Experiencing Rowland M925 4-chassis reference amps


My pair (or should I call it my quartet?!) of the new SS Rowland M925 reference mono amps were finally delivered yesterday.... Needless to say, I am excited!

The 430W M925 monoblock amplifier is a hefty affair: The amp is formed by four chassis: two power supply chassis and two audio chassis, amounting to a total weight of 380 Lbs in the four boxes, and 320 Lbs in their birthday suits. Each chassis is double boxed, protected by heavy urethane foam inserts, and then bagged in a heavy cloth sleeve tied with a drawstring.

Each power supply box also contains an accessory carton, featuring a power cord terminated at one end with a 20A IEC connector, a heavy ombilical to carry DC current to the audio chassis, and a skinnier ombelical, which I conjecture carries control signals and may have an additional grounding line. A baggie contains 3 1-inch spherical delrin footers that can be screwed into the divets at the bottom of the SMPS chassis if if you do not use 3rd party spikes/footers. A smaller baggie contains 4 smaller delrin beads... They fit into the dimples milled into the top of each the power supply chassis, and are used to keep top and lower chassy from touching when the two are stacked.

I am using Nordost Titanium Sort Kones instead of factory-provided footers. Each power supply chassis stands on top of 3 divet-centered Kones. The whole thing sits on top of 1.5 inch thick granite slabs, which have been patiently waiting in place for the M925 amps since 2011.

The audio chassis are even heavier... They will get into place in the next few days, one way or another. Rowland recommends the stacking be a two-person job.

In order to break-in both output terminal in each unit, I will connect each amp to my Vienna Die Muzik with a form of shotgun wiring: Aural Symphonics Chrono and Cardas Golden Ref for the time being. The Aural Symphonics speaker wire connects to the single 5-way binding post of the Muzik speaker with bananas; the Cardas Golden Ref connects to the same posts with spades... I have already tested the configuration using other mono amps... Works flawlessly. Of course, I have no idea if M925s benefit from shotgun wiring... This will be part of the discovery fun!

The amps will be fed by the Criterion linestage through Aural Symphonics Chrono B2 XLR ICs.

Power cords will be Aural Symphonics Magic Gem and Ultra Cube XXV, plugged into a dedicated 20A circuit served by Furutech outlets.

According to Jeff Rowland, breaking may be excruciatingly long, because of the oversized input transformers and power supply. I suspect that the process may extend well into the summer months... I will log my periodic observations on this thread.

For sake of completion, here are the amps specs as far as I know them:

Monoblock Power Amplifier OUTPUT POWER: 430 watts @ 8 ohms/850 watts @ 4 ohms
Monoblock Power supply: 2400 W regulated DC SMPS per channel, with Active Power Factor Correction (PFC).
FREQUENCY RESPONSE: 5 Hz - 50 kHz
INPUT IMPEDANCE: 40k ohms
THD + NOISE: 0.004%, 20 Hz- 20 kHz
OVERALL GAIN: Switchable 26/32 dB
Combined AMPLIFIER chassis & POWER SUPPLY chassis WEIGHT: 160.4 lb / 73 kg (per channel)
TOTAL DIMENSIONS (H/W/D): 16.5" x 15.5" x 16.25" (per channel) 419mm x 394mm x 413mm

Saluti, Guido
guidocorona

Hi Sam,

 

in some past, the single box design inherently compromised the performance of an integrated... Just to site an example, a single power supply was mostly used for all subsystems because of size limitations, thus cross-talk and distortion could leak among subsystems. Conversely, on devices such as Daemon, there are individual regulated SMPS on various subsystems.... In the amplification section, there is a dedicated power supply on each channel, making Daemon's amplification a dual-mono design.

 

But I realize that in the end, proof of goodness must be in the pudding... So I will eventually compare the performance of Daemon feeding Die Muzik directly to that of Daemon feeding M925, and those into Die Muzik speakers.

 

BTW, all my wiring is by Cardas... Clear Beyond XL for power cords, and Clear Reflection for speaker wires and analog ICs... I found that Cardas has extraordinary synergy with Rowland equipment, and am in fact amazed about the glorious sound I am getting, even though the Reflection line is at least a couple of levels below Cardas's Clear Beyond, which is Cardas's top of the line for analog ICs and speaker wires.

 

Saluti, Guido



Hello Guido:

 I hope you are doing well and am sure enjoying hearing about your journey with the Daemon. I still think separate components would be sonically better, however I will await your final analysis. 
Look forward to your future up-dates.

Stay well,
Sam












Hello Guido:

 I hope you are doing well and am sure enjoying hearing about your journey with the Daemon. I still think separate components would be sonically better, however I will await your final analysis. 
Look forward to your future up-dates.

Stay well,
Sam












Yes, my beloved Rowland M925 monoblocks have been making fantastic music without a glitch since May 2013... For the last few years, I have been feedin M925 directly from an Rowland Aeris DAC,this powered by the Rowland PSU ultra-capacitor-based external power supply. Yet, I have been wondering for some time if my audio nirvana could ever be uber-nirvanized, as the technology of audio reproduction has continued to evolve. So, when Rowland released its statement integrated amplifier in the form of Daemon, I became curious. Could an integrated equal, or at least get close to my Aeris + PSU + M925 trio?             


Thus,  I have been long hoping to evaluate the Rowland Daemon 1500W Superintegrated amp. Could a class D integrated fulfill my yearning for sonic bliss, or would Daemon leave me pining for the wonderful music of my separates? Eventually, a Daemon review unit was delivered on February 28th. I Started break-in the following day, and have been scribbling my listening notes since… The writing project will continue for at least a few months, until the device has stabilized, and I have exercised several of its many input and output features. I have been waiting for a long time for this 99Lbs single box critter. It is Jeff Rowland’s integrated statement. The DAC + Preamp + 1500W/8 (2500W/4) dual-mono power amp in a single chassis measuring 17.5” x 15.25” x 9.5” is sounding amazing after just a little more than 300 hours of break-in.

 

Discovering the extraordinary musical beauty that Daemon produces is being a fascinating experience… Already I am stunned by Daemon's power reserve and unreal tonal grace. Join me to chat about my adventure with this integrated flagship around its new Audiogon watering-hole:

 

https://forum.audiogon.com/discussions/jeff-rowland-daemon-reviewing-the-jrdg-superintegrated-flagsh...

 

And, feel free to PM me with any questions about it.

 

Saluti, Guido


I'd look for a used 625 or 625 S2 which is possible under $10K.  Superb amplifier....
Guido - jimmy augustine from texas here. Greetings! I still haven’t done anything to improve my system since we talked a few months ago. I don’t have 925 money. But could you suggest an amp upgrade path in the 10k cost range pre owned? Still running the n10 to Berkeley to your old Rowland amps to audio physics Scorpio.
pls and thx!
Much thanks to Al and Guido for the comments on the 925. Guido I find your insights and commentary quite comprehensive. Thank you! 👍
Hi @guidocorona 
I wait for your Cardas cables review, I suppose in the Cables section.

Very curious about the new C.Beyond XL Power (vs C.Beyond Power, I never fell in love with) but also Clear Reflection Speaker (vs Golden Reference; I need 2 pairs for shotgun and Clear Speaker would be too expensive).
I know well the C.Reflection XLR, I replaced it with the superb C.Beyond XLR because the former sounded too fat in the midbass in my system and room, while the Clear XLR was "too neutral" (thin, washed out, lacking of bass energy).

@astewart8944 in the Cables section wrote the Beyond XL sounds with more detail in the high frequencies but less listening fatigue than the "etched" (I agree) Beyond (I prefer Clear Power on the digital source), and also with tighter bass and expecially midbass...
I did not understand if these changes affect tonal balance, pushing it towards "too much neutrality" (like Clear XLR interconnects) losing bass impact (I would not expect this from an "heavy gauge' power cord).

Many thanks

Thank you so much @Alstewart... You summerized my own M925 experience to a T!


The reason why M925 monos never get really hot to the touch is that they have an efficiency of approximately 93%.


Ther power is approximately 430W into 4 Ohms, reaching 850W into 4 Ohms. Their 2500W DC power supplies let them generate a peak current of 45A per chassis. I never heard them breaking a swet on my Vienna Die Muzik speaker, even with the extremely high dynamics of Mahler symphonies at high SPL.  


The M925 have achieved recently a new quantum plateau in my system. I have adopted a full loom of Cardas cables in my system.... I started with the new flagship Clear Beyond XL power cords, and so to leave still room for future upgrades, the Clear entry level Reflection for XLR and speaker wires.... The result still stuns me: there is definitely a magic synergy between Rowland and Cardas, because I have never heard my system as refined and immersive as it is now.


Interestingly, the break-in process for Cardas wires appears to be quite benign.... About 300 hours likely takes the entire loom to over 90% of their performance potential.... Even from the first few hours one can tell that there is something truly special goiong on..... Of course, there is a bit of performance fluctuation for the first 70 or so hours, after which the performance arrow points steadily up. Did I mention that bass is spectacular and harmonic development is to die for? And I have heard sweetness of treble that I do not believe that any other wires have yielded until now.


Yes, I have loved my M925 monos since 2013 and have never suffered of an audiophilic wandering eye about them... But with the addition of the Cardas loom, these amps have achieved peaks of musical beauty that even I did not believe possible.


I am working on a detailed review of the Cardas loom in the context of my system.... I am still gathering some technical information.... I'll post the full review to Audiogon as soon as it is ready.


Saluti, Guido







 

   




  

  

@chazzy007 I share your dampened enthusiasm concerning whitecamaross' methodology on short term amp listening and then resulting public proclamations. Like Guido, @guidocorona, I own the M925s. I have been running them for about a year with the Rowland Corus/Aeris/PSU combo. I use Cardas CB XL PCs for the M925s. Otherwise, I have a full Cardas CB loom. I share Guido's enthusiasm for these amplifiers. I'm confident that they need the 1500 hours of break-in Guido recommends. I went on this wild ride personally--the first 24-48 hours were really good, then the M925s got brittle--so much so I PM'd Guido and had him give me encouragement. And the ups and downs lasted a long time--but every time they seemed to plateau, then go down then sidesways, then reach a higher dimensional plateau. This continued for about 6 weeks. I'm surprised whitecamaross did not have this experience--it seems to be fairly common. Anyway, Guido's descriptions of break-in are, frankly, spot on. He truly knows and describes Jeff Rowland gear very accurately. I can't help you with meaningful comparisons between side by side M925s and other amps. But some listening history may help you. I have owned the JR Continuum S2 (which whitecamaross would love apparently since he is currently doing integrateds now). I have heard the JR 625S2 on multiple occasions. I have also heard the Daemon Integrated twice at AXPONA last year and this year. And I have heard other M925s besides mine at a dealer recently driving Magico speakers. I can easily state that IMO the M925s perform at a level worthy of being Jeff Rowland's flagship. Admittedly, I really like the JR sound--if it indeed has one--some have said it is the absence of having a "sound" that makes the current products special. The recent models I have heard all provide excellent SQ. But, nothing else in the JR amp line-up I have heard is as effortless as the M925s in providing power with headroom aplenty and a deep black background. Very, very quiet. And very very cool--it is hard to believe that these big audio blocks are always cool to the touch, even when driving highly dynamic music. Simply put, unless you absolutely need 500W or more at 8 ohms into your speakers, I doubt you are going to find amps that will exceed what M925s can offer. IMO this includes the currently hot Swiss and German makers. I'm not criticizing them. I'm saying the JR M925s are on par--or better.
Regards
Al 
@guidocorona 

Thank you for the response. 
I follow and post on WCSS's thread,  but he had his 925's less than 3 weeks before he sold them. His descriptions and comparisons were fairly brief. 

Hello Chazzzy, the most notable discussion of M925 on Audiogon is by WhiteCamaroSS, Audiogon's very own amp marathon-man... He  considers the Rowland M925 monoblocks the best amps he has ever had in his own system. He has chronicled his enthusiastic comparative experience with M925 on his thread, starting at:

 

https://forum.audiogon.com/discussions/my-long-list-of-amplifiers-and-my-personal-review-of-each?pag...

 

Look at his posts mentioning M925 on the page above, and the following pages, starting on 04/30/2018.

 

Outside Audiogon, Marc Mickelson has posted an extremely favorable review of M925's stereo sybling, the M825:

 

http://www.theaudiobeat.com/equipment/jeff_rowland_model_825.htm

 

Note that M925 and M825 share the same design... Only difference is that M825 has two output stage converters to serve in stereo mode, and a single 2500W DC power supply that feeds both channels.

 

As for myself, I am ever more in awe with my M925 monos, which I have owned since 2013. Lately I decided to feed them through the new Cardas Clear Beyond XL power cords, with Cardas Reflection XLR ICS and speaker wires, and Clear coax to complete the cabling loom.... The result is even more jaw-droppingly resolving and musically immersive than the high performance level I was used to until now.


I'll be happy to chat with you about M925 if you send me a PM.... Or post your questions about the monos to this thread.



 

Regards, Guido

 

 

  

Such a great thread.
Thanks @guidocorona 

Is there an in depth review of yours and maybe a comparison to some other amps somewhere in these forums???
Hello Guido, I am writing from montréal (quebecois, french canadian). I read your discussion about the 925. I just bought a pair, last month (demo). So I have the 925, the corus and the psu. My speakers are DAYTON WRIGHT XG8. My reader is the ayon cd2. I absolutely want to go to streaming. Here are my options: I listened to a reseller, the ESOTERIC N-01 (integrated dac with the streamer). I liked but the listening was done with an amp and preamp ESOTERIC. My other option: the dac AERIS plugged into my PSU (very laudatory criticism on hi-fi advice) with the aurender W20. (I do not need the cd storage). I only want streaming. What do you recommend to me? On the one hand I am told that only one machine is preferable. On the other hand I am told that in 2 pieces, it is easier to change either the streamer or the dac. Entrez votre texte ... 
N.B. Jeff Rowland's reseller in canada tells me that the aeris and the w20 is the best choice, even if he also sells Esoteric.
Thank you very Much.  I'll apperciate you experience with JR.
It's ashamed. The amp blew again after 10days. When it arrived, I have it switched it on for 9 days even without playing and it was alright and did fine. The sound was promising as times but some times it went into a mood swing. This I presumed is normal as it needed to run in as Guido has described. But even then, I was enjoying playing symphony pieces thru the vinyl like Handel's Watermusick. It plays the symphony music very well. Handles the crescendos superbly and piano notes and violin sounded so real and natural. Yes the highs, the crispness and the abilities to separate percussion highs from electric guitars, etc, essentially able to create a sense of space between instruments were fantastic. Soundstage, though already better than my 625, is still evolving. In fact in all aspects, the sound is still evolving. Only one area that the 825 has not yet come to match the 625, is the female vocal. Linda Ronstald tracks in the album, Simple Dreams has not sounded as sweet and warm compared to 625 but then it's jusr 30 hours of playing. The 825 plays bass excellently and has a tight grip on the woofers of my sonus Faber amati Anniversario. It fully controls and plays the Amati to the fullest never once I suspect it doesn't have the power and grip. This I realized when playing Carl Orff's Carmina Burama Paul Hindernith: Symphonic Metamorphosis, Robert Shaw The Atlanta Symphony Orchestra and Chorus. For all I knew over the short time I had with the amp, I was confident that the amp will show up its best (no doubt) later when fully burnt in. On the tenth 10, I switched it off in the morning and on the evening I switched in on and played for an hour or so before I switched it off to switch the gain from 32db to 27db. After selecting the gain, I switched on the amp again and heard that eerie, "clung" sound again inside the amp. I knew it.

I called my dealer immediately and they got a reply from Jeff that it would be replaced as soon as possible ..... With a 725 without topping up. The 725 now cost USD800 more than and the 825 now. Yes, I reckon I am fated with class A/B and had no luck with 825. Will upgrade to 925 in future. No worries.
Hi Bernard, glad that your M825 replacement has arrived.... Its sound will keep evolving for a couple of months. You can play 24/7 as the unit generates very moderate heat. When you are not listening to music, you can feed it interstation white noise from an FM tuner.

Expect that, particularly during the first few hundred hours, you might experience a few sonic ups and downs.... This is normal.... But overall, the performance curve will point very much upwards.

Do keep us posted,

Guido
Finally the replacement of my 825 arrived. Was told by the local agent that Jeff made some modification to prevent the capacitor from giving way in the future. It was sheer joy just looking at the 825. It's beauty second to none. After about 4 hours of listening, I can't say much about it. Only that it sounds bigger and larger than my previous 625. Vocal now sounds more prominent and the tonality sounds sweeter. Overall it still doesn't sound warm and bloom as my well run in 625. Btw, just got the Aeris. Sounds excellent. Never mind about it can't play DSD files or upsample PCM more than 192khz. It just play more of my CDs musically. It's holographic, detail without sounding clinical but organically pleasing.
Im using a Rowland 8T which i love i once had granite you will get much better sound using Symposium Ultra Steath amp stands just my thoughts.
Hi Bernard, I spoke to Lucien at Rowland this morning... Your dealer is in close contact with the factory... They are working together to solve your issue ASAP.

Concerning your other questions...

The audible performance of a brand new M825 is not faintly close to what the amp will be doing once it has completed break-in of 1200 to 1500 hours... I fully expect that a brand new M825 would not sound as sweet as a well broken in M625.... But before long, will leave the lovely M625 in the proverbial musical dust. As you can read in my M925 break-in log in this thread... Patience is golden.

Switch mode power supplies (SMPS) range from 25 cents parts for charging cheap phones to sophisticated and highly reliable units developed for aerospace and mission-critical applications... Rowland uses these highly reliable and expensive SMPS in its amps... Fact is that Rowland has been using exclusively high grade SMPS for the last 15 years because of their superior sonic performance and high reliability, and failures in Rowland SMPS are extremely rare.

Guido
Found out that a condenser (capacitor) swelled and that it also emits a smell when the cover was opened on the main unit (not the power supply). The power supply unit was alright.
Hi Guidoo

I was so excited to receive the 825 last Thursday. Setting up took quite awhile as a large effort was made to put this monster into the Finite Elemente Pagode Aps rack as the space just only fit the monster. After playing for 2 hours I realized the potential of what it can do to my sonus faber Amati Anniversario. It presents a bigger soundstage better imaging and detail except that its raw and lack the finesse as compared to my previous 625. The bass was already better than 625. This is without doubt as the 825 packs with much more power. However, the next day when I switched the amp on again, i heard a loud crank sound inside the chassis and thereafter there was no sound coming out from the speaker. Yes no signal. Following day, the dealer took it back promising to replace a new one. This happening prompted me to learn more about class d amp. I saw this website below and read it had to say. I m particular concern that it said that the switch mode power supply is so complex that if it stay on operating pass 7 years, then you are lucky. More often than not it wouldn't survive pass the 7 year mark. What it is trying to say is that the reliability is limited in a switch mode power supply and that it virtually can't be repaired AT ALL. What's your take on this?

http://education.lenardaudio.com/en/12_amps_6.html
Sorry Bernard, the generalized class X versus class Y discussion is meaningless... In practice, no class is inherently superior to any other class... There are amps ranging from superb down to mediocre in every class... The only thing which matters is the individual design, and how its sound is in synergy with your particular taste in sound and in music.

The only SS brand in a similar price level as M825 and M925 that peaked my interest at RMAF 2013 was Solution.

Guido
Thanks Guido. Btw, how is the sound of this Jeff reference compare to class A classics like Gryphon Antileon and the newer Gryphon Memphisto. I heard the Vitus and I am not for it. So are the Plinius which are also Class A design but does not sound as musical as the Jeff class AB design of M625. If there is any amp out there that can give Jeff's newest design a challenge, it must be the Gryphon as these are truly class A. If so, then one could say, class A design still rules the pantheon. If not, then Class D has finally arrive at the pantheon to replace Class A.
Hi Bernard, here are the reasons why the cooling blocks of M825 and M925 look the way they do....

* The semi-enclosed Venturi chimneys of these cooling units are more efficient than traditional blade designs in accellerating upwards air-flow and dissipating heat.

* The Venturi chimney design was first introduced in the M10 and M12 amps, and then re-introduced and finalized in the M625, with the prismatic faceplate first introduced in mid-production M312. Since M625, higher end Rowland amps have maintained the same consistent design.

* M825 generates more heat than you might imagine... Only NCore modules in M825 operate in class D, and by themselves generate more heat than old ICEpower modules used in old M3xx series... And there are two NCore modules inside M825. The rest of the circuit does generate larger amounts of heat than the power conversion modules, particularly in the power supply unit, where the SMPS and the PFC unit are quite massive... My music loft reacheas a normal temperature of 86F under air conditioning during summer months: in this season, the Venturi chimneys are a real blessing, because the unit becomes uniformly toasty to the touch... The uniform heat distribution ensures that internal components do not overheat, and so long term reliability is maximized.

* Of course, the total designs does contribute to pride of ownership... Doesn't it *grins!*

G
Hi Guido, did you ever wonder why, the heat dissipators or sinks of current amps are so huge? The size of the dissipators take almost half the width of the amp unlike the old amps like models 8 and 9 where the the dissipators are relatively smaller than the overall width of the amps. The fact that the m825 and m925 emit lesser heat because their output stage is Class D, they actually do not require dissipators as large as m625 or m725 in terms of the ration of the width of heat dissipators over the overall width. The reason I am asking this is was it because they want them to look beefy rather than functional?

Bernard
Guido, you are simply the best. I am placing the order for that beefy 825. Will update about the sound some time later. Dealer here in Singapore told me, Jeff is struggling to meet demands as he personnaly checks every piece that goes out the factory. Waiting time could be awhile.
Excellent questions Bernard, let me try to address them…

• You are correct about the inherent sonic/musical limitations of old amplifiers based on the past generation of ICEpower modules. Without a lot of work from the amp designers, ICEpower ASP series modules invariably yielded sterility.
• NCore NC1200, and a few other new generation modules, are completely different creatures. In my own experience, even simple NCore NC1200 implementations, such as the Merrill Veritas that I have reviewed for PFO at
http://positive-feedback.com/Issue68/merrill_audio.htm
exhibit a degree of musicality and control of intermodulation distortion which is rare in amplifiers of any technology.
• I have listened to M825 at some length at RMAF 2014 over three days. I used my standard test CD that I have been using for all auditions during the last 7 or so years… Grand piano; string sextet with double bass; Diana Krall with her band; Symphonic; vocal ensamble + sax in a cathedral, Anne Sophie Mutter on violin with orchestra…. There was no audible trace of any harshness in the treble, which would have been the tell-tale sign of intermodulation sidebands. Neither multipart treble sostenutos of high strings, woodwinds, high brass, or fff transients showed any sign of ever breaking apart…. There was never any hardness nor shrillness, just exposed harmonic complexity.
• Compared to M925, I could not detect any M825 degradation of staging and images, which would have been the sign of cross-talk leaks.
• You are correct… If your Amati speakers are not bi-wirable, part of the benefit of adding a second M825 unit might be lessened.
• I have owned M625, M725, and M925… I comfortably prefer M925 over M725 for every conceivable audible parameter. Conversely, I found M725 to be somewhat closer to M625, although I still prefer M725 over M625.
• The difference in frequency response between M725 and M825/M925 has no bearing on any audible parameters of music reproduction…. The sonic/musical advantage goes to M825/M925 by a significant amount.
• Traditionally, amplifiers with very high damping factor have shown a propensity of generating hard cardboardy bass…. Not so NCore based amps… The bass resolution of M825 and 925 is controlled in the sense that it has no wooliness or pillowing, but it is deep, correctly fast, and filled with harmonics starting at the fundamental…. Do not be concerned about M825’s high damping factor.
• Class D designs do continue to evolve, and so do other class of operation…. However, while class A and A/B designs, with some exceptions, seem to be evolving relatively slowly, The underlying technology in some class D amplifiers have recently performed a quantum leap in inherent musical performance… Of course, to experience the absolute magic they are capable of, one needs to have the patience to go through a lengthy break-in process, as I have outlined earlier on this thread.

Bottomline.... M825 and M925 are phenomenal amps in the absolute sense... , Hope this helps... Let me know if you have more questions,
Guido
Morning Guido

The frequency response of the 825 is 5hz - 50kHz compared to the 725 which has significantly higher range (5Hz-350kHz). What this means to the music playback? Is 50kHz sufficient? If not the 725 may be a better pick.

The damping factor for the 625 comparing to most other class a/ab amps is relatively high except comparing with class d amps which have very high damping factor. Was told that a higher damping factor would be good to tone down speakers that are too bassy. But how much do u need actually. Maybe 200 is more than enough. Arc tube amps have damping factor less than 50! I noticed that Jeff does not specify the slew rate of his current models exept in the past. Don't know why as slew rate is an indication of fastness.

I m also concerned that class d technology for audiophile amplifiers is at its evolution stage while class a/ab amps are now at the peak and plateau. That means one could say that there will be better class d amps to come, whereas the 625 is already at its best in its class. Its difficult to accept that a class d amp in its evolution stage is already better than the class ab amp in its plateau stage of development.

I want to believe that 825 is a better choice than 725 but I m still struggling to leave the old school of thought that a/ab is the safer choice as the development is at its mature state,

Hope you can sway me more to accept 825. Please. 😄. Thanks

Bernard
Thanks Guido for your enlightening advise. Some years back, before I purchased the m625, I was using the M8 which was excellent until the point I found M625. I auditioned the Ice powered amps I din enjoyed it as the presentation was too clean and lacked the musicality. Just like CD and LP, the latter sounds more musical. Assuming the Ncore is superior over the traditional A/B output, the stereo block M825 has crosstalk and inter modulation distortion because both channels are sharing the same DC supply and in the same chasis unlike in a monoblock. Don't know whether the SMPS powers supply would have crosstalk distortion. Amati speakers have only one level of input and I presumed biamping is not possible. The M825 certainly looks more juicy and beefy and sophisticated looking from the rear end and my visual perception intuition tells me that M825 is the way to go however, my past experience of class d Jeff amps including the feedback from users of class d amps in the various forums and the crosstalk thing affects me in making a decision as to which is the right and better amp. Am I right to say that I won't be getting so much of a difference if I upgrade from m625 to m725 rather than to M825?
Excellent choice Krell888... While M725 remains an exceedingly fine monoblock amplifier, I found M825 to outperform it.... More revealing than M725, and more musical at the same time.... And I fully expect a single M825 to deliver a larger stage and more authority than an M725 monoblock pair... M725 delivers 330W/8 with a 1200W DC power supply on each chassis... The M825 stereo delivers 400W/8 and 750W/4, and shares a 2500W DC supply for the two
channels.

There is also a direct growth path in M825 without loosing your investment... You will be able to add a second M825 chassis at a later time for even greater authority... A toggle switch in the back of M825 ties the left and right channels... This means that the two NCore NC1200 modules, would be processing the same input signal... You would connect one M825 output channel to the lower binding posts of an Amati Anniversario, and the other output channel to the upper binding posts of the same speaker. You would then connect the second M825 the same way to the other speaker.

Best, Guido
I am planning to upgrade my 625. Considering 725 but after reading about 925 from Guido, I am considering 825. I am using it to drive sonus faber Amati Anniversario
All, besides waiting for Aeris, my next crucial step, which might take up to one year to finalize, will be to equip the system with a loom of wires, and possibly power management products, that maximize synergy with my speakers and Rowland electronics... and meet my goldilockian preference for evenly textured musicality and broad frequency coverage.

Based on my RMAF 2013 visit, and on prior experiments, I have narrowed my short list down to three fantastic product lines, which all bear further examination, listed below in totally random order...

* Nordost Valhalla 2 -- What a stunning surprise... In olden days I sometimes felt that the original Valhallas were a smidgin to slender and trebly inclined... But the new series that I auditioned in Blanca Peak is magnificently harmonically texttured, and is an incredible imager/stager, while maintaining the broad frequency extension
that the Nordost Valhalla line is well known for.

* Cardas Clear and Clear Beyond -- performed magnificently musical and resolving in all Rowland-based system that I heard at the show;

* Shunyata Z-Tron Anaconda and Pythons -- A long time love that is still going strong... I experienced their synergy with Rowland and Die Muzik in my own
system a couple of years ago.. No reason to believe that I would love Shunyata products any less today.

I am positive that any of the three series above would make for heavenly system-wide looms in their own special way... If you have experienced any of these products, do let me know your observations, comparative or not as they may be.

Saluti, Guido
All, here are my assorted Rowland-related ramblings from RMAF 2013….

M925 was on static display in room 2000. Conversely, M825 was making music in two suites. In room 8032, M825 + Aeris + Capri S2 were driving a pair of Joseph Audio speakers… The system was connected by a complete loom of Cardas Clear / Clear Beyond wires, ranging from PCs to speaker wires… The total result was enchanting: I visited repeatedly to listen to more music. As the equipment had time to settle, the musicality became more and more “organic” for lack of a better word.

In 1122, M825 drove a pair of Lawrence Audio speakers… Apparently, the speakers were fresh off the Lawrence factory floor and showed it…. On Friday afternoon, total synergy was still less than perfect, as the unbroken-in speakers were generating a fair amount of artifacts in the treble region. By the end of the show, I was told that the sound was a lot more organic, but I had to leave by 4:00 PM on Sunday, so I did not have the time to visit the suite for a second listen.

In room 2001, Rowland showcased the brand new Continuum S2. Fed by the Aeris DAC, the new integrated drove a pair of Raidho D1 monitors. Initially the D1s were not perfectly setup, and so showed their propensity of overwhelming room acoustics with midbass… By Saturday afternoon, the positioning of the speakers had been optimized and the result was quite delicious for its musical purity and clean authority. If Continuum S2 had been hidden away from sight, no one could have guessed that D1s were driven by a integrated targeting the market under $10K.

While the chassis of S2 is virtually undistinguishable from its Continuum 250 and 500 predecessors, except for the display, S2’s finely textured sound is miles above from what I remember possible with the performance of the original models. Interestingly, Continuum S2 could be further enhanced by the PC-1 PFC-based rectifier… However, No PC-1 was being used… Hope to hear an A/B comparison at some future time.

I was totally delighted by the Nordost suite in Blanca Peak: Expansive, rich, and emotionally involving was the sound, and enveloping was the music… The room featured a complete loom of new Valhalla 2 wires, with a complement of Titanium and Bronze Sort Kones supporting Rowland electronics, while twin quartets of brand new Bronze/Aluminum adjustable Sort footers coupled Audio Physics Virgo 2(?) speakers to the floor… . After three long visits, Nordost V2 wires and Sort Kones are in my very short list of highly desirable and musically goldilockian reference candidates to connect and support my system.

The Sort footers are designed specifically for enhancing heavy speakers, and not to support electronics. Under the Audio Physics, they were clear contributors to the overall magic of the Nordost room. Admittedly, I would love to gage the effectiveness of these footers under my own speakers… Unfortunately, the positioning of the Vienna Die muzik with their swivel-heads is a total bear to optimize, thus replacing the Muzik’s factory footers with the worthy Nordost Sorts would force a new detailed round of split-raking optimization… Not something that I would relish doing without professional assistance. Hmm… Now that I think about it, I just got a wild idea… Experimenting with a double trio of hefty Sort Footers under my 160Lbs M925s may be an intriguing proposition if it were only feasible… Mumbledee mumbledee..

Saluti, Guido
Hi Guido,

Glad to know that Mr Rowland breaks into the new frontier with Class D top gears. Also looking forward to your sharing with M825 as well.

Cheers, Fred.
Fredmiu and all, apologies for my oblique posts last week.... A couple of days ago, JRDG has finally posted a partial list of M925 and M825 technical features and specifications... Bottomline is that yes, you are correct. In the output phase of these amps there is a circuit running in class D... based on the fabulous Ncore NC1200 technology to be more specific.

http://jeffrowlandgroup.com/kb/categories.php?categoryid=212
http://jeffrowlandgroup.com/kb/categories.php?categoryid=213

Note that The amps do not utilize the small companion Ncore SMPS made by Hypex... Power management is designed by Rowland specifically for these amps... a PFC rectifier feeds high voltage DC into a large 2500W SMPs... Seems that the resulting low voltage DC is then cleaned up further by 4-pole capacitors. Signal imputs are transformer-coupled with large Lundahl transformers... There is a little bit more info on the links above, but not quite as much, or as clear as I would like to see.

I will try to gather more details from Jeff, Lucien, and Brandon while I am at RMAF.

Saluti, Guido
All, I have received the list of RMAF suites where we will be able to listen to Rowland amps coming Friday through Sunday:

The M825 stereo amp, Aeris DAC, and the Capri Series 2 preamp will be playing in suite 8032 with Joseph Audio speakers and Cardas Clear wires.

M825 and Aeris will also be heard with Lawrence Audio in Tower Room 1122.

The Continuum S2 integrated will be making music in public for the first time in Tower 2001 (the Rowland suite), together with Aeris… If I remember things correctly, they may be using Cardas Clear and Clear Beyond wires, and Raidho speakers.

Other Rowland products will be mostly on static display in room 2000 and 2001: including M925 monos, M725 monos, M625 stereo, M525 bridgeable, Corus linestage, and Capri S2 pre.

Saluti, Guido
Yes PSAG, you are correct... I compared M201 and M501 in the same systems a couple of times... M501 have a sonic signature very similar to M201.... With more grunt, dynamics, stage/imaging size, but no greater microdynamics, harmonic content or treble detail. M3xx series are different creatures instead... But if you feed M201 through a PC-1 PFC rectifier box, you should obtain a good portion of the audible refinements of the M312.

G.
Hi Guido, I had them driving a benign load (Vandersteen 5a) in a smallish room. At 250 wpc, they certainly had ample power to drive the Vandersteens to extinction if need be. I was never aware of them clipping or running out of steam. The consensus is that the 501's sound identical with a benign load. Also, its safe to say that Jeff Rowland would never put out a product if he didn't believe in it. But I have no doubt your amps are the more evolved and refined product.
Hi Psag, I appreciate your misgivings. I heard M201 monos a few times... Driving Maggie 1.6, Maggie 3.6, Vienna Mahler, Vienna Beethoven Grands... In all cases, M201s ran out of steam at the first indication of dynamic excitement... When they did not run out of steam, the sound was clean, sweet, and transparent, but not highly emotionally involving.

M201 were not representing the state of the art in class D amplification at the time of their release. They were based on mid-power ICEpower 500ASP modules, and were implemented as an entry level product. They had neither the power to drive demanding speakers like M501s, nor the power supply / PFC refinements of all the old M3xx series.

By extension, they are not indicative of the behavior of any current products, from M525 upwards.

G
Fred, the problem with 3XX series is that it covers two generations of amps.... Results differed greatly, depending on model and internal revision...

* I found the original M302 stereo to be sweet sounding, but lacked ultimate emotionality and dynamics.

* M312 stereo was an almost complete internal redesign... And the difference was telling... Much denser harmonic content, finer macro/micro dynamics.... Result: very involving/emotional to my ears.

M301 monos... Really this was two amp models instead of one.... The first series -- I believe up to serial number 68 or so, was based on internals similar to M302, and showed the same shortcomings. Subsequent serial numbers were based on M312 design, and shared many of M312 sonic attributes... I still preferred M312 though.

Having said this, M725 greatly surpasses M312 and late M301s... While M925 is simply in a totally different league for all audible parameters. I have not heard M825 yet... But my understanding is that it might sound extremely similar to M925, but has half the power supply capacity. I will hear M825 at RMAF next week.
Hi Guido

Many thanks for your comments.

I think I should have more serious listening of 825/925 in the showroom coming months - probably a gift for the New Year.

Cheers, Fred
Hi Fredmiu, while I loved the M725 monos, the performance of M925 is simply of a totally different caliber. M925 combines a an immersive transparency in its harmonic density, an authority that seems to have a natural right to its existance, rather than forcing itself on the user. Yes, M925 has loads more authority, transparency, and detail than M725.... But not in a sterile manner that means detail for sake of audible acrobatics... It is a presentation that gives you much deeper insight into the music: both from the point of view of the music composition/song, and of the depth of the performance/interpretation.

This is a very long topic... PM me if you would like to chat offline.

Guido
"Even if you have to have "the best", i would hope that sound and reliability would be the primary criteria to determine the choices made."

Thank you French_fries for pointing this out. Yes, I choose my gear based on my own subjective perception of extremely high musical/sonic performance, as well as of manufacturer's track record of high reliability. As you know, I am blind. As such, esthetics is for me of secondary relevance only, and not a purchasing criterion per se... It remains however, a charming bonus not to be despised or otherwise shunned out of facile masculine pride.

Bottomline, I judge the tree by its fruits, not by its roots... But I think you heard this paraphrase of Stravinsky's Poetics of Music from me before.

G.
My understanding Class D operation refer to the output stage, aiming at delivering power and dynamics, ability to deal with speedy and transient responses.

Frankly I was not too impressed with the previous 3xx models in class D. Yet the 925 sounds real sexy in the showroom with its ability to drive demanding speaker systems.
Guido, I have no doubt that its a wonderful-sounding amp. My first high end amp was one of Rowland's Class D offerings. Ultimately I felt the need to let it go, as it lacked the ability to convey (for me) real musical excitement. It took me a long time to realize that something was missing. Since then, I've occasionally read comparable things about other Rowland amps from a few of the more discerning reviewers. At this exalted level, I think it comes down to personal preferences.
The 825/925's are Class D? And they sound gorgeous? Sacrebleu!
Ahh, the progress of technology. Hurray for that.