Review on Linear Tube Audio Aero DAC

@teajay 

I also used my favorite 6SN7 tube, NOS 1943 TungSol black glass/round plates. Everything in my description of the Aero DAC’s performance with these tubes went even higher.

After reading about how you found the DAC's performance to be even better with NOS 6SN7 tubes, I thought I would look around and maybe purchase a set prior to receiving the DAC, so I could maximize its performance during my 14-day trial period.  Holy crap, I had no idea of where prices have gone on 6SN7 tubes!  It seems $400 to over $1K for a pair is not unusual.  Therefore, leaving the DAC powered up for best sound, as supported by LTA, would be a much more expensive proposition if using NOS tubes.

Can you elaborate on the specific sonic attributes, as well as the relative degree of improvement - i.e., subtle to significant, that you heard when using NOS 6SN7 tubes?  Do you believe 6SN7s in general may sound better than 12SN7s in this DAC?  Thanks for any additional thoughts you can share regarding the impact of the tubes used.

Hey mitch2,

Of all the 6SN7s I have in my collection the TungSol black glass/round plates have always been my favorites for three reasons: 1) The air and spatiality they create is really very remarkable. 2) The beauty of timbres/colors is very pristine and very close to what I hear in live music. 3) There is an ease/effortlessness that it produces which I experience as the music is just oozing and flowing into my listening space. 

With all that, when I used the TungSols in the Aero it did not produce a qualitative shift (what I believe you would call significant) but a subtle addition of the traits I described above. The DAC sounds absolutely terrific with the GE NOS 12SN7s that it shipped with. Using the NOS TungSol black glass/oval plates 6SN7's is like "the icing on cake". So, if you go through with your purchase of the Aero and love it,, which I think you will, you could treat yourself later with a pair of 6SN7s. 

Finally, you are correct they have become scarcer and more expensive, but you can still score them for relatively reasonable prices. If you get a good pair they tend to be very long lived. The way the LTA Aero uses its tubes they should last a very long time, indeed.

Teajay 

Good to hear, on all accounts.  Thanks Teajay.

@mitch2 If you do decide to buy NOS 6sn7 tubes this is a must read.  There are reasonably priced tubes (Sylvania, Rca, Raytheon) that sound fantastic but requires some searching and leaps of faith. Interested in your feedback on the LTA Aero once you get some time with it.  
 

https://forum.audiogon.com/discussions/shootout-of-nos-6sn7-tubes

@tksteingraber - Thanks for linking the tube thread.  Based on my web search, if I decide to keep the DAC, it seems I should be able to find a tested and matched pair of suitable NOS tubes, like SYLVANIA VT231s, for under $300, which seems an acceptable price assuming they improve the sound.  I wish LTA had those DACs in stock and ready to ship as I am looking forward to hearing it.