Rich; organic true balanced amp w good detail $6k


Suggestions welcomed & appreciated- here are the Criteria:

- fully balanced architecture
- rich, organic sound, extended bass, silky highs, but not at the expense of obscuring detail
- No OTL (too many tubes/heat)
- SS (Class A bias) or tubes OK
- 20-200 wpc ok, the lower the better though all things being equal- well built power supply crucial
- stereo amp easier to put on my Sistrum rack, but mono-bock architecture also considered if better performance
- $6k or less used would be ideal, but would consider up to $8k used if there are no world-beating contenders at the $5k-$6k used price point

Preamp is a modded Sonic Frontiers Line 3- extremely neutral, hence the desire for a richer-sounding amp to balance. High efficiency speakers from Coincident- large open concept room (main floor of house). Re: tubes, have used ARC VT-100 MKIII- good- airy w big soundstage, but meatier mids would be better. Also had Wyetech Topaz 20-watt SET, superb, if slightly lean in the mids (and not fully balanced, but shows you how powerful 20 watts can sound with a well-built power supply) For SS, am considering Pass XA.5 series (they now can run balanced from what I understand?); Clayton Audio M-200 (but unfortunately over the price-range).

Thanks in advance for any suggestions- I have an open mind, so bring it on!
sutts

Showing 3 responses by t_bone

Personally, I would choose the 861 (or the pair). I own an 859, which uses the same tube (also has beefy transformers, ETM output, sounds so silky smooth it is ridiculous, alas has only 13.5 watts and I need more) and I love it. The 861 is basically a larger ('push-pull') version of the 859. They both sound wonderful. The 869 (1-2 watts more than the 859 but otherwise almost identical) is also good.

I happen to like Tim de P's circuits. He doesn't use feedback much, he likes trying to get SET 'taste' with more power and is willing to experiment with circuits to get there.
I have and really like VTL 450s from a few years back (no autobias and different caps than before). I think they are great. However, if you have high-efficiency Coincidents, the 450s might be a bit of overkill (like they are with my speakers). The Coincidents are reasonably benign loads as well so I think you could get away with less "beef."

Another couple of amps I can toss in the mix if you can find them used would be EAR 890(s) or EAR 861(s). They are both stereo amps which can be bridged and used as monoblocks. The 890 uses a KT90 tube and the 861 uses a EL519 tube (originally a TV set tube) in "enhanced triode mode". Both amps (and almost all EAR amps) have quite beefy transformers. They both have true balanced inputs, both work in Class A, both are quite easy on their respective tubes (the EL519 has a VERY long life) and both amps are very easy on the user (autobiasing, very little to do, long tube life).

If it were my choice, I might go for a PAIR of EAR 861s (which, when bridged, would put out 64W per channel). They have no feedback, are extremely linear, and I find the midrange and highs to be absolutely wonderful with this tube and depending on which Coincidents you have, you might be able to get by with a single amp just fine (the 890 would be no problem as one amp is 70Wx2). If you found them used, they would probably be in the price range for two (ditto for one 890). And in any case, you could get one, use it, and if you decided you needed a bit more oomph later, you could get a second. I love the tube...
The amp is the end of the chain when it comes to differentially balanced or not, and if there is anything to the "SET" nature of your amps, it will not matter a great deal I expect. I am not a circuit specialist, but given the way that the circuit runs through the tube, I cannot imagine how the "fully balanced" will matter to a true SET - I imagine it will only matter if it is triode-ified push-pull, and even then, circuit implementation will matter far more than whether the amplifier circuit is fully differentially balanced or not (the next part of the chain is speakers, which will not care whether the amp was differentially balanced or not).

The VTL 450s (the old ones, at least) have a triode/tetrode switch on the back (do NOT switch while the amp is on - some speakers do not like it).