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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

Showing 1 response by tomcy6

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tomcy6
2,632 posts
 
I think the Phillips/Amperex tubes that people are recommending are tubes made in the Amperex factory at Heerlen, Holland. Phillips sold these tubes with many different labels. Phillips owned many tube factories, Amperex, Siemens, Mullard, Valvo and many more, and tubes made in one factory were often labeled with another factory’s "brand." Your Phillips Miniwatts could have been made at Heerlen.

You can tell a Heerlen, Holland tube by the left facing right triangle that is the first symbol in the bottom line of the etched tube code. You can read about these codes here:

https://frank.pocnet.net/other/Philips/PhilipsCodeListAB.pdf

Any tube you’re likely to come across these days would have the ’New’ Code, illustrated on page three, etched on the side of the tube. The "tube type" code for a 12AX7, the first two symbols on the top line, would be I6.


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