My thoughts on my first Class D amp


I recently started 2 threads on this site, Narrowing down choices in a Power Amp  and also High Power Amp, Does it Matter at Lower Volumes.

I am grateful for all the input, and thought I would share the results of those posts.

Summary is: I have a Baetis Audio Server, going into a T+A Dac8, into a Mark Levinson ( ML ) 326S into a ML532H power amp. The amp loses a channel on occasion, with strange popping noises sometimes, other times just a single ( not very loud pop ). Time to get this amp fixed or buy another amp.

Well, I am getting the amp fixed, but I bought a Class D RCVTech set of monoblocks. 

So, having said all this, WOW. Very happy.

My wife and I sat down last night, and played a variety of music, from the Baetis server. No new music, no streaming, existing tunes we have listened to for years. Nothing but an amp swap.

The RCVTech MPA-1200 monoblocks 

1)  definitely better stereo separation, 

2) definitely way better bass, these monoblocks double down to 700 wpc at 4 ohms, something the ML532H did not do. A world of difference on bass

3) overall better sound, even at low volume.  Not bright or fatiguing at any time. 

4) more detail, listening to existing tracks we have owned for years, more small background detail, 

I wasn't fully sure of what I was buying, but, now, I realize that while I will repair the ML532H, its future use is in question. I am keeping these Monoblock RCVTech MPA-1200 amps in place. 

The buying process was easy, the right questions were asked, delivery was fast, for a customized build.

I have the Class A input with 380 wpc at 8 ohms, 700 wpc at 4 ohms, 700 wpc at 2 ohms, THD + N = 0.0009%.

Since this is Class D, not sure how much more money I would have to spend to better this with a conventional build Class A amp?  I was considering Pass Labs, who were suggesting XA100.8 or larger.  Some day I may actually get to hear these Pass Lab amps, but, there is no urgency, now.

 

robeffy

@hilde45 you are correct.  If a class D amp sounds like either a tube amp or solid state high end amp, I don’t need both.  It’s been a while since I had a tube amp but to my memory none of my class D amps sounds like a tube amp.  And even though none of the class D amps sound the same, to my ears, they have some modest weaknesses and strengths that seem to allow them to be distinguished from my superb JC1 monoblocks.  If I did not have spare amps sitting around that I could move in and out in under 5 minutes then I would have perhaps suspected but never definitively proven to myself what I have been saying.  For sure, there are class D amps that I have not heard such as the AGN lineup.  My current reference system is transparent and dynamic as heck with superb clarity and tonality: Melco server and CD transport, Aric Audio Motherlode XL preamp, Teac NT-505 DAC, Space_Tech Super Rectifier, Zafino Silver Dart RCA interconnects, Huffman Pharoah and biwire speaker cables, Huffman Pharoah power cords on my amplifiers, Tekton Ulfberht speakers, EnigmaAcoustics Soparino super tweeter, Puritan PSM156 power conditioner, Teac clock, Synergistic Research network switch, and the Network Acoustic MuonPro ethernet network filter, and QSA Lanerdi power cord filters.  I have been chasing incremental audio system performance for 5 decades.  Some may look at my system and say that I have not advanced very far up the audio chain.  However, I not only chase sonic performance but also kit that is not exorbitantly priced that gives superlative performance.  And through trial and error I have assembled a system, plus spare amps, that creates various presentation of real music that are pleasing to my ear/brain.

@jaymark 

What impresses me with your description is the quick-swap setup — being able to move amps in and out in under five minutes is probably the single most useful methodological advantage a home listener can have. It comes out in your observations' precision. 

My own setup is similarly configured for easy amp and preamp swaps, which I've found indispensable for allowing for different tests leading to reliable conclusions. 

I also appreciate your value orientation. Five decades of careful system building without treating price as a proxy for quality. Excellent. And you're distinguishing what you've actually heard from what you haven't — flagging the AGD lineup as unknown territory — is refreshing in the hobby.

Oh, and while I agree that commenters' broad characterizations of entire amp classes probably overgeneralize, I strongly suspect that does not fully dissolve the observations either. In other words, there does seem to be something sonically emblematic at the class level that shows up consistently enough to be useful as a (at least temporary) rule of thumb.

Generally speaking, Class D is where is at if you want to listen to music as it was intended by the artist. So clean and efficient.

I'm a broken record on this topic. If you want to hear class D that has meat on the bones and sounds like real music, try the Wyred 4 Sound ST-500. Used ones sometimes come up F.S. in the $550 - $650 range. It's a steal if you can find it.

I've had mine since 2018. Pretty sure it was 3 years old when I bought it. The class D module is ICEPower. This amp is absolutely bulletproof, unflappable. It just works, sounds great and actually has a pretty nice purple light. This is a nearfield system with a changing cast of 2-ways speakers: Harbeth 30.1s; ATC SCM12 Pros; Aerial Acoustic 5Bs; and vintage KEF 103.2s. All sounded very nice indeed on this amp.

I first "experimented" with this class D amp out of necessity, because I don't have the room for a class A/B amp. But now I wouldn't use anything else. I ended up getting 2 Bel Canto amps, one also using ICEPower, and monoblocks that use NCore amp boards. They all sound wonderful to me.

The original Tripath amps had the warmth and meat but they were not very high power. The Gan Systems evaluation amp boards had the ability to turn loop feedback off and in that configuration they have a lot of the Pass sound. I prefer the feedback off on those amps personally. Gan Systems made those evaluation boards to demonstrate the higher linearity of the GaN devices and less need for feedback however I do not know if manufacturers followed their lead or opted for feedback and lower THD specs vs pure sonic results.