Most transparent amp you've heard?

Sean, based on those specs, I think that JA is right and tubes amps are not the way to go. As transparent as the Atma-spheres are, they seem like less than an ideal match, even though some may chime in that you can make it work with a speltz transformer which would defeat the transparency rationale to some extent. IMHO, you need SS and in that camp, I think you could do a lot worse than auditioning the Pass XA.5 series (the best SS I have heard, but I'm a tube guy so take that with a grain of salt), I do think that XA-60.5s would be enough power for you - they have a lot more drive than their specs would suggests and they are by any definition transparent. Oh, and did I mention they are uber reliable? An alternative is to consider the X-Series which gives you more watts per $$$, but are not quite as good to my ears (but still excellent amps).

Sean and Pubul57, if transparency is what you crave (lack of distortion, I'll get to that in a bit), then it is to your advantage to keep the impedance of the speaker as high as possible. This is true regardless of the amplifier technology, tube, SS or class D. IOW 4 ohms and less is not practical **if detail (transparency) and general musicality is your goal**. If instead you crave volume, lower impedance speakers will winnow that out of transistor amps.

This issue is so profound that the Speltz autoformer is beneficial to any amplifier that has to drive 4 ohms **it can make the impedance translation better than any solid state amplifier can**. IOW, transistor amplifiers will sound better driving 4 ohms through the ZERO than direct.

Figuring out what 'transparent' is was a serious issue that we had to face before we could even build anything. We solved it by going back to the microphones- then building the best mic preamps we could, then running them directly into the amplifiers and then auditioning both amps and speakers. It also required someone playing an acoustic instrument, so we could compare live vs. reproduced.

This allowed us to build our first reference, which we used to audition master tapes, and from there, LPs (CDs were just barely getting started...).

Ultimately transparency turned out to be "a lack of audible distortion, which would otherwise mask detail". The human ear/brain system perceives sound using a certain set of rules that all humans respond to the same way (taste is not an issue here). In this case, the rule is known as 'masking', wherein a louder sound will mask the presence of a quieter sound. So, low-level distortion will mask the presence of detail. Remove the distortion, and the detail is revealed. The distortions we are talking about here are at very low levels, yet our ears, via the masking rule, can easily hear the difference, and yes, you don't need a master tape to tell; the phenomena of 'not having heard that before' in a recording you know well is completely valid- you remove some low level distortion and voila!

Tvad- You managed to quote exactly what I said about the sound in my listening room being true "largely"(look it up- It means "generally") true to what I heard during the recording sessions. I also mentioned, "No claims to perfection." Then You entered into an immediate rant about claims I never made in that statement and reminded me so much of my ex-wife: It triggered an old response. So- I added another log to the fire. It cost me dearly to rid myself of her irrationalities. Gratefully- It won't cost me anything here. The TacT 2.2X (RCS) is not an amp. Over the years many have depended on my hearing, and paid for my services. I must be hearing and doing something right, as I've got a lot of happy customers. Enjoy whatever you enjoy!

the most transparent amp i've heard is the darTZeel NHB-108 using the darTZeel NHB-18NS battery powered preamp and connected with the 'zeel' BNC cables.

the dart is a solid state design but it's sound is like music. no solid state sterility, grityness or upper mid-range glare, that wonderful solid state high frequency extension but with a sweetness instead of hardness. the dart also has that 'breath of life' of tubes without the darkness or roundness. with a very short signal path, minimum number of output devices and no global negative feedback you have a 'see-thru' quality, delicate nuance, naturalness, and an extremely low noise floor yet excellent micro-dynamic energy.

the dart does not impose a character on the music; instead it gets out of the way and achieves an amazing level of transparency and it's sound is the sound of real music.

the closest thing to a darTZeel in transparency in my experience would be the very best OTL tube amps; my favorite of which is the Tenor OTL and then the Atmasphere.

i have not heard everything out there.....