Rowland M925 monoblock amplifiers -- Break-in Notes

GuidoCorona

Well-Known Member
Apr 23, 2010
327
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Summerville (SC)
I just heard from the Rowland factory today: coming Friday, I will receive my pair (or should I call it my quartet?!) of M925 mono amps.... Needless to say, I am excited!

At 320 Lbs combined for the 4 creatures wearing their birthday suits (380 Lbs when boxed) my first challange will be to carry them upstairs to my music loft without mangling my back.

I will use Nordost Titanium Sort Kones instead of factory-provided footers... Each lower chassis has three divets caarved on its bottom plate, where footers are usually screwed in. Each amp will stand on top of 3 divet-centered Kones. these will sit on top of 1.5 inch thick granite slabs, which have been patiently waiting in place for the M925 amps since 2011.

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 speakers with bananas; the Cardas Golden Ref connects to the same posts with spades... I have already tested the configuration on the M725 monos... 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.

I suspect that the break-in 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
 
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Jazzhead

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Congratulations on your new acquisition , look forward to reading your adventures with the 925 as they unfold :) .... Good Luck !
 

DaveyF

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Jul 31, 2010
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La Jolla, Calif USA
Guido, I'm sure your new amps will sound amazing. Do post when you have them up and running. BTW, if you can get your hands on some Nordost cabling, you might try that....Nordost and Rowland amps work great together, IMO.
 

LL21

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Dec 26, 2010
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Big news! Congrats and look forward to reading your notes. Enjoy!
 

GuidoCorona

Well-Known Member
Apr 23, 2010
327
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Summerville (SC)
Thank you guys!

I just found out from Brandon at Rowland that each lower chassis has three divets caarved on its bottom plate, where footers are usually screwed in. In the Rowland factory showroom, Jeff leaves the amps without screwed-in footers. Instead, he uses the divets to sit the M925 amps on top of Nordost Sort Kones (Titanium). I will do the same... So each amp will sit on top of Titanium Sort Kones on top of granite slabs. Because of the divets, apparently the setup is mechanically quite stable.

Guido
 

rockitman

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Sep 20, 2011
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Nice to see another amp manufacturer that provides separate chassis for power supply and gain stage for each channel. I am sure they will sound spectacular.
 

Frank750

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Jul 8, 2011
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Nice to see another amp manufacturer that provides separate chassis for power supply and gain stage for each channel. I am sure they will sound spectacular.

Nice avatar Christian
 

GuidoCorona

Well-Known Member
Apr 23, 2010
327
38
413
Summerville (SC)
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

G.
 

GuidoCorona

Well-Known Member
Apr 23, 2010
327
38
413
Summerville (SC)
Exciting!!!!

The 4 boxes were delivered today. Thankfully the van driver carried them upstairs for me....

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 someone does not use 3rd party spikes/footers. A smaller baggie contains 4 small delrin beads... They will fit into the dimples milled into the top of the power supply chassis, and are used to keep top and lower chassy from touching when the two are stacked.

The two SMPS chassis are now in place, perched on top of 3 Nordost Titanium Sort Kones each, sitting on granite slabs.

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

Guido
 

Mrdean

Well-Known Member
Mar 13, 2013
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I installed a pair of these about a 2 months ago. I lifted and held the amplifier section above the power supply, and had my girlfriend help align it to the top of the supply below. It was actually pretty easy.
You are in for a real treat. While they are amazing out of the box, they are astounding after a month of continuous music!
 

GuidoCorona

Well-Known Member
Apr 23, 2010
327
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413
Summerville (SC)
Hi MrDean, yes your right, the stacking operation is simple enough... The audio chassis are just a little heavier than what I am comfortable lifting. The factory recommends this to be a two-person operation, hence the current delay.

How many hours of music making does your M925 pair have, and has the sound stabilized completely yet?

Saluti, Guido
 

Mrdean

Well-Known Member
Mar 13, 2013
48
2
313
Hi MrDean, yes your right, the stacking operation is simple enough... The audio chassis are just a little heavier than what I am comfortable lifting. The factory recommends this to be a two-person operation, hence the current delay.

How many hours of music making does your M925 pair have, and has the sound stabilized completely yet?

Saluti, Guido

These beauties are not mine; I was involved with the sale, set up etc. I was floored by how great they were out of the box, but with more time on them, they just get better and better. I have to get back and hear them, but I have missed the past 2 weeks of break-in. I think Jeff Rowland himself will be hearing this installation soon. I can't wait to hear what he says about it. Expect things to get better for the next 500 hours, at least.
 

GuidoCorona

Well-Known Member
Apr 23, 2010
327
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413
Summerville (SC)
This afternoon the M925s yielded "first sound". You were absolutely right MRDean, rather than just encouraging, the sound was a bit of an OMG experience.

I managed to connect M925 without breaking anything and without shorts...
I was expecting the usual shrieky time, but... M925 is so musically revealing after 30 minutes of playing that it is spooky... By the way, this has been the First time that my better half has made unbidden positive comments on a component right out of the box... Less than 10 minutes into playing time actually.

What’s astonishing is that, factoring in very minor early oddities, M925 already convey a grandness, poetry, and realism that I have never heard from my own system.

I fully expect for musical beauty and detail to wax and wain for quite a spell, but for the time being, the cadenza in the introduction to the Dvorak string sextet with double bass Op. 48, is almost free of artifacts, which is something I have not yet experienced with a brand new amp.

Likewise, my other test piece by Antonin Dvorak "In the Old Castle", played by Inna Poroscina on what is likely a Bosendorfer Imperial grand, is already showing signs of pedal and felt sounds, which is quite unusual on a brand new amp.

But perhaps the most encouraging sign is that I felt just like sinking into my couch and immerse myself into the music... Will this last? We will see as the break-in enfolds!

G.
 

Mrdean

Well-Known Member
Mar 13, 2013
48
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Guido, it sounds like you are having fun! I think one of the more intriguing qualities of these amps is the way they extend the sound field behind you. Even if it is a "created" space, the field wraps around your head. And it gets deeper over time. There is nothing about it that sounds "phasey", it just becomes a part of the music.
I look forward to reading about your experiences.
 

GuidoCorona

Well-Known Member
Apr 23, 2010
327
38
413
Summerville (SC)
You are absolutely right Mrdeam. Even at 20 hours, the stage has already a nice depth to it.... And resolution is intriguing. Yes, I am discovering some of my CDs anew.... And often in unusual ways. E.G. I have a set of Bach Well Tempered Klavier played on harpsichord... And I had never realized that there some cute errors in the performance... Not wrong notes per se, but errors in timing between the two hands, and some rhythmic imperfections. Until M925, such minutiae were blended into the background.

By the way, I had a little "excitement" today with M925: I had a friend over to help me with the chassis stacking operation... Yes, it is a breeze with two people. But when I powered up the right amp, the right speaker started to emit a bizarre multi-frequency burr, as if I had a mad cicada in rut inside the coaxial flat driver... And no music signal could be heard at all from that side... Disconnected and reconnected the whole amp to no avail.... Called up Jeff -- he was driving to the New Port Beach show with a pair of M525 amps in the car, and getting lost along the loopy highways system around Los Angeles) ... Jeff assured me that I must have done something wrong with my connections. True enough: I eventually discovered that the source selector switch was inadvertently flipped to RCA. Flipped the switch back to XLR balanced and reconnected... Both amps now purr like kittens.... of a supersized Maine Coon persuasion, that is *grins*

G.
 
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GuidoCorona

Well-Known Member
Apr 23, 2010
327
38
413
Summerville (SC)
With hour 21, the amps have decided it is high time to go into a bit of break-in funk. Image is more recessed and has lost some airiness. The voice of Mezzo-soprano D'Althan in Exulta Filia by Claudio Monteverdy has developed a bit of a steely burr on the sostenuti at end of phrases, where the incompetent recording engineer is fooling around with artificial reverb to enhance the echo of the recording venue.

Today I have inserted a tuner into the system, so to exercise the amps 24/7... Nighttime the amps will be served a diet of FM interstation hash.... Extremely healthy and highly decongesting!

G.
 
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DaveyF

Well-Known Member
Jul 31, 2010
6,129
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458
La Jolla, Calif USA
Guido, I presume you are using one of Jeff's preamps with your new 925's. You might want to try a tube preamp, as IMO Jeff's amps work magic with tube preamps. If you can get your hands on a CAT or a Lamm or a BAT REX or even an ARC Ref 5SE or another good tube preamp, I think you may hear what I am talking about.
 
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GuidoCorona

Well-Known Member
Apr 23, 2010
327
38
413
Summerville (SC)
Hi DaveyF, thank you for the suggestion. yes I am feeding M925 with my Rowland Criterion. But I do have also an ARC Ref 3 out of system. I will test the effect of Ref 3 on M925 once the amps are completely broken-in.
 

Mrdean

Well-Known Member
Mar 13, 2013
48
2
313
My experience has been that the Rowland Aeris, Corus and 925s create the absolute quietest background I have ever NOT heard in a system. And this is in a purpose-built sound room, underground. The best room I have ever heard, and by a wide margin. I will bet you end up sticking with the Criterion. I think the level of silence really enhances the low (and I mean LOW) level information.
 

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