6SN7 and microphonics, and other ramblings

[John Roman]

I've been reading lately that micro-phonics can be an issue with the 6SN7 tube. I'm considering this change to my EFP3. I've bounced back and forth between a 7N7 or a 6sn7. I'm currently using  some 12au7's by RFT that I replaced the stock tubes with and have very much enjoyed them. They are not micro-phonic at all. The noise floor on my EFP is beautifully quiet and I don't want to add any distraction. I've been listening to a lot of Pandora radio via my Music Streamer II lately and am really at times mesmerized by the sound. It is not in my character to use hyperbole when it comes to characterize my system. I choose the word mesmerize because lately I find myself losing track of time when I listen. IMHO there is way to much embellishment lauded in the audiophile realm as to make evaluation near impossible. I recall reading Grainger's footnote, "Remember, you are the only one....." for the first time and being a "newbie" was unsure what that meant. Now it makes thorough sense. I think sometimes I get in to much of a rush and make changes almost for the sake of change alone. Thus not allowing a proper "listen" if you will, to what I already have. A hindrance to the evaluation process without question. My apologies for the meandering post. Just couldn't sleep tonight, up at 2 and have been listening to the non commercial Pandora. The quiet early hours have become my favorite time. My best to the group!

Can't wait to get my BassZilla's finished! Time for Starbucks......

[Laudanum]

I dont know if this will help John but maybe it will.  I finished my Seduction but havent started my FPIII.  It wont be the extended version.  I plan on building it with Octal sockets for 6SN7's right from the start.  I've been rolling 6SN7's in Crack with an adapter.  I dont have a slew of them but I do have some GE's, Sylvania Chrome Tops, a couple Sylvania VT231's and a Brown Base Jan sylvania.  Also some RCA's but I havent spent much time with them.  Mostly rolling the various Sylvanias and the GE's, I havent run into a microphonic tube yet.  I have read that the adapter makes it even more likely.  That's not to say that the same good fortune will remain with the FPIII.  I dont know if the 6SN7 in the FPIII will have more of a tendency for microphonics than when run in Crack.  Not sure how that works.  But I like the 6SN7. I think the FPIII is the perfect component (for me) to use them in as it is a "central" piece of gear that should impart the 6SN7 flavor into the signal chain for all sources.  I plan on going back to the 12AU7 in Crack after FPIII is in the signal chain.   Hopefully there wont be any issues with microphonics, but as I mentioned, I havent had any with any of the 6SN7's in Crack.  Fingers crossed.

Maybe this helps some.

[John Roman]

Desmond,
Thanks for the reply. This microphonic issue arose from reading a post at diy audio. I wasn't sure how much of an issue it would be, thus I queried this forum. I may yet try the 6SN7's. Would you care to share which specific tube you like best? I'd like to keep cost reasonable. I bid on some VT-231's on Ebay but lost out. Any suggestions would improve the rolling curve so to speak. Thanks again!

[Laudanum]

I've read about the possibility of the 6SN7's being microphonic as well.  There were some posts on this forum too.  I just think they may be more prone to it than some other tube types.
I like the Sylvanias in general, atleast in Crack.  The top 6SN7's are expensive, you are right.  I was able to pick up two VT-231's in 2 seperate auctions for 20 dollars each.  But to be honest, the Chrome tops dont give up much to the VT-231's to my ears.  But my ears are not golden by any stretch.  I think that the VT-231 may be a little smoother up top but I cant A/B them against the Chrome Tops to be sure and I can live very happily with the Sylvania Chrome tops.  I have two pairs.  I didnt pay much for them, one pair is labeled Baldwin and they were NOS, they are 6SN7 GTB's.  I think I paid under 20 for the Baldwin pair, about the same or a few bucks more for the Sylvania labeled pair which are 6SN7 GTA's.  They both sound the same to me.  I have a brown base 6SN7 WGTA which is a ruggedized tube, JAN I think. I think it has just a hint stronger bass than the Chrome Tops but very similiar sounding all around. Unfortunately, it's the only one I have.  Ive seen a few on Ebay but havent been able to grab one, they were bid up to more than I was willing tp pay.  I got it in a lot with 4 or 5 other tubes for cheap, there were also a couple GE's and RCA's including a cool coin base.   All the Sylvanias I have are similiar sonically to my ears.  The GE's are warmer sounding.  They dont seem to be a extended up top but they are smooth and a bit stronger on the bottom. Probably a more "vintage" sound.  I like them in their own right but quite different than the Sylvanias.
I didnt spend much time with the RCA's. The Sylvanias and GE's to a lesser extent just kinda caught my ear over the RCA's when I was first rolling the tubes and I havent gotten around to really spending any time listening to RCA's.

Anyway, that's my take on what little bit of experience I have with the relatively few 6SN7's I've picked up.  Bang for the buck, I would say try the Sylvania Chrome Tops (Domes).  Quite a few ebayers are overcharging for them but you can find them for good deals too as re-labels or auctions rather than BIN's. 

[Laudanum]

Just a follow-up.  I finished the FPIII build with Octals for 6SN7's.  It's only been up and running for a day or so.  No microphonics from the two Baldwin labeled Sylvania 6SN7's Im currently using in FPIII.  They may be more prone to microphonics but again, 6SN7's arent necessarily microphonic based on what Im hearing.

[John Roman]

I appreciate the follow up Desmond.

[Laudanum]

No problem.  And I should mention that this was with my turntable as the source and seduction as the phono stage.