I agree with Tubegroover, the Berning ZH270 should be more than a match for the Cary Cad211, especially if you are sensitive to noise and hum. The Berning does not have a power transformer or a heavy output transformer (the amp weighs less than 5 kilograms!) so there is absolutely no transformer buzz at all. Furthermore, the tubes in the Berning -- 2 pairs of 12AT7/ECC81 tubes for voltage gain, 1 pair 12AV7/5965 tubes for driver tubes, and a quad of 6JN6 sweep pentodes (wired as triodes) for output are heated with radio frequency AC. The two voltage gain stages and the driver stages are single-ended, without interstage coupling capacitors. In fact, there is only one input capacitor in the entire signal path, otherwise the amplifier would faithfully amplify DC. The Berning ZH270 is the quietest tube amplifier I have owned and the most transparent amplifier I have owned period.
The Berning ZH270 also has three feedback settings -- normal(a low 12 dB), medium (a lower 7 dB), and low (3dB); which you prefer will be a matter of taste and the impedence of your speakers. Without the conventional output transformer in the way, the first thing you will notice about the Berning ZH270 is the bass extension and the high frequency extension, relative to the Cary. The Berning also has two sets of inputs as well as internal volume control -- I run my DAC straight into one set of inputs and bypass my preamp altogether. There is no preamp, like no preamp, I know ...
As for the palpable mid range of SET amps, you can achieve that sound in the Berning with a judicious choice of input tubes. If you like the rich mid range of single ended amps, then using richer sounding NOS input tubes such as the mid 1960s (or earlier) Mullard Blackburn ECC81 or the 1950s RCA black wing plate 12AT7 at the lower feedback settings will give you this style of sound, plus keep the bass and high frequency extension of the Berning.
:-)
One strong tube recommendation I would offer would be to purchase a quad of the matched, cryo-treated output tubes from Allan Bhagan (info@zotl.com) as well as getting the internal silver wire and capacitor upgrades from Allan too. At least with the output tubes, you can listen to the amp while you wait for the tubes to arrive.
If you prefer an extremely transparent, live sound then the Berning ZH270 works very well with any of the top 12AT7/ECC81 types known for their transparency -- e.g. Siemens, Telefunken, etc. -- exactly which one is a matter of taste. The Berning is so transparent that you can easily hear the (not always subtle) differences between the different highly regarded vintage 12AT7 tubes available from top NOS tube dealers such as Tubemonger (here on Audiogon) or Andy Bowman at Vintage Tube Services. The Berning ZH270 autobiases all of the tubes and tube sections separately using servo cicuits to keep the DC plate current constant. This means that the Berning ZH270 will find the correct negative grid voltage bias for each dual triode section independently so that they stay in their correct operating points over their entire lives. This feature alone makes the Berning ZH270 one of the most user-friendly tube amps in existence.
