Which tube? ECC82, 6SN7 or 6SL7

[CambshireGordon]

I am interested in buying the Heresy Tube/Mosfet preamplifier for my Autocostruire T-Amp. This is available in three versions, with either ECC82, 6SN7 or 6SL7 tubes.
see - http://www.autocostruire.com/catalog...roducts_id=267

I appreciate that sound quality is very much a personal experience, but what are the individual merits / characteristics of these three tubes and which is considered to be "the best" when it comes to that all important sound quality? Tube size is not an issue.

I am using the Autocostruire T-Amp to drive my Quad 63's with excellent results, but I am also interested in hearing "that valve" sound which is so much talked about amonst audiophiles. I listen mainly to FM radio and CD's with a preference for Classical rather than pop.

Whilst the Forum "Tube Choice for tubed crossover" has some interesting posts, they do not appear relevant to my situation.

Thanks in advance for advice and recommendations - CambshireGordon

[andyjevans]

I'd use the 6SN7 - it's the best sound. The 6SL7 is warmer and fuller but less neutral, and probably has too much gain to be really suitable. I question the value at €250 - the parts are pretty basic.

[Original Burnedfingers]

I would go with the 6SN7 also. The price seems very high considering the parts count. A diy 6SN7 linestage would surely be better sonically.

[amperex]

No brainer here- 6SN7

[SY]

Depends on your goals.

From their website:

Here's a very small tube preamp that can really change the sound of your hify system.

Well, if you want the preamp to change the sound of your system, you do not want to use a linear tube, so the 12AU7 would be the best choice. If you want the preamp to be a silent partner, doing nothing other than switching sources and raising/lowering the volume, perhaps a different design might be in order.

[Geek]

How 'bout a 6CG7/6FQ7, best of both worlds

[ray_moth]

It seems an odd set of options: 6SN7 and 12AU7 are very similar medium mu, low anode impedance tubes (although, as already stated, the 6SN7 is more linear and sounds better). The 6SL7, however, is quite different, having high mu and high anode impedance. The 6SL7 also can have rather high Miller capacitance, causing roll-off of audible high frequencies, if the impedance of its input circuit is too high. For example, if it is preceded by a volume control pot, the resistance of the pot should not be greater than 250k and preferably 100k or less.

6SN7 would seem to be the best choice here.

[CambshireGordon]

Hi ,
Thanks to all for your advice and guidance. Your clear vote is that I should go for the 6SN7.

Interesting too that some find the Autocostruire Heresay kit a bit on the expensive side at 250 Euros - (about 168 GBP at Nov '05 exchange rates). I too had that opinion & I believe there is still a power transformer / supply to be factored in! If one of you has experience of this piece of kit, would you let us know, (a new topic heading?) is it value for the money?

The (initial) attraction for me is that it is a kit of parts with a printed circuit board too. Here in UK it is not so easy to locate all of the various parts from one source. However, indications are that I could do better (on price and maybe quality components) by building from scratch. Not beyond me providing I have a schematic.

Now, where to look for a good 6SN7 design with quality components readily available ... ... There must be a forum here somewhere ... ... javascript:smilie('')

CambshireGordon

[andyjevans]

Now, where to look for a good 6SN7 design with quality components readily available >>

I can help you if you email me - I'm in London UK. Andy

aeatartsandmedia~at~aol~dot~com