Deciding between Purifi, Nilai, NC502MP or NC500x?

1 minute ago, alanbd said:

The LTA Velo looks great and probably sounds amazing.  So, you are using headphone amplifier as preamplifiers? I guess that the impedance is not an issue since you are using line level inputs in your real amplifier? and I wanted to ask you, what was your experience with the Orchard Audio Gan amplifiers? and did you order a Purifi, Nilai or NCx500 from Apollon?

 

Last night, I received the WE396A tube, non D Getter. I placed it in the tiny Aiyima T8 and the improvement in sound was nothing short of dramatic, all in all very positive. I lost significant focus in imaging, mainly in instrument separation and soundstage accuracy, but the sound became very pleasant. I also lost some dbs from 12Khz up, but I gain some dbs in the bass region  although probably the bass became a bit loser. The soundstage did not shrink horizontally, just lost some focus, but it gain a lot of depth. I am amazed by this tube. I have a GE 5 star triple mica, and a Russian 63n, tube coming to further experiment. 

 

Having said that, the midrange was the best i have been able to extract from the Apollon NCx500 and that may be enough to close the deal. I listened to some of my classic jazz favorites, (Hawkins, Webster, Quebec, Peterson, etc) and it was very a pleasant and long session. Long is important because I did not develop any sound fatigue. 

 

I will buy an Aiyima T8 (the same one I am using now) for now and relax a bit. And then later down the year, I will take the time to choose a very good tube preamplifier (or a headphone amplifier that serves as pre) but that has a small footprint.

 

In the meantime, I can gain some further body in the sound when I soon change my speaker cables from the incredible Duelund DCA16GA to the Duelund DCA20GA.

The OA GaN monos are incredibly detailed but have some grunge in the mid range. Listening to the Apollon NCx500 dual mono that just arrived I no longer hear that so hopeful that Ive made the right choice. The MZ2 has a pre output, sounds better than pre sections I’ve compared to such as a Prima Luna integrated and CJ PV10A. Like the LTA line as pre because the patent design minimizes euphonics, has fast transients and no transformer to muck with low bass frequency response

25 minutes ago, davide256 said:

The OA GaN monos are incredibly detailed but have some grunge in the mid range. Listening to the Apollon NCx500 dual mono that just arrived I no longer hear that so hopeful that Ive made the right choice. The MZ2 has a pre output, sounds better than pre sections I’ve compared to such as a Prima Luna integrated and CJ PV10A. Like the LTA line as pre because the patent design minimizes euphonics, has fast transients and no transformer to muck with low bass frequency response

Thanks for sharing your experience with the OA GaNs. It is very interesting. If you did not listen to that grunge in the NCx500 dual mono you made the right decision. I do not hear a particular grunge in my stereo Apollon NCx500. Once I positioned the speakers properly, the midrange is clean and very present. Surely, it does not have the 3D bloom of tubes but we know that. 

I actually bought the Apollon NCx500 without hearing any of the good offerings of Class D nowadays. I only had listened to the Aiyima 07, Aiyima 07 Max, Aiyima 08 Pro and the Fosi V3. And all those mini amplifiers were promising enough for me to consider getting either a Nilai, Purifi or Hypex. I only went for the NCx500 because my current speakers are around 84.5db, very not efficient. So, I feared I was going to run out of steam, sometimes, with the Purifis. Also, I talked with some friends who I trust and listened to some of the manufacturers of these amplifiers (Buckeye, VTV, Boxem, Apollon, etc) and they all agreed that the difference between the new Hypex modules (NCx500) and the Purifi was not substantial (with Purifi having a bit of better midrange and Hypex having a better bass) and that depending on how good were the speakers you may not be able to notice. So, I went for power. And as much as I almost pulled the trigger for a VTV, I read many comments on the high standards of manufacturing of Apollon. And so I went. 

I come from tubes. I had a Conrad Johnson MV50, a custom build 45 SET stereo, a custom built 300B stereo, a custom built DHT preamplifier, a Sonic Frontiers preamplifier, etc. At that time, I had some huge Danley Synergy horn SH50 in my living room, I never (and that was sad) managed to make them image properly, simply never. So, as much as the sound was amazing, and it all seemed to come from one single point source, there was no soundstage.

So, the tube sound will never abandon me in my personal journey searching for the ultimate tone. But, I need to recognize that none of those tube amps above had the dynamics, the bass control, and the detail that I am getting with the NCx500. So, I am very happy. 

The Microzotl MZ2 surely fits the bill for me in terms of footprint. And, your comments make it an interesting choice. For the resolution of the system I have now (limited by the NHT C3s speakers which are perfect for my room being a sealed design), the MZ2 may be enough. I will check hifi shark to see if there are some units for sale. 

Please let me know how it goes when the LTA Velo arrives in the system.

11 minutes ago, alanbd said:

 

Thanks for sharing your experience with the OA GaNs. It is very interesting. If you did not listen to that grunge in the NCx500 dual mono you made the right decision. I do not hear a particular grunge in my stereo Apollon NCx500. Once I positioned the speakers properly, the midrange is clean and very present. Surely, it does not have the 3D bloom of tubes but we know that. 

 

I actually bought the Apollon NCx500 without hearing any of the good offerings of Class D nowadays. I only had listened to the Aiyima 07, Aiyima 07 Max, Aiyima 08 Pro and the Fosi V3. And all those mini amplifiers were promising enough for me to consider getting either a Nilai, Purifi or Hypex. I only went for the NCx500 because my current speakers are around 84.5db, very not efficient. So, I feared I was going to run out of steam, sometimes, with the Purifis. Also, I talked with some friends who I trust and listened to some of the manufacturers of these amplifiers (Buckeye, VTV, Boxem, Apollon, etc) and they all agreed that the difference between the new Hypex modules (NCx500) and the Purifi was not substantial (with Purifi having a bit of better midrange and Hypex having a better bass) and that depending on how good were the speakers you may not be able to notice. So, I went for power. And as much as I almost pulled the trigger for a VTV, I read many comments on the high standards of manufacturing of Apollon. And so I went. 

 

I come from tubes. I had a Conrad Johnson MV50, a custom build 45 SET stereo, a custom built 300B stereo, a custom built DHT preamplifier, a Sonic Frontiers preamplifier, etc. At that time, I had some huge Danley Synergy horn SH50 in my living room, I never (and that was sad) managed to make them image properly, simply never. So, as much as the sound was amazing, and it all seemed to come from one single point source, there was no soundstage.

 

So, the tube sound will never abandon me in my personal journey searching for the ultimate tone. But, I need to recognize that none of those tube amps above had the dynamics, the bass control, and the detail that I am getting with the NCx500. So, I am very happy. 

 

The Microzotl MZ2 surely fits the bill for me in terms of footprint. And, your comments make it an interesting choice. For the resolution of the system I have now (limited by the NHT C3s speakers which are perfect for my room being a sealed design), the MZ2 may be enough. I will check hifi shark to see if there are some units for sale. 

 

Please let me know how it goes when the LTA Velo arrives in the system.

 

Will do. Another nice feature of MZ2/3/Velo is that you can use 12SN7s so good NOS options available vs scarce 6SN7s

On 1/13/2024 at 11:21 AM, alanbd said:

Regarding op amps, I am not fully sure that all op amps make a difference.

Yes, they do. I would say op amps made a bigger difference than the change from NC500 to a NCx500, both from different manufacturers. 

On 1/29/2024 at 5:25 PM, alanbd said:

was able to do a couple more listening sessions and the first fact is that I noticed that I develop listening fatigue way faster with the Apollon NCx500 than with the Fosi V3 or with my previous NAD 3020 D. 

Dude, don't even bother posting listening impressions of any kind until these have at least 200 hours on them of continuous playing time- break in is a real thing. 

And do you have a decent power cord on it? Power cords on hypex amps make a huge difference. 

On 2/1/2024 at 4:45 AM, alanbd said:

And as much as I almost pulled the trigger for a VTV, I read many comments on the high standards of manufacturing of Apollon

As someone who owns both, yes the Apollon has a much higher build quality, and many custom parts including proprietary copper binding posts. Attention to detail is evident from the person who builds this. And yes, it must not be the same person who ships it. 😉

the VTV by comparison has wires that have plier marks in them so deep the bare wire is exposed. But yes, if one desires Weiss op amps (me) the VTV is much less money to do so. 

On 2/4/2024 at 10:50 PM, watts said:

Yes, they do. I would say op amps made a bigger difference than the change from NC500 to a NCx500, both from different manufacturers. 

Dude, don't even bother posting listening impressions of any kind until these have at least 200 hours on them of continuous playing time- break in is a real thing. 

 

And do you have a decent power cord on it? Power cords on hypex amps make a huge difference. 

Thanks for the heads up about break in for the NCx500. I may have 35 hours or so. I believe break in is a thing, but I read somewhere that even Hypex said that their modules did not need break in, or they were not affected by break in. 

As of now, I am using the stock power cord, I have had dramatic improvements replacing stock cords in tube amps. Again, I did not imagine it was going to be the same with Class D. Do you recommend a particular power cord?

And yes, lol, you are 100% right, it seems that the person who puts together the Apollon amplifier is not, at all, the person who actually packages and ships it!!

2 hours ago, alanbd said:

Thanks for the heads up about break in for the NCx500. I may have 35 hours or so. I believe break in is a thing, but I read somewhere that even Hypex said that their modules did not need break in, or they were not affected by break in. 

As of now, I am using the stock power cord, I have had dramatic improvements replacing stock cords in tube amps. Again, I did not imagine it was going to be the same with Class D. Do you recommend a particular power cord?

 

And yes, lol, you are 100% right, it seems that the person who puts together the Apollon amplifier is not, at all, the person who actually packages and ships it!!

 I don't know what they are getting at. Perhaps this was posted on ASR to satisfy some flat-earthers- perhaps they measure the same before and after, I don't know. But absolutely a class D amplifier sounds horrible new. Absolutely they require many hours to sound less tight, etched, strident, cold, and will sound more full, rich, open, warm and relaxed the more the playing hours pass. I have had 4 different class D amps, 3 of them new. You will see. Don't touch anything, don't make any adjustments, just listen to the same tracks each day and you will see. 

There are many capacitors in the signal path- which all of the SMPS have many of, and the modules as well. Yes, I am a believer that everything that passes "electricity" needs burn in. No, I can't prove it. But some items are not as pronounced as others- on another forum thread recently someone asked about burn-in on the Puritan PSM156, and I recall some very positive sound improvements immediately after plugging it in, even stone cold, and it most likely improved as the hours piled but that was not as noticeable as many other components like speaker cables etc. In my system with me ears and brain of course. 

Unlike many others I have not been through dozens of power cables, so I am not good to recommend a good match, and it has to do with matching your other components in your system/speakers/cables etc. as well. Honestly you gotta try some to compare and see which "flavour of ice cream" you prefer. And I am quite new to higher-end cabling: My first "real" power cord I bought less than 2 years ago.  But I can say my first "wow" was when I replaced the stock power cord in my Nord NC500OEM to an Audio Sensibility Testament, which is a well-constructed and very reasonably priced power cord, and they are quite popular in Canada, so they are readily available used on Canuck Audio Mart. I have since upgraded to Zavfino Silver Darts and I have 4 of those. An even bigger "wow" was experienced going from a $300 to that Zavfino $1000 power cord, and I'm sure I would say the same "wow" again if I tried an Audioquest Dragon, so I am not going to 😉. But yes, with most things in life you get what you pay for. I have some other brands on my radar to try out, I'll get around to trying them against the Silver Darts eventually. 

I also don't have any experience with power cords on any other amplifiers, the Mcintosh amps I had before the class D had attached cords, so unless I wanted to do some major surgery it was not an option. I do notice that all the modern Mcintosh amps have detachable power cords now though. 😊 I wish I could tell you power cords on class D have a bigger impact than replacing power cords on a class A/B, say a Pass labs, but I have not had the opportunity to prove that to myself. 

But I do know you have not heard how good the NCx500 is until you put a "quality" power cord on it. 

On 2/6/2024 at 1:09 PM, watts said:

 I don't know what they are getting at. Perhaps this was posted on ASR to satisfy some flat-earthers- perhaps they measure the same before and after, I don't know. But absolutely a class D amplifier sounds horrible new. Absolutely they require many hours to sound less tight, etched, strident, cold, and will sound more full, rich, open, warm and relaxed the more the playing hours pass. I have had 4 different class D amps, 3 of them new. You will see. Don't touch anything, don't make any adjustments, just listen to the same tracks each day and you will see. 

 

There are many capacitors in the signal path- which all of the SMPS have many of, and the modules as well. Yes, I am a believer that everything that passes "electricity" needs burn in. No, I can't prove it. But some items are not as pronounced as others- on another forum thread recently someone asked about burn-in on the Puritan PSM156, and I recall some very positive sound improvements immediately after plugging it in, even stone cold, and it most likely improved as the hours piled but that was not as noticeable as many other components like speaker cables etc. In my system with me ears and brain of course. 

 

Unlike many others I have not been through dozens of power cables, so I am not good to recommend a good match, and it has to do with matching your other components in your system/speakers/cables etc. as well. Honestly you gotta try some to compare and see which "flavour of ice cream" you prefer. And I am quite new to higher-end cabling: My first "real" power cord I bought less than 2 years ago.  But I can say my first "wow" was when I replaced the stock power cord in my Nord NC500OEM to an Audio Sensibility Testament, which is a well-constructed and very reasonably priced power cord, and they are quite popular in Canada, so they are readily available used on Canuck Audio Mart. I have since upgraded to Zavfino Silver Darts and I have 4 of those. An even bigger "wow" was experienced going from a $300 to that Zavfino $1000 power cord, and I'm sure I would say the same "wow" again if I tried an Audioquest Dragon, so I am not going to 😉. But yes, with most things in life you get what you pay for. I have some other brands on my radar to try out, I'll get around to trying them against the Silver Darts eventually. 

 

I also don't have any experience with power cords on any other amplifiers, the Mcintosh amps I had before the class D had attached cords, so unless I wanted to do some major surgery it was not an option. I do notice that all the modern Mcintosh amps have detachable power cords now though. 😊 I wish I could tell you power cords on class D have a bigger impact than replacing power cords on a class A/B, say a Pass labs, but I have not had the opportunity to prove that to myself. 

 

But I do know you have not heard how good the NCx500 is until you put a "quality" power cord on it. 

Thanks for all the advice. The fact that the break in will change the sound of the NCx500 in a positive way is great news!!  Starting today, I will let it run the whole day to speed up the break in. 

Also, thanks for the power cord suggestion. I just ordered a nice power cable. It should be here in a week or so. I will report back the results.

On another note, I am about to pull the trigger on a Moreplay kit tube preamplifier from Bottlehead to add to the system to instill some tube flavors, not sure yet. I was also looking at a Audio Research SP-16 (maybe too big and I want to stay in the minimalistic side), or an Audible Illusions tube preamplifier. 

Late to the discussion I know, but what about a Class H amplifier like the Benchmark AHB2? My experience with this amp and a Nord Ncore based Class D is that the AHB2 has the efficiency benefits of the Class D (small footprint, cool running) with the sound of a Class AB, and great measurements to complete this odd ball package.

On 4/19/2024 at 11:54 AM, Arcticair said:

Late to the discussion I know, but what about a Class H amplifier like the Benchmark AHB2? My experience with this amp and a Nord Ncore based Class D is that the AHB2 has the efficiency benefits of the Class D (small footprint, cool running) with the sound of a Class AB, and great measurements to complete this odd ball package.

Thanks for the suggestion!
That benchmark surely is a great option but somehow beyond my current budget. 

I have been using the Apollon Stereo NCx500 and it is working really good for my system. I am planning to make it a dual mono. Not sure if that would be a big improvement. I know that some Class D owners here have a dual mono and so they may be able to help me decide if the dual mono is worth it. 

Still curious about the Hypex Nilai though...

Here are nice DIY Nilai kits, single and dual amp module versions. Looks like no soldering is required which makes it viable for someone like myself! There is also a measure discussion over at the ASR forum.

https://www.diyclassd.com/products/diy-amplifier-kits/nilai500diy-500w-mono-power-amplifier-kit

https://www.diyclassd.com/products/diy-amplifier-kits/nilai500diy-250w-stereo-power-amplifier-kit

On 2/1/2024 at 7:00 AM, davide256 said:

grunge in the mid range.

This phase is a new one for me,  grunge in the mid range,  You meaning trash, not clear etc...Can you clarify

On 4/22/2024 at 1:19 PM, alanbd said:

 

Thanks for the suggestion!
That benchmark surely is a great option but somehow beyond my current budget. 

I have been using the Apollon Stereo NCx500 and it is working really good for my system. I am planning to make it a dual mono. Not sure if that would be a big improvement. I know that some Class D owners here have a dual mono and so they may be able to help me decide if the dual mono is worth it. 

 

Still curious about the Hypex Nilai though...

As Apollon Audiooffers all these amp modules in its amplifiers, and you are a customer already, why don't you ask them?

43 minutes ago, Apollo said:

As Apollon Audiooffers all these amp modules in its amplifiers, and you are a customer already, why don't you ask them?

I asked Tibor, the owner, weeks ago. He wrote:

¨The dual mono has more power, better channel separation and sounds a bit better due to better headroom and dynamic range.¨. 

But I also wanted to know what the users think. 

1 hour ago, alanbd said:

I asked Tibor, the owner, weeks ago. He wrote:

 

¨The dual mono has more power, better channel separation and sounds a bit better due to better headroom and dynamic range.¨. 

 

But I also wanted to know what the users think. 

 

I have Apollon Audio mono poweramps, based on NC1200. Speakers are Magico V3's (power hungry!)

Personally, I would always go for a separate (internal) power supply, so indeed dual power amp (or as in my case - mono amps)

Dual Power amp is in most cases (depending on distance to your speakers and dispossible room for heat ventilation) best choice.

In the end, it all depends on the load of your speaker on the amp.

Dirk

4 hours ago, Apollo said:

 

I have Apollon Audio mono poweramps, based on NC1200. Speakers are Magico V3's (power hungry!)

 

Personally, I would always go for a separate (internal) power supply, so indeed dual power amp (or as in my case - mono amps)

Dual Power amp is in most cases (depending on distance to your speakers and dispossible room for heat ventilation) best choice.

 

In the end, it all depends on the load of your speaker on the amp.

 

Dirk

Thanks for sharing. My speakers are  NHT C3, 84db, so very hungry and not efficient at all. Impedance curve around 6 ohm.  With the Apollon NCx500 Stereo, with only one, shared, power supply. I am not running out of power, but I believe separation indeed.

On 4/23/2024 at 9:01 AM, mav52 said:

This phase is a new one for me,  grunge in the mid range,  You meaning trash, not clear etc...Can you clarify

Compared to their treble and bass, the StarkRimson monos don’t have the same low volume level resolution in the midrange, so some nuance is blurred, indistinct for softer midrange instruments in the background

Hi All, 

I had the opportunity to listen to the Orchard Audio Starkrimson Ultra 2.0 in my system, and it was really interesting. I got into the amplifier tour in another forum and I was able to spend a week with this amazing amplifier. I wrote my impressions here.

Does anybody else here had the chance to compare the Apollon NCx500 (or any other NCx500 for that purpose) with the Starkrimson Ultra 2.0?

Hi Alanbd I’m in a similar situation. I’m looking for a final amplifier capable of driving mine b&w 802 d2. I have listened the nad m33 (purifi) versus the Cambridge nx plus the edge final (class ab). The Cambridge sound dramatically more pleaseant to me. I hoped there were other class D technology/ implementation that could sounds better (to me). The NCx500 was my target but reading your impressions, even the op amp switching is not effective. So at the moment I have no close for a better sounding final amps, close to the Cambridge class ab sound, that could replace my old Jeff Rowland 201. If anyone have any suggestion please share ideas. Best

2 hours ago, MicheleMilano said:

Hi Alanbd I’m in a similar situation. I’m looking for a final amplifier capable of driving mine b&w 802 d2. I have listened the nad m33 (purifi) versus the Cambridge nx plus the edge final (class ab). The Cambridge sound dramatically more pleaseant to me. I hoped there were other class D technology/ implementation that could sounds better (to me). The NCx500 was my target but reading your impressions, even the op amp switching is not effective. So at the moment I have no close for a better sounding final amps, close to the Cambridge class ab sound, that could replace my old Jeff Rowland 201. If anyone have any suggestion please share ideas. Best

Hi MicheleMilano, 

Yes, it is exactly as you described it. I am actually selling my Apollon NCx500. In my experience and in my system, the Apollon lacks significative amount of body or presence in the midbass and that affects the realism of the presentation, the suspension of disbelief. And I have tried it all, I tried cables, tube preamplifier, different tubes in the preamplifier, different op amps. I even built a Western Electric 111C Color box. Nothing really worked. All made a little difference. And without further comparison those differences seem to get me somewhere. But, once I plugged the Starkrimson Ultra in the system and I listened to it, I realized that all the changes I made to push the sound of the Apollon to a more full bodied rendition of midbass and lower midrange, was only getting me 10-15% beyond the original sound of the Apollon, or 10-15% of the place I wanted to be with the sound. So, I was about to buy the Ultrakrimson, but then I had a realization. Before investing myself so heavily into Class D, I needed to go back to what has always for me represented the best suspension of disbelief in audio, and that is tubes and high efficiency speakers. So, I am selling my speakers and the Apollon. And I bought a pair of Lii Audio full range drivers F15. I am building an open baffle for them. And I bought a Japanese Single Ended amplifier that can use 45, 2A3 or 300B tubes. 

I should add that regarding low level retrieval, the Starkrimson Ultra is in a complete different league in comparison with the Apollon Ncx500, even if I use the Sonic Imagery Ticha 994 Op Amps in the Apollon. Those op amps are super revealing, but they do not get to the level of low level retrieval of the Starkrisom. Also, the Apollon NCx500 sounds better with the Sparkos SS2590, those op amps are significantly less revealing than the Sonic Imagery (at least in my system), but they add a bit of body to the midrange, and that helps a lot with the sound.

For your case, if you really want to stay in solid state amplification, I do not know how to get that Class A, or AB, sound with Class D amplifiers. The only sort of Class D amplifier that I have listened to that has that sound is the Starkrimson. 

The only reason I am going to tubes is because my speakers are really not efficient, 84db in reality, and so that is why I needed so much power to move them. Now, with the F15s, they are 94db, I can move them even with 4 watts, and that opens a lot of options, less expensive ones, in the tube arena and also in the solid state arena. 

I used to have horn speakers with single ended amplifiers. But, I have not listened ever to an open baffle speaker, less had one in my system. 

So, as David Coverdale wisely sung decades ago, Here We Go Again!!!

I have NCx500 monoblocks with SMPS1200A700 power supplies, built by Deer Creek Audio. I like them pretty well, though I needed a bit of adjustment time from my prior solid state amp which was an Aragon A2004. The more I listen to the NCx500 the more I appreciate their clarity, unlimited dynamics, and speed, though their bass tends toward the overdamped side, which has been my experience with all NCore amps. I can recommend the NCx500 for you if you have speakers that need to be controlled.

If you buy an amp based on NCxxxMP modules, make sure you invoke your warranty if the modules have any sort of weirdness. I've had a NC252MP that made a high pitched whine just above the noise floor that was audible within 12" of the speaker, and the NC122MP I bought to replace it has an epic turn-off pop that makes me fear for my tweeters. Hypex's competition doesn't have these issues with their mains-powered amp modules, and the IcePower 300AS1 has 3dB lower SINAD than the NC252MP, so Hypex needs to get it together in that product area. I have also heard of NC502MP modules having weird interactions with long speaker cable runs. If you buy one of the MP modules, pay very close attention and if there's any strange behavior from them that you don't particularly like, it's time to send it back.

On 7/19/2024 at 5:59 AM, alanbd said:

Hi MicheleMilano, 

 

Yes, it is exactly as you described it. I am actually selling my Apollon NCx500. In my experience and in my system, the Apollon lacks significative amount of body or presence in the midbass and that affects the realism of the presentation, the suspension of disbelief. And I have tried it all, I tried cables, tube preamplifier, different tubes in the preamplifier, different op amps. I even built a Western Electric 111C Color box. Nothing really worked. All made a little difference. And without further comparison those differences seem to get me somewhere. But, once I plugged the Starkrimson Ultra in the system and I listened to it, I realized that all the changes I made to push the sound of the Apollon to a more full bodied rendition of midbass and lower midrange, was only getting me 10-15% beyond the original sound of the Apollon, or 10-15% of the place I wanted to be with the sound. So, I was about to buy the Ultrakrimson, but then I had a realization. Before investing myself so heavily into Class D, I needed to go back to what has always for me represented the best suspension of disbelief in audio, and that is tubes and high efficiency speakers. So, I am selling my speakers and the Apollon. And I bought a pair of Lii Audio full range drivers F15. I am building an open baffle for them. And I bought a Japanese Single Ended amplifier that can use 45, 2A3 or 300B tubes. 

 

I should add that regarding low level retrieval, the Starkrimson Ultra is in a complete different league in comparison with the Apollon Ncx500, even if I use the Sonic Imagery Ticha 994 Op Amps in the Apollon. Those op amps are super revealing, but they do not get to the level of low level retrieval of the Starkrisom. Also, the Apollon NCx500 sounds better with the Sparkos SS2590, those op amps are significantly less revealing than the Sonic Imagery (at least in my system), but they add a bit of body to the midrange, and that helps a lot with the sound.

For your case, if you really want to stay in solid state amplification, I do not know how to get that Class A, or AB, sound with Class D amplifiers. The only sort of Class D amplifier that I have listened to that has that sound is the Starkrimson. 

 

The only reason I am going to tubes is because my speakers are really not efficient, 84db in reality, and so that is why I needed so much power to move them. Now, with the F15s, they are 94db, I can move them even with 4 watts, and that opens a lot of options, less expensive ones, in the tube arena and also in the solid state arena. 

 

I used to have horn speakers with single ended amplifiers. But, I have not listened ever to an open baffle speaker, less had one in my system. 

 

So, as David Coverdale wisely sung decades ago, Here We Go Again!!!

I get it 😉 Since my last comment here I have picked up a tube pre, and 100 watts of Coda class A power which I use for the high channels. This is a solid-state style sounding tube pre, with clean non-warm NOS tubes installed, and it definitely adds body to the sound and roundness to images. The Coda has gained me more detail with no lack of speed or clarity, and enough power for my Magnepans- and added realistic richness- I love them both. The really odd part is the Coda has a surface temperature lower than the "efficient" class D Apollon NCx500. I still have the NCx500 powering the bass channels. But it is a heck of lot more money spent so it better sound better. 🤑