Hi,
the choice of the tubes depends mostly on your needs.
The overall gain is half the mu of the input tube, while the driving ability is mainly due to the output tube.
With modern sources (CD) I'd choose the lowest mu double triode available, in my system E88CC was too much when using the Aikido as normal preamp, so 6CG7/6FQ7, 6GU7, 12AU7 (but also 6N1p, E88CC and similar if you don't mind having more gain) are nice tubes.
For output tube ECC88 (bearing in ming its max plate dissipation), 5687, e182CC, 6N6p, 6N30p are possible (but not the only) choices.
Please note that not all share the same pinout and heater voltage.
Cheers
Andrea
the choice of the tubes depends mostly on your needs.
The overall gain is half the mu of the input tube, while the driving ability is mainly due to the output tube.
With modern sources (CD) I'd choose the lowest mu double triode available, in my system E88CC was too much when using the Aikido as normal preamp, so 6CG7/6FQ7, 6GU7, 12AU7 (but also 6N1p, E88CC and similar if you don't mind having more gain) are nice tubes.
For output tube ECC88 (bearing in ming its max plate dissipation), 5687, e182CC, 6N6p, 6N30p are possible (but not the only) choices.
Please note that not all share the same pinout and heater voltage.
Cheers
Andrea
The 5687 can't be used in the standard 9 pin board. Mr. Broskie sells a board designed for the 5687:
http://glass-ware.stores.yahoo.net/56steraikpcb.html
http://glass-ware.stores.yahoo.net/56steraikpcb.html
I am really tempted by the new partial kits from Broskie, still miss a certain tubepre I once had
But I am really in doubt whether I should choose the "all 6cg7" ... I reckon I may need to change them once a year, so they must not be too expencive or hard to find
Does anyone have any experience with his bargain "stepped attenuator" - why should one use the 100kohm with 2db step and not the more attractive 20khz with 1db steps
Any ideas about which would be best with small solidstate poweramps
But I am really in doubt whether I should choose the "all 6cg7" ... I reckon I may need to change them once a year, so they must not be too expencive or hard to find
Does anyone have any experience with his bargain "stepped attenuator" - why should one use the 100kohm with 2db step and not the more attractive 20khz with 1db steps
Any ideas about which would be best with small solidstate poweramps
Thanks for the repies. It seems the 6cg7 or 6fq7 would be the choice for input. I have looked at the board and it would be easy to modify to suit the 5687 as an output. Is there a comparable tube with the correct pinout for this board. BTW I will be driving a solid state poweramp.
Thanks again,
Paul.
Thanks again,
Paul.
I´ve just received my 9-pin mono PCBs from Broskie (wow - high quality PCBs !!!). I am thinking of using the 6CG7/6FQ7 as input tube and the E88CC / 6H30 (6N30) as output tube.
I see that Stax uses the 6CG7/6FQ7 for their electrostatic headphone amps so I think that this tube must be an OK choice (confirmed by Broskie in an email to me).
However, I am a little in doubt about which of the output tubes to go for. The 6H30 has a very good reputation (at least here in Europe) and it has a life time of 10.000 hours. OK, maybe it will not last for 10.000 hours but at least it should not be a tube which has to be renewed "too often".
A B+ of 250 V for the 6CG7 will be fine, but what about the 6H30? Will it make more sense to go for a B+ of 200 V when using the 6CG7 and the 6H30 together in the Aikido???
Any comments?
Karsten
I see that Stax uses the 6CG7/6FQ7 for their electrostatic headphone amps so I think that this tube must be an OK choice (confirmed by Broskie in an email to me).
However, I am a little in doubt about which of the output tubes to go for. The 6H30 has a very good reputation (at least here in Europe) and it has a life time of 10.000 hours. OK, maybe it will not last for 10.000 hours but at least it should not be a tube which has to be renewed "too often".
A B+ of 250 V for the 6CG7 will be fine, but what about the 6H30? Will it make more sense to go for a B+ of 200 V when using the 6CG7 and the 6H30 together in the Aikido???
Any comments?
Karsten
I guess its no secret that JohnB likes the 6SN7 ... could the reason be that the Aikido, being with very low distortion and pure sounding, might tend to sound just slightly "cold" or too solidstate-like(the better ones) ... it has been mentioned before, and John has clearly stated that he likes the varmer and more natural "vintage" sound of the 6SN7 .... maybe a symbyotic "match in heaven" ?????
Nope, the 6SN7 tubes are simply the lowest distortion tubes that you can get. I have a book that studied this in some detail, and found that the later tubes all had higher distortion. It seems that negative feedback became more popular in the time of 9-pin tubes and thus tubes could get away with higher distortion. As the aikido does not rely on feedback, then the naturally lowest distortion tubes are preferred.
I really don't think the 6SN7 aikido sounds warmer than the 9-pin version, in fact the opposite might be true. More accurate and cleaner is how I would describe it (having built at least two of each type). And I certainly would not describe it as sounding solidstate-like. Or tubelike. That great thing about the aikido is that it lets you see how just about everything else is colored.
As for output tube instead of 5687, the ECC99 (JJ) is worth a try.
I've been playing with the driver and output tubes in my Octal Aikido....and my favorite combination to-date is 6BX7s for the drivers and 6SN7s for the outputs.
In the Output stage, the 6SN7 is the champ. The 6BX7 and 6080 sounded wooly and oddly enough had loose and boomy bass.
In the Driver stage, the 6BX7 sounds great. Tighter bass and a seemingly more musical midrange than the EH 6SN7s. I need to pick up some NOS 6SN7s, and reevaluate. The 6080s also sounded pretty decent as drivers, but they were quite microphonic and hummed like crazy from the high heater current draw.
But, I gotta say I am impressed with the 6BX7. When used as a driver, it has *grip*. I am stunned by the deep, articulate bass response.
Now...if only I can solve my power supply issues....
In the Output stage, the 6SN7 is the champ. The 6BX7 and 6080 sounded wooly and oddly enough had loose and boomy bass.
In the Driver stage, the 6BX7 sounds great. Tighter bass and a seemingly more musical midrange than the EH 6SN7s. I need to pick up some NOS 6SN7s, and reevaluate. The 6080s also sounded pretty decent as drivers, but they were quite microphonic and hummed like crazy from the high heater current draw.
But, I gotta say I am impressed with the 6BX7. When used as a driver, it has *grip*. I am stunned by the deep, articulate bass response.
Now...if only I can solve my power supply issues....
Jayme : what are your power supply issues?
The best tubes I have found are the special russian 1578 (a version of the 6SN7). They are amazing, but hard to come by, costing more than $100 a pair on ebay. They are better even that red base RCAs imho
I will give the 6BX7s a try..thanks for the tip.
The best tubes I have found are the special russian 1578 (a version of the 6SN7). They are amazing, but hard to come by, costing more than $100 a pair on ebay. They are better even that red base RCAs imho
I will give the 6BX7s a try..thanks for the tip.
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