ClassD amps and their performance

I have read some previous threads on class d type amps,Nufotce,Bel Canto etc but I wondered if anyone has had time to live with some of these designs and can provide a view of their overall performance. I dont really want an argument over whats best valve or Class D .I currently use valve but I am not opposed to alternatives .Also what about the amps from Hypex that seem very reasonable at 500 or so euros??

 

I feel i may be very well placed to answer this... having owned a bel canto S300i and having borrowed for extended periods the ref1000's

Class D was interesting when it came along, in that it offered a lot of power, a lot of resolution and a lot of clarity, for not a lot of money. In that respect class D does what it says on the tin. Fantastic grip (on the larger models) and a heck of a lot of punch, also on all models that ive heard, the midband texture and detailing are superb.

But, and heres the few exceptions that i found over long term ownership. the lower powered modules, like the 300w module in the S300i, struggle into tougher loads, the amp didnt enjoy trying to run my Dynaudio contours of the time. The ref1000's were faultless in this respect.

The other issue i had with the class D amps was their treble. I found them just a touch dry at the top end, a little too clinical and on occasion just a bit bright. There was a slightly glassy hardness to the highest frequencies via the class D that my focals just exposed brutally.

The ultimate test came recently, when my friend, the owner of the ref1000's moved to a brand new accuphase E-550 amp, which is a 30w class A design. In all ways it bettered the bel canto's. It was smoother, more dynamic and had a cleaner and sweeter top end that was far more listenable.

If you have smooth, warm slow sounding speakers, the highly damped and dry nature of the class D amps may work well, but on clean, fast and open speakers like my focals, the combination was not one i could live with myself.

They are worth hearing for their sheer clarity, and texture and IMHO the cheaper amps and integrateds offer better value for money than the big monoblocks.

Before their departure, i had a chance to hear the S300 power amp along side the ref1000 monoblocks, and in many ways the S300 was remarkably close, and in some ways, even slightly better, a tad richer in the mids, and a bit more enjoyable. Just lacked the drive and grunt of the bigger amps.

If your going to get into class D, try one of the cheaper lowe powered models, like the S300 and see how you get on

 

Like any amplifier they will depend on system matching to get the right sound for you.

Within the arena of class D there's a huge amount of variation - Class AD, Class BD, fixed-frequency modulation, variable frequency modulation, open loop, closed loop, analogue input, digital input, etc, etc. Performance levels also vary enormously, from the very poor to the outstanding.

"Highly damped" is not an inherent property of class D amplifiers. In fact, many have very poor output impedances relative to class AB designs - it's a matter of output stage and power supply design, as well as feedback design (if any).

Class D is a technology that is on the move. Just as solid-state linear amplifiers offered relatively poor performance when first introduced and subsequently improved significantly, so has/is class D.

 

I've owned my Bel Canto Evo2i for 3 years now, and have felt absolutely no inclination to change.
I've heard the newer IcePowered BCs, i.e. both the S300 and Ref1000s. Both do "hi-fi" better, but somehow were IMO less involving. When compared to non-class D amps, they just run rings around most stuff I've heard.
They have no background noise, are coherent across the full range, happily control deep bass that most valves would say "no thanks" to, and yet have the smoothness of some valve amps.

The only thing I'd say negatively is that I could see some finding it a little "boring" when mated with the wrong gear. I use a pair of horn loaded speakers which sound downright nasty when driven with say a Naim amp. With my BC, just gives lovely sound.
I think the "boring" is because most amps seem to imbue their own little character on music, the BC does less of that than most I've come across.

My biggest problem is what I'd ever replace it with if it failed. BC don't make them anymore, I've tried a 300B valve amp and didn't think it was any better (unless you look at something like a Wavac) and the normal transistor amps just sound positively coarse.

 

Thanks this is exactly what I was after,I feel I would like to give them a try ,probably the best thing to do is borrow some and try them with my Audiophysics.I like detail and sondstage and feel that class d may be an interesting option rather than SS. Dont know if I can leave valves behind though.

 

Where in the country are you?

 

I'm not sure whether this will be any use, but I offer it since you mentioned Hypex units.

My father recently experienced a fault with his DPA amp which was driving Quad 2905s. He has since acquired a pair of mono amps based on Hypex modules and built by Chevin Audio. As part of his evaluation he asked me to take over my Berning ZH270 for a comparison. In short, we agreed the Hypex units were very impressive and "clean", but the Berning was just as detailed, more natural sounding and, overall, preferable (on these speakers with these sources and this type of music etc). However he went with the Hypex units, since he blanched at the thought of paying the going rate for a second hand Berning and did not want the "hassle" of valves.

Before recently acquiring the Berning I had been using SS amps and my father has only had SS amps. Previously we tried the 2905s with another set of (expensive) mono valve amps of similar power to the Berning (but with a different source) and on that ocassion we found the sound far too soft (however this may have been due to the source and/or the room in which we heard them).

Obviously trying the amps you are considering in your system, will give you a much better feeling for them than any number of opinions from others.

Good luck

 

I am in Scotland,I rather fancy building a kit using hypex modules and on therewebsite is a link to a TNT review of what they refer to as a kit from AVA in Italy.It is for similar reasons as your father that I am thinking of trying the d route. I just need to either find the right kit or a design and a source of a good casing.

 

I cant see anything on the Chevin site could you provide any more details?

 

as a bel canto and focal owner, I have some sympathy with the posts above, but would just point out that those judgements depend on oh so many other factors. In my listening room, which is well furnished, with my front end (Copland CD and Ortofon cartridges) and my taste in music, AND my ageing ears, which must, by now, be rolling off a lot of top end anyway, the 300/1007 combination is just excellent, and was clearly preffered on audition to Class A valves and Class A SS amps.
Something about synergy and home demos ....

 

I love my Lyngdorf TDAI2200, to my ears it's the best amp I have ever heard. Incredibly detailed yet totally fatigue free would be my description.

There is a cheaper way to get full digital amplification...

You might consider a Panasonic XR57 amp and Oppo DV980H DVD player, both modded by Shawn Fogg of www.switch-box.com. This would give you a totally digital signal path with dejittering for CD, SACD and DVD-A, both 2 channel and multi channel, for a fairly modest outlay.

 

Seconded. I went from a WAD KaT88 valve amp to the TDA2200 and have no regrets - it is as described above, but I would add beguiling liquidity, towering dynamics and great flexibility to the list. The jury's out on the Lyngdorf Room Perfect room correction system, though (my amp does not have it).

 

everyone should find the sound he likes. valves are not for everyone.

 

A lot of loudspeakers don't really allow you to hear the difference between amps.

 

sure, though switching from a 2x25w tube amp to a 2x250w class D amp (or vice versa) leaves me with more doubts about owners than about speakers.

 

I lived with a lot of class D, and on comparing a series of bel canto's best offerings to the 30wpc accuphase E-550 left me in no doubt that it was the significantly superior performer.

It's all down to the treble, classD treble just doesnt work for me.

 

Why?

 

because probably every decent amp no mater if SS, tube or digital can have a good use. however there are not many speakers on this planet that can perform superb with such a variety of amps. lots of us waste time in trying impossible, following reviews, or simply not knowing their gear and how to get a maximum out of it.

i have 110+db sensitive speakers. there are plenty of amps out there which i may like for different reasons but only a few of them make sense to partner with.

 

I recently changed from Bel Canto's PRe2 and a pair of REf1000 monoblocks (all modified at great expense by Coherent Systems) to a Karan KA I 180 integrated. The Karan is in another league to the BCs. The sound is much more 3 dimensional, natural, flowing and smoother. All of the Class D amps i've heard have been clean and powerful, but they just don't make music sound human. I believe in a few years Class D amps may just outperform all solid-state amps on the market. Still a fair way to go until the best of Class D can live with the likes of Karan, Dartzeel et al. A work in progress IMO.

 

I appreciate the info so far and a lot of the information is along the lines of most of what I know. The initial question was really more to do with where do I go next .I currently use a 300b but was thinking of a change maybe a pair of class a mons ,but class d was of interest. I am not quite sure of the direction,I love my amp so if I could have my amp with some more clout would be the ideal solution.