Anyone using class D amps? What's the general opinion here? I know they are considered crap in some circles but I've been quite impressed with the sound quality of some recent models with computer and DAC as source.
Location: Merseyside
Posts: 12
Anyone using class D amps? What's the general opinion here? I know they are considered crap in some circles but I've been quite impressed with the sound quality of some recent models with computer and DAC as source.
Sam, they're widely used in Car Audio, AV Processors and with companies like B&O, they aren't as good as the analogue Amplifiers, but they are better than some.
They're becoming popular with Studio Monitors too because a DSP chip can be used on the input to act as a crossover for the Sub and Tweeters and any tonal alterations deemed necessary. Since they output a digital signal, Class D modules for the amps make sense and it gives it all a USP.
The principal advantage is reduced power consumption and not needing expensive heatsinks, but there are insoluble problems.
Ash
Location: gone
Posts: 11,519
I'm gone.
I've owned TacT/Lyngdorf SDAi2175 integrated and SDA2175 power amps, NuForce Ref 8 power amps, Veritas P400 power amp ... and even the little plastic Sonic Impact T-amp. All Class D of a sort. RRPs range from £30 to £3,000!
An amp on a chip - but so what?
I think they are all wonderfully musical beasts.
Definitely recommend folks at least try them. Some folks like them, some folks don't (although it baffles me why anyone wouldn't!)
I paired a £30 10wpc T-amp with my Kharma Ceramique 3 speakers (rrp £5k) - wonderful!
.
Hi Sam,
Welcome to the forum
I've heard a few Class D amps, and they're quite muscial, as Jerry says, although a bit 'dry' for my tastes. There's nothing to touch pure Class A done well, in my opinion. Listening to something like a Sugden A21a, it has a way with music that you don't get any other power amplifier circuit - runs hot, though, and you'll always have limited power output, but in the right system Class A designs can be magical.
Marco.
Main System
Turntable: Heavily-modified Technics SL-1210MK5G [Mike New bearing/ETP platter/Paul Hynes SR7 PSU & reg mods]. Funk Firm APM Achromat/Nagaoka GL-601 Crystal Record Weight/Isonoe feet & boots/Ortofon RS-212D/Denon DL-103GL in Denon PCL-300 headshell with Funk Firm Houdini/Kondo SL-115 pure-silver cartridge leads.
Paul Hynes MC head amp/SR5 PSU. Also modded Lentek head amp/Denon AU-310 SUT.
Other Cartridges: Nippon Columbia (NOS 1987) Denon DL-103. USA-made Shure SC35C with NOS stylus. Goldring G820 with NOS stylus. Shure M55E with NOS stylus.
CD Player: Audiocom-modified Sony X-777ES/DAS-R1 DAC.
Tape Deck: Tandberg TCD 310, fully restored and recalibrated as new, by RDE, plus upgraded with heads from the TCD-420a. Also with matching TM4 Norway microphones.
Preamps: Heavily-modified Croft Charisma-X. LDR Stereo Coffee. Power Amps: Tube Distinctions Copper Amp fitted with Tungsol KT-150s. Quad 306.
Cables & Sundries: Mark Grant HDX1 interconnects and digital coaxial cable, plus Mark Grant 6mm UP-LCOFC Van Damme speaker cable. MCRU 'Ultimate' mains leads. Lehmann clone headphone amp with vintage Koss PRO-4AAA headphones.
Tube Distinctions digital noise filter. VPI HW16.5 record cleaning machine.
Speakers: Tannoy 15MGs in Lockwood cabinets with modified crossovers. 1967 Celestion Ditton 15.
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I have lived with 2 Class D amps
Channel Islands Audio D100 Mono Blocks, What surprised me with these was they have bags of power and would drive quite difficult load speakers without sounding like they were running out of steam. A very open and controlled sound with loads of drive for the bass.
I also had the RedWine Audio Sig 30.2 Now these baby’s really are special. I have to say very valve like in sound and presentation. A nameless person didn't actually realise he was listening to the RedWine amp rather than my normal Almarro 50125. One big advantage of the RedWine is they are Battery Powered and are disconnected from the mains during use. Therefore no mains to bugger up the sound.
I was impressed with both of these amps, and would recommend anyone to at least give Class D a try. they have come a long way recently and are worthy of consideration
Andy - SDDW
hi jerry,
i have built a few versions using the tri-path chips and their performance have been very acceptable,and like ash mentions there are certain aspects of their design that make sense in using them in certain aplications, but there are also compromises that make some purists cringe!!!
anthony...
Location: gone
Posts: 11,519
I'm gone.
Fair enough - I'm not a techie. I just listen. And to me there is much sonic merit in the Class D approach - of the Class D amps I have heard there is definitely a sonic resemblance, a distinctive "Class D sound" - "fluid musicality" perhaps sums it up - along with "musical coherence", the musical presentation somehow seems more of a piece than with some other solid state amps which can seem to chop music up into separate components (if you know what I mean! ).
I've heard slightly higher rez sounds, and perhaps as a result the soundstaging can be a little generic. But that's being a bit picky - there are some fine audiophile sounds to be had from this type of amp, imo.
.
The only way to make a switching amplifier work properly (IMHO) is to use the module as an output stage, and creat a fully discrete front end. (or design your own!)
Some modules used on chip fets, these produced some cracking results and with reasonable power (80W rms) at 0.001% THD.
Some are dry ( most mass produced units) and can be clinical too.
This is no small part to the power supply, imho a linear PSU is far more sonically preferable to smps. We have own own transformers custom built for the specific application. More to it than just a psu I would agree, (however as with anything that works, proper design/lay-out,testing and component selection pays dividends)
Switching amps can be pretty special, as quality SS are (Dartzel). Never been that struck on all class 'a' designs (Pass labs X350/600 owner too) they do certain things very well again, yet far short in the total coherence states.
Personal preferences again will set the camp you love/hate.
The can be a picky on mains too, so a quality lead helps here too.
As with all things, try the units in your own system against something you have as a known quantity.
Coherent Systems
Real high end sound with musicality not hifi
mr C,
there is definately something in that, imho the main problems i have heard are down to the front end, but you do need to use as bigger PSU as is physicaly posible to get the best from them, although this may seem to some to defeat the object of using eficient class D technology in the first place!
anthony...
Dave Alner who used to build AVI and had a hand in the design of our now finished Lab Series Integrated, "designed" and built the Veritas Amp using a Tri-Path Module. I don't know why but they were very unreliable.
Martin doesn't like Class D and www.ls-design.co.uk who are a design consultancy and manufacturer (they make our electronics but we design them) have considerable experience of them and don't like them either. Naim are using 10 International Rectifier Class D modules in their contribution to the Bentley Radio.
We had an approach from Sequoia Technologies (Crystal Semiconductors) to demonstrate one of the latest and best Class D Chipsets and we decided to hear it. It sounded quite good but with a hint of the hashiness that comes with crappy CD players. The power supplies are also quite complex to implement as all the rails must come up at different times and if they don't nasties occur, which is why we decided they were no use to us. They were going to cost more than two far better analogue amplifiers. However there are plenty of hi fi amps that sound worse than Class D and get unjustified, good reviews, so it isn't surprising that people like them.
The problems in them that Martin describes are: Jitter, noise, out of band hash, varying output impedance which sabotages the perceived power output at lower frequencies. He is of the opinion that they've probably been developed as far as they are likely to be and that they are not suitable for very high quality high power sound reproduction. But since most British hi fi manufacturers aren't making powerful enough linear amplifiers for the dynamic range of modern recordings, it may well be that they see this as a cheaper way to get the extra power they need without having to pay premium prices for Copper and Aluminium. The Chinese take the Lion's share.