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Let's roll: what pre-amp tubes should I consider next?

I am looking for some guidance from experienced vacuum tube amp users. I have a Unison Research S6 (most recent model) which runs six x EL34 power tubes and two x 12AX7 pre-amp tubes.

Having gone NOS in the pre-amp section, I've had great results over the new manufacture Tung Sol 12AX7s that come stock with this integrated. The tubes I've played with are the Philips Miniwatt 12AX7s and the Siemens 12AX7s. I like what both have to offer, but there are differences. The Miniwatts being warmer and contributing to an overall more subtle listening experience whereas the Siemens are more precise, producing a sound that has attack, excitement and thrill in abundance. However, I find the latter can be a bit too much in the upper mid/lower treble region some times. Is there another new manufacture (thinking Psvane?) or NOS (Brimar, Mullard, Mazda) that would give me the best of both worlds? Good tone and timbre while maintaining a sense of involvement through speed and attack?

What are your recommendations?

funcrusha


funcrusha
funcrusha OP
4 posts
 
Thanks for all the responses. Lots to think about on the NOS front. I have tried Gold Lions 12ax7s, and they didn't suit my tastes. In my system, they sounded lean and a bit bright up top - though I know they have a reputation for being dead neutral.

Will seek out a pair of Psvane 12ax7s and either Sylvania or Mazda old stock.

funcrusha
wolf_garcia
6,742 posts
 
I’ve noticed some clear differences between 6SN7GTBs that both my pre and power amp currently use, and NOS GEs are my faves for those. I continue to use 12AX7s in my guitar amps (and previously in my Jolida 502p amp also, although I no longer own that amp). I did wind up using Gold Lion 12AX7s though, as they sound great, are consistent, and are readily available.
verdantaudio's avatar
verdantaudio
1,515 posts
 
For NOS Tubes I love the Mazda's.  Top end sparkle and a very dimensional.  I am running 12AU7s in the input stage in a power amp and love them.

NOS Mullard's are decidedly warm.  Wonderful tubes if you like that sound profile.  Not sure I would pair them with an EL34.

For current manufacturing, I would look at Sophia.  Great sounding tube with no real weaknesses.  

https://artaudio.us/products/sophia-electric-12ax7-tubes-ecc-83

If you are interested in rolling your EL34s the Sophia Coke-Bottle EL34 is freaking amazing.  

https://artaudio.us/products/sophia-electric-el34-st


audition__audio
1,572 posts
 
A Telefunken smooth plate 12AX7 might hit a good balance between the Amperex (Philips) and Siemens.

I dont like any Mullard 12AX7. I also dont care for any U.S. made 12AX7 except perhaps for the old stock Tung-Sols.

If you can live with roughly 30% less gain, 5751s are great tubes. Best of these are: Raytheon Windmill Getter (double mica), GE and Sylvania triple mica black plates. For less money, the double mica Tung-Sol is also good.


itsikhefez
63 posts
 
I'm not an expert here but for my 300B I was told that the gain stage tubes may have more influence than the power tube, and that the Telefunken is the best choice and best 12AX7 produced.
I went with smooth plate as understood it is slightly more refined and less sparkle than the ribbed plate.

Whether its the best or not I can't say because I haven't compared, but the amp that uses them is the best I've ever heard

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