How do the Electro Harmonix 6sn7's sound?

Jppenn, Do yourself a favor, you don't have a huge tube roll here. Don't mess with the non NOS tubes. It's a waste of time and money. Go for the old valves. Experiment a little. For me all of the Sylvania's the W(40's), GT & GTA(50's), and GTB(50's to 60's) are wonderful and are far superior to the current manufactured tubes such as the Electro Harmonix you mentioned. Sylvania has it all sonically, few could argue. The Sylvania 6SN7 IMHO is the finest American tube ever made, bar none. In general they are progressively better the further back you go by some measure but that said the GTB's have smoked any current production tube I've ever heard in my applications. Just keep in mind that the price goes up with the scarcity and age of the tube. I run ten of them in my Atma-Sphere OTL MA-1 amps and have never heard these amps sound better. I have a friend that runs them in his phono amp and loves them.
Happy Listening!

Thank you for all the input. The reason I asked the question is because the older, good sounding vintage tubes are relatively expensive, i.e., a tung sol round plate for 125.00+ etc. So I thought I would ask about the EH. For my preamp I have found nothing that gives me the detail and smoothness as the TS round plate, everything else is a compromise. I do like the sylvania W's, the Raytheon WGT's and the sylvania vt-231's. One has to wonder why noone has duplicated the architecture of some of these great old 6sn7's?

I just picked up a set of Sylvania 6SN7GTB's from Andy Bowman of Vintage Tube Services for thirty-six dollars each and they were tested as new by him. Very nice stuff for the money and Andy is the best vintage tube guy I know.

R_f_sayles
Which 6AS7's do you use in your Atma-Sphere amp?
Dennis

"...the older, good sounding vintage tubes are relatively expensive, i.e., a tung sol (sic) round plate for 125.00+...". Indeed, but your example is the MOST-expensive 'N7* I'm aware of. And going to the EH could be viewed as moving from the best to the worst (or close to it; I think the Sovteks are the worst-sounding 'N7).

So what did your preamp cost? What do you have invested in your system. Do you enjoy listening to it? (I sure enjoy mine.) How long does the great sound from a pair of tubes last? If the RP TSs are a little rich for you, try the Ken-Rads. Seems to me there are enough alternatives out there to please you woithout spending $125 per 'N7.

On building tubes, it's not just the physical architecture. Apparently, tube manufacturers had secret formulas for materials, etc., and even those varied from one tubemeister to another, and I think that's one reason why one tube's sonics varied over the eras--another tubemeister was building them.
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* I've stumbled into ONE TS RP, and it tests very well and operates well, but I've not listened carefully to it (without a mate). Probably I'll sell it.
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