Rowland M925 monoblock amplifiers -- Break-in Notes

[GuidoCorona]

Hi Mrdean, I selected Criterion as my reference linestage a few years ago when M312 was my Reference amp: I did prefer Criterion over Rowland Capri, which I prefered over ARC Ref 3...

But I still own Ref 3, so it will be fun to test my original opinions with M925 in the system... Once the amps have stabilized, which may take 2 or 3 months.

Aeris+Criterion is definitely in my mind as an intriguing thought for some future.

Saluti, Guido

 

[Mrdean]

Guido, that Aeris is another OMG listening session! Really something special.

 

[GuidoCorona]

Mrdean and all, has anyone tried to apply an external power conditioner on M925? Which brand and models? What results positive/negative were observed?

Guido

 

[Mrdean]

Mrdean and all, has anyone tried to apply an external power conditioner on M925? Which brand and models? What results positive/negative were observed?

Guido

I doubt there is much to be gained. The SMPS is Power Factor Corrected. My friend has dedicated 30 amp 240V lines for each amp.

 

[GuidoCorona]

Hi MRDean, I have experienced that different Rowland products featuring a PFC rectifier behave differently with some power conditioners. For example, with 120V operations, on either a 15A shared line or a 20A dedicated line, Criterion seems to be insensitive to external conditioners and power cords. Conversely, the M312 amp under the same conditions has responded positively from the application of a Shunyata Triton, and its sound seems affected in various ways by different PCs.

Hence my open ended question about M925. Note that I do not have a Triton available to me at this moment.

Guido

 

[XV-1]

Where are the photos?

 

[GuidoCorona]

Good point Turntable, Wizard has posted a few pics of M925 on related threads...

http://www.whatsbestforum.com/attachment.php?attachmentid=7520&d=1357718109

M925 with Avalon Isis at Kaohsiung show, Taiwan:
http://www.whatsbestforum.com/attachment.php?attachmentid=8834&d=1363546366

http://www.whatsbestforum.com/attachment.php?attachmentid=8835&d=1363546396

Back view:
http://www.whatsbestforum.com/attachment.php?attachmentid=8836&d=1363546426

I will try to source more pics... I am a blind audiophile... I may have some delusions of inner "vision", but definitely have no sight to operate a camera. took my last pics with my beloved Nikon 30 years ago.

Saluti, G.

 

[Mrdean]

Hi MRDean, I have experienced that different Rowland products featuring a PFC rectifier behave differently with some power conditioners. For example, with 120V operations, on either a 15A shared line or a 20A dedicated line, Criterion seems to be insensitive to external conditioners and power cords. Conversely, the M312 amp under the same conditions has responded positively from the application of a Shunyata Triton, and its sound seems affected in various ways by different PCs.

Hence my open ended question about M925. Note that I do not have a Triton available to me at this moment.

Guido

Guido, I doubt this pair of 925s will ever see a PC, so your experiences will be appreciated by the rest of us.

 

[GuidoCorona]

Hi MrDean, what power cords, speaker wires (single/bi wired?), and ICs is your friend applying to M925?

What is the rest of his system?

Guido

 

[Mrdean]

Bi wire Cardas Clear/Clear beyond for speaker cables. Balanced Cardas Clear for IC, and Clear beyond power cords with some 240V, 30 amp AC connectors.

 

[GuidoCorona]

Thank you MRDean, Cardas Clear and Cardas Clear Beyond seems also to be the wires that Jeff Rowland is currently using in his demo system.

Is your friend also supporting M925 on the Nordost Sort Kones (Titanium) that Jeff and I use under them?

Saluti, G.
Guido

 

[Mrdean]

Thank you MRDean, Cardas Clear and Cardas Clear Beyond seems also to be the wires that Jeff Rowland is currently using in his demo system.

Is your friend also supporting M925 on the Nordost Sort Kones (Titanium) that Jeff and I use under them?

Saluti, G.
Guido

So far, just the original Delrin balls. I have had some thoughts on alternatives.

 

[GuidoCorona]

Please keep us posted on your explorations of alternatives to the factory-supplied delrin balls.

G. G.

 

[samgar]

Hello Guido:

I presently own a pair of the Rowland 725 Monoblocks and would love to hear your oppinion on the difference in sound between the 725 and the new 925 monoblcks. I am wondering if it is worth the much higher price for the up-grade.

Thanks and looking forward to your reply.

Sam

 

[audio.bill]

I'm a very happy owner of a Rowland 625 amp, and I'm afraid to find out how much better the 725 and 925 are!

 

[GuidoCorona]

Hi Sam and Bill,

Concerning M625 and M725... The two devices show much more than a vague family resemblance. The most obvious difference is the sheer ability of M725 to drive my Vienna Muzik speakers with an authority and ease that I found to be extremely satisfying, and that by the way edges out that of the nominally more powerful 500W M312 stereo amp. Conversely, M625 may be more at home with slightly smaller speakers, like the Vienna Kiss that Roy Gregory has used in his review of the amp. Both M625 and M725 easily exceed the harmonic density and subtlety of my beloved old M312. But, as the M725 monos use ceramic boards and a few other technical solutions that have not been applied to M625 (4-pole capacitors?), they seem to be even more nuance and transparent than the already excellent M625 stereo.

as I already mentioned, the M925 are extremely promising this far, but with only 97 ours of full power operations, and about 35 hours on additional break-in of input transformers while on standby, they are apparently far from giving their best performance. Yet, factoring in some of the usual break-in anomalies, M925 yield a vast stage, solidity of image and profound authority that is new to my system.... They seem to be an ideal synthesis of all that limitless silky power that I remember being so fond on the old classic Rowlands like the Model 7 monoblocks, which I owned for over 10 years, combined with a new and very special musical resolution, purity, and total effortlessness that I simply never heard before.

Can M925 justify the price difference with M725: well, that is really a subjective thing, but.... This far, I suspect that they might.

PM me if you like to chat directly.

Guido

 

[GuidoCorona]

I have not posted listening impressions in a few days, so here are some updates:…

Approximately 100 hours of operations, and an additional 45 hours on standby with the linestage feeding FM hash from the tuner into the M925's input transformers… The rather jarring steeliness in the resonance notes that I earlier reported on the young soprano Tania D’Althann in Monteverdi’s Exulta Filia Sion (Girlande Sacre, Ghirlande Profane Arts Music redbook) has been reabsorbed by about 75%... She does sound significantly more natural than a few days ago. The other side of the coin is that minor blemishes in her intonation, breathing, and rythmic technique, which I had not noticed with my previous amps, are gradually coming to light because of M925's low level resolution.

At 150 hours of operation plus 50 hours on low level standby – The undue ringing (I cannot call it steeliness any longer) is barely detectable on a couple of notes only…. E.g. The closing note of the motet…. Images are continuing the fleshing-out process, and traces of acoustics from the recording venue (a small Church in Venice( is starting to emerge. The portatif organ used for accompaniment is impressively crisp and deep…. The overall effect is starting to be musically immersive and “rather wonderful” (comment of my better half, who tends to be merciless when commenting about the sound of my system).

On an non auditory matter, the amps take 12 to 24 hours to stabilize thermically, and so become warm to the touch…. During hot evenings they feel rather toasty, if not as much as M725 or M625. Temperature seems completely uniform on each chassis... But power supply chassis are noticeably warmer than audio chassis.

Saluti, Guido

 

[AMP]

Hi Guido,

Glad to hear you finally got your 925s! I've been following your progress and it appears that you are going through many of the same phenomena that I did with mine. I'd definitely recommend not shutting them off as they do, indeed, take some time to stabilize. Based on my observations I'm fairly certain that the power supplies were actually heating the amp sections.

 

[GuidoCorona]

Hi Andrew, great hearing from you. I am sure that some heat radiates from the top of the PS chassis across the airgap into the audiochassis... On the other hand, when I was operating M925 in an unstacked setup, with the audio chassis resting on a solid wood surface, I was experiencing a similar heating in the audio chassis as I do now.

Like you did, I operate the amps 24/7... Or at least have them on standby and feed the input transformers with FM interstation hash from the tuner (per Jeff's recommendation)... Except when, like right now, there are thunderstorms going on or in the forecast... Would hate to "Quantum Tunnel" the little darlings to a state of industrial slag *grins!*

Given the climate of Austin, thunderstorms, and my somewhat underpowered air conditioning, I suspect break-in might protract until the late summer!

Saluti, Guido

 

[samgar]

Hello Guido:

It has been very quiet. Is there anyhting new to report as the 925's go through their break in. I am very currios to hear what you feel the 925 monos brings to the table compared to the 725 monoblocks. I would hope there would be some substantial improvements on sound quality for the 925 compared to the 725's.

Thanks for your input.

Sincerely,

Sam