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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
elliottyeh
3 posts
 
how is it compare to jeff rowland 9tihc battery verion with 925 ?
french_fries
815 posts
 
Interesting that Elliottyeh mentioned battery powered Rowland amps. I heard thru the dealer that the amps had no "guts" on battery power and therefore speakers with greater power demands were not a good match. so i am curious as to whether the M-9tihc (high-current) amps could even operate properly with battery power supplies.
So little has ever been written about the Model 9's, but they were
extremely exotic as well as expensive for their time- I also remember the ML-33's at 400 pounds/each. or the Krell Master Reference amps- 1000W each.
A steinway piano might have weighed a bit more, but not by much.
BUT I imagine with a refreshed
set of caps and other critical parts, the M-9's might still blow most of us away even in 2013. I am not saying the 925's are not everything Jeff wants to achieve at this point, but as in the case of the new Pass XS line as well as any other 4-box arrays, you are talking about a LOT of hardware to power your speakers.
perhaps when the Rowland 825 stereo amp (two-box) comes out that might
be a little more practical - and shares the same level of technology with the 925's. As to when you might see the 825 "on the shelf", that's another chapter yet to be written. Plus every extra "box" of 6061 aircraft aluminum adds a lot of money to the cost of the final product.
guidocorona OP
4,298 posts
 
All, I do not have direct experience with Model 9 variants, so my opinion is conjectural. Based on what seemes to be the sonic trend in Rowland amps since Model 7 through M825/M925, I suspect that Model 9 variants are somewhat warmer and midrange-centered than M925, with a little less resolution and clarity of staging/imaging. I further conjecture that they may be a little nmore prone to mid-treble distortions... But, as I said, this is somewhat conjectural.

Regarding M825, the device is now shipping, with a list price of $32K.
denon1
331 posts
 
Guido, do you know when Rowland will start shipping Continuum S2 integrated, how do you think it will differ from 500 model?
Thank you.
guidocorona OP
4,298 posts
 
Hi Denon1, I will call the factory next week and will ask about Continuum S2 status. meantime, on pure conjecture, based on the fact that Rowland has selected a new more advanced supplier of power conversion modules for Continuum S2 (Pascal), and that Rowland changes component parts only if warranted by more desirable audible performance or reliability, I suspect that the new S2 is likely to sound sweeter than C500.

CS2 also uses the circuit of the new Capri S2 as linestage (designed in partnership with Holm Acoustics), and is compatible with the new DAC card designed for Capri S2. Continuum S2 will also be compatible with the external PC-1 PFC-based rectifier.

Saluti, Guido
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