To Doug Schneider,

In the past you have tested the Orpheus Laboratories Three S and the Belles 350A Reference amplifiers. I own an Orpheus Three S, love it, but have some technical problems with it now. So I was thinking of swapping it for the Belles 350A Reference (not the V2). Both amps had good reviews from you, and though I understand they will be different, I was wondering if you could give me your opinion on how they compare to each other and whether this would be a good swap. I am using the Orpheus with Audio Physic Caldera MkII loudspeakers (also great!).

Thanks much for your opinion!


Wow, it's been so long since I’ve had the original Three S in-house that I had to go and look it up so I could be reminded of what it was about. Now that I've looked into it again, I remember that it was unique in that it had a module in it called a Power Loop, which made it into a constant-power amplifier, meaning it delivered similar power into 2, 4, or 8 ohms, which is not unlike a tube amp with a really high output impedance. Most solid-state amps don't behave like that, including the Belles. I remember talking to the designers about it and they said its main benefit was better control over the drivers in the speakers. The downside is that most speakers expect constant voltage, not constant power, so, as a result, the amp’s frequency response will vary depending on the speaker’s impedance curve, which will result in that amp having a sound unique to the speaker it's being used with. The only time you wouldn’t get a frequency-response change is if the speaker’s impedance is flat, which rarely happens. I'm not sure what the impedance curve on your Audio Physic speakers is like.

I never reviewed any Belles amps, but Doug Blackburn did and I know he loved them. But despite not knowing the products well, I do know a bit about designer Dave Belles and, from what I can tell, he’s an outstanding engineer who really knows his stuff. In fact, I’ve been thinking about calling him up for some time to talk about review gear, since some of his latest products look to be very interesting. Sorry I can’t tell you more, but if you do get that Belles amp (and I can’t see any reason you shouldn’t), please write back and tell me more. . . . Doug Schneider