The Truth about Modern Class D

Ladies & Gents,

It's about matching technology to assemble a HiFi system.

I've been a HiFi'r since I was old enough to manipulate the arm on my Dad's Bogen/Lenco in the mid 50's. Over the decades I've heard many 10s of amps with the latest buzzword technology. Not all moved the ball forward in the context in which they were heard.

I have TC-50, BiWired and recapped, and tri-amped LFT-8b. Both speakers are renowned for their phase coherency, a property without which I cannot listen. AND a long list of absolute failings.

I have 4 amps: Rotel bipolar, NuPrime ST-10 Class D,  PrimaLuna Prologue 5, and a pair of VTA M-125s I reworked. Each has its ±.

Depending on program material AND time of year, each trounces the others. ALL present an excellent and engaging sound stage.

As Ralph can attest, there are 1001 details to get right, some of which are diametrically opposed. Each has it's foibles. Some genuinely beautiful boxes have no soul in some systems. AND all can be severely compromised with poorly mated cables and companion components.

The proof of the pudding is ALWAYS in the eating. AND you must eat the whole pudding!!!

O.K. I just got home from the first day of the Rocky Mountain Audio Fest. There were two things I was excited to hear: the Kii speaker system and the AGD Vivace amps. The Kiis were a non-starter. Although I didn't do a long audition, I didn't like what I heard at all. They are internally amplified with Ncore amps. The Vivace amps ($15,000/pair-mono) however, were very close to changing my preconceived ideas of Class D. They were sweet and dynamic and very enjoyable until they got into the upper midrange/treble, think trumpets. There, they were hard and grating and generally unpleasant. I first thought it was the recording, but I continued to listen as I was truly enjoying the experience (speaker was Sigma Acoustics Vector XAC, $185,000 or so), but recording after recording exhibited the same harshness. I could have been the speakers, I suppose, but probably not. I pulled up this thread to see what others were thinking and a post by stereo5 was first with the same complaints I had. Class D is still in it's infancy and after today I have great hopes, but it's not there yet.

Again, calling all Class D amps the same, or blaming them all for the failings of one specific model is just prejudice.

@jdl57 - I've run much less expensive class D through incredibly revealing speakers and not heard the problems you experienced.

Best,
E

None of my 3 Class D amps sound "hard and grating". In fact the exact opposite..... Smooth and detailed....most non-fatiguing.