FS: Aikido Tube Preamplifier

[ClefChef]

This is Aikido tube preamplifier that I built for myself and was enjoying it for quite a while. I am selling it to fund my numerous other projects that are awaiting completion.

This preamp is built on a custom aluminum chassis with 6n1p - 6n6p tube pairs using Hammond iron, Alps Blue volume pot, Kiwame, Dale, and TKD CM2 resistors, audiophile grade capacitors, teflon silver cable - all highest quality parts I could source.
It has two pairs of RCA inputs and one pair of outputs.

$625 PayPal shipped in CONUS.

 

[wireswithgain]

What are the tubes in this preamp? 6n2p and 6n6p?

 

[ClefChef]

This preamp is built on a custom aluminum chassis with 6n1p - 6n6p tube pairs

 

[JZatopa]

Any chance you would be interested in a partial trade for a decware csp?

 

[ClefChef]

What I am really interested in trading it is for Mac Mini.

 

[ClefChef]

I realize that inside pic is outdated - it was taken before significant upgrades were done: Hammond filter choke in power supply, coupling caps are K40-Y9 PIO...

This preamp has raised eyebrows of local audiophiles and some were embarrassed to hear this preamp to outperform their high dollar units.

Here's the current pic of the inside of preamp.

 

[bekim]

Hi

I am interested to know, after you add choke in the preamp, did you hear the difference and what is your comment on that?
I am about to finish aikido preamp soon and still I didn't put choke inside as I thought to try it without it and afterwards to add the choke.

thanks

 

[adason]

nice build ClefChef!
I build two aikidos, one octal with 6n7p and one with 5687s
never tried 6N6P in aikido even I have few...I used those for lampization projects, nice tube
your box looks professional (mine sucks)

 

[ClefChef]

Hi

I am interested to know, after you add choke in the preamp, did you hear the difference and what is your comment on that?
I am about to finish aikido preamp soon and still I didn't put choke inside as I thought to try it without it and afterwards to add the choke.

thanks

There is a big difference in sound, particularly in dynamics and detail. Choke provides lower DCR and therefore low voltage drop in power supply, not to mention lower noise. 10H 65ma Hammond choke will be enough here.

 

[ClefChef]

nice build ClefChef!
I build two aikidos, one octal with 6n7p and one with 5687s
never tried 6N6P in aikido even I have few...I used those for lampization projects, nice tube
your box looks professional (mine sucks)

Thanks adason, the box takes most of the effort, considering all the tools and hardware involved.

 

[bekim]

There is a big difference in sound, particularly in dynamics and detail. Choke provides lower DCR and therefore low voltage drop in power supply, not to mention lower noise. 10H 65ma Hammond choke will be enough here.

Thank you for the reply.

I was thinking to add 8-10H max 100 mA (50-70mA is enough) just, I need to find smallest choke size as possible, as my case isn't roomy enough.

 

[bekim]

Hi

I check few threads for Aikido design and I want to ask you again, if you don't mind, that I have same setup of tubes 6N1P and 6N6P, so the question is, in your design what resistors you use Rk for the input tube and Rk for the output tube?


thanks

 

[ClefChef]

the value of Rk largely depends on B+ at the anode. Let's say you have 250V at the top anode, that's 125V per triode, Rk for 6n1p and 6n6p could be anywhere from 150R to 470R depending on what you like in the sound. 6n series russian novals like to be run hot. I would use 330R at 250V, but again you have to experiment with the values of anode (final CRC) resistors, cathode resistors, and B+; even the values and type of grid stoppers make a difference. I use the same values for input and output tubes.
Using high quality parallel resistors in the last CRC stage will cut the resistor thermal noise in half.

The pic you attached is that of White Cathode Follower, not strictly Aikido...

 

[bekim]

the value of Rk largely depends on B+ at the anode. Let's say you have 250V at the top anode, that's 125V per triode, Rk for 6n1p and 6n6p could be anywhere from 150R to 470R depending on what you like in the sound. 6n series russian novals like to be run hot. I would use 330R at 250V, but again you have to experiment with the values of anode (final CRC) resistors, cathode resistors, and B+; even the values and type of grid stoppers make a difference. I use the same values for input and output tubes.
Using high quality parallel resistors in the last CRC stage will cut the resistor thermal noise in half.

The pic you attached is that of White Cathode Follower, not strictly Aikido...

Ok.
Yes, psu is 250 on B+, and I put 430 ohms /Rk for both tubes [all four].
I think I have to decrease resistor for 6N1P to 220 ohms as I saw in documentation to reach 5mA. But for 6N6P there is not any data on resistor value.
Can you please, post schematics you're referring.. I would like to see if I did something wrong.

thanks

 

[ClefChef]

You can keep Rk for 6N6P the same.
Aikido schematics is on TubeCad website.