Jeff Rowlands Amp and Dac vs. VAC amp and DAC

All, looks like I am a little late to this Rowland/VAC watering hole... Here are some clarifications about M625 S2 and Aeris DAC....

1. The M625 series operates in higher bias class A/B. It does not run in class D, as someone seems to hav suggested instead.

The current version of M625 is M625 S2. This model delivers 325W / 8 Ohms instead of the 300 of the original. Internally, it has several enhancements over the original and its sound considerably more refined. A while ago I received some details from the factory:

...

The 625 S2 improves upon the original 625 in a number of important areas.

We have taken the existing circuit topology and improved the important distortion specification at higher frequencies (above 2kHz) to a virtually unmeasureable level extending beyond 20 kHz .

This was accomplished with an innovative error correction technique previously unknown, or never implemented in the art of amplifier design.

The S2 incorporates a new custom designed input transformer and linear phase low pass filter for improved input signal buffering and EMI immunity.

Gold plated Cardas XLR input connectors with Rhodium contacts and teflon insulation provides a  visually distinguishing appearance from the original 625 and provides improved signal integrity.

The S2 amplifier incorporates ceramic Rogers circuit board material for reduced dielectric energy storage.

The S2 Power Factor Corrected regulated Power supply improves upon the original 625 by incorporating Jensen four-pole capacitors  which offers nearly an order of magnitude

 reduction of output impedance and noise suppression. The power supply output voltage has been increased slightly to yield a 25 watt increase in total amplifier power output.

...

I have received the M625 S2 manual complete with technical specs. Here is a link to it on my public DropBox.

https://dl.dropboxusercontent.com/u/53640097/JRDG_M625_S2_MANUAL_REVA1.pdf

And here is a link to the January 2016 review article on HiFi News:

https://dl.dropboxusercontent.com/u/53640097/HFN_Jeff%20Rowlad%20625%20S2_hires.pdf

All Rowland amps can be driven successfully from the Aeris DAC without a preamp in between... I drive my own Aeris directly into my M925 monos. If you use a preamp between Aeris and amp, you should set the Aeris attenuation to the DAC's equivalent of unity gain: per the Aeris manual, the right volume LED is lit up solid without flashing.

I have used Aeris on its own as well as with the Rowland Criterion linestage. Criterion is the now discontinued battery-powered version of Corus. With Criterion between amp and DAC the presentation is slightly softer/warmer, while driving Aeris into amps directly, resolution and transparency is maximized and background noise essentially non existent.

It is worth pointing out that Aeris as well as Rowland amps take a very long time to break in completely.... Complete stability is achieved at approximately the 1500 hours mark. Particularly, evaluating such electronics with less than 800 hours on them will yield false results... Aeris for example may still sound subtly peaky in the treble... Yet, there is nothing peaky in a fully stabilized Aeris... Sound is extremely complex and rich, without emphasis on any particular band of the spectrum.

As for Rowland delivering magic... Yes, Aeris + my M925 monos do deliver extreme magic to my ears. It is my conjecture that the combination of Aeris with M625 S2 would be as satisfying, while not attaining the same enormous scale of power-dependent parameters. Eventually, I hope to be able to verify this hypothesis in my own system.

BTW, there is now M725 in production.... Essentially same circuitry of M625 S2, but in monoblock configuration. 330W/8 with 1200W DC SMPS and dedicated PFC unit in each chassis.

Let me know if you need further information.

Regards, Guido

Hi Richard, I freely admit that the UI for volume attenuation/gain on Aeris is a little, ahem.... Techno-terse.

I would have prefered an LED with attenuation values, in addition to an independent indicator that would light up when the unity value optimum for direct use into amps is reached.... E.g. same solid LED, but with label "Direct".

In general, you will find the Aeris manual to be a pretty good source of operational info on the device. Volume control for direct use into amps is discussed on page 16.

Delighted that with Aeris at 0dB attenuation, your M625 S2 delivers all the juice you need for your hungry speakers!

Saluti, Guido

Al, the Aeris volume control is neither purely digital nor purely analog. Per the Rowland knowledge base, it operates by varying the reference voltage in the DAC chip. See:

http://jeffrowlandgroup.com/kb/questions.php?questionid=617

There is a variety of other technical information on the Aeris DAC in the Rowland knowledge base:

http://jeffrowlandgroup.com/kb/categories.php?categoryid=205

Regards, G.

You are correct. there are no speakers impedance adjustments in the Rowland M625 S2... Its output taps are expected to work for all common speaker varieties.

If you connect Aeris to M625 S2 directly, use the Aeris remote for setting volume at your preferred level. If there is a linestage between Aeris and M625, Set Aeris gain to unity/unattenuated... Solid right volume LED lit up, and then use the linestage to set listening level.

Bear in mind that results have a lot to do with the degree of break in of the devices you are testing.

Regards, G.

I concur with GPGR4Blu... "ARC which will be more transparent, open and expansive, but not strident."

In my experience at RMAF for several years, ARC amps have been consistently my favorite amps, together with Rowland and Solution. They all meet my sound/musical concept.

Unfortunately, high power tubed amps like ARC require upkeep to maintain top notch performance -- tubes sag over time. I personally prefer to have "launch & forget" devices in my home.

G.

Hi rinpoche, unless the M725 monos on sale are the S2 version, the M625 S2 that you are considering will deliver a much purer, more musical sound.

The original M725 of course will be more powerful than M625 S2, because each monoblock is equipped with its own 1200W SMPS and PFC unit.

Thus, unless sheer power / authority is a factor, I recommend you go for the M625 S2.

For the best of both worlds, there is now an M725 S2 in full production.

Saluti, Guido

Hi rinpoche, if budget precludes the new M725 S2, I warmly recommend the M625 S2 over the original M725.

As for VAC vs Rowland, I personally prefer the organic sound of Rowland electronic.

With Rowland gear, Elrod wires would not be my first choice.... In my system, Elrod PCs tended to filter the treble and swell the mid bass.

Brands of wire products with which I have had amazing results are Shunyata, Nordost Valhalla II, and High Fidelity Cables (HFC) made by Rick Schultz in Dallas.

G.

Hi Rinpoche, SS vs tubes is not the best way to look at the problem of amps... Rather, the thing to look at is the actual sound of individual amps, or at least the house sound of particular brands. Hence, you are doing well in your current path to final choice... One Rowland SS, and one VAC tubed... Yes, definitely you will find marked differences between the two amps... Yet their audible personalities have much more to do with the sonic phylosophies of the two designers, then about one amp using SS and the other one tubes.

Good idea to evaluate amps or any other component always with the same set of recordings... I have been using the same 6 audio tracks for the last 15 years... THis has helped me to create a stable frame of reference.

I use mostly the following pieces...

Antonin Dvorak -- In the Old Castle (from a 4-CD set of all Dvorak piano works on Brilliant Classics CD) with Anna Poroscina playing a a Bosendorfer grand... I look there for harmonic exposure and stability of the piano tone across the 7 octaves, naturality of attacks, persistance of decay, and extent of low level information (sounds emitted by the performer, felt noises, piano bench).

Antonin Dvorak -- introduction to string sextet with double bass. The introduction has some passages with the higher string parts bunching together in the mid treble during the cusp of cadenzas.... Many amplifiers cannot handle such closely scored sostenuto in the treble region and break apart: The sound becomes shrill, strident, and unlistenable because of intermodulative artifacts.

One more Dvorak... 2nd movement of the Symphony from the New World Op. 95 with the Israel Phil under Leonard Bernstein... My favorite performance of this work.... Look at the following:

* How does the amp handle the opening fanfare for lower brass...

Can you hear the individual horns and trombones, or does the image become homogeneous and an indistinct musical pudding?

Gradually the brass section shows some cuivre.... Does it remain coherent and musical... Or does it exibit signs of intermodulative strain?

Are the timpani pitched or tubby?

How well can you hear the hall in the low level information?

How clear is the double bass line.... deep and well pitch, or surfacy and tubby?

What happens in the ff at the end of each section? Does the amp sail through without effort with all instruments still clear and sweet.... Or Does the image seem to saturate with a front-to-back collapse of stage and images, and the appearance of hardness?

Can you hear Bernstein stomping his feet to encourage the players some 12 minutes into the movement?

Can you hear him subvocalizing during the final brass fanfare in the movement?

Few amps can do these things correctly even if they are fully broken in. The M625 original version (except for the very first few serial numbers) negotiated all the scenarios above without any issues... The S2 version is much improved over the original.

I do not have sufficient experience with the VAC amps to make a meaning ful comparison.

Regards, Guido

Hi again rinpoche? Are you in Canada? And is your dealer Angie Lisi from American Sound? If this were the case, please say hi to Angie from me... He was singly responsible for making me discover the magic of the Rowland sound in 1998.

Concerning Einstein, I heard their products a few times at some length, but never managed to like them much. Regretably, the word "rough" seemed to apply more often than not... With my test tracks, Einstein never reached terribly close to the top of the musical heap, and tended to blow tubes on sharp . Treble intermodulation was too easily present... On the other hand, the brand might have improved since a couple of years ago.

Hi rinpoche, I echo the recommendation to postpone any cable quest until you have selected your amplifier and broken it in to perfection. If you fiddle with cables prior to the equipment having stabilized completely, you are bound to get results that are as bizarre as they are fleeting.

Meantime, your Crystal cables are very fine wires... They will constitute a stable platform onto which to baseline your eventual wiring quest.

Best,  

Thank you Facten, you are absolutely correct. I was merely pointing out that not only Nirvana is perfectly achievable with SS preamplifiers instead of tubed ones... But the complete abscence of a preamplifier in the chain need not be a limiting factor in the enjoyment of music.

As for my admittedly beloved M925s... No performance comparison with M625 S2 was implied.

Saluti, G.

Congrats Rinpoche for your preliminary selection.

Just in case Angie does not have the Rowland M625 S2 Manual yet, you can quickly download it from my Dropbox public folder....

https://dl.dropboxusercontent.com/u/53640097/JRDG_M625_S2_MANUAL_REVA1.pdf

Concerning preamps / linestages, Rowland currently has two offerings... The Capri S2, and the flagship Corus with external power supply. I suspect that Angie might have at have one or both of them to listen to... No worries, just like the M625 S2, these creatures do not sound shallow or solid statish *grins!*

On the other hand, I have my Rowland M925 monos fed directly by the Aeris DAC, and I am not suffering a ... in heaven *grins!

Saluti, Guido 

Al is correct, Aeris has only digital inputs. According to the factory, the best input on Aeris may be the SPDIF/coax inputs... And that I waht I use, with Aeris fed by an Esoteric X-01 used as transport only... Fab sound.

But for all I hear, OPPO players are also excellent when used as transport.

Hi Rinpoche, in the Rowland field, there is also the Continuum S2 integrated. I ssuspect its cost in Canada might be 60% to 65% of M625 S2. CS2 is an absolutely marvellous sounding amp... Approximately 400W per channel. I heard it several times at RMAF and it is incredibly musical and resolving. You can either feed your Aeris in its line level inputs, or bypass the built-in Capri S2 linestage circuit, and feed Aeris directly into the amplification stage inputs.

Here is Roy Gregory's review of Continuum S2 on The Audiobeat:

http://www.theaudiobeat.com/equipment/jeff_rowland_continuum_s2.htm

Guido

Hi again Rinpoche, "problem" is that by listening to M625 S2 you have set your reference point very high. I suspect that if you get any other amp, including Continuum S2, you will place yourself onto a path of regrets and second guessing yourself, followed by an unavoidable course of "upgraditis furiosa".

Rather, why not try to megotiate a price break with Angie?

Regards, Guido

My aplogies Inna, I really have no experience what so ever shopping oriental bazars, so I have no idea about negotiation practices therein. Want to help me with that next time I have the opportunity?

Conversely, I have negotiated all my musical purchases since 1970... Both sides of the Pond, both North and South of the 49th. Have I broken etiquette again on this thread by suggesting the application of such uncooth acquisitional techniques?

G.

Congratulation Rinpoche, I knew you would love M625 S2... And an early Happy Birthday to you as well... on the 4th of July if all days!

Saluti, Guido

Hi RinPoche, Richard of course is correct. If your M625 S2 is factory-fresh, you can expect it to evolve for as much of 1500 hours.

It is quite likely that during the first 500 hours or so you might experience days in which the sound is strangely anomalous... perhaps dark or univolving... These dips are short term. The overall trend is towards purity, subtlety, and resolution.

By about 800 hours, the break-in progress becomes asymptotic, with progressive tapering of sonic evolution towards completion.

Guido   

Hi Rinpoche, looks like you are a real lover of music instead of an obsessive audiophile... Stay the course... Enjoy the magic of music... And do not fall prey to Upgraditis Furiosa -- an extreme form of Audiophrenia Nervosa, whose perils are discussed in the seminal article linked below...

http://positive-feedback.com/Issue46/audiophrenia.htm

Saluti, Guido

From an experiential point of view, I found Nordost Valhalla II, Shunyata Z-tron and CX, Cardas Clear Beyond, as well as Furutech Evo II and bulk wires to be "goldielockian"... That is, the wires are extended, musical, have significant harmonic exposure, but do not give preferential treatment to any particular section of the audible frequency band. Furthermore, they are all wires that do not easily intermodulate high friquencies... This means that they are not clinical but are immersive instead, and do not easily create yield a jarrying sound in complex treble parts.

G.

   customizations  

Yes, all Rowland components have been differentially balanced for the last 25 years or so. All components use XLR connectors. Most of them also have

Hi Rinpoche, here are some pointers about wire products with Rowland gear.

Jeff Rowland in his factory's demo system uses almost exclusively Cardas Clear and Clear Beyond, as well as Nordost Odin II. Internally, all Rowland products are wired with Cardas wires. I have heard Jeff's system connected with Cardas wires and it was amazing.

Nordost wires are incredibly expensive, thus unless you have an uber-generous budget, you will likely not consider them.

In my own system, with a variety of Rowland components, over the last 18 years, I have had best results with:

Nordost Valhalla II -- Not the original Valhalla, which sounds thin, but the 2nd iteration, which is still marvellously extended, but is also harmonically rich throughout the audible range. But once again, the problem with Valhalla II is the same as with Odin... The cost of ownership is very high.

* A variety of Shunyata wires... Helix, CX, and the original Zitron Anaconda. Absolutely phenomenal wires... I have not heard the very latest iteration, but have been told that the newest middle-priced Z-tron Cobra might exceed the performance of all previous Anacondas.

If you were seeking wires that are even more moderately priced, I have found the Furutech Evo II to be exceptional price performers, and some of the Furutech bulk wires to be even a little better than EVO II. Furutech wires can be ordered and custom-terminated by Elite Audio. You can contact Scott Markwell at Elite...

Elite Audio Video Distribution
P.O. Box 93896
Los Angeles, CA 90093
Phone: (323) 466-9694, x.22
email address: scot.markwell@themusic.com
web address: http://www.eliteavdist.com

  Having said all of the above,  until your M625 stabilizes, any audition of wires will yield unreliable results... They will emphasize or overcompensate any temporary performance anomalies of M625 S2. Only after equipment is stable, auditioning wires is a useful exercise.

Saluti,    

Hi RinPoche, is the M625 your own unit now, or is it a demo that you need to return to Angie, and then will receive your own unit in the new year?

Sorry... Slightly confused. Guido 

Hi Rinpoche, I am not familiar with the Blue Yonder.... I am thinking that before you go for the swap, you give the cable an in depth audition.... In general it does take 300 to 500 hours for a new IC to yield its best.

In the end, you will be able to determine quite reliably on your own if the Blue Yonder is worth your Devialet in trade in, or it is not. As usual, trust your ears, and listen to our pronouncements solely with the proverbial "granu salis". Cur verba volant, sed sonus manet.

G.

G.

Uhrn... Mayhaps Rinpoche is a "student", but in the sense of being a questing scholar, not in the sense of being in a subordinate position  akin to the child who is expected to follow the teacher's ex cathedra pronouncements. So, let us share our experience, bering in mind that we are not the keepers of the "Trueth"... Lest we could start writing for Pravda.

Not sure what Bodhidharma might have enjoyed, as he seems to have decamped some 1500 years ago... But I might ask my cousin Luca about it.

As for WAL, I hope that RIMPOCHE will let us know soon about its synergy with Aeris and M625 S2... As far as I know, this might be a World's first application in this particular context.

Saluti, G.

You might be right Richard, I have played with some exceptional wires in my system. It is quite possible that they have enabled me to part with the linestage. The Audioquest WAL that Rinpoche has purchased is completely unlike any ICs I have ever used... Silver solid cores, that I believe are buried inside air dyelectrics. Will WAL induce Rinpoche to try out a line stage sooner than later, or will it have the opposite effect... Impossible to predict.

As for me trying the linestage route once again... Never say never again *Grins!*

Hi Richard, to be more precise, my experience has been with Criterion rather than Corus. I have applied it to M312, M625, M725, and my current M925 monos over sevral years. While I am incredibly happy about driving my system without preamplifier, I do recognize that some might prefer Corus in the chain.

I might give Corus a try actually, as Rowland will be releasing the external 3-outputs power supply based on ultracapacitors, called PSU. PSU can power up to three compatible devices with DC power 24/7... Currntly, it is compatible with Aeris and Corus... Yes, both connected at the same time. People who have tested said its effect is transformative. Eventually, I hope to verify this on my own system... I would not be surprised if I fell in love with Corus all over again.

G.  

Hi Rinpoche there are a number of good servers on the market today. One of the brands that seems to have gained the most respect is Aurender. They have servers ranging for below $3K up to $17K. The higher end models are extremely flexible in I/O, and apprarently incredibly musical sound. One of the features that makes Aurender most interesting is that they incorporate a mass storage system... Some of the higher end models have a two-tier system... A very large HDD for storing your entire library, and a solid state drive where the devices moves material for playback... SSD is faster than HDD, and has negligible jitter.

For output to Aeris, you can use USB, or even better, SPDIF/coax if you select M10 or W20, which is the transfer mode which seems to be most used by the Rowland gang on their shows demos.

Have a look at the various Aurender product and list prices:

http://www.aurender.com/

N100, M10, and W20 include the two-tier storage system. N100 has only USB output, while M10 and W20 have also SPDIF/coax.

Aurender has Canadian as well as US dealers... Including our mutual friend Angie of American Sound:

http://www.aurender.com/page/dealer-audiophile

But the answer is no... I do not have an Aurender server... I am still using my trusted Esoteric X-01 as a transport into Aeris... But... One of these days *Grins!*