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New Rowland Criterion 2-chassis battery pre

Jeff Rowland Design has just created a page for its upcoming statement-level, twin chassis, battery powered full function preamplifier. Detail is still scant, but a little bit of info is already available, in addition to front and rear view pics. Here’s the page:
http://jeffrowland.com/Criterion.htm
And here’s the front view:
http://jeffrowland.com/Criterion-front.htm
And here’s the rear view:
http://jeffrowland.com/Criterion-back.htm

You will find a few specs already on the site. JRDG should be publishing more info in the next few weeks. I will post here as I receive it. in addition to the published specs that you can read on the page above, here are a very few additional tidbits that I have learned this far:

. Uses Burr Brown TI OPA1632 high speed fully differentially balanced modules.
. Includes phono stage.
. Uses standard NiMH D-cell batteries available in most electronics stores, loaded in 2 rear-inserted tubes of power supply chassis.
. Capable of AC/DC operation . . . will recharge batteries on independent circuit during AC operation.
. Full remote control
. Target price $18K (not sure yet)
. Availability: probably early Fall 2008.
. Will be featured at RMAF in Soundings Hifi suite Marriott 503 or 505 from Oct 10th to 12th in Denver.

And sorry folks, I have not heard this device yet. Nor I have any good third party reports on its sound. Any speculations on Sonics from my part would be just. . . pure speculations. I’ll keep everyone posted as I learn more.

Guido
guidocorona
raquel
841 posts
 
It's a II (manufactured February 1999). For those curious about the differences, Rowland's website states:

"Q. What is the difference between Coherence Series I and Series II?

A. The Coherence Series II was released April 1997. The Coherence Series II upgrade involves the redesign of the attenuator amp circuitry. The actual circuit topology is similar; however, all of the circuit components were improved, taking advantage of recently available modern surface mount technology. The output amplifier is a newly developed, dual high-current transimpedance amplifier which handles both phases of the output circuit on one isothermic, copper lead frame power device. This output amplifier and all associated surface mount circuitry allow significant reductions in circuit loop area and path length yielding wider bandwidth, faster setting time, reduced dielectric absorption and greater thermal tracking stability. The overall sonic result is greater clarity during complex music passages and increased resolution of intertransient silence."
guidocorona OP
4,298 posts
 
Thank you Raquel, one difference in the output stage between Coherence I and II appears to be--according to the copies of the manuals I have--that the older varsion had an output impedance of 300Ohms unbalanced and 600Ohms balanced, while verion II seems to have 50Ohms regardless. Manuals also say that Coherence outputs are direct coupled. I suspect this may mean that there isn't the transformer-coupling present in later designs, whose function, among other things, is to maintain impedance invariance. Whether this has had any bearing on your results with the coax2XLR adapter experiments, is of course, anyone's guess.
raquel
841 posts
 
Guido: Thanks. My Coherence II does feature output (and input) transformers.
guidocorona OP
4,298 posts
 
Thank you Raquel. . . looks like the manuals are a little vague in that case. . . they talk about "direct coupling" what ever that means. . . your updated and correct info on the subject is very much appreciated BTW.

Now on Corus, Capri, and Criterion. . . Corus does not replace capri at all. . . Capri remains the JRDG 'entry level' preamplifier at a price point less than $3K. If what I have heard is correct, Corus has much more sophisticated internals in the same class of Criterion, and targets the $10K pricepoint. Criterion remains the JRDG flagship at approx $18K. I'll find out the Criterion vs Corus differences in the next several days and will post here.
brazcole
63 posts
 
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.
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