Current mode vs voltage mode

Yeah, I agree with Sean. The sound you get with XLRs is probably the closest to Halcro's true sound.

Sean,

Good post, but I think you're mistaken on a couple counts.

The first is that people who judge amps based largely or mostly on THD (and sometimes IMD) don't exist anymore. They do - some of them spend $40,000 on Halcro amplifiers, for example.

The second is that tubes sound good because of harmonic distortion. That's at best a small part of the reason and at worst - and what I think is accurate - completely mistaken.

Tubes sound better becuase their higher linearity results in simpler circuits with fewer parts and much less (or NO) negative feedback. That's it in a nutshell.

Paul

Paul: I didn't say that the only reason why tubes "sound good" ( obviously, a subjective opinion ) was due to distortion. What i did say is that ( typical ) digital recording and playback circuitry and "typical" tubed circuitry ( if there are such things ) tend to form complimentary colourations that many people tend to prefer. That is, in comparison to "typical" SS gear with "typical" digital recordings and playback gear.

Tubes can have several different design advantages to them. On the other hand, they also have several different design limitations to them. Same goes for SS devices. As such, i can't understand why more manufacturers aren't combining the two i.e. not so much "hybrid" SS & tubed circuits, but actually using tubes that have quite a few "solid state" traits. That is, high voltage tubes that can also pass high levels of steady state current.

These are used in commercial RF devices all the time. How & why they haven't trickled down into audio in greater quantity is beyond me. Obviously, the reason isn't price, as there are companies willing to charge and people willing to pay massively high prices. Sean
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Thanks Bob

Your informative post is very helpful. I'm not sure if impedances are the entire story, however, as what I am reading in the Halcro manuals is very similar to Krell's description of their CAST/KCT technology with "infinite" output impedance on their preamp current outputs and minimal, under 100 ohm, input imedances on their amp current inputs. Or is the Krell current tunnel technology nothing but a choice of impedances to simulate a tube amplifier?......sorry if my electrical background is lacking.

Brian