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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
french_fries
815 posts
 
Hi G., I just wanted to pipe in here with still another vote for my Mark Levinson #53 amplifiers which have not been well regarded due to certain factors that i won't expand upon here. this is simply to say that in reading through your increasing enjoyment of the 925's, i have come to similar emotional connections to many of my cd's. Just yesterday i listened to a female vocalist album that put me in a mental state of lying in a warm bath melting away, so sweet was her voice. I couldn't have faulted some nuance or detail in that state of bliss even if i had wanted to, but when the piece was over i was disappointed that it couldn't have contained (many) more tracks.
I am just glad the audiophile BS hasn't ruined my ability to get off like i used to do back when i listened to dorm room stereos.
guidocorona OP
4,298 posts
 
Hi FrenchFries, I am delighted that you are experiencing long term nirvanic persistancy... Very rare among us sufferers of Degenerative Audiophilic Chorea (DAC).

At my end, the entire lovely review loom of Aural Symphonics wires had to go back to the manufacturer... While I am pleasantly surprised about how well M925 are doing fed by simple stock power cords, I am looking for alternatives that will bring their performance to the next level... I will be scouting RMAF for likely candidates.

Guido
french_fries
815 posts
 
Hi Mr. G, the dealer never gave me any power cords with my amps (!) I know!
anyway, i obtained the best PS Audio power cord they make, along with some
very well made but inexpensive cords and (of course!) a PS audio wall outlet
(for good luck i guess...). long story short, the sound coming out of my speakers are in "balance" already. they don't "shout" at me or bite my ears off,
which is not always easy when you turn up the volume.
but the GOOD NEWS is that, even with a ton of detail being presented along with the music, the artistry comes shining through as well. I was afraid at one point i had "overdone it" with all the upgrading i have done. OR maybe some elements were still breaking in, as you have suggested. i am just really pleased it all worked out.
psag
518 posts
 
Jeff Rowland is certainly one of the top amplifier designers. His designs are stunning, exude quality, and demonstrate a favorable price to value ratio. Its nice to read a rave for a company that really deserves it, but without more of a frame of reference (Pass, Soulution, Gryphon, Dartzeel, Ayre, Boulder to name but a few possiblities), it might be misleading to other potential owners. The fact is, Rowland gear has a house sound that may or may not appeal. The Rowland sound is highly refined, but clearly there are some aspects of great sound that are better served elsewhere.
guidocorona OP
4,298 posts
 
Thank you Psag. My intent on this thread was not to "rave" nor to mislead, but to share my own experience with these amps in as much detail as possible throughout a break-in process that was replete with ups and downs. At the end of the process I do adore these devices... But I will never say that they are "the best", or that they are "better" than anything else... I am prepared only to tell you what they do for me... What is in my ears correct, and the reasons why.... And if I hear a flaw, you will read about that as well. Since the 1050 hours mark I have not heard obvious defects.

I have a lot of respect for some of the brands you mention, as well as some of the brands you have not mentioned, like ARC and VTL. AT RMAF I am looking forward to have my first listen to Solution, and hopefully to the Boulder 3000 series, and a few others.

If I have the opportunity of listening to M925 or M825 in the same context with other top shelf amps, and the exhibitor or owner manages to convince me that the amps are completely broken-in, I will talk about the differences that I perceive.

G.
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