Excellent Solid State or Hybrid Monoblocks Recommendations

Good Luck on your search. 

@joey54 I know of them but have never heard them.  I am overrun with superb monoblocks right now - PSAudio Signature 300s, Atma-Sphere class ds, and heavily modded Parasound JC1 monoblocks.  I will put them on my seek and listen list for sure.

You should look at any of the Aesthetix hybrid monoblocks They are all amazing sounding amplifiers.

@tweak1 sorry to hear about your Voyager GAN mishap. These amps show up for a little over a grand on this site. Ric modded mine. It is not the best amp that I have for sure. However, the are really good and, for the money, is a great little amp.

@yyzsantabarbara I am not really class D amp expert though I do currently have two. Class D has come a very long ways. The Atma-Sphere amps are very high performers to my ears. I have never heard the Peachtree amp.

@jaymark Congrats on the new amps. You are likely the GAN expert on this site with all the GAN amps you have owned.

I have the Ric modded PeachTree GAN1 on the sidelines for over a year now. However, I will put it back in my Livingroom system today as I sell all my amps, except the CODA #16. The GAN1 is not powerful enough for the Livingroom but it is all I got until I get something else.

Hey Jay, happy to hear you really like Ralphs monos, though Im not at all surprised, and as to the M1200s, prior to them being available Ric Schultz offered a ground up amp (including Italian chassis) using dual mono IcePower AS 1200 modules, plus all his pixie dusty. I also have a Voyager GaN 350 but sadly I managed to take out one channel,  so have  re-enjoying Rics amp for well over a year.

Well, the Atma-Sphere 100 wpc class D monoblocks are very fine amplifiers. In listening to them I cannot identify anything in its sonic signature that screams class D. I have been surprised that the class D monoblocks seem to power my Aerial Acoustic 7ts effortlessly. The sonic signature of these amps is clean, pristine, non-fatiguing with very solid imaging. Nevertheless, I could see how it’s sonic signature would not be for everyone. While avoiding the nasties of solid state, is it tubelike? Perhaps it has some sonic traits of a very good hybrid or contemporary non-romantic tube amplifier.

I bought the PSAudio monoblocks and these amps virtually simultaneously. I like them both very much as neither amp will be returned or put up for sale.

I have been running the Atma-Sphere Class D monoblocks for a little over a week. I really like them. I changed out my speaker cables to Acoustic Zen Absolute and these amps just came alive. I'm running a Lumin U2 to T+A Dac 200 to Class D amps. Very happy with my set up. Ralph is a magician!

@jaymark , Looking forward to reading your comments on Ralph’s D amps, as I have been reading this entire thread. Amplifiers are my thing as well. Enjoy ! MrD.

My Atma-Sphere 100 wpc class D monoblocks just arrived today. Beginning tomorrow they are going to start getting serious run in my reference system. I got about 5 amps now down by reference system. Oh well, life is short.....

@jaymark Glad you're enjoying them!  I have an old A23, but haven't heard any of the newer John Curl designs.  It's a fine amp, but the BHK 250 is in another league.  Ironically, it also developed a random channel dropout issue once it warms up.

@audition__audio my settling on solid state over tube amps has been to pair high caliber tube preamps - Aric Audio Motherlode - with a clean, powefuul solid state amp with great clarity.

I always liked the Aerial speakers that I have heard. Get more things right than many other dynamic designs. 

@ncdogdoc u can reach Doug Jesse at asi_tekatyahoo.com.  

@audition__audio my Aerial Acoustic 7Ts were modded by Doug Jesse of Asi Teknology.  They for sure like like current.  The difference post-modification is the clarity, delicacy and imaging.  

@pynkfloydd I have about 70 hours of play time on the BHK 300 monoblocks.  I can easily state that these are the best stock amplifiers I have ever had in any of my systems.  I absolutely love their sound which is clean, clear, slightly forward, tremendous wide and deep sounds stage, rich tonality, very solid low end and powerful.  I bought the without ever listening to them and they are everything that I could ask for.

Relative to the modded JC1s, I for now declare a dead heat.  They do not sound exactly the same but the differences do not give one amp an advantage over the other.  The 300s are without question better than the stock JC1s.

I know that some models of the Aerial speaker line tend to like a good deal of solid state power. I am not sure if your speakers fit into this category. I could never find a solid state amp for under $ 40K that I liked. I did like the Trilogy monos which are still pretty expensive. 

@jaymark How are you liking the BHK 300s compared to the JC1s so far?  Hope you were able to get a few good listening sessions in!

Update on the PSAudio BHK 300 monoblocks - what a difference 13 hours makes.  These amps sound clean, powerful, dynamic with vivid tonal colors.  Really nice clarity and excellent imaging.   These are not TAS approved boat anchors.

I was talking about pairing the Atmasphere class D amps with the Wilson Alexx V

@carey1110 They should be fine with the Alexx's from all the reports we have.

Just installed the BHK 300 monoblocks into my refernce system.  I am going to let it play continuously for long stretches before seriously listening.  Nevertheless, before I left this house this morning - with less than 1 hour of playtime - I came away saying "Not bad".  I could hear the clarity and upper end finesse along with the low end heft.  The meat on the bones body and tonality in the upper registers are, as expected, not there yet.  I am excited to hear the sound evolve with continual play.

I ran Aerial 7b with a pair of Veloce Audio Saetta Hybrid monoblocks. The amps are battery units with a pair of 6H30 tubes on the input to a Hypex class D module. MSRP was $18K, used price is all over the map.

I've owned the Veloce amps for a couple of years now and I've had them on a range of speakers including Altec Lansing, Martin Logans, and my current ProAcs. On the 103dB Altec A7 they were dead quiet, no hiss at all. Same on the Altec Valencias. Plenty of power for most sensible speakers.

(Full Disclosure - I listed them for sale as I'm moving to SET)

I was talking about pairing the Atmasphere class D amps with the Wilson Alexx V

I’m wondering how they would do driving difficult loads like the big Wilson’s. 

@carey1110 That depends on the class D amp, like it would if it was a class A amp. Some will do great. IME the Wilsons have a low impedance but otherwise are not hard to drive- no weird phase angles and such.

@carey1110 

I’m using Tannoy Turnberry (93db sensitivity / 8 ohms nominal/ 5 ohms min)

@veerossi What speakers are you using the Class D amps with?  I’m wondering how they would do driving difficult loads like the big Wilson’s. 

@jaymark Sorry to go off topic but how do you get in touch with Doug Jessie at ASi Teknology?

Some 5years ago a then friend had a Pathos hybrid. It developed a problem and he went crazy trying to get it serviced in the US, and too expensive to send back to Italy. Hopefully US support has been resolved

@jaymark I'm just dipping into the German tubes since there's such a price premium and the market is flooded with fakes, but the ones I've tried have sounded great.  Have you checked out Brent Jesse's stock?  For ~$100 more for the quad, he's got the Siemens Cca, which is supposed to be the top of the line Siemens tube.

My current favorite is Mullard's 6DJ8/ECC88.  If you enjoy acoustic performance, piano or vocals, they sound the closest to live music to me and very addictive.  There's a premium on the original Mullard branding, but generally can still find them for $100-150/pr for NOS and all sound very similar.  You can find some of the rebrands for under $100/pr. with Brent Jesse selling a top end E188CC/7308 version for $375/pr..  I've noticed I need to turn up the volume a bit more to get good solid bass with Mullards, but its mid-range is what sets it apart from other tubes. 

Tungsrams are on the soft side and opposite of the stock tubes that come with the BHKs.  They're worth having as a spare set, but (in my systems) make voices seem further back and bass response a bit too soft.  Not as soft as the Valvo E88CC I have, but definitely on the soft end.  As a cheap Russian NOS, the 7308/E188CC National branded Vokshod sounds very close to the big name European NOS and not a bad tube.

I'd highly suggest checking out Amperex 6DJ8 A frames as a reference point.  They're such a well-balanced tube and have been very helpful with testing equipment changes and diagnosing issues.  NOS are easy to find under ~$70/pr. and sound great with livelier music, even at lower volumes.  Strong across the whole range with great imaging, just not a standout in any specific area. These may be a good starting point where you can make decide how you'd like to tweak the sound or what may sound best with your equipment.

Generally, I've tried 6922, 6DJ8, ECC88, 7308 and PCC189 and prefer the 6DJ8/7308.  These smalls tubes really don't get too hot and the red light in back will go out ~10 minutes after you shut off the main power switch, so it's safe to switch out with a gloved hand.  I also noticed the Acme fuses narrowed the gap between tubes and improved bass response with the softest sets, but just my experience.

Pathos is nice, Canor too.

I second Pathos hybrid InPol design. My Heritage MKii is integrated and is my endgame.  Rock solid bass and air mids and highs. I’d assume their hybrid separates are of equal quality.  Worth a listen. Especially sublime with my Tannoy Kensingtons. Also enjoyed my BHK300’s a few years back with the BHK pre.  I only let them go as I needed to downsize boxes and so went integrated.  Good luck.  Many good products out there.   

@pynkfloydd I have been recommended the Siemens NOS 7308 tubes.  Will set me back 1200 bills for 4.  Also tungsram ecc88s.  Any recs based on your listening would be appreciated....

@atmasphere thanks for the above explanation!  Great talking with u recently as well.  I am still interested in your class d amps as I rotate amps thru 4 two channel systems at two homes.

many thanks.  I was going to pick up a pair of used PS Audio BHK 300 monoblocks used then got cold feet when the seller did not know how old they were and the serial numbers were non-sequential.  So I ordered a brand new pair from P SAudio and traded in one of my amps in my collection.   Glad to know I should be OK with 15a lines.

@jaymark Any time and congratulations!  Bascom King's designs are so well-regarded that you can't go wrong, especially since these ended up on many "best of" lists.

You may also enjoy the tube rolling threads on PS Audio's forums:  PS Audio - BHK 250 / 300 Tube Rolling Thread

Something really nice about the BHK amps is that they accept the 6922 variants without any special configuration.  Bascom replied on one of the PS Audio threads and recommended the Tungsram PCC88, but it's a very laid-back tube.  I went on a tube binge and have tried ~15-20 different sets, so let me know if you'd like any tube suggestions.  I also had a positive improvement from Acme's silver ceramic fuses, which were ~$130 per amp for the set of 6.

Hope to hear your impressions after you're able to set your new monoblocks up!

I suspect that the gan fet is a chunk of this progress assuming it is well implemented.  I am gonna pick up some class D monoblocks in the near future.....

@jaymark What GaNFETs bring to the table is low noise. You really do want a class D amp to be low noise because that noise can leak out through the air or on the AC power line. It can get into other components and mess with them. So its not enough that the class D amp meet EU Directives for low noise (or in this country FCC 'part 15'); it needs to be a lot lower so things like digital audio, FM radio, a phono section, don't get upset by the operation of the amp in proximity.

A major source of noise in class D is something called 'parasitic inductance' which is might be a lead of a part or a trace on a board that is long enough that its able to resonate and transmit noise like an antenna. GaNFETs typically don't have leads making them inherently lower noise than MOSFETs, which usually do have leads.

GaNFETs also tend to have a very low 'On' resistance, so low that a lot of the time they don't even need a heatsink, because with lower on resistance there is also less energy dissipated in the device. The inherently faster speed of the devices also means less deadtime to accomodate their operation. Deadtime is a period of waiting in the circuit so time is given for one device to turn off before the other is turned on (otherwise the devices can heat up very quickly and fail). Deadtime contributes to distortion- reducing it can make the amp smoother and more detailed.

@pynkfloydd many thanks.  I was going to pick up a pair of used PS Audio BHK 300 monoblocks used then got cold feet when the seller did not know how old they were and the serial numbers were non-sequential.  So I ordered a brand new pair from P SAudio and traded in one of my amps in my collection.   Glad to know I should be OK with 15a lines.

Have there been many changes to the PS Audio BHK 300 monoblock amplifiers over the past few years?

@jaymark Seems like there were some revisions that affected early units.  In case you're interested, PS Audio has a good forum where you can even find old posts from BHK himself.  Here's the thread about revisions:

PS Audio Forum: How To Tell If You Have The Latest Version Of BHK Signature 250, 300 or Preamp???

Do PS Audio BHK 300 monoblock amps require a 20 amp line?  If not require one would the sound better with one? Or is a 15 amp line sufficient?

15amps should be okay, but 20amps would likely be preferable if you're running off of a single circuit.  I run through a few conditioners and the Furman SPR-20i averages ~2 amps for the BHK 250 at moderate listening levels.  I'm assuming with all equipment powered and running BHK 300s, you could be pushing ~10 amps continuous draw for everything, but, for reference, the BHK 250/300 uses 10 amp fuses so you'd never surpass 10 amps per amp even at full throttle.

A Neurochrome 365 or a Purifi EIGENTAKT Class D Amplifier are both able to be produced as a Monoblock.

I know the 365 and the lower powered versions down to the 65 very well, to the point, I do believe the 65 might be my last owned Amp' when I come away from the present system.

I also know an owner of the 365 with a few Mod's incorporated who has been recently familiarised with a Purifi EIGENTAKT, the result being they are very impressed and are now building their own one with a few mod's learnt from an Amp builder/measurement group.

These can be housed in an very nice aesthetically pleasing enclosure and might require an EE's assistance.

I would bet all in any of these Amp's would come in at $2.5K max to build as Monoblocks.

In relation to the Commercial World of Retail Pricing, the BOM for these Amp' Types alone, if attached to a retail product, would put Amp's being supplied retail into the $20K - $40K zone, especially if a very fancy aesthetic was also part of the pricing for the upper end in the suggested price range.

The first Time I heard a Neurochrome Amp' it was on a £200K+ System, where the Soulution Power Amp' at approx' £50k was in use for approx' 2 Hours as the base Amp' used for Phonostage Demonstrations.

The Soulution was swapped out and replaced by the Neurochrome. For the 3-4 Tracks allowed for the Demonstration, the Neurochrome did not show any signs of having a Amp' immediately available to be put back to use, that could show it to be a underperformer, even though it did have a slight variation to how it delivers the end sound.  

On the same occasion following the Neurochrome, an individual known to have very adept EE Skills and has produced very attractive audio demonstrations, put into the system, their £400 purchase, that was a 4 Box Class D Monoblock imported from China. The builder had spent approx' £100 doing their own design hooks for the schematic/topology.

The system owner who also has a audio retail business claimed he might as well throw in the towel.

The Chinese Import was not as good as either of the previous Amp's, but if an individual was able to receive a Demo; of the Import Amp' and the Soulution, it would be some sales person that convinces a person to spend the extra £49500 on the Soulution Amp'.

In relation to the Neurochrome vs Soulution, the individual in the Demo' would need to be a Soulution die hard fanboy, to decide the Soulution was the one to spend the extra £47500 on to take it home.

In no way am I knocking Soulution Amp's, I have as an estimate heard them in use in the same system, for near 20 Hours of play time. I would be very very Happy to use one.

I am also a fan of the BHK 300 mono blocks.  I have used them with Tekton Moabs, Magnepan 3.7s and now Magnepan 20.7i's.  I heard a friend's 3.7i's being driven by a D'agostino S300 amp and even though his room wasn't very good his 3.7s sounded a lot better than mine ever did.  That led me to consider getting a high powered amp and used BHK 300's were the first ones that came up at a price I could afford.  They transformed the 3.7s which finally managed to outperform my Moabs which I still have and love.  What surprised me is the BHK 300's sounded better with the Moabs than my Aric Audio Super 300B SET amp with KR Balloon 300Bs and the Moabs sounded REALLY good with that 300B amp.  Getting the 20.7i's was another big upgrade to the system.  I had also tried the PS Audio M700's but I didn't really like those.  I think the BHK 300's at used prices are a genuine value and a great performer.

I own a pair of BHK mono blocks. They are hybrids because they have a tube input stage.  They drive PS Audio FR-20 speakers.  Great amps. 

@tweak1  I do have a modded Voyager GAN.  It is a very fine amplifier.  Not as good to my ears as my modded JC1 monoblocks but mighty fine.  I like having a menu of amps to rotate or have as backups.  Never used any of the contact enhancers - might give them a try.

The Hypex Nilai 500 Class D amplifiers are getting great reviews. 

The absolute best amps I heard running Aerials were Jeff Rowland amplifiers (of course this was decades ago, so YMMV).

On the other end of the economy scale, I’d suggest checking Odyssey Audio monoblocks; they offer terrific bang per buck.

Good luck & happy listening!

@jaymark 

I thought you had a moded Voyager. Many times the itch for something else doesn't pay dividends you hoped for

Do you have all you cable connections treated with something like Mad Scientist Graphene Oxide Enhancer. It is jaw dropping. I did one component at a time starting with my transport. It was incredibly obvious, but I persevered staying with one component at a time. Each time the sound got better and better

hth

Would suggest checking out Concert Fidelity monoblocs

I too have a pair of BHK 300 monos powering my Kef Ref 5's.  Front end is a DCS Bartok. I haven't got round to tube rolling yet but one day .... 

What I can say is I push my system very loud at times and it just keeps on giving. The amps barley get warm. They seem to have so much left in reserve. You can switch them into 'standby' which turns off the tube input stage but maintains power to the electrictronic circuits. All I can say is I am very happy with them

@ yyzsantabarbara I sold my Coda #16 amp last year.  My modded LSA Voyager GAN amp is worth a lot more to me than I could ever get for it by selling it.  Class D has come a long damn ways.  I suspect that the gan fet is a chunk of this progress assuming it is well implemented.  I am gonna pick up some class D monoblocks in the near future.....

@jaymark Since we have a few common amps, Ric’s modded GAN amp(s) and the CODA #16 let me add my 2 cents. The CODA S5.5 amp is supposed to be a bit like the #16 but supposedly a bit better on top (maybe less warmth). I have not heard it yet, but I am intrigued because I want something a tiny bit less warm than the #16 for my Livingroom. I am looking at monos since I want a bit of power, though I do not think these are true monos.

Another amp that I am giving a lot of consideration too (the leading contender) is the new SimAudio 761 North Collection. This is a stereo amp but is reportedly better sounding as monos. It is a more neutral sounding amp.

I just learned from another thread that KRELL is coming out with upgraded Duo amps. I love the Duo amps and these upgrades are likely trickle down from the top end KSA i400. Supposed to be around June timeframe (just a rumor from me).

I am going to demo this stuff in the summer.

+1 Michi M8

Maybe stretch to AGD Gran Vivace