Class D???

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JLM

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Re: Class D???
« Reply #20 on: 8 Oct 2020, 11:43 am »
A couple of newest and currently very best class D come from VTV/Purifi and Orchard Audio BOSC. 

Stercom

Re: Class D???
« Reply #21 on: 8 Oct 2020, 11:51 am »
A couple of newest and currently very best class D come from VTV/Purifi and Orchard Audio BOSC.

I agree.  Again, it's about the speed of the frequency switching and filter implementation. This is how Orchard Audio explains the BOSC:

"GaN technology enables BOSC to switch at ~800kHz which is 2-3 times faster than traditional class d amplifiers using silicon transistors. This very fast switching allows for the use of a simple LC (inductor and capacitor) filter, which allows the amplifier to have no phase shift from DC (0Hz) to 30kHz. The filter is a very important part of a class d amplifier. BOSC uses oversized very high-quality oxygen-free copper (OFC) inductors and a very high-grade film capacitor."

Looks like VTV uses Hypex with various input buffers. Sort of like PS Audio which uses the ICE modules for the output and its "Gain Cell" for the input stage. Its marketing but thats fine they are trying to convince you their input stages are better in order to sell their products.

mav52

Re: Class D???
« Reply #22 on: 8 Oct 2020, 12:17 pm »
Always enjoyed the Bel Canto s500 amps and the new Black series. 

JLM

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Re: Class D???
« Reply #23 on: 8 Oct 2020, 02:52 pm »
I agree. 

Looks like VTV uses Hypex with various input buffers. Sort of like PS Audio which uses the ICE modules for the output and its "Gain Cell" for the input stage. Its marketing but thats fine they are trying to convince you their input stages are better in order to sell their products.

VTV uses the Purifi technology, which yes is another Bruno Putzey (of Hypex fame) design but a generation newer.  Here's a couple of links:

https://purifi-audio.com/eigentakt/

https://vtvamplifier.com/vtv-purifi/

https://audiophilestyle.com/ca/reviews/purifi-ptt65-woofer-and-1et400a-amplifier-technology-review-r866/

Stercom

Re: Class D???
« Reply #24 on: 8 Oct 2020, 03:16 pm »
Always enjoyed the Bel Canto s500 amps and the new Black series.

I know this is going to sound argumentative but I truly am interested in your thinking. The Bel Canto Black series Class D amps are well over $10,000 each. They use Hypex class-D nCore modules designed by Bruno Putzeys. Have you heard them against say the Orchard Audio that JLM recommended or other recent Class D amps? For example, if you want a "name brand" amp the Jeff Rowland 125 is $3,000, its WAY over built and sounds excellent. It just seems with Class D amps you reach the point of diminishing returns very quickly. Unless, there is a significant reason, which I'm not aware of, to spend five figures on one.

HT cOz

Re: Class D???
« Reply #25 on: 8 Oct 2020, 03:17 pm »
Im running an early maybe the 1st VTV Purifi amp with VTV custom Sparkos buffers and I'm happy.  I see that they have been making improvements and have good customer service.  They are reasonably priced.  I'm finished looking for amps and recently purchased a Denafraps preamp and dac.  I'll evaluate how well this setup works with my speakers, but I'm fairly certain that I'll be happy.  I'm at the end of a journey and then will focus on enjoying the fruits of my labor.   :rock: :rock: :rock: :rock:

Endo2112

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Re: Class D???
« Reply #26 on: 8 Oct 2020, 05:27 pm »
I would also consider the Weiss op amps in that VTV, I had op amp rolled several different ones a year or so ago and to my ears they sounded the best. I've also owned/heard all of the currently available class D amps with the exception of the Cherries and I would agree with JLM as the Orchards are quite nice as well and have a very linear sound from top to bottom, I too, would highly recommend them.

Don

steve k

Re: Class D???
« Reply #27 on: 8 Oct 2020, 07:49 pm »
I built a pair of ClassDAudio SDS-470 and SDS-258 amps to biamp my Magnepan IIIA's several years ago. They replaced a pair of VTL MB-125's and MB-300's. I found the ClassDAudios to be much quieter and more detailed and open but still maintaining a sweet midrange. The highs are smooth and not harsh.

I never looked back. They are very economical, bullet proof and their customer service is out of site. They're efficient and run cool (the VTLs heated my listening room.) I built kits but now Tom is selling them complete in cases. They're really excellent amps at a reasonable price. He's also gearing up to produce Class D amps with Gan-fets.

J@ck

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Re: Class D???
« Reply #28 on: 8 Oct 2020, 07:58 pm »
I feel the class D amps provide a different feel than the SS or tube amps. It is hard to describe but sometimes the sound is too "clean" for my ears.
I would recommend to start with a vendor who has an excellent return policy or in home trial service.

JackD

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Re: Class D???
« Reply #29 on: 9 Oct 2020, 12:52 am »
I've owned four different models and found them all to be at their best fronted by a tube preamplifier.

rotarius

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Re: Class D???
« Reply #30 on: 9 Oct 2020, 12:57 am »
Every ancient competent mosfet design seems to better any Icepower amp I have tried.  I bought a TI TPA3255 evaluation board and that seems be a step up from Ice stuff when coupled with a good power supply.  Pretty good for the money, I'll have to try Hypex next.

mav52

Re: Class D???
« Reply #31 on: 9 Oct 2020, 12:58 am »
I know this is going to sound argumentative but I truly am interested in your thinking. The Bel Canto Black series Class D amps are well over $10,000 each. They use Hypex class-D nCore modules designed by Bruno Putzeys. Have you heard them against say the Orchard Audio that JLM recommended or other recent Class D amps? For example, if you want a "name brand" amp the Jeff Rowland 125 is $3,000, its WAY over built and sounds excellent. It just seems with Class D amps you reach the point of diminishing returns very quickly. Unless, there is a significant reason, which I'm not aware of, to spend five figures on one.

Never said I was going to buy them, I own a pass amp and I'm happy..   I have heard both series and they sound pretty good. The implementation that BelCanto does with the technology and adds their "spin" to it, seems to work.  If I was going to buy, it would be the used market.  All audio equipment reaches a point of diminishing returns, like everything else a person could buy. 

Ric Schultz

Re: Class D???
« Reply #32 on: 10 Oct 2020, 05:20 pm »
Most of the current class d amps use the same switching frequency (around 500K) and the same ferrite core coil based output filters they used back in the early 2000s.  Only a very few amps switch higher than 500K (Technics, New Class D, Orchard, Cherry? and some Nuprime come to mind).  The output filters they all use are pretty much the same.  All Hypex, Icepower (including IceEdge), Purifi and Pascal all switch at 500K (and always have).......and all class D amps use ferrite core coils on the output (except maybe Merrill and myself).  The raved about expensive Merrill class D amps switch under 500K.  Even the AGD $7500 amps switch at 500K. 

I am not against raising the switching frequency......but what exactly does it do sonically?  We have yet to find out.  There are tons of things that effect the sound of a class D amp......every single thing you do to the thing changes the sound.  Every amp with an Ncore module in it will sound different.  Yes, there is a basic "stock Ncore sound"......but this can be at a basic sound level or a super sound level if tweaked to the max....same with anything.   So, when someone says they have heard all class D amps......well.....not hardly.  A stock IceEdge amp sounds nothing like my modded ones I sold last year.  Bel Canto just released their latest class D stereo amp for $6k that uses the same stock Ncore modules and stock Hypex power supply they used in their last set of $6K monos.  What they upgraded this time was the front end buffer....instead of op amps and 3 pin regulators they are now using their own discrete input stages.....no doubt, these babies sound better than the last version. The class D revolution is just starting........but everything has to be done at a super level for this to happen.

As far as value goes....it it hard to beat the VTV amps.  The same stock Hypex power supply everyone uses.....stock Purifi modules (most feel sound slightly better than the NC500), discrete Pro Sparko labs input op amps, discrete Sparko labs regulators.......all for $1350 including shipping and 30 day money back.......compare that to Bel-canto at $6K.

mav52

Re: Class D???
« Reply #33 on: 10 Oct 2020, 05:43 pm »
Most of the current class d amps use the same switching frequency (around 500K) and the same ferrite core coil based output filters they used back in the early 2000s.  Only a very few amps switch higher than 500K (Technics, New Class D, Orchard, Cherry? and some Nuprime come to mind).  The output filters they all use are pretty much the same.  All Hypex, Icepower (including IceEdge), Purifi and Pascal all switch at 500K (and always have).......and all class D amps use ferrite core coils on the output (except maybe Merrill and myself).  The raved about expensive Merrill class D amps switch under 500K.  Even the AGD $7500 amps switch at 500K. 

I am not against raising the switching frequency......but what exactly does it do sonically?  We have yet to find out.  There are tons of things that effect the sound of a class D amp......every single thing you do to the thing changes the sound.  Every amp with an Ncore module in it will sound different.  Yes, there is a basic "stock Ncore sound"......but this can be at a basic sound level or a super sound level if tweaked to the max....same with anything.   So, when someone says they have heard all class D amps......well.....not hardly.  A stock IceEdge amp sounds nothing like my modded ones I sold last year.  Bel Canto just released their latest class D stereo amp for $6k that uses the same stock Ncore modules and stock Hypex power supply they used in their last set of $6K monos.  What they upgraded this time was the front end buffer....instead of op amps and 3 pin regulators they are now using their own discrete input stages.....no doubt, these babies sound better than the last version. The class D revolution is just starting........but everything has to be done at a super level for this to happen.

As far as value goes....it it hard to beat the VTV amps.  The same stock Hypex power supply everyone uses.....stock Purifi modules (most feel sound slightly better than the NC500), discrete Pro Sparko labs input op amps, discrete Sparko labs regulators.......all for $1350 including shipping and 30 day money back.......compare that to Bel-canto at $6K.

I wish we had a like button.   

Stercom

Re: Class D???
« Reply #34 on: 10 Oct 2020, 06:22 pm »
Most of the current class d amps use the same switching frequency (around 500K) and the same ferrite core coil based output filters they used back in the early 2000s.  Only a very few amps switch higher than 500K (Technics, New Class D, Orchard, Cherry? and some Nuprime come to mind).  The output filters they all use are pretty much the same.  All Hypex, Icepower (including IceEdge), Purifi and Pascal all switch at 500K (and always have).......and all class D amps use ferrite core coils on the output (except maybe Merrill and myself).  The raved about expensive Merrill class D amps switch under 500K.  Even the AGD $7500 amps switch at 500K. 

I am not against raising the switching frequency......but what exactly does it do sonically?  We have yet to find out.  There are tons of things that effect the sound of a class D amp......every single thing you do to the thing changes the sound.  Every amp with an Ncore module in it will sound different.  Yes, there is a basic "stock Ncore sound"......but this can be at a basic sound level or a super sound level if tweaked to the max....same with anything.   So, when someone says they have heard all class D amps......well.....not hardly.  A stock IceEdge amp sounds nothing like my modded ones I sold last year.  Bel Canto just released their latest class D stereo amp for $6k that uses the same stock Ncore modules and stock Hypex power supply they used in their last set of $6K monos.  What they upgraded this time was the front end buffer....instead of op amps and 3 pin regulators they are now using their own discrete input stages.....no doubt, these babies sound better than the last version. The class D revolution is just starting........but everything has to be done at a super level for this to happen.

As far as value goes....it it hard to beat the VTV amps.  The same stock Hypex power supply everyone uses.....stock Purifi modules (most feel sound slightly better than the NC500), discrete Pro Sparko labs input op amps, discrete Sparko labs regulators.......all for $1350 including shipping and 30 day money back.......compare that to Bel-canto at $6K.

So you think statements from Cherry, New Class D and this from Orchard Audio on the BOSC is just marketing?  You believe the input filter has more to do with quality sound?  (Please don’t say everything matters I’m trying to understand your comments about faster frequency speeds and output filters and hopefully learn something here)  Thanks

"GaN technology enables BOSC to switch at ~800kHz which is 2-3 times faster than traditional class d amplifiers using silicon transistors. This very fast switching allows for the use of a simple LC (inductor and capacitor) filter, which allows the amplifier to have no phase shift from DC (0Hz) to 30kHz. The filter is a very important part of a class d amplifier. BOSC uses oversized very high-quality oxygen-free copper (OFC) inductors and a very high-grade film capacitor."

Early B.

Re: Class D???
« Reply #35 on: 10 Oct 2020, 06:43 pm »
I am not against raising the switching frequency......but what exactly does it do sonically?  We have yet to find out.  There are tons of things that effect the sound of a class D amp......every single thing you do to the thing changes the sound.  Every amp with an Ncore module in it will sound different.  Yes, there is a basic "stock Ncore sound"......but this can be at a basic sound level or a super sound level if tweaked to the max....same with anything.   

So, to answer the OP's question, yes, Class D has arrived, but you have to tweak the hell out it to get the best sound just like Class A or A/B.

I used to own a Class D amp in a small form factor. I was very impressed, at first, but realized it lacked something. Switched it out for a higher priced Class A/B and the magic came back (more energy, authority, weight, dynamics, etc.). Being non-technical, I equated the sonic differences with the power supply. The Class D amp ran on a computer charger vs. a 50 lb. amp with a huge toroidal transformer. No contest. I'm guessing the better sounding Class D amps are likely to be overbuilt just like any other high end amp. And they will be expensive ($5K+).   

High end audio needs to undergo a technological revolution that improves the sound and lowers the cost. Perhaps we should consult Elon Musk. We'll go from music to muskic.

Ric Schultz

Re: Class D???
« Reply #36 on: 10 Oct 2020, 08:21 pm »
The measured switching frequency of the Orchard amp is around 700k.....not much higher than the others.  As i said, all class D amps use a coll and cap on the output to filter the sound.  Yes, the filter frequency might be higher in the Orchard or other amps.  As to what it does, no one is sure except those who have listened to a lower switching frequency and the raised it to hear the difference.  All other noise is just conjecture.  The only thing that matters is the sound that comes out of an amp.  I just read yesterday that someone thought the stock Orchard and some stock Purifi sounded very similar.  One thing does not make great sound.....as I keep stating.....everything makes a difference.  Switching frequency is just one factor out of an infinite things that affect sound.  BTW, you do not need GaNs to switch at higher frequency.......Nuprime does 700K with mosfets, New Class D uses Sicfets for their 800K switching.

BTW, 700K is not 2 or 3 times 500k.....yes, that is marketing nonesense.

Stercom

Re: Class D???
« Reply #37 on: 10 Oct 2020, 08:50 pm »
Very helpful Ric.  Changes my thinking on these amps.   

HT cOz

Re: Class D???
« Reply #38 on: 10 Oct 2020, 09:32 pm »


As far as value goes....it it hard to beat the VTV amps.  The same stock Hypex power supply everyone uses.....stock Purifi modules (most feel sound slightly better than the NC500), discrete Pro Sparko labs input op amps, discrete Sparko labs regulators.......all for $1350 including shipping and 30 day money back.......compare that to Bel-canto at $6K.

Bingo - When I bought my VTV Purifi with Sparkos buffers the parts were about the same cost and the power supplies were out of stock at Hypex. It’s a no brainer. 

The AudioXpress article is worth a read if you can find a copy.  These are end game amps.

Djs7901

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Re: Class D???
« Reply #39 on: 10 Oct 2020, 11:21 pm »
I've tried a few, Wyred 4 Sound, Nad. The lack of weight appealed to me, but the sound quality has not appealed to me. Dry, non-musical.