Aikido choice of valves (or tubes, if you will)

[Beelzebub]

Hi Everyone,
I've been looking at John Broskie's Aikido cct for a while now, and I've finally taken the plunge and bought 2 of his mono 9-pin boards. Now the question I have before me is, what valve to use? My first thought was the Russian 6H30, as it can deliver low output resistance - but is this as much a benefit as I think (I doubt I'll be running cable-runs more than a couple of meters)?
The list of valves, along with component values on John's site is great, but it is a bit of a case of too much choice!
I have looked back at previous posts, and found a diversity of opinion (as you might expect), although no single thread appears to be dedicated to this question - so I thought I might start one.
Ladies and Gentleman, your opinions please

 

[Giaime]

Hi Beelzebub,

my choiche for tube 1 goes to 6SN7 (for the octal version) and 6CG7 (for the noval).

For tube 2, I didn't hear too much difference, anyway I choose the 5687.

 

[Beelzebub]

Hi Giaime,
I did think of going Octal with the 6SN7 or 6SL7, but I remember them sounding a bit dark in a previous cct I built many years ago (to be fair, this was probably down to poor component choice/arrangement on my part).
I will look at the 6CG7 and the 5687, see what they offer.
Thanks!
Jim

 

[SY]

I've built a 6SN7 and 6DJ8 version and thought both worked quite well.

 

[Giaime]

It's difficult to make it sound bad, in my opinion. Only *few* details changes from tube to tube.

Probably the only tube you wouldn't use in the first position is the 12AX7/ECC83 or the 5751, way too much gain, and noise.

 

[Burnedfingers]

Probably the only tube you wouldn't use in the first position is the 12AX7/ECC83 or the 5751, way too much gain, and noise.

Or a 6SL7 as a first tube. Or any high gain tube in the first position for that matter.

 

[Giaime]

I guess that, with short lines and high impedance input on the power amp, the 12AX7 in the second position might be interesting. I never tried such a thing, but why not?

 

[Beelzebub]

This is great guys, just the feedback I was looking for, thanks!
For myself, I don't need much gain, as all my sources are fairly high level - hence one of the resons for looking at the 6H30 (low gain, high current). The comments on Octal valves will no doubt be appreciated by those going that route. Keep it coming!
Kind regards
Jim

 

[Greg3333]

I'm making the same choice at the moment.

From reading different threads on the forum, it seems like 6N6P, 5687 and 6CG7/6FQ7 are the most popular choices.

Anybody got any comments on the relative merits of these tubes?

Greg

Edit: perhaps not the most popular choices, but the most fervently recommended!

 

[Burnedfingers]

The 6N1P, 6922, and 6FQ7 make a good choice in the first tube slot. The 5687 is good in the second slot. There are a number of us that feel the 6FQ7 is the best sounding of the input tubes. My choice for the nine pin tubes is the 6FQ7/5687 and for the octal tubes the 6sn7/6sn7. Granted it can also be replaced with the 5692 or a nice Russian tube that is similar to the 5692.

 

[arnoldc]

I will be using WE407A just because I have a couple that I can't consume in my lifetime don't know how they will sound though, but should be worth a try.

 

[cm_ls1]

i used 6cg7 input , and 6922 as the output ... very happy , crystal clear.

 

[Giaime]

It's interesting that nobody is using 12AU7/ECC82

 

[arnoldc]

hi bob why 12AU7 when there are better tubes (subjectively)

 

[Burnedfingers]

It's interesting that nobody is using 12AU7/ECC82

I think Giamie is baiting us. Per a prior thread it was brought up that the 12Au7 has a lot more distortion. There are a lot of better tubes out there. The 12Au7 has lent itself to some primitive commercial line stage applications for the first time builder. The more experienced here are wanting to use a better valve.

 

[rjtpeters]

I have build the aikido using the following configurations:

- 6CG7/6H30
- 6DJ8/6H30

Front running @6mA, 6H30 @30mA

I was very...and i mean very hard to hear any difference
(using the aikido as headphone amp, with senheiser HD650)

It was interesting to notice that i prefer an 10k-300E output trannie (connected to the output with an 6uF Auricap) i.s.o only a black gate output cap. The latter was too warm for me..

Should i go for more juice in the pre-tubes?

Furthermore, i will also build the octal version for comparison with 6sn7/6sl7, recieved the tubes last week.

 

[Beelzebub]

I have build the aikido using the following configurations:

- 6CG7/6H30
- 6DJ8/6H30

Front running @6mA, 6H30 @30mA

I was very...and i mean very hard to hear any difference
(using the aikido as headphone amp, with senheiser HD650)

It was interesting to notice that i prefer an 10k-300E output trannie (connected to the output with an 6uF Auricap) i.s.o only a black gate output cap. The latter was too warm for me..

Should i go for more juice in the pre-tubes?

Furthermore, i will also build the octal version for comparison with 6sn7/6sl7, recieved the tubes last week.

Hmm.. very interesting, could the o/p section be paralleled, and drive a speaker; 4 stages in parallel would give 30-odd ohms o/p resistance at maybe 4-5 watts? Anyway, I'll stick with a pre for now
Regards,
Jim

 

[2004ex]

I've built a 6SN7 and 6DJ8 version and thought both worked quite well.

Helped a friend built a 6SN7/6SN7 version recently based on John's octal board. Embarassed to say that we are still struggling with hum/noise problems (I know, aikido should be good in that department and we must have been stupid and doing something wrong), but would you share what values of cathode resistors are used in your 6SN7/6SN7 built? TIA.

 

[jackomancy]

Hi.

I used ECC85's ( 6AQ8 ) in first position, ECC88's (6DJ8 ) in second, having limited filament current available. DC fils and ~200V B+ in external PS--> humless operation.

No problems at all--an invisible line stage, magic.....

Will ultimately build a bigger PS to use 6CG7's and 5687's, which I believe would be optimum choices, run at 300V for preference.

Nevertheless that my initial "odd" choice does so well--indicates the capability of the design to absorb so many variations.

Good luck!

 

[jackomancy]

Should add I used the diyAudio noval board (thanks Basil et al! )and the cct using 430 ohm cathode resistors, 6N1P's and 5687's--one of JB's earliest.

I'd reproduce it if the system made it easier--defeats my simple mind....

My image does not have an URL so what happens then???

Cheers.