) Will post pics of the build once I get it rolling!

 

http://glass-ware.stores.yahoo.net/aikidolv.html

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post #2 of 20
12/21/10 at 1:12pm

Sweet!

 

There was an akido thread here a while back. 

 

I had a 24V akido (with mosfet output stage) on loan for a while, it was a nice little amp. 

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post #3 of 20
1/3/11 at 6:39pm
Thread Starter 

FINALLY got in my LV! Felt like forever but the holidays must have slowed shipping down. Initial thoughts on the kit....

- Packaging was excellent, no complaints. Everything was clearly labeled and came with the manual printed!

- Circuit board... Good lord thing thing is 3x thicker than I thought it would be for such a small board. One thing is for sure, you could press and pull on tubes all day long and this baby is not gonna break or flex!

 

Will get around to solder slinging in the next few days and have to dream up the enclosure, then order tubes. Still have not made up my mind but will probably start with 4 JJ ecc99 gold pins at 48V and then reference everything off those for my tastes.

 

Some pics of the kit and the crazy thick board....

 

AIKIDOLV.jpgAIKIDOLV2.jpg


Edited by Garage1217 - 1/3/11 at 6:43pm
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post #4 of 20
1/3/11 at 9:42pm
Thread Starter 

So I got anxious tonight and jumped on the project :) Soldered the whole unit up / reverse flowing the solder to make sure it is uniform throughout the via. Turned out decent I think! I have not soldered in either coupling cap yet as position will depend on the chassis. I also have not soldered in the 9 pin minis yet as I may change them out to a little fancier gold plated units. Yes I know, I know I will not hear any difference but the ones I am looking at have the center of the socket open so I can shine an led through them if I wish. Riced out tubes FTW! Also to note, I soldered all of the other caps on the bottom so I can mount the circuit board higher up in the chassis to show off the tubes more :)

 

Last note for those with a keen eye, Yes R17 is missing... someone forgot to put it in the package *LOL* Not worried about it, can snag that locally.

 

AIKIDOLV3.jpgAIKIDOLV4.jpg

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post #5 of 20
1/3/11 at 11:37pm

It looks nice.  I thought broskie was out of stock on kits and only had pcbs?

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post #6 of 20
1/4/11 at 9:58am
Thread Starter 

He just got them back in from what I understand in December / All new boards.

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post #7 of 20
1/4/11 at 10:13am

Looking good so far, I think you'll like the amp. I have a 24v Aikido with 6GM8 tubes that I use as the preamp for my speaker amps and its also my favorite headphone amp for my dynamic cans.

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post #8 of 20
1/4/11 at 10:36am

Garage:

 

My LV is in transit but I'm planning on a 24 volt version with 6GM8's (bought a few some years ago before the prices went crazy). 

 

Will you be building a headphone driver as shown in the 24 volt Aikido manual http://www.tubecad.com/2008/02/04/24V%20Aikido%20Stereo.pdf or power your phones directly with a big output cap?  You might just get away with it on the HD650's as they are 300 ohm 'phones but I don't know about the other 'phones you mentioned.  I'm planning on the solid state HP driver hard-wired off board of course because it will need some heat sinking.

 

What will you use for a powwr supply?  Switching wall-wart or a linear supply?

 

FYI, I've just finished building an Aikido 9 pin All In One HPA/LSA in the HPA version using 6CG7's and 6DJ8's.  It's not completly broken in yet and I'm waiting for some RTI power supply bypass caps shipping with my LV order but I'm intrigued so far with the performance.  I'll go out on a limb here but I think the Aikido design uses tube non-linearities against itself to lower distortion and decrease power supply noise.  Tube rolling is to my mind is finding the tube non-linearities that most appeal to you.  The Aikido as I've experienced it so far is more independant of tube rolling perhaps because of the afore mentioned non-linearity-cancelling circuit design.  Just my 2 cents worth. 

 

In my humble experience you need to run a new amp for at least 48 hours (with signal) to break-in the tubes and caps before coming to any sonic conclusions.

 

Let us know your progress!

 

Cheers, Steve

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post #9 of 20
1/4/11 at 11:57am

How much current can the output tubes drive?  and the Zout?  Or perhaps remove the output tubes and use a sand buffer...  I'm wondering if I should mess with the LV Aikido or just go to the HV octal.

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post #10 of 20
1/4/11 at 12:34pm
Thread Starter 

Awesome to hear! I cannot wait to hear this thing, very excited about it!
 

Quote:
Originally Posted by Coreyk78 View Post

Looking good so far, I think you'll like the amp. I have a 24v Aikido with 6GM8 tubes that I use as the preamp for my speaker amps and its also my favorite headphone amp for my dynamic cans.

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post #11 of 20
1/4/11 at 12:38pm
Thread Starter 

The manual you posted is to the much older style LV, this one should be good to go from what I understand for headphone or line use. Still researching as I build haha! Here is the manual it came with... http://tubecad.com/Product_PDFs/Aikido%20LV.pdf so now I am a little worried as it does not speak about headphone use DOH! Will have to email in and ask to make sure. Hopefully at the most, it will be a capacitor change if I do have to do anything...
 

Quote:
Originally Posted by Old Ducat1 SS View Post

Garage:

 

My LV is in transit but I'm planning on a 24 volt version with 6GM8's (bought a few some years ago before the prices went crazy). 

 

Will you be building a headphone driver as shown in the 24 volt Aikido manual http://www.tubecad.com/2008/02/04/24V%20Aikido%20Stereo.pdf or power your phones directly with a big output cap?  You might just get away with it on the HD650's as they are 300 ohm 'phones but I don't know about the other 'phones you mentioned.  I'm planning on the solid state HP driver hard-wired off board of course because it will need some heat sinking.

 

What will you use for a powwr supply?  Switching wall-wart or a linear supply?

 

FYI, I've just finished building an Aikido 9 pin All In One HPA/LSA in the HPA version using 6CG7's and 6DJ8's.  It's not completly broken in yet and I'm waiting for some RTI power supply bypass caps shipping with my LV order but I'm intrigued so far with the performance.  I'll go out on a limb here but I think the Aikido design uses tube non-linearities against itself to lower distortion and decrease power supply noise.  Tube rolling is to my mind is finding the tube non-linearities that most appeal to you.  The Aikido as I've experienced it so far is more independant of tube rolling perhaps because of the afore mentioned non-linearity-cancelling circuit design.  Just my 2 cents worth. 

 

In my humble experience you need to run a new amp for at least 48 hours (with signal) to break-in the tubes and caps before coming to any sonic conclusions.

 

Let us know your progress!

 

Cheers, Steve


Edited by Garage1217 - 1/4/11 at 1:22pm
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post #12 of 20
1/4/11 at 1:22pm

Garage:

 

I'm not trying to be a smart a** or rain on your parade but I think you'll need a sand based HP driver if you are planning to use low impedance 'phones.

What I wanted you to see was this bit of the 24 volt manual:

 

Configuring the Headphone Driver Portion of the PCB

The standard Aikido is a thoroughly single-ended affair, nothing pulls while something

else pushes. Unfortunately, wonderful as single-ended mode is sonically, it cannot

provide the larger voltage and current swings that a push-pull output stage can. Singleended

stages can only deliver up to the idle current into a load, whereas class-A pushpull

stages can deliver up to twice the idle current; and class-AB output stages can

deliver many times the idle current. For a line stage, such big voltage and current

swings are seldom required; headphones, on the other hand, do demand a lot more

power; really, a 32-ohm load is brutally low impedance for any tube to drive.

Unfortunately, a heavy idle current is needed to ensure large voltage swings into lowimpedance

loads, something that the little 6GM8 (or any other tube) cannot do with

just 12V on the plate.

 

The same I belive will apply to the LV run at 48 volts.  The 24 volt version could also be used with higher voltage tubes (12BH7's and Ecc99's) see page 10 of the 24 v manual.

 

If you are going directly from the LV to your phones put a couple of thousand uf (electrolytic cap) in parallel with C3.  This is what the All In One LSA / HPA does for low Z 'phones.

 

 

Holland:

 

Check out the link in my earlier post, the sand HP driver comes after the output tube.  As far as I know, with my somewhat basic knowledge, is that if you don't mind a sand buffer after the tubes a low voltage Aikido will do.  If you want to go from the tubes to your phones you need a high voltage version.  My All In One LSA / HPA runs about 150 volts on the tubes, not too high compared to a monster tube power amp.

 

 

 

Guys:

 

I don't wish to offend or seem a know-it-all, I just don't want you to be disappointed if it falls short of your expectations.  The Aikido All In One LSA / HPA runs a lot more voltage and current on the output tubes and has a over 350uf of output coupling capacitance.  Unfortunatly Mr. Broskie does not share all of his circuits on-line.  Some like the All In One LSA / HPA require purchase to see the manual.  

 

 Regards,  Steve

 

 

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post #13 of 20
1/4/11 at 1:40pm
Thread Starter 

ANY help is appreciated so no worries! And yes, looks like I overlooked a BIG part of this build, I must have gotten the original 24V LV info confused with this one and boy I have egg on my face now.  Very irritated since I have already pretty much built the freakin thing :(

 

Also I did not see this portion until I did a lot of digging on the site as there are / were two LV Aikidos.....

Why No Headphone Buffer? I decided to leave the solid-state headphone buffer off the LV Aikido PCB for several reasons. I have mentioned one already: the extra required real-estate. Another is that many do not own high-quality headphones. Why should they pay extra for something that they are not going to use? Thus, it seem to make more sense leave the solid-state buffer off the board. Which is not to say that I have forsaken the headphone option, as the relatively low-voltage operation cries out for a headphone amplifier service. Think about how crazy it is to build a tube-based headphone amplifier that runs a 240Vdc B+ voltage and an insanely high idle current just to swing 1V into a headphone driver. Well, a 24V B+ is ten times less insane. My hope is to design a fine standalone, solid-state, unity-gain power buffer that can be used with the LV Aikido board. This explains all the Triadtron circuits with which I have abused the pure-tube-of-heart readers recently. I want something special. Not the generic diamond topology, although such a buffer made from discrete components can sound surprisingly good, but just not good enough.

 

confused_face_2.gif

 

Not sure what to do now. I am very skilled at soldering, kit building, chassis design but a novice at best when it comes to audio circuit design Unless he has a kit out soon to make this LV good for headphone use as he described in a post then I guess I am SOL. :( Soooo irritated that I got the 24V and LV confused functionality wise... what I get for late night reading and a quick paypal trigger finger. 


Edited by Garage1217 - 1/4/11 at 2:52pm
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post #14 of 20
1/4/11 at 3:09pm
Quote:

Originally Posted by Old Ducat1 SS View Post

 

Holland:

 

Check out the link in my earlier post, the sand HP driver comes after the output tube.  As far as I know, with my somewhat basic knowledge, is that if you don't mind a sand buffer after the tubes a low voltage Aikido will do.  If you want to go from the tubes to your phones you need a high voltage version.  My All In One LSA / HPA runs about 150 volts on the tubes, not too high compared to a monster tube power amp.

 

Thanks Steve.  I do not mind hybrids, in fact I quite like them.  At the same time I'm curious why it goes after the output tubes.  I can't say I'm overly familiar with his Aikido, I tried to follow up on it once, but it seems like his Tube Cad Journal is one tweak of the circuit after another, and it's hard to say what's better.

 

I'll P2P his input tubes directly into a push-pull mosfet buffer, when I figure out what his circuit actually does. :)  I don't like the cap on the output.  I think I remember this circuit.  I should probably test it, but I wasn't keen on listening to a LM317 as the output buffer.

 

Thanks again.

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post #15 of 20
1/4/11 at 3:24pm
Quote:
Originally Posted by Garage1217 View Post

Not sure what to do now. I am very skilled at soldering, kit building, chassis design but a novice at best when it comes to audio circuit design Unless he has a kit out soon to make this LV good for headphone use as he described in a post then I guess I am SOL. :( Soooo irritated that I got the 24V and LV confused functionality wise... what I get for late night reading and a quick paypal trigger finger. 


There are a number of hybrids out there.  There is a generic diamond buffer, that Broskie didn't want to use, a JISBOS (JFET input/BJT output) buffer from AMB, Cavalli Audio used a SE BJT buffer for the SOHA 2 (which is a fine buffer IMO).  There are dozens of output stages you can steal, but they won't exactly be a glue.  You can even try his original LM317 buffer, though I would say the generic MOSFET SE buffer, with a CCS and a big cap on the end might sound better than the LM317.  I have no experience with the LM317 on the output though.

 

You can glue a MOSFET Source Follower onto this ciruit easily.

 

http://gilmore2.chem.northwestern.edu/projects/szeke1_prj.htm

http://www.pmillett.com/starving.htm

http://www.headphoneamp.co.kr/bbs/data/diy_sijosae/MHHAv2.gif

http://www.head-fi.org/forum/thread/402067/a-super-simple-6dj8-headphone-amp

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