What made you change to a 6SN7 preamp?

"Unrelated to the thread topic but important to those looking to optimize their purchases regarding NOS tubes, Andy @ Vintage Tube Services is the guy. Give him a call, you’ll be rest assured he knows his tubes and upon ordering you’ll also find yourself grinning from ear to ear. He’s a passionate and perfectionist audiophile."

@tubegroover I did order some 12au7s and 6922s (Mullards and Amperexs) from Andy over 20 years ago and he did make me laugh. He had some strong opinions about manufacturers that wouldn’t be fair (to those manufacturers) to share. About 7 or 8 months ago I upgraded my 12AU7 pre to a 6sn7 pre, and I am about to upgrade the tubes. I have been putting off my decision of who to buy the tubes from, but I guess I’ll give Andy a call on Tuesday.

I am running a Musical Design Chameleon preamp made by John Hillig.  The same well known and respected person that has made many people ecstatic with their systems.  The Chameleon has several daughter boards that snap onto the motherboard and provides an easy way to compare differences in tubes and tube types.  I find the 6sn7 board with my Tung-Sol 6sn7GTB provides a good soundstage and a rich tone that you can listen to for hours.  I swap different boards and tubes.  Presently I am using a board with 2 Telefunken 12au7 tubes.  I really enjoy the outstanding sound and flexibility this preamp provides.

@sjackso1 "...I find the 6sn7 board with my Tung-Sol 6sn7GTB provides a good soundstage and a rich tone that you can listen to for hours. I swap different boards and tubes. Presently I am using a board with 2 Telefunken 12au7 tubes. I really enjoy the outstanding sound and flexibility this preamp provides."

This is an interesting ability to compare the two tube types using the same preamp.

Are you utilizing new "re-issue" TS 6SN7GTBs to compare to vintage Telefunken 12au7s?

It was said that Vintage Tube carefully tests all tubes for microphonics.

Testing equipment has no way to do this.

The only way is to plug the tube into your component and wait a bit.

Tube sellers cannot do this. Hoarders may have the best tubes. But even then, you need to buy more than you need just in case.

I paid $750 for 4 Psvane 6SN7 Globes and they were all microphonic.

Andy @ Vintage Tube Services is a great guy and helped me decide on the best 6SN7 for my monoblocks.   Question-I have not had microphonic tubes in 50 years of audio gear.  For the past 20+ years, my pre-amp and phono stage uses subminatures which have a reported life of 100,000 hours, really thick (bomb use) glass and great sound.   Can using various dampening rings such as Herbie's reduce or eliminate most microphonics?   Or is the microphonic the result of internal parts vibrations?