The Dynaco Tube Audio Forum

Dedicated to the restoration and preservation of all original Dynaco tube audio equipment - Customer support for Dynaco VTA tube amp kits, all products and all products

    My 6SN7 review.



    Posts : 234
    Join date : 2014-06-23

    My 6SN7 review.

    Post by Dogstar on Sun Jul 09, 2017 3:45 pm


    A few months back through reading the forums I found out I could run a 6SN7 tube in the VTA ST-120 amp that I have now had since the Spring of 2013. Shortly after getting the amp I purchased a quad of TungSol KT-120's and a Webber WZ68 SS rectifier.

    I also purchased a quad of Genelex Gold Lion KT-88's and a GZ34 tube that I saved for a rainy day.

    Last fall one of the KT-120's red plated and thankfully I shut the amp off in time before anything else could fail. I finally installed the Genelex tubes and they've been running fine since then.

    I am still running the TungSol 12AU7's without a problem since the same time as the KT-120's. Thanks to this forum I got the urge to roll which brings me to the 6SN7's.

    About two months ago I bought a Patricia Barber CD in a Half Priced Books store and discovered how clean and dynamic her music is. I then bought 2 more of her CD's at Amazon and though all the music is not exactly my favorite it is a good test for how well a complete system is or at the least a good way to compare tubes. Of the 3 CD's I have I prefer her modern cool CD.

    I have found that to really test the 6SN7's I needed to have the amp running for at least 30 minutes. Until then I think the amp components are still working on getting to their optimum environment.

    Forum member eickmewg was nice enough to send me a 12AU7 to 6SN7 adapter and two tubes. The first is a Raytheon 6SN7GTB tube which was very noisy. Upon startup I immediately heard clicking and popping that eventually stopped for a 15 or 20 seconds or so and then became noisier. Pretty soon the clicks and pops were very loud and the hissing got louder and louder. Sort of like listening to a bad LP and experiencing a tube going microphonic. I told him of that issue and he immediately sent me a Baldwin 6SN7 tube which was like night and day. The Baldwin tube made the amp sound really nice.

    The following 6SN7's were loaned to me by fellow forum member wntrmute2. I was asked to describe what I like or dislike the tubes. :

    CBS 6SN7GT 210 5748 - Smooth and three-dimensional, my favorite. Handles the dynamics of the recording without any sign of stress. I keep coming back to this tube.

    RCA 6SN7GTB - Smooth and clear. This one is a very close second. I think if I listened to music with this one installed longer I'd feel the same way about how multi-dimensional this tube sounds.

    RAYTHEON 6SN7 VT231 - Very clean

    SYLVANIA CHROME DOME - Sounds very good.

    BALDWIN 6SN7 - Sounds very good.

    ELECTRO HARMONIX 6SN7 - I will give this one another listen tonight. I don't remember my feelings towards this one.

    SYLVANIA JAN-CHS-6SNYG VT-231 - Hissing flat sound. Maybe the hissing sound distracted me from paying attention to dimensionality

    KEN-RAD JAN-CKR-6SN7GT - Some clicking and popping. I really was hoping this one was going to sound good only because not many people have heard of this tube brand.

    Sorry for the bad photos. I put this together while waiting for a file transfer from work.

    VTA ST-120 by Blake Shellman

    6sn7 Tubes by Blake Shellman, on Flickr

    Posts : 435
    Join date : 2012-11-30
    Location : SF Bay CA

    Re: My 6SN7 review.

    Post by arledgsc on Sun Jul 09, 2017 6:28 pm

    Thanks for your report and observation. I've had mixed luck with NOS 6SN7s. Some have more distortion than others and many of them really roll off the highs. But chrome domes and bad boys hang with the best.

    I have a Black Treasure CV-181 I would like to donate to the pass around listening club. It has very minor rushing noise occasionally on warm up. But I'm listening to is now and sounds great. Will give you an excellent glimpse what they can bring to the mix.

    Posts : 111
    Join date : 2010-11-21

    Re: My 6SN7 review.

    Post by WntrMute2 on Mon Jul 10, 2017 6:58 pm

    I too like the CV-181s. I've now acquired 8 of them so I can run them in all my preamps. They occasionally show up on Audiogon or Canuck Mart for about half what new ones are. Very smooth with all bases covered nicely. If I had the extras I recently acquired, I would have sent Dogstar one to try. Don't expect much from the EH, it is a modern 6SN7 that I found lacking as MOST new manufactured tubes sound to me. The Black Treasures and the Tung-Sol KT-120s excepted.

    The Baldwins are supposedly rebadged Sylvanias selected for good tone in Baldwin organs and I cannot tell the difference from similarly constructed Sylvanias. Well, my wallet can tell the difference, as everyone wants the Sylvanias while the Baldwins fly under the RADAR.


    Posts : 234
    Join date : 2014-06-23

    Re: My 6SN7 review.

    Post by Dogstar Yesterday at 10:05 am

    As much as you guys are speaking highly of the CV-181's I think they are out of my price range.

    As I previously posted WntrMute2 gave me the opportunity to audition 8 tubes and he allowed me to purchase a few. I chose the CBS, RCA and Raytheon tubes even though other spoke highly of the chrome domes.

    I'm pretty sure Bob Latino said there was no difference in sound quality between the 12AU7's and the 6SN7's but to me there is a difference. Even though I too argue that in reality the differences in sonic quality are so small they are undetectable between modern tubes and NOS tubes, or one brand to another, or in this case, from one type of tube to another. Of course that observation comes from having only one sound system to listen to and nothing to compare it to. If two systems were set up so they could be AB'd then it definitely is possible.

    Anyway now that I have 6SN7's tubes in my amp and I have given them about 30 hours of audition time. Of the 30 hours the three I chose have more time.

    And of course I have to also thank eickmewg for giving me an adapter and a few tubes to test out and got me into the 6SN7 club. One of those was also a Raytheon but it was noisy from the start. The other is a Baldwin tube that I'm told are bulletproof. That one also sounds better, to me, than 12AU7's.  

    But now I'm thinking that maybe it's the brands of the 12AU7's that I have.

    Rolling is an uphill quest.

    Sponsored content

    Re: My 6SN7 review.

    Post by Sponsored content

      Current date/time is Sun Jul 23, 2017 10:41 am