Class D amp with Tube Preamp Combo?

Hi Guidocorona,

It was a massive, single chassis stereo amp. I think the model number was 302, but, I am not sure. The owner used it to power Kharma speakers, but sold it in favor of a Hovland amp after buying a pair of Sonus Faber Anniversarios. We got to play with it prior to it being shipped to a buyer in the far east.

To a great extent, component compatibility is unpredictable, and the only way to really know is to actually try different combinations. However, as a general rule, I have found that the idea of mixing and matching so that the strengths and weaknesses of one are "balanced" by contervailing strengths and weaknesses of another hardly ever works out; one tends to lose the good qualities of each as a result rather than attaining balance.

I have tried solid state linestages with tube amps, as well as the other way around, and while some mixes worked out reasonably well, for me all tube worked the best. Some of the worst combinations I tried were tube linestages feeding solid state.

I've only heard the Bel Canto Class D amp and a very expensive Rowland (@ $14k). A bunch of friends had fun trying the Rowland in their systems. The Rowland worked best in a system where it was fed by a balanced Hovland preamp. While "not bad" in this system, it did not sound great either. The top end seemed shut down and microdynamics were slightly blunted.

In the other friend's system, which is a very sensitive and very picky custom horn system (fed by a custom tube linestage), the Rowland sounded much worse. It had an odd, unnatural sound that I could not exactly place what was wrong (not an obvious tonal problem). Again, the top end was almost completely missing, but, more troubling was a loss of the sense of notes naturally blooming into space and decaying naturally. Musically, the system lacked "soul" and sounded lifeless compared to what it sounded like with very small triode amps. It may be the case that the amp would be at its best delivering much more power as these speakers require very little power (they are about 106 db/w efficient).

Both of these systems have been carefully constructed over the course of many years, so a quick drop-in test hardly says anything about the inherent qualities of the Rowland amp. But, it does demonstrate that they are hardly the panacea for any ALL systems.

Hi Guidocorona,

It was one of the earlier Class D amps, though I don't recall the model number. I bet it was still low on the learning curve and subsequent models have been improved.

I am hesitant to talk about "tube magic," because it means different things to different people, and because MOST tube gear I hear completely lack what I look for in tube gear (particularly, high-powered pentode amps driven by KT-88/6550s disappoint). In my setup, I did not fully get what I was looking for until I found a suitable tube linestage and a tube phonostage to match with my parallel single ended triode amp. The Levinson No. 32, which I still keep as a backup, did not quite deliver what my Emotive Audio Epifania delivers.

I am not saying that tubes are superior. In systems where more power is needed, I think that solid state is often much more desirable than high-powered tubes -- different horses for different course. I bet Class D would be the appropriate choice in some applications. The point is, one cannot make a generic choice, trial is the only reliable method. Also, I think one will usually not find success trying to compensate for strengths and weaknesses based on perceived individual qualities of particular components; the results are too haphazard for that.

There is a lot of practical sense in sticking with one brand for amplification or to go with an integrated -- usually, a good designer has worked out such compatibility issues.