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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!!!

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?

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.

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.

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...

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.

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!!

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.

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.

¨Teething¨ fits the bill. Having said that, once I managed to position the speakers in the right place (after three hours), the center image was very solid. I use the Mini DSP as a preamplifier since I can connect even the phone pre to the Mini via the analog input, and I can bluetooth to the Mini and also connect a USB to my laptop and use the DAC of the Mini. For now, it is more than enough. I would only add a ¨second¨preamplifier, a tube one, if the tests with the mini Aiyima T8 give promising results. Also, once I locked the speakers in position, since the midrange came alive, the frequency spectrum was way more balanced and so the major issues with harshness were gone. But, not the ¨teething¨, for that I need tubes. Even using the a PEQ curve in the Mini DSP will not solve it. The challenge, when the time comes, will be to find a tube preamplifier that round the edges, adds presence, give a bit of tube bloom and decay, without muddying too much the sound or cutting dbs at the extremes of the frequency spectrum. That is a tough bill, I was contemplating a Supratek pre but I would really prefer something small with a small footprint.

Just today, before packing the amplifier. I decided to reset my whole speaker position to zero and turn off the subwoofer. I followed the Sumiko method with Jennifer Warnes´Ballad of the Runaway Horse, as I have done several times. And, wow, what a difference. Surely, the edges are still there, but the center image is solid like a brick, and midrange is not recessed anymore. It is incredible how much change pays to properly position the speakers. Surely, there is still much to improve, to give a more 3d character to the center image and to smooth out those high frequencies, but having a solid center midrange that is good starting point. I will get the Western Electric 396A tube, and will do a test to see how far can tube preamplifier can take me. Now, that I am starting to see the real sound of this amplifier, I think it needs a good tube preamplifier that does not color a lot the sound, just softens the edges, gives presence, and leans a bit on the side of neutral (as opposed as super warm).

The Class D journey continues.... I 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. I did further testing with all the gain settings in the Apollon but the sound signature did not change much. I also played with the Parametric Equalizer in the Mini DSP Flex trying to bring out the midrange and further flesh out the sound. It did not work. The sound was better when I added anywhere from 3 to 5db around 200hz with a Q of 1.5 or so, lifting a bit the surrounding frequencies. But, not even that was able to fix the problem with the midrange. Surely, that EQ brought out the midrange, but it did not round the edges. The sound was still very harsh and flat in the midrange. Then, a friend of mine brought a inexpensive Aiyima T8 Tube preamplifier, it only has one tube. I put the Aiyima in the chain right between the 2 volt output of the Mini DSP and the input of the amplifier. That worked much better even when the Aiyima had just the stock tube. It also made the soundstage smaller and the sound muddy. But, we are bringing a western electric 396A tube this Friday and that should work better in the Aiyima T8. I am just doing this test with the Aiyima to taste how the sound can improve. If it goes somehow well, I will have to buy either a tube preamplifier such as an Audio Research SP16 or Tube4hifi SP14, or even the Elikit TU-8500, which are all in my price range. But, if what the Aiyima brings with the WE tube is not promising then I will just sell the Apollon. Something I noticed when I was listening with the Aiyima tube preamplifier in the chain is that despite the fact that everything got somehow muddy and the elements in the soundstage lost pinpoint accuracy, the sound was way more pleasant, engaging and non-fatiguing. So, that is something to think about. My friend also brought an Aiyima 08 Pro amplifier, no tubes. And we hook it up replacing the Apollon, without the tube preamp, just with the Mini DSP. The sound was way fuller (although not as accurate and clean as with the NCx500), the midrange was way more natural and full bodied. If I need to choose, I would easily prefer to lose some of that defined imaging and horizontal separation in the soundstage that the NCx500 provides for a more natural midrange and a more non-fatiguing sound.

I get it. Thanks. Let me see what I can find. What about Audio Research SP-8 or SP-10? are these also good choices? And what about a Conrad Johnson PV-5?

Yes, thanks, I will surely try that. I wonder if a Schiit Saga would be enough to smoothen and flesh out the midrange. I already tried even the highest setting and it did not improve much.

Just a short update. The Apollon NCx500 arrived yesterday. Packing was not the best, but maybe customs changed it. Surely, customs opened the box so that is a possibility. When I opened the box, the amplifier was only protected with a very thin paper and nothing else. Surely, it had some styrofoam corners but that was all. Not impressed by the packing to be sincere. I hooked it up immediately and started listening, testing the different gain settings. I tried them all but the highest. Having the 2 volts coming out of the Mini DSP Flex, I mainly listened to a lot of music in the third setting, one before the highest. The first two settings did not provide enough power to make a real difference. The first and second were close to the max power (regardless of distortion) provided by the Fosi V3. It is all subjective below and, surely without a doubt, it is all specific to my case. So, in that sense, my comments only apply to my specific situation and pertain to my experience with less than 10 hours with the amplifier. Pros: - Soundstage became 20-30% wider horizontally - Instruments were easier to discern in space. - Bass became louder and tighter. - Background is really dead. - No hum and no noise when turning the amplifier on or off. Surely, if the amplifier is turn on or off in the right sequence with regards to the other components. Cons: - Soundstage depth got reduced. - Frequencies around 10khz to 15khz became more prominent. They are not louder than before, but probably due to the higher Sinad they are easier to discern. - Frequencies from 80hz to 300hz, the midrange, are somehow lost in the soundstage. This did not happen with the Fosi V3. Still, too early to even confirm this properly. I will play with some PEQ in the Mini DSP and see what I can do. Some songs that have a prominent midrange eq, around 80 to 300hz, do not have that problem. I should say that the portrayal of voices by this particular amplifier, in my short experience, is not too pleasant to my ears. And knowing my friends, many of them who are talented musicians and also listen to a lot of music, they will share my opinion. I did spend a couple of hours moving the speakers closer to the back wall, and away from the wall, as well as placing them further apart or closer to each other (to reinforce that center midrange image), but this sound signature did not change much. I will listen further to the amplifier with the higher gain setting and report back. For now, unexpectedly, I find myself in the side of those who want to go by the numbers, or the efficiency of Class D, but find that regardless of the great measurements performance, some Class D amplifiers simply do not produce a pleasant sound. And when I say pleasant sound, I am clearly being 100% subjective to what I like. Because, beyond the numbers there is that learned experience, that develops into taste. Until now, and this is still very early, I would dare to say that regarding the critical frequency range of 80hz to 300hz, where most voices fall, the Fosi V3 with its stock op amps sounds better (in my system, in my room and for my ears and for my mind) than the Apollon NCx500. I truly hope that as I further experiment with the Apollon gain settings, speaker position, and even PEQ in the Mini DSP, that statement above will radically flip to the other side. Sincere subjectivity...