what is the best sounding Class D amp you've ever heard

[HAL]

Scott,
The Class D amps have come a long way in the last few years.

The Gallium Nitride (GaN) FET output devices now in use make the amp circuit much simpler and sound better.  The higher efficiency of the devices make the overall amps much smaller.  The higher switching speed of the devices make the output filter much smaller with better filter components.  Also most do not need heatsinks as the devices can run at 200C. 

My friends test is to use an AM radio by the speaker cables to see what noise is being generated.  The new amps are much better from that aspect as well.  Distortion and RFI is very low. 

The prices of these amps like the Orchard Audio Starkrimson amps have also dropped from the early days where the one mfg wanted $33K for their GaN FET amps.  The 150watt GaN monoblocks with GaN based power supplies are under $2K. 

I have three pair of monoblocks driving my AGN Line array prototype speakers.  I use one pair for the Magnetar II speakers.  They sound wonderful to me.  I will have a pair of Starkrimson monoblocks running the Magnetar II speakers in my room at LSAF.  You can hear them for yourself.  And everything is running from a DSP processor including a balanced input phono stage in the dspNexus 2x8.  If things work out, will also have a special surprise in that system. 

[S Clark]

Thanks for the info, Rich.  So is the GaN FET the key upgrade for Class D?  Is this why they have made such gains in the past few years?

[Nick B]

Scott,
The Class D amps have come a long way in the last few years.

The Gallium Nitride (GaN) FET output devices now in use make the amp circuit much simpler and sound better.  The higher efficiency of the devices make the overall amps much smaller.  The higher switching speed of the devices make the output filter much smaller with better filter components.  Also most do not need heatsinks as the devices can run at 200C. 

My friends test is to use an AM radio by the speaker cables to see what noise is being generated.  The new amps are much better from that aspect as well.  Distortion and RFI is very low. 

The prices of these amps like the Orchard Audio Starkrimson amps have also dropped from the early days where the one mfg wanted $33K for their GaN FET amps.  The 150watt GaN monoblocks with GaN based power supplies are under $2K. 

I have three pair of monoblocks driving my AGN Line array prototype speakers.  I use one pair for the Magnetar II speakers.  They sound wonderful to me.  I will have a pair of Starkrimson monoblocks running the Magnetar II speakers in my room at LSAF.  You can hear them for yourself.  And everything is running from a DSP processor including a balanced input phono stage in the dspNexus 2x8.  If things work out, will also have a special surprise in that system. 

Thanks for the very useful info, Rich. I’m certainly enjoying my Starkrimson Ultra. More power, better resolution and clarity than my AVA SET 120 which I really enjoyed.

[jimbones]

Thanks for the info, Rich.  So is the GaN FET the key upgrade for Class D?  Is this why they have made such gains in the past few years?

No, its just one type of device used in Class D Amps. The NAD doesn't use GAN but sounds very good. I really like the AGD but they are very expensive. I am seeing a trend of big heavy hi power amps being traded in for smaller lighter cooler running class D. IMHO it is the future.

[Response Audio]

We have become very  interested in GaN FET designs. My partner has a set of mono blocks drive a pair of Pure Audio Project Quintet15 speakers with Horn 1. Is the base design around our new 300 watt  Hybrid GaN amps coming out this summer. The horns sounds amazing as compared to other Class D amps we have played with in the past. I’ll be using a pair of PAP Trio15 Classics and Raven Audio Corvus speakers for the voicing of the new design.
I’m am still a tube guy which is why we will be using our tube products in the R&D stage. I too think GaN FET will be a new standard in Class D.

[HAL]

Thanks for the info, Rich.  So is the GaN FET the key upgrade for Class D?  Is this why they have made such gains in the past few years?

Scott,
In my opinion the GaN FET have lead to much improvement in Class D amplifier design.  Most Power MOSFET designs need extra signal processing to overcome the parasitic effects of the device to make it switch faster to make the output filter easier to design with better parts, since the higher in switching speed you can go, the smaller the L and C component values need to be.

The GaN FET parasitic effects are so low the design is simplified since they are not the same problem any longer.  They switch at much higher frequencies to start with.  Orchard shares the graphs of the response of the Starkrimson monoblocks I have.  The switching frequency is around 750KHz.  The best Power MOSFET versions I have seen that are stable is in the 300KHz range. 

I had some beta test Class D amps once with Power MOSFETs and the switching frequency was supposed to be 1MHz.  Put a fairly complex speaker crossover load and it blew up, boiled the ferrofluid in the tweeters and went back.  Never heard about the amps again and what happened.  Not tried that with the GaN FET's since the speakers are no longer available.

I have my Starkrimson amps with a 2ft speaker cable directly tied to the planar driver from 190Hz to 20KHz.  Very simple load and sounds really good.  Tried them with the Super Minis/Monoliths and the same sound quality.  All simple loads since they are resistive, but very open and dynamic sounding. I wish my old pair of Pass Labs Aleph 2 Class A monoblocks were still in good shape, but the PS caps need replacing from age and heat.  Not sure they would sound better.

Ok, enough with the EE speak.  Time to listen to some music!

[Nick B]

Thanks for the info, Rich.  So is the GaN FET the key upgrade for Class D?  Is this why they have made such gains in the past few years?

Scott,
In my opinion the GaN FET have lead to much improvement in Class D amplifier design.  Most Power MOSFET designs need extra signal processing to overcome the parasitic effects of the device to make it switch faster to make the output filter easier to design with better parts, since the higher in switching speed you can go, the smaller the L and C component values need to be.

The GaN FET parasitic effects are so low the design is simplified since they are not the same problem any longer.  They switch at much higher frequencies to start with.  Orchard shares the graphs of the response of the Starkrimson monoblocks I have.  The switching frequency is around 750KHz.  The best Power MOSFET versions I have seen that are stable is in the 300KHz range. 

I had some beta test Class D amps once with Power MOSFETs and the switching frequency was supposed to be 1MHz.  Put a fairly complex speaker crossover load and it blew up, boiled the ferrofluid in the tweeters and went back.  Never heard about the amps again and what happened.  Not tried that with the GaN FET's since the speakers are no longer available.

I have my Starkrimson amps with a 2ft speaker cable directly tied to the planar driver from 190Hz to 20KHz.  Very simple load and sounds really good.  Tried them with the Super Minis/Monoliths and the same sound quality.  All simple loads since they are resistive, but very open and dynamic sounding. I wish my old pair of Pass Labs Aleph 2 Class A monoblocks were still in good shape, but the PS caps need replacing from age and heat.  Not sure they would sound better.

Ok, enough with the EE speak.  Time to listen to some music!

Rich,

Just curious about those beta Class D amps. Were you doing the design or was it a manufacturer? If so, did they keep working on Class D and get them to be speaker friendly?

Nick

[HAL]

Nick,
They were from a mfg as beta test units and they made newer designs that are out for sale.  Never went back to try again. 

The Strarkrimson monoblocks are far better sounding than those other beta units. 

I did get the new GaN 300W power supplies to go with the Starkrimson pair of monoblocks.   Trying those now with the dspNexus 2x8 when the EA unit arrives on Monday!  Has the new ADC board with phono gain for trials.  Now to see if my Oracle Delphi MKI needs a new belt.  I know the Linn Sondek LP12 a friend gave me does and found a replacement.  Will try bringing one to LSAF if I have room in the van.

[P.I.]

Nick,
They were from a mfg as beta test units and they made newer designs that are out for sale.  Never went back to try again. 

The Strarkrimson monoblocks are far better sounding than those other beta units. 

I did get the new GaN 300W power supplies to go with the Starkrimson pair of monoblocks.   Trying those now with the dspNexus 2x8 when the EA unit arrives on Monday!  Has the new ADC board with phono gain for trials.  Now to see if my Oracle Delphi MKI needs a new belt.  I know the Linn Sondek LP12 a friend gave me does and found a replacement.  Will try bringing one to LSAF if I have room in the van.

I'm looking forward to see you and your menagerie! 

[HAL]

Dave,
Me as well!

Just hope my paint guy can finish in time! 

Hopefully the back-up plan will be done tomorrow, so good either way for the speaker baffles.  It's always something!

Rich

[Nick B]

Nick,
They were from a mfg as beta test units and they made newer designs that are out for sale.  Never went back to try again. 

The Strarkrimson monoblocks are far better sounding than those other beta units. 

I did get the new GaN 300W power supplies to go with the Starkrimson pair of monoblocks.   Trying those now with the dspNexus 2x8 when the EA unit arrives on Monday!  Has the new ADC board with phono gain for trials.  Now to see if my Oracle Delphi MKI needs a new belt.  I know the Linn Sondek LP12 a friend gave me does and found a replacement.  Will try bringing one to LSAF if I have room in the van.

Rich,
Those are external power supplies or do they fit inside those small mono chassis?
Those are nice tables. I had a Linn and always liked the looks of the Oracle. I think Brooks Berdan modded the Oracles years ago. I went out to his store in so. California a few times 25-30 years ago.
Nick

[P.I.]

Dave,
Me as well!

Just hope my paint guy can finish in time! 

Hopefully the back-up plan will be done tomorrow, so good either way for the speaker baffles.  It's always something!

Rich

Painters.  The bane of prototype production....

[HAL]

Nick,
They were from a mfg as beta test units and they made newer designs that are out for sale.  Never went back to try again. 

The Strarkrimson monoblocks are far better sounding than those other beta units. 

I did get the new GaN 300W power supplies to go with the Starkrimson pair of monoblocks.   Trying those now with the dspNexus 2x8 when the EA unit arrives on Monday!  Has the new ADC board with phono gain for trials.  Now to see if my Oracle Delphi MKI needs a new belt.  I know the Linn Sondek LP12 a friend gave me does and found a replacement.  Will try bringing one to LSAF if I have room in the van.

Rich,
Those are external power supplies or do they fit inside those small mono chassis?
Those are nice tables. I had a Linn and always liked the looks of the Oracle. I think Brooks Berdan modded the Oracles years ago. I went out to his store in so. California a few times 25-30 years ago.
Nick

Nick,
For the monoblocks they are external PS with a connector.  An easy swap!

Got the MKV chassis upgrades for my Oracle Delphi MKI and it is much easier to setup.  Still using the original Papst DC motor and still working well after probably 40 years.  Probably time for some electrolytic cap replacements as they dry out with age.  Just needs a new belt and they are reasonable.  I have seen the Brooks Berdan upgrades, but Oracle has them as well now.  Sent in my sub chassis to have the counterweight and new bearing installed.  Along with the new shock towers I installed, made setup much much easier.  Fun Stuff!

[HAL]

Dave,
Me as well!

Just hope my paint guy can finish in time! 

Hopefully the back-up plan will be done tomorrow, so good either way for the speaker baffles.  It's always something!

Rich

Painters.  The bane of prototype production....

Dave,
Yes, I am lucky that I found him.  He does automotive paint for classic cars. Problem is he is booked, so fits me in.  His latest project was to repaint a car for a person that had just spent $6K on another paint job and he did not like it.  He was still sanding the same car down for 2 weeks to get it ready for the paint booth.  Speaking of that, he also can custom paint an 18 wheeler box in the paint room!  It is HUGE!

[P.I.]

Dave,
Me as well!

Just hope my paint guy can finish in time! 

Hopefully the back-up plan will be done tomorrow, so good either way for the speaker baffles.  It's always something!

Rich

Painters.  The bane of prototype production....

Dave,
Yes, I am lucky that I found him.  He does automotive paint for classic cars. Problem is he is booked, so fits me in.  His latest project was to repaint a car for a person that had just spent $6K on another paint job and he did not like it.  He was still sanding the same car down for 2 weeks to get it ready for the paint booth.  Speaking of that, he also can custom paint an 18 wheeler box in the paint room!  It is HUGE!

I had a guy like that.  We went to high school together and he opened a body shop and specialized in building street rods.  Pat's paint jobs are legendary here.  He retired and sold the business... drat!