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).
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
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
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.


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
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.
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
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