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Class-D amps - a different re view

Martin Colloms, the editor of HiFi Critic (ad-free mag from the UK) have recently published the review of several different Class-D amps, together with an in depth technical analysys and measurments.

His conclusions were not favourable, to say at least:

"I regret that not a single model merits unqualified recommendation. Price is not the issue; the poor listening tests speak for themselves. (...)
At present we have to take the prudent view that good sound might be possible from switching amps, but we haven't heard it yet."

BelCanto REF1000 (ICEpower) - score 10.5 pooints
"The ICE power module used has a dependable reputation, and the design is well built and finished as a whole. While I would not suggest that you shouldn't try this amp, on sound quality grounds alone I cannot recommend it for audiophile use."

Channel Islands D100 (UcD) - score 13 pooints
"While I have reservations about a number of aspects of sound quality, and advise personal audition, given the solid lab results (...) the overall performance and the moderate price, these CA Audio monos do make it to the 'worth considering' cathegory."

NuForce 8.5V2 (proprietary technology) - score 9 pooints
"Yes, the price is good for the power output. Yes it's pretty, light, small and runs cool. However, the sound quality simply does not justify recommendation." (on top of that the NuForce amp measured very poorly - Elb)

Pro-Ject Amp Box (Flying Mole) - score 5 points
"I'm sorry to say that Project (...) was a real disappointment in the listening tests, and can't be recommended."

Just as a point of reference, recently reviewed Krell 700CX scored 100 points, CJ Premier 350 - 110 points and ARC Ref 110 - 135 points.

At least someone have had the balls to say it. This is why HiFi Critic is THE mag to subscribe.
128x128elberoth2
g_georgi
18 posts
 
Partially agree with Atmasphere on semiconductor comment.

I've done some work in my SS class AB amplifier, I have the service manual and parts such diodes, transistors, capacitors (i.e. things that are most likely to break) aren't hard to come by at all.

I agree with you thoughts about class-d though, they have a lot of IC's and surface mount devices. Even if you do find the part you need, installing it will be a pain and expensive (if you choose to let a shop do the repair work for you)
eldartford
4,262 posts
 
Mrtennis...Not an absolute predictor, but a useful indication. Why else do we contribute opinions, pro or con, on this web site?
dcstep
1,518 posts
 
I've been mightily impressed by the sound of the Rowland Concerto intergrated amp driving various Vienna Acoustics speakers. Some time soon I plan to put one in my system, against my old Bryton 1B/2B system and also compare to Conrad Johnson that my dealer carries.

I'm not worried about what some twit wrote. I trust my own ears, after 50-years of trumpet playing and about 43-years of audiopilia. Early signs are, to me, Class-D can sound very good.

Dave
guidocorona
4,298 posts
 
Dstep, your post is like Music to my ears! I have heard at some length the Primare CD21 + JRDG Concerto preamp + JRDG 312 + Vienna Mahler combination in the Soundings/JRDG suite at RMAF two years in a row. The sound was awesome with IMO unparalleled musicality. . . so much so I have suffered a major audiophilic breakdown during the Summer. . . and as a result just last week I have taken delivery of a brand new pair of Vienna Mahlers. . . . . . . A new amp will hopefully replace my trusty old JRDG Model 7M monos this time next year. . . Have not yet made up my mind completely, but Rowland 312 and Spectron Musician 3 Sig are currently high on my prefs list.
dcstep
1,518 posts
 
Hi there Guidocorona. Soundings is where I first heard the JRDG monos about three years ago, driving the Strauss. Being in the midst of moving from Dallas to Denver, I set my mind on the Strauss in a large basement music room. The soft real estate market has kept me from leaping into a house and three years later I'm still in a nice high-rise apartment in DTC.

This summer I finally decided to reconsider my speaker choice a chose something that would work in my 2100 sq ft apartment and took the plunge with the Beethovan Baby Grands. (I'm entirely happy with that choice).

Anyway, the second time I heard the JRDG equipment/Vienna Acoustics combination was at the 2006 RMAF. After a day of bleeding ears, hearing horrible set up after horrible set up, I stopped by the Soundings/Sumiko room where Rod and his boys had the Rowland/VA setup. Oh what a relief to the ears. Those guys know how to set up a room. They start with good equipment and really get the most out of it. I'm sure that lots of the other exhibtors had very fine equipment, but most of it was unlistenable to me, most likely due to poor setup.

I've about got the Beethovan's broken in and my new Pro-ject RM10/Blackbird TT/cartridge setup. Late this month I plan to have Rod over to optimize my speaker placement. After that in December or January, bonus dependent, I'll be doing the JRDG/Conrad-Johnson/Bryston comparo. It might be easiest to do a JRDG/CJ comparo in-store and then bring the winner home to compare to old faithful Bryston. (Evidence is showing the Bryston pretty darn good; however, I found the Pro-ject Tube Box superior to the Bryston's onboard phono stage, though it didn't blow it in the weeds).

See you around maybe.

Dave
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