Amplifier Pairing with Coherent 15s

Hello all,

About to finalize an order for a pair of Coherent 15s (yay!) and now I'm starting to look at possibilities for amplification for them. Since they are very efficient (I believe 106db efficiency), they can work well with flea amps+, so there's a wide range of possibilities.

I have a few criteria though: I would prefer an integrated amplifier vs separates/mono blocks, both for cost and space reasons, so something like AirTight is out (plus, a bit too expensive anyway). Looking around the $10k range at the higher end.

I don't listen to things super loud, and tend to prefer tube amplification. Music tends to lean majority Jazz, with some other things throw in here and there, but Jazz is the most important genre to get right.

Frank (from Coherent) recommended a couple -

Tektron Two 2A3/50S-i
Mastersound Compact 300B

Some others I've looked into:

Tektron Two 211-i
LTA ZOTL Ultralinear Integrated

I do have a few concerns with hand-crafted, more 'custom' made amps, especially by manufacturers overseas (I'm in the US) - mainly inability to demo them and ease of service/warranty. They also tend to be more difficult to sell in the case of deciding to go a different route, though this is of a lesser concern.

Anyone have any experience with any of these, have any other suggestions to explore, or any other comments?


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@soix : What type of sound characteristics are you after with the new amp?

Wide and deep soundstage, wonderful midrange and vocals, not overly harsh on the top end, full bass without being too sloppy. Overall, I lean toward liking the slightly more lush/musical tube amps I've had in the past vs the hybrids/solid states.

@yogiboy :This Audio-Research should fit the bill! Audio Research I/50 Integrated Amplifier (

Thanks for the suggestion! I've looked at their amps before, but from what I've read, when tubes are replaced it has to be done by a technician, which I do not like the idea of. I don't want to have to send it off for extended periods of time every few years (and pay) to get tubes replaced when there are plenty of other options where I can just do that myself.

Leben CS600 with KT66 would be great. the little 300 is great too but I liked it more for guitar and vocals than thumping bass type of music. I've owned the Mastersound 300BPSE, great amps. There's a compact 300B for sale on Audiomart from a well known speaker maker. 


Have you heard the Coherents? I got close to ordering the 12 m a few years ago but just needed to hear them and couldn't. Please post some results.