Underwood HiFi's Voyager GaN amp $3K/200wpc should be shipping soon. They seem to have a trade in policy to boot!
Markmuse:
I quite liked the M700s, but in my 20 x 40 x 12ft peak, even though my speakers at the time were 93dB (but the woofers were only 10"s I just couldn't get the coupling spl I wanted. Also, Ric introduced his EVS 1200 for about the same price I bought/sold my M700s for, and he offered a 30 day money back.
Best move I made until recently, when I got a pair of EP 3.4s which do not have woofers BUT have 12" carbon Fiber midrange with concentric polyester tweeters. These have taken the music up a few notches, but am anticipating receiving EP 2.8s tomorrow. In addition to the same 12" woofer/tweeter, these have dual 15" carbon fiber woofers in a D'appolito configuration. Needless to say- I CAN'T WAIT
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I run the PSA S300 fronted by a Rogue RP-1 with Mullards. I also acquired a DAC that was reviewed as having "warm" characteristics. Did this for all the aforementioned reasons. The sound is good enough for my needs. I really like the way it fits into a tidy space and runs relatively cool. It certainly has a volume level sweet spot. I tried running it plugged directly into the wall vs my Furman Elite 15 dmi and could not discern degradation with the Furman so thats where its attached. I use entry level PSA power cords and Marrow interconnects. I would like try a tube or A/B amp some day but not sure I want to deal with the heat and power consumption. I can't do much of a compare as my previous amp was also class D. And PSA gave me a really good trade in for it. So the S300 was Buck Bang for sure.
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45 years in audio. I’ve never sampled Class D. Why? Because Class A is so satisfying. |
45 years in audio. I’ve never sampled Class D. Why? Because Class A is so satisfying.
Hard to tell which came first though. It's like mom's home cooking, if that's what you like and want to have nothing else will do. Best, E |
I tried the M700s and the Stellar Dac/Pre. The dac/pre was dry, did not throw a good sound stage. IMHO, it needs a outboard PS, which PSA often does. I questioned Paul about the lack of it, but of course, he held the party line.
I found the M700s quite good, even though at that time I was plugging various class D amps into my Core Power 1800. At that time Ric Schultz came out with the EVS 1200, at a comparable price to what I bought and could sell the M700s for, but the 1200 had ~ 50% more power (which I need in my 20 x 40 x 12 ft peak room, AND was essentially hand tweaked by Ric who knows his tweaking and cuts no corners, as most commercial products (especially ones costing M700 money), are forced to do.
I started out plugging the EVS 1200 into the 1800, but one day my Spidey Sense told me to plug it direct into my 20 amp dedicated line. WOW. Just doing that ONE simple thing made a HUGE improvement
I suspect there are many more changes that need to be made before one should critique class D in their systems.
hth
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I certainly appreciate all of the logical and rational comments on this thread. Would like to hear more about your experiences with class D amplification.
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Discussion of Class D Amps Application &
What a few of the gurus of the audio industry think then, and basically still do today, because not much has changed in design.
This was an Absolute Sounds Round Table discussion with the industry top dogs on Class-D, the only one in favor is the one that manufactures them Jeff Rowland but had little to say amongst his peers. Bob Carver
"I built many of them right here in my own laboratory with the thought they could and would fulfill that final promise.... I was never able to build a Class D amplifier that sounded as good as a linear one."
John Curl (Parasound, CTC, Vendetta Research, Constellation)
"Some version of hybrid Class A/D looks like the future in optimum audio design."
Cyrill Hammer (Souloution)
"if you want to have your product performing at the cutting edge it is not possible with today’s known switching technologies. In order to come close to the performance of the best linear design we would need high-current semiconductors that provide switching frequencies of several MHz or even GHz."
Lew Johnson (Conrad Johnson)
"I tend to think that Class D circuit design is an approach best relegated to producing low-cost, physically manageable multichannel amplifiers—where one might accept some compromise in sound quality for the sake of squeezing five, six, or seven 100 watt channels into one moderate-sized package for a budget home-theater installation."
Vladimir Shushurin (Lamm)
"No, it is not. And I would like to respond to the second part of this question with an allegory. Any field of human activity defines a number of requirements which, when properly implemented, guarantee a positive outcome.
For example, the basic requirement in the army and sports is an able-bodied individual. So, it would be quite natural to concentrate on searching for such an individual (especially as we know where to find him).
However, out of the blue we decide to choose a feeble-bodied person who, on top of that, is encumbered by various diseases. Having made this decision (which is a priori improper) we start justifying it to ourselves and others by citing the great state of our medicine, which is capable of curing many ailments."
Fumio Ohashi (BAlabo)
"No. Class D can’t really be considered for super-high-end performance in its present stage of development, although it can be fine for mid-market products."
Nelson Pass (Threshold, Passlabs)
"Does a $10 bottle of wine compete with a $100 bottle? Of course it does, and it often wins based on price. Right at the moment Class D designers seem to be still focusing on the objectively measured performance of their amplifiers. I expect that at some point the economics of the marketplace will encourage them to pay more attention to the subjective qualities, and then they will probably play a greater role in the high end."
Jürgen Reiss (MBL)
"I have worked a lot lately with Class D. Ninety-nine percent of Class D circuits are not competitive with linear circuits.
Most Class D sounds sterile. It’s tricky to figure out what to do to compensate for that."
Jeff Rowland
"I consider Class D to be highly competitive in the present, and to offer an evolutionary pathway of audio design that may produce even more astonishing results in the future."
Thorsten Loesch I have yet to hear a pure class D Amp I’d rate above "below average for solid state" (which is not very high performance). In a little update of my classic "Valve Analogue Stages for DAC’s #" I wrote:
"Perhaps more crucially, so called Class D Amplifiers, which have in recent times sprouted up like mushrooms after a warm rain, continue to use the straight two or three level modulation scheme described above. And thus they still require the use of heavy handed noise shaping to attain anything like acceptable 16 Bit Audio performance.
The clock frequencies for these amplifiers are usually at 300 KHz to 1MHz in the best cases. That is 3,000 to 10,000 times lower than what is required to attain 16 Bit / 44.1 KHz performance without noise shaping and other forms of signal manipulation!
And again, one is baffled and perplexed by the rave reviews many Class D amplifiers receive, as baffled as one was about the late 90’s reviews of timeslicing dac’s. The best of breed I have auditioned were certainly not bad; however in direct comparison to the best available valve and solid state amplifiers they do not produce a very good sound. Well, at least they offer novelty and the reviewers something to write about other than another (however good sounding) 8 Watt valve amp.
Incidentally, the best sounding Class D amps tend to be really low power single chip devices (putting out little more than the 8 watt valve amps), presumably because they are faster AND because they always work near what one might call “full scaleâ€, if they would be dac’s. On second thought, they of COURSE are DA Converters and where a Class D amplifier accepts analogue input directly it is an A2D converter followed by a power D2A converter!
What an insight!?" Mark Levinsons Interleaving of multiple Class D Amplifiers is potentially a step in the right direction, but does not go far enough.Personally I think that the best option would be something that combines a Class D Amplifier for the heavy lifting with something Class A for fine detail. Probably implemented in the style I did for AMR’s AM-77 "Jikoda$" Style. In this case both of the circuits involved can operate fully open loop.
In many ways the problems in Class D Amplifiers are analogous (but not identical to) those in Class B Amplifiers (but without an option to implement Class AB or Class A) so similar solutions apply.
All Class D amplifiers are essentially delta-sigma DAC’s.
If the input is not digital PWM signals (aka "DSD") but analogue audio then it is also a Delta Sigma Analogue to digital converter...
Now DSD (aka SACD) which to my ears fails to come close, never mind equal true PCM CD Replay in most aspects of sound quality, operates at 2.8MHz switching, or around 10 times as fast as common Class D Amplifiers...
Why anyone would want to listen through an A2D followed by an D2A Converter that are around 10 times worse than single speed DSD is beyond me.
But with enough hype and snazzy naming it cannot help but sell high and wide.
Cheers George
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George's ability to cut and paste is unsurpassed by anything other than his passion of convincing those who like Class D that they must be mistaken.
Whatever you personally have experienced, it's irrelevant because George has an ancient article to share.
Hahahaha.
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Tried D,
not for me, back to a/ab
more open, airy, and all around better.
YRMV |
i bought a set of levinson class d mono blocks about 10 years ago, largely on recommendation of some retailers and levinson's brand name
they were truly awful sounding - all the cliches about class d were true - lifeless, thin, one dimensional, lacking in drive PRAT
for an expensive set of amps i don't remember another one i turned around and resold as quickly
been about a decade now, i am giving it another chance, trying one of ej sarmento's wyred4sound units as i have very good luck with his digital gear and feel he has very good ears
we shall see |
Front what I see the WFS Class D amps use older stock Icepower modules and just stick a fet front end on it. Very old school. Average, at best. Try Merrill ($16K+), AGD ($7.5K+), Megachino Cherry ($6.2K+), and EVS modded Purifi/Ncore 1200 ($2.4K-$4K).....these amps will show you what Class D can do now.
Yes, I remember the audio mag review on those Levinson amps.....he did not like it much at all. |
The new NAD M33 that uses the Purifi amps looks interesting. I would avoid "modded" versions of kitchen table builds. |
BTW: I like some class D a lot better than some class A.
I’ve had audiophiles in my home and not once has anyone said "wow, those amps really sound like Class D."
You could not tell a class D from a good linear amp as being Class D. You can hear differences like you can with any amps but none of the tired tropes about class D deficiencies need apply here.
Best,
E
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Two, very interesting but lots of competition for Class D at $10k |
+1 erik
Gfi
if you wanted to make a pertinent point, you should have provided dates of these comments
I love my EVS 1200 even more that I now have the EP 3.4s.
I can’t imagine Rics new venture could possibly be better, well, perhaps in smaller rooms it might |
The EP3.4 speakers are rated at 96.5db.....so let’s say that at your listening position it is 87.5db.....then 100 watts will give you 107.5db peaks. Do you listen louder than that?!? I hope not! So, do you really need 600 watts? Maybe you just need a big power supply so your 100 watts you are maybe listening to are up to par (bigger power supplies will usually sound better). This is what a 1200 watt amp module will provide. I am making a mono version of my modded Purifi amps that use a 3000 watt power supply for each channel.....way bigger than what is in the ICEpower IceEdge module. I can also mod the Ncore NC1200 modules the same way (using the 3000 watt supplies)....they are 400 watts into 8 and 1200 into 2 (for those that have current hungry speakers). The NC1200 and the IceEdge 1200AS have the same current rating (38 amps). However, I doubt you need that much power.....you just need control...which is what a big power supply will give you.
The IceEdge module is completely different from the Purifi/NC1200 modules. There might be lots of things that can make the Purifi/NC1200 sonically better.....However, 3 things really stick out as advantages:
1. The input stage on the IceEdge is a built in integrated circuit. On the P/NC modules you can use any discrete input stage you want and run it off your own discrete super duper regulators.
2. The power supplies on the IceEdge are completely built in....so you cannot make them bigger or tweak them very well. The P/NC modules let you put giant 3000 watt supplies, etc. on them.
3. Now this is serious!!!!: You cannot change the ferrite output coil on the IceEdge module to an air core coil (I know, I fried one module trying). However, the P/NC modules can take an air core coil. You would never use an ferrite core coil in a speaker crossover in the mids and highs.....because it is known they wreck the sound). So, why have all the class D amps (until now) used a ferrite inductor? Well, there are some practical reasons, but no sonic reasons. I want sonics...and so do you. A great sounding (they all sound different....must tweak!) air core coil reveals way more information....the sound is way more holographic, pure and fast. The sound of an amp is only as good as its weakest part. The output filter coil on a class D amp is the last part on the output before the signal goes out. Do you want your amp filtered with a ferrite core coil? If you do then buy all the other class D amps. Mine are not filtered (well, not as much.....there is no perfect coil).
Every moment is new and miraculous. There is no final amp....or whatever. Whatever someone did yesterday....will be be surpassed in some today. We don’t need much imagination to realize that.....it is fact. |
An air coil will have more resistance than ferrite unless it's huge. 3000 watt power supply is crazy, 600 watts is plenty for a purifi module, use a 1200 watt on dual.
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There is post filter feedback on these self oscillating amps do not touch the coil, others do not buy an amp where some nut has messed with the coils. |
Some people have direct experience and others just have opinions. It is universal (to those that have listened and tested on their own system) that larger power supplies with lower impedance sound better.....even when using less than one watt.
Yes, there is tons of feedback around the coil.....so what. It sounds better with an air core coil. This I know because I listened to it. All theories are just that......opinions based on non experience. Only those that actually listen to what they talk about have any truth. Truth is experience.....not a bunch of made up stuff.
Who are the "others"?....There are lots of "others" who trust their ears and not someone’s opinion that is based on non experience.
There will be feedback soon about how the amp sounds and also there will be amps on tour so people can hear them in their own home and judge for themselves.
A quote by djones51:
"For example Take a stranded copper cable of 0awg and one of 12awg running 10 feet connected to any amp with a DF >300 and a nominal 8 Ohm speaker and there is no difference in sound. "
So, he thinks all cables sound the same? Every single piece of wire sounds different from any other brand.....even using the same construction.........Every piece of wire has directionality.....this I have heard. Every type of insulation has a sound. Damping a cable effects the sound. Whether it is stranded or solid core....the purity of the wire....whether it is cryoed or not.....everything changes the sound....AND....none of the above can be measured.......but you can hear it......if your mind is open.
Every coil I listened to on the output of the Purifi amp sounded different.....in serious...ways. Just like the type and gauge and purity of the wire in the coil....just like everything in audio.
DO NOT BELIEVE ANYTHING I or anyone says.....believe only your experience......and in audio.....that means what YOU hear in your system.
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As long as it's what I hear not what I assume I hear while looking at it. |
It is all about trusting yourself. Back in the late 70s my friend knew the owner of Sumiko (who imported Supex cartridges, among other things)....so he borrowed 10 brand new Supex cartridges and we mounted each on on a universal head shell and put a number on each one with masking tape. We spent all day listening over and over again to each one.....and all three of us in the room agreed on which ones sounded best. A couple were not very good at all.....most were in the middle and three were at the top......and one was clearly the best. The frequency readout sheets that came with each cartridge showed practically the same response on each one......which had no correlation with the sound they gave. Once you do these kinds of listening tests with others in the room (all of whom are open minded) then you really start to trust what you hear.
I have been mind blown several times over the years.....I would think this "MU Metal" cable cannot sound good.....no way.....then it does sound good.....of course, there are way better cables now than those Lindsay-Geyer cables......
I sure hope that today’s cartridges are less variable than those made back then....BTW, we did the same test with 5 Fidelity Research cartridges and they all sounded different, as well.
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All audios journeys are tied to dollars and rooms My room is huge volumetrically speaking: ~ 20 x 40 x 12ft peak in open beam ceiling, front wall is 70% glass floor to ceiling, while the back wall is actually 3 sided all glass from floor to ceiling, plus up/down stairwell in the middle of one long wall, all of which add up to needing more umph to load this room. Approximately 3-4 years ago I purchased Emerald Physics KCIIs knowing they would be out of their depth, BUT, they came with a BOM (bass management) and I already had 2 @ 12" SVS powered subs, whose volume controls are the WORST, driving the amps to play WAY too loud when barely cracked, and was hoping the BOM would solve it, but no bueno. I even have an pair of EVS attenuators, which I tried on the SVS sub inputs running their built in VC at full volume, but adjusting the attenuators starting low, again no bueno. Various Class D amps included Emerald Physics 100.2 SE monos with upgraded fuses, but they didn’t do it for me, followed by Audio Alchemy DPA-1, followed by PS Audio M700s, which did a very good job, and I would have kept them longer, BUT, they are stock, AND, at that time (a year ago?) Ric introduced the EVS 1200, which was only a couple hundred dollars more then what I knew I could sell the M700s for. For me that was a no brainer, whether I need all that power or not, it is a hot rod of Rics tweaking abilities. And, I totally agree that bigger power supplies can be HUGE on smaller wattage amps The 1200 combined with the 3.4s is quite magical on quality recordings, but lower bass is still missing IN THIS ROOM. I have been impatiently waiting for EP 2.8s which are 97db when single amped. The speakers are arranged in D’Apolito each with 2 @ 15" carbon fiber woofers in addition to the same 12" carbon fiber concentric driver/ polyester tweeter as in my 3.4s. Once they’re in the system, I could evaluate your Purifi amp, and am still in line for the LSA Voyager GaN amp MSRP $3000 for 200/400wpc: I am told it has a bigger PS than needed for the same reasons Ric mentioned. It is possible that the EVS 1200 could eventually be used for the bass and one of these amps for the mids/tweeters (be still my beating heart). In this case possible likely means probable https://www.underwoodhifi.com/products/lsa-electronicshth |
maybe for 2 grand i would take a flyer and try a 'creme de la creme' class d amp
for 5-8-10 grand, no thank you - just don't care enough to LOL
curious but not THAT curious
not like my Odyssey, VAC and Audio Research amps aren't leaving me feeling something is lacking |
I agree with you. Part of the appeal of class "D", at least to me, is the huge price differential. If you have to spend an amount equal to my class A/B well then.......
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You can't compare a Class D feedback loop with a linear amp's feedback loop. Stop it.
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The Veros PWR picture should have something next to it for size comparison. Damn thing looks huge.
Low and behold, in the September Stereophile, Herb Reichert reviews it, complete with hood open view for you techies
But $10K? Damn
Major hugs to Tweak Audio and Underwood HiFifor keeping pricing accessible so that more audiophiles can enjoy the tech
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I'd like to hear Kii 3 or Dutch and Dutch 8c both which use class D one of those might be my next speaker. |
Hi everyone,
Anyone care to venture an informed opinion regarding Red Dragon Audio's S500 class D amps?Seems though they were very well regarded for a spell and then I haven't heard or read much about them for some time now...Want to move up from a Peachtree Nova 125 integrated and have an opportunity to score a pair of S500 I'd mate with a tube preamp to drive maggies. The two amps and preamp would run around $4k, so I need to make sure there aren't glaringly better options out there... In fact, I am open to all classes, just enjoy good SQ at a budget I can afford. Thanks for you input, opinions, and eventual suggestions. jlr261
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have an opportunity to score a pair of Red Dragon Audio S500 I need to make sure there aren’t glaringly better options out there They are basically the same as the Rowland Contiuum S2 built with the same Chinese Sanway Class-D subwoofer module in a less glitzy chassis. From 6 Moons
"Continuum S2. Red Dragon’s S500 beats with the same heart in a less high-end chassis for roughly half the price." Cheers George |
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I have a Rogue Audio Sphinx integrated amp that I am quite happy with, driving KEF LS50’s. Sound is clean and clear and plenty of power for the LS50’s . Also, it was not expensive— I think around $1,400 or so a few years ago. It replaced a Hafler Dh 110 pre-amp and Hafler Dh 220 power amp and I think it sounds much better.
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The VTV Purifi based stereo amps start at $979......$1335 with Sparko labs Pro discrete op amps....that price includes delivery, 2 year warrantee and 30 day money back. Unbeatable value. These are the amps that I will mostly be modding....for that very reason. Also, they have mono blocks using 3000 watt power supplies (my idea) that they sell for $2228 a pair including the Sparko labs op amps.......way, way better value than any other company......and if you want to take them to the moon....well, I am here for that. Yes, I can mod the Apollon and Nord amps as well....but why buy those when the VTV is less money and you can get a bigger power supply for less.
https://vtvamplifier.com/product/monoblock-high-power-version-vtv-amplifier-with-purifi-1et400a-module-with-input-buffer-options/
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My sense is that this technology is still emerging and what is "great" today may be outdated rather quickly. The good part is the technology keeps developing so equipment should be better and less expensive in the future.
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A perfect example of very good class D is Marantz KI ruby integrated amp, not only a dual mono Ncore design but many tricked out
like a analog output section feedback after the output section
more stability they state descreet custom transistors instead of opamps most use. Custom matched parts, power supply ,seperate toroidal power supply for the preamplifier and no cheap alps volume pot,100 step microprocessor control volume Copper isolation and a bunch os other things .it sounds like a good hybrid
class AB amp with a couple tubes in the circuit ,at $4k a true bargain ,the last design before Ken Ishiwata passed away not long after his 40 th year at Marantz RIP. |
Hi Ric - Hope you’re staying saldé. See, the heaviest hand in anyone’s shoulder is the one followed by of the utterance old: “I told you so”. I’m sure you will not remember when I hinted there would be possible new ‘tweaks’ to your 1200 and your response was: “I doubt it”. Anyway I’m enjoying my unit. So, are you modding it to the next level. Please advise. Best regards
Manny
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Manny, next level tweaks for out beloved and bespoked 1200s?
Where did you hear this? |
Yup! But do me a big favor. Stay safe. Thanks,
manny
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Ric - Maybe I misunderstood the post regarding the VTV Purify was a possible tweek for the 1200. Kindly enlight me as I may have it all wrong. Manny |
I went from: Parasound P7 / A23s to P7 / IcePower 250 ASP to Luxman 507ux The first change was audibly neutral. I could not tell the difference between the Parasound A23s and the equivalent IcePower modules, for the good and the bad. I switched to Luxman because: - Meters! < grin >
- Tube-like midrange- Better extension in the bass and treble- Transparent tone controls (which the P7 did not fully have)
All of these to me sounded better than Pass, which to me sounds lean and scratchy, as if I’m listening to a dirty record even when the source is digital. Did I switch from IcePower to Luxman because Class A/B was better than D? Absolutely not. My trials with Parasound and IcePower proved those two models were simply indistinguishable. And this was the real problem. In retrospect the A23s and IcePower module were too warm and syrupy. The Luxman more open and made the previous two feel constrained. In retrospect I can't really say if the character of the Parasound/IcePower was really due to the amps or the preamp itself. It might have been. Hope this helps, Erik |
@falconquest One thing I’ve observed over the years is that every amp I’ve owned has sounded different from the others; sometimes the differences were small, sometimes large. I’ve concluded that there is not better or worse as much as which amps satisfy the most preferences and at the same time have the least objectionable features/sound. Three years ago I owned my first class d amp…a Crown XLS 2000. The overall presentation of this inexpensive amp was slightly forward, strong low end (not especially detailed), decent midrange, a little hot on the top end (especially the sibilance region)…big soundstage but with no depth. For the heck of it I decided to try a Nuprime STA 9 which they advertise as class A+D with the class A part being the input front end. This amp sounded similar to the Crown but with more depth to the soundstage and maybe a little more sibilance. Next I decided to go back to class A/B with a Parasound Halo…better in every regard than the Crown or the Nuprime, smooth, musical, powerful. Then after reading a number of user reviews referencing a blending of solid state and tube characteristics in the Digital Amplifier Company products, I decided to try their new 2Cherry…class d not based on modules but on discreet circuitry designed/engineered by the company founder. Right out of the box I was pretty surprised…not only did it seem that a layer of haze that I didn’t know was there was lifted, but the music just came alive. Not only were the dynamics improved, but so was the tone and the sense of aliveness…and the soundstage became much more holographic. Eighteen months later, I still love this amp. People love their Pass Labs, their Halos, their Nords…etc. They may or may not like a Cherry Amp better than their current amp….the only way to know is to utilize the return policies and give them a try. And, for those who prefer monoblocks amps or amps that weight more than 20lbs. Cherry has Class d versions that will satisfy those people as well. |
Snaps +1
I never tried the Cherries, but after 14 months and a speaker upgrade I still love my EVS 1200
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