some more pictures http://www.flickr.com/photos/metropolismusic/4261312831/ |
Husk, I'll know more about Corus product availability in the next couple of weeks. . . but the prediction of 4 months out for Corus does not match anything I have heard this far from JRDG. Claude, Erick Lichte seems to be correct about Model 925 pricing, but pessimistic about product availability. . . His crypto-reference to audio jewelry is very cute. G.
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Guido, It looks like the Corus production is 4 mos out. Is that your understanding? |
All, it looks like our Criterion and related products thread is back in business after a brief abscence caused -- no doubt -- by a minor quantum fluctuation in the probabilistic Landscape that powers the Multiverse. My thanks to all that contributed to the cloning of the appropriate superstrings that allowed the threads return.
Regards, G. |
mark, Criterion uses large scale integration for its optical volume encoder, rather than discrete components. The dynamic range of the Criterion circuit is expected to be much wider than in previous JRDG preamplifiers, including that of various versions of Synergy and Coherence. I am not sure about the part number / manufacturer of the volume encoder module. |
Thank you Guido re the description of the volume control. The Synergy is similiar in that it also uses a optical encoder under microprocessor control. I am curious about what electronic circuit (whether chip or discrete) is used to implement the volume control. Cheers Mark |
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Mark, here is what I know about the control knob on Criterion.. . .
The knob first of all has 2 distinct ways of operating. . .
turning the knob adjusts volume for primary and secondary zones, right to left balance, input offsets, output offsets, menu scroll.
Pressing the volume knob utilizes the knob as a selector for entering menu mode and activating a selection.
I do not know what chip/module the volume control is based on, (it may be an HP part but I am not sure(, but it is an optically encoded system, therefore the knob can be rotated continuously clockwise and counterclockwise without ever reaching a stop position. When Criterion is turned on, volume is always at 0dB. The volume is speed sensitive: turning the knob slowly or pressing single taps on the remote control volume buttons changes volume in 0.5dB increments. . . rotating the volume control faster or holding down remote volume buttons changes volume in 1.5dB increments. . . the loudness range is 0dB to 99.5dB. Per my notes, precision/stability is said to be within 0.01dB. Furthermore, the volume control is said to cause the audio bandwidth to remain unrestricted at all gain levels, without the volume becoming a bandpass filter at low SPLs. Also when using the volume to change offset values, balance, and volume for secondary zone, the volume knob remains velocity sensitive.
It is my understanding that the volume control does not act on the audio section directly. . . The volume control is in the control chassis.. . it communicates with a microprocessor controller in the same chassis. . . when a volume change is requested, the microprocessor awakens a communication bus. . . sends appropriate control codes to the audio circuit in the audio chassis that alters the gain of the OPA1632, then powers down the data bus until new controls are required. So the controller is always offline, unless it is needed to change a preamplification parameter. . . and the change takes place in a fraction of a second.
From an experience point of view the volume control is extremely quiet. it turns with a little less friction than on Capri. I can hear very soft volume change clicks only when rotating the knob quickly beyond the 93dB mark on the display. . . which is something that I do only if no music is playing. The background noise is essentially completely quiet up to the top of the gain scale.
Let me know if you need more information. . . but this is all I know up to now. Guido |
Ok, let me explain more in detail. This is how my 501 amp for the center channel gets it power:
Wall outlet -> Nordost Odin power cord -> Burmester 948 AC conditioner -> Nordost Brahma power cord -> Rowland PC-1 -> T+A custom built power cord -> Rowland 501.
The main reason why I have the Odin cord from wall to the Burmester 948 AC condition is because I also have my two channel front end gear connected to it. So get me right, I did not buy the Odin with the purpose to use it with the 501! That us just a bonus the way I have set it up.
I have not connected my 301´s to the 948 of two reasons; the 948 has not enough capacity for that I think and also I have two dedicated AC lines for my 301´s. The power cords I have for the 301´s (Wireworld Gold Electra) unfortunately are not in the same league as Nordost Odin. That is the reason I said that the performance from my 501 are almost in the same league as my 301´s and why I also think I need two more Odins (for mye 301´s).
Hope this helped. |
I also have a 501 that I use for my center channel. It improved a lot when I got the PC-1, but was still definately behind my 301´s.
...
But believe me, it improved even more when I later on connected the PC-1 to my Burmester 948 which is powered by a Nordost Odin power cord!! Now I think the 501 are almost in the same league as my 301´s
sorry I don't understand ??? |
Hi Guido,
Can you describe the volume control technology used for the Criterion?
I currently own the Synergy IIi - the volume control design is based on the CS3310 IC. Rowland were careful in their design to maximise the performance from this now IC.
So I am curious if Rowland has moved on to newer technology?
BTW, I really enjoy the Synergy, but hoping to upgrade in the future.
Thanks in advance.
Regards
Mark |
Yes, Audiophrenia being the most virulent known form of audiophilia nervosa. See:
http://positive-feedback.com/Issue46/audiophrenia.htm |
I also have a 501 that I use for my center channel. It improved a lot when I got the PC-1, but was still definately behind my 301´s.
But believe me, it improved even more when I later on connected the PC-1 to my Burmester 948 which is powered by a Nordost Odin power cord!! Now I think the 501 are almost in the same league as my 301´s - got to throw in another pair of Odins I think! BTW, I think someone mentioned audiophrenia in this thread... |
Guido -
One of my symptoms is contentment. When I received my Rowland gear (all at once), I just hooked it all up and left it that way. I have never compared anything since. That will be two years in April.
To be honest, I have entertained thoughts many times of replacing those pieces but I like their size, looks and ergonomics so much that I an unable to mess with it.
I did read your comments about using Capri sans PC-1 and told myself I should try it but til now inertia has stood in my way. Maybe tomorrow. |
Macro. . . I am glad that your case of audiophrenia is milder than most. . . may I ask you about PC-1. . . how has it affected 102 and Capri? I did prefer Capri without PC-1. G. |
I should be the envy of all of you. I use a Capri preamp, a 102 amp and a PC-1. I find that I am quite happy with equipment at this level and do not have to spend thirty, forty, or fifty thousand dollars to be temporarily satisfied. It is my sincere wish that all of you are able in time to find a plateau where you are comfortable.
The use of good horn speakers has helped me to reach my plateau. |
Braz, the 'device' is a power rectifier based on a technology called Active Power factor Correction (PFC), followed by a bank of capacitors for filtering furter the DC before the actual switch mode power supply. As far as I know, the technology is used only by JRDG and by Chapter Audio. I suspect it is a significant factor in the 300 series sweetness of sound. The new amps are apparently also using active PFC and SMPS, although the core of the amps is not class D, but class A/B. Guido |
As I have the Model 312 for only 1 year, I can keep it until the review of the future 825.
But I think I known what is the difference from the old 301 and the 302 for the new Class D devices.
Once I read, always in Audiogon forum, there was a PROJECT MISTAKE in the early serie 300 and in others Class D devices, like the 501. And Jeff Rowland projected a little device to use externally together with those amplifiers.
I think it's true, because I found a store, in Dinamarc or Finland, that sells Jeff Rowlands devices on line and they have a observation that you need to buy that little device to use together with the amp to improve the sound and THEY STILL have the price for it as well.
At the same time, they say that the Model 312 has this little device already INSIDE the amp's gabinet.
Because of this I bought the 312 with confidance. |
Kawika,
unfortunately I have no experience with the Criterion. I have Burmester frontend with the 069 cd and 077 pre, both in the reference line. I just love what these products did with my system so I must admit I am leaning more towards getting a full Burmester system than getting the Criterion. I had the 301 amps before I invested in the Burmester gear. If cost wasn´t an issue I would get the huge 909 monos from Burmester, but I would like to know the Rowland 925´s performance and if they maybe could be a better alternative. |
Cappuccino, Not sure if I or someone else has asked you this, but have you any knowledge of the comparitive performance between your 301 mono's and the 312 that Guido & I both have being run by the Criterion. Also, have you tried or already own the Criterion? Aloha, David. |
Cappuccino, in that case the more recent 301 batches must be quite special. . . as much as I found the original 302 lacking, I am still in love with the 312. But I'm looking forward to hearing the newest 925 in my own system. . . probably Q2 or Q3. We'll see what the newest design does for living. G. |
Guidocorona,
I believe it is the same difference as for the stereo amps, I mean the old 302 against the current 312. I have not heard the old 301 monos or the 302 stereo amp so I can not comment on the difference myself, but those who have say the new model is quite a bit better. |
"very sensitive to other equipment and cabling"
Capuccino,
very interesting posting ! ... I think you are right
Power cables can make a huge difference and of course also interconnects. That's also why J.Rowland developped his PFC1
Read what Gary Koh from Genesis says about class D ...
interview:
"
N.D. -I would like a few words about your class D amplification, which is a relatively modern implementation in the high-end audio business – it has been mostly seen in consumer applications. Do you believe that it might even account for the future in amplification?
G.K. -The first working model of a class D amplifier was designed by John Ulrich, it was called «The SWAMP» (SWitch WAve AMPlifier) and was delivered in 1976 by Infinity. One of the founders of Infinity, Arnie Nudell was also the one who founded Genesis. In 1991 Infinity was already using class D amplifiers; we’ve been using class D amplifiers for the past nineteen years!
N.D. -So it is a myth that class D is not adequately developed to serve its purpose…
G.K. -It was not developed adequately. Until a couple of years back, class D amplifiers… I could not sit and listen to, they did not deliver music. Class D was very, very good for bass, which is why Genesis speakers used class D amplifiers since 1991 for the servo-bass part of the system.
My class D amplifier came with a story. I was trying to find a more reliable, a better amplifier for the bass and I reviewed all the available class D amplifiers; all those that were available as modules or as designs. After about two and a half years, I finally settled with the Hypex amplifier module, for the bass. Around that time, I don’t know if you are familiar, but I developed a tube amplifier for Genesis...
N.D. -Yes, I saw that they are sold out!
G.K. -The tube amplifiers are sold out… The tube amplifiers were done for only one reason: They were proof of concept that a cheap amplifier can be used to drive Genesis loudspeakers. You see, the designer of Genesis Loudspeakers, Arnie Nudell, was very famous for making speakers that are very difficult to drive; they had very low impedance, they demanded a lot of current and a lot of dealers said that -at that time the equivalents the 5.3s were like, I think, $14.000- to drive a $14.000 loudspeaker they required a $30.000 amplifier! I told them “no, this just means that the amplifier is not designed properly!”. So, a very famous dealer -I won’t mention his name- looked at me and said “if you think you can, you design an amplifier that’s cheap and can drive these spakers!”. It took me… two years; two years later I brought a pair of the M60 monoblocks to his store, I put them down and said “OK, which preamp do you want to use?”. He picked a preamp, he connected it in, then we connected it to… that was the 5.01 and it drove it perfectly. So he lost his bet; I won my bet… Here was a $4.000 amplifier that drove, at the time, a $14.000 loudspeaker!.. The problem with tubes, though, is that the moment you buy the amplifier, it begins to deteriorate, so I didn’t want to really continue making those. However they were a proof of concept; if I can design it -and I am not a famous amplifier designer- then everybody else can design it! That’s the amplifier, I’ve proven my point that you don’t need an expensive amplifier to drive the Genesis speakers.
N.D. -It was like an etude, a study on the subject.
G.K. -It was a proof of concept, it was a study.
N.D. -Your current class D modules, do you design them or are you still using Hypex?
G.K. -I still use Hypex, but I heavily modify the Hypex modules. The reason is that if you listen to a lot of class D amplifiers, they don’t have what I call the “soul” and the emotion of music. You know, you don’t feel that the singer sings of a lost love or you don’t feel that the singer is actually in love with you and she’s singing to you. The problem I solved -after actually discovering that it wasn’t a problem of the module- was the problem of the power supply. I designed a power supply that works perfectly with the class D module, to deliver that soul and emotion.
N.D. -Is it a linear power supply or a switching one?
G.K. -It is a linear power supply… I couldn’t make a switching power supply work; I tried.
N.D. -I know it is quite a bit of a challenge, but, if anyone can do it, I believe it’s you.
G.K. -Thank you!" |
Cappuccino, what design/sonic differences are there in the recent 301 amps vs the original series? I have heard that there some differences, but I do not know what these may be. Guido |
I have a pair of the latest 301´s and also very interested to know how these new 925 amps will sound in comparison.
What I have found out during the years I have owned my 301 is that they are are extremely neutral, but also very sensitive to other equipment and cabling. You can get very different sound from them dependant of the rest of your gear. I think many have underestimated class D products because of this. As I see it the amps in the Rowland 300 series have a tremendous potential but require a lot of the owner to reveal this potential, maybe more than with traditional amps. Maybe that also is one of the reasons of slow adoption of class d amps in the high end market. |
If they exceed the music performance of JRDG 312, currently my favorite amplifier regardless of underlying technology, I will be extremely impressed. |
Well Guido, I asked about the sound wondering if it would be more like the Models 6 and 8 than the recent ICE equipped pieces. That would be a question for Jeff and he isn't available just now. So we shall all be called upon to exercise the virtue of patience. Given the price of these things, I may need quite a bit more than patience. It will take a minor miracle or a major irresponsible charge. |
Thank you Macro, your source is impeccable. . . I suspect this is just a matter of subtly different wording. . . not terribly important. . . truth is we haven't heard these devices yet. . . can't wait to find out how they sound. |
Guido - I was not at the show and have not seen any of these new items. Kelly told me the units at the show were not active. The dash lit up but the motor would not start. She attends every show, and this one in particular, as it was Rowland's 25th anniversary at CES. Kelly has been with him for 21 years and I've known her the whole time.
I don't mean to contradict you but my source is pretty good too. Maybe she wasn't supposed to tell me that -- or I wasn't supposed to tell you. |
Macro, The units at CES were powered, but not connected in system. FCS is still tentative. Power rating is still undergoing finalization. I source info from JRDG.
Claude, 312 is certainly a marvellous product, but it is now almost 4 years old. . . and nothing is static in our domain. We'll see what the new products do for living, regardless of underlying class of operation. G. |
I talked to Kelly at JRDG yesterday. No delivery dates have been established and output power is not even certain as yet. The units on display at CES lit up but were not powered. We are getting ahead of ourselves. |
Guido,
my dealer guesses he will get the Corus in spring and the 625 "later".
I am surprised to read that the 312 is "no longer in production" ... ?
it seems really that Jeff Rowland is changing strategy and going bach to class AB amplifiers. Is this now because there are really better or just because class D was never really accepted by High End Audiophiles ?
BTW I have the 501 + 2 PFC1 with special cabling un beetween ... I still had no time to compare it to the 312.
A nice day to everybody |
Just dredged up some more info. . .
Corus is companion product of 625.
625 is not exactly a replacement for 312. The 312 amp -- which is no longer in production -- will eventually be replaced by a class A/B stereo amp called 825, for which there is no delivery date yet.
The current Criterion preamplifier is intended as a companion piece for the 925 and the future 825.
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That's fine, because the electronic signature from the 625 or the 925 wil be, more or less, the same signature.
Let's do it, Guido. |
Braz, I will definitely post any listening observations about the new JRDG amps when I get my hands on one. . . we'll see if it is a 625 or a 925. Guido |
Claude, the interesting comparison will be between 312 and 625. . . 501 uses a generally more basic design without PFC in the front end, and its sound lacks the subtlety of 312. If 625 exceeds the music performance of 312 it will be a very special amp indeed. One detail I do not have yet is the current rating of 625 and 925.
Regarding Corus, the comparison with Capri should be a very interesting one.. . if my scant info is correct, Corus should sound very similar to Criterion, which is IMO significantly more refined than Capri.
Has your dealer told you when he should be receiving his units?
Guido |
Clavil, one of the Audiogon's master, your post is interesting. I want to keep my Criterion "forever", but I could change my 312 for a JRDG Class AB, so I'm going to wait for your and Guido review from the 625.
If I remember or I read well, you wrote in another post the reasons of why JRDG starts once again to make Class AB amplifiers. If they realise Class AB is really better than Class D. IMO the reasons for those new Class AB devices is MONEY, because the impact for the market with Jeff Rowland's Class AB is huge, they will sell many more units than with another and another Class D amplifier.
For instance, you have already ordered the 625.
I'm going to wait ansious for your review.
Thanks, man. |
my dealer has already ordered the Corus and the 625. I am very curious to compare them to the Capri and especially the 625 to the 501 and 312.
"All the truth" beetween Class D & Class AB ;-) ? |
Claude. . . spoke to JRDG marketing director this morning.. . unless things change, prices are as follows:
Corus preamplifier: $10,800;
625 stereo: $12,500;
925 mono: $48,000 a pair.
Note that while 625 and 925 are class A/B, 301 remains a top level current class D product at $29,500. Furthermore, it is my understanding that class D will continue to be used for integrated amps and other amplifiers up to 500 series included.
I have heard that the new amps are expected to be fairly energy efficient and not run hot to the touch.
Late March deliveries for the amps, and perhaps earlier than that for Corus.
Still awaiting firm specs and pics.
G. |
the 625 - 350 watt stereo - $12500
the 925 - 550 watt mono - $45-50000 pr
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curious, Jeff Rowland suffering the critics or better said the absence of critics from the american press, because going class D (and making miracle with it) is steping back ?
I am surprised |
Clavil, the monster amp is called 925. I still do not know too much about it. . . a 4-chassis design, operating in class A/B, probably with a switch mode power supply and PFC rectification, probable power rating between 500W and 550W per channel. Price between $45K and $50K.
There is also a new 625 stereo amp: once again, my information is incomplete and not definite: single chassis, 330 to 350 Watts per channel, SMPS + PFC. Listed between $12000 and $13000.
I'll add more info as I learn it. G. |
Photos of the Corus can be seen here:
http://www.facebook.com/photo.php?pid=3117378&id=72837407592
photos of the new monster amplifier here:
http://www.facebook.com/photo.php?pid=3117378&id=72837407592#/photo.php?pid=3117377&id=72837407592&fbid=258312222592 |
I got it, Raquel.
Thanks very much. Take care and happy 2010. |
Brazcole:
I just sent you an e-mail in Portuguese.
Abracos, |
The technology they use is purely incidental...
That's it.
Well done, Guido. |
Braz, we could argue the fine points of which technology best couples what other technology until we turn blue in the face. . . In reality it does not matter too much at all. . . what matters are only your ears.. . and the particular combination of a real preamplifier with an equally real amplifier and how you react emotionally to them. . . The technology they use is purely incidental, and even the mutual impedance compatibility does not tell the whole story. Only your heart can. G. |
Hi Guido,
did /will you have the oportunity to compare the Criterion to an FM Acoustics preamp like the 255 for example ?
This would be very interesting!
Kind regards |
Raquel, I don't known if you will come back in this thread, because Guidocorona had answer your question, for what I could understand with my little English, but I bought my Model 312 only because you and Guidocorona wrote very well stuffs about JRDG amplifiers. And because I also read the Model 312 is so sweet that looks like there are tubes hidden inside.
You said in another thread that the best combination is a solid state preamp with tube amplifier and explain the reasons.
When I said that statement in a Brasilian Audio Message Board, the guys said I was wrong and the best combination is the opposite, I mean, a tube preamp with a solid state amplifier. Because severals of them have the Reference 3 or a BAT preamp. As I trust in you because you post many very tech messages, I reply that they were wrong and I transfer your statement from Audiogon (without putting your name) as a review from one of the best reviwer in Audiogon. They still said the reviwer was wrong.
First, is very nice to known that you have a Coherence, because I want to keep my Criterion a lot of years.
And, if it doesn't bother you, could you tell if you still prefer a SS preamp with a tube amp or you change your mind. |
