I am loking for an amp to drive my HD600s (musical tastes: classical, opera and jazz). Source will be an Opera Consonance CD 2.3 Ref. Mk. III (an upsampling player roughly equivalent to the CD 2.2 Mk. III available in Europe, minus the volume control on the single-ended outputs). The CD player has tube single ended and solid-state balanced outputs.
Ultimately, I would also like to be able to use the amp to drive HD800s (when funds allow!).
Currently, I am using a Little Dot Mk. III (CV4010 driver valves), and am enjoying the transparent, liquid midrange and excellent soundstaging. However, I find the treble slightly rolled off and "veiled", and the bass to be a little slow and ponderous (the extension is there, but the speed and control aren't). Generally, a little more detail and resolution wouldn't go amiss - my ideal is the "Stax sound" (I also occasionally use a Lambda Basic, for chamber and choral music but never for Wagner!), only with proper dynamics, much faster bass and greater treble extension.
I am investigating a number of alternatives to upgrade from the LD Mk. III (which will continue in my desktop system, hooked up to a PC and a LD DAC_1). I am only considering local Chinese-made amplifiers, as import duty is very high here:
- Matrix M-Stage: very cheap here in China, and apparently based on an excellent Lehmann amp. However, I've heard that the performance falls significantly short of the Lehmann's, and it would be a sideways move rather than a step up from the LD. If it looks too good to be true, it usually is......
- Darkvoice 337SE: about GBP 550 here, with a good reputation for soundstaging and transparency. However, it seems to need quite a bit of exotic glassware (and DV have a reputation for installing fairly ropey stock Chinese tubes). Will it cost another GBP 500 in NOS tubes to get the best out of it? Also, will the bass be tight and fast enough with the HD600s, or should I really be looking at solid state amps?
- Audio-gd C-2.2: newly-launched, about GBP 240 here: seems to do what I want (good midrange and soundstage, extended treble, proper dynamics and impact), and offers the opportunity to fine-tune the sound using op-amp modules. Would this be a significant step up from the LD? Will it be capable of doing HD800s justice when the time comes? Finally, is it possible to connect the balanced outputs of the CD player to the ACSS sockets, or will I just have to use the RCAs?
- I have also been offered the Opera Consonance Cyber 20 (1x 12AU7 + 2x EL84, with output transformers), for a price of GBP 280. Would this be a good alternative? I have heard that it sounds "faster" and more dynamic than the OTL amps, and works well with Sennheisers. I would, of course, fit good British NOS tubes 
(Brimar and Mullard).
At the moment, I am inclined to go for the Audio-gd or the Opera Consonance. Any views or experiences?
