Jeff Rowland's Continumm


I've been interestingly putting my eye on the new continuum range from jeff Rowland for some time and have a question based on some discrepency within the information I have gathered; some claims new continuum uses the same module that was used in 201 and 501 while other claims Continuum uses the same module as 302 and 312.

Can anyone solve my curiosity?
facias

Showing 17 responses by guidocorona

Thanks Pinkus .. . and for my earlier question. . . how many hrs did you put on Capri, and at which point did it stabilize?
The 501 does not have the same module used for 201. If I remember correctly, the 501 and the 312 may use the same modules instead. The Continuum 500 -- which is the model variant I would suggest -- essentially contains 2 501 circuits, for the amplification component, a Capri-like pre-amplification circuit, and a Power Factor Correction (PFC) capacity capable of delivering 1500W of DC current at 385V. This last one is essentially twice the DC current delivered by a single PC1 external unit. Please note that a massive PFC capacity is one of the major reasons for the sonic advantage of 312 stereo over the 501 monos.

By contrast, the Continuum 250 has no PFC circuit, and if I recall correctly uses the same power conversion modules used in the 201.

One note of JRDG trivia. . . Continuum 500 is selling like hot cakes, and may be JRDG's hottest best seller yet.

DCSTEP can comment on the sonics of his COntinuum 500.
Good suggestion Macrojack. JRDG is at 719-473-1181. Be aware that they are in US Central time. They are most easily contacted from 9:00 AM central to 12:000 PM. Then again from about 1:30 PM central to 4:30 pm central. . . but hrs may vary.
I also suggest you get in touch with one of the major JRDG dealers like Soundings, at 303- 759-5505, and speak to Rod, Shanker, or Mark.
Hi Facias, I suspect you may find it easier to get in touch with Jeff by phone than by eMail. 302 and 312 do not contain the same ICE modules. 302 had a discrete power supply. I believe that the newer 312 uses a 3rd generation ICE module with integrated power supply. . . . and having said that, it has more authority than older 302. It is worth remembering though that JRDG uses ICE modules as basic low level building blocks, and only 102, and 201 should be deemed relatively minimalistic designs. Particular Continuum 500, 312 and 301 devices all have complex circuitry designed/implemented to support the ICE modules. I believe that Continuum 500 uses integrated power supplies which are fed 385V DC current by the PFC 1500W front end rectifier. G.
"clarity, nuance, gestalt, palpability, etc"

I agree with you Macrojack, I wouldn't know how to palpate a nuanced gestalt if one sat in my lap. And yes, 'findings' sounds so much 'more better'n' personal opinion. I also agree that using colorful terminology freely imported from the competitive team sports arena may at times be slightly less than helpful. That is why I much prefer to offer my listening experience in terms of equipment context, musical context, and finally as much as possible concrete description of my observations. . . and in the end, just in case, I call everything 'preliminary' no matter what.

Pinkus, I am very much looking forward to giving one more round of hard listening to AYRE at the next RMAF in the Fall. Unfortunately last year's AYRE suite was -- to my great surprise -- slightly disappointing for its etched sound. . . . but so were most other suites. Guido
Hi Pinkus, how many hours did you put on the Capri? And how many hours did it take to break in and stabilize. I am of course looking forward to listening to the KX-r at the first opportunity. completely?

PS. To anyone wondering if we are straying out of topic, the pre circuit in the JRDG Continyuum is closely based on the JRDG Capri.

G.
Thank you Pinkus and apologies. Indeed I missed your post about break in. I appreciate your position on little breakin reqd. My subjective impression is that both my Ref 3 and Capri took over 500 hrs to settle. While Ref 3 was quite hideous in the very beginning until about 150 hrs after which it started progressively to sing, Capri was initially already reasonably listenable -- perhaps because of factory burn in of 75 hrs -- then I thought steadily improved until well over 500 hrs.
Yes, I have. Jeff has in fact suggested that significant breakin may needed because of power supplies, transformers and other components being initially 'magnetized'. As such, Jeff was not at all surprised that even the 312 I have in the system, which is not at all new with several thousand hrs of operation, but had been in storage then truck plane/cold/vibration for a spell required several hundred hrs to restabilize. Rod and Mark at Soundings also suggested to me that Capri -- like most other pres -- may require over 500 hrs of operations to stabilize.

Comparing a well broken in Capri or any other device with its counterpart fresh off the factory floor would be a fascinating experiment. If I have the opportunity I will attend it. . . no need to put too much effort into making it a blind experiment either, all Capris look identical to me, regardless of livery.

G.
Hi Dave, I just read yesterday that -- according to an official personnel training document on the 2008 Bejin Olympics site, the politically correct term is now 'optically disabled'. Suchly, next Fall in Denver, I'll be delighted to participate to any optically disabled test. test
Spoke to JRDG today. From my conversation notes. . . The chips in the preamplification boards for Capri and Continuum, and the upscale boards for the upcoming Criterion, are OPA1632 ADSL differential in/differential out line drivers from Burr Brown TI. They have a 180mhz bandwidth, as such, strictly speaking, they are not phono modules. They are defined as hi performance fully differential opamps, but they are not opamps according to typical definition of opamps.
Noise floor is rated in nanovolts per hertz square root.
The devices are more typically used for driving high speed DAC circuits.
Bandwidth is further measured at 40mhz at 0.1db flatness.
distortion output is at 2k load is 0.000022%.
The chips are indeed very small 1/10th of an inch square. Internal topology of Capri is confirmed to be minimalistic. OPA1632 tiny geometry contribute to maintaining extremely short signal path crucial to audio performance. . . as we all know. One more desirable quality of OPA1632 is to have almost unmeasurable energy storage, which yields faster/deeper signal rising/decay, with consequential more transparent / 'blacker' background. G.
Yes Coffeey, very similar experience. I also have listened to a couple of 'digital' amps that were rather underwhelming. . . I have even listened to a couple of tube amps that were quite honestly terrible, and I have heard a couple of traditional SS amps that were rather painful to bear. . . my conclusions? try not to generalize from matched pairs of bad apples, or. . . quit audio and pick up Origami. G.
Coffeey, I am also not a great fan of Red Dragon, heard it at RMAF in '06 for over 1hr. . . great macro dynamics, but little micro and exceedingly dark. As for Bel Canto, there are several Bel Canto models, which one did you use, and how many hours did you put on it/them? G.
That's correct, every device is different. Different devices are created with differing goals, expectations and price points. Various designers have very differing philosophies. And regardless. . . every device needs be broken-in completely and properly warmed up. . . otherwise any listening observations become moot. And in the end. . . everythings gets filtered by personal preferences and opinions anyway.
If anyone were interested in some of my latest a/b comparison between JRDG Capri and ARC Ref 3, see:
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1200110667&openmine&zzGuidocorona&4&5#Guidocorona

Guido
Jeff Rowland has finally updated its web site with a page dedicated to the new Continuum 250 and 500. Here it is:
http://jeffrowland.com/Continuum.htm
And here are some specs for all lazybugs (grins!):

* * * *

Specs: 250 Version / 500 Version
Output Power, Continuous RMS watts, both channels driven 250 watts @ 8 ohms / 500 watts @ 8 ohms per channel /
500 watts @ 8 ohms / 1000 watts @ 4 ohms per channel
Frequency Response 5 Hz – 60 kHz, -3 dB @ 8 ohms / 5 Hz – 45 kHz, -3 dB @ 8 ohms
Peak Output Current 35 amps / 40 amps
Dynamic Range 117 dBa / 120 dBa
Load Impedance Range 3 ohms – 16 ohms
Input Impedance 48 k ohms
THD and Noise, 0.1 watts to Maximum Output < 0.05%, Typically .006% @ 1kHz / < 0.1%, Typically .01% @ 1 kHz
Damping Factor @ 1 kHz > 1000 / > 1000
Gain Structure Preamplifier Section 14 dB, Amplifier Section 26 dB
Volume Control Range 99.5 dB
Volume Control Resolution 0.5 dB +/- 0.05 dB Over Entire Range
Common Mode Rejection Ratio > 85 dB, 20 Hz to 20 kHz
Inputs 2 pair Balanced (XLR), 2 pair Unbalanced (RCA)
1 pair Unbalanced (RCA), Unity Gain (Bypass)
Outputs 1 pair Balanced (XLR), 1 pair Unbalanced (RCA)
1 pair CE-Approved Speaker Wire Clamp
Power Consumption Idle – 25 watts, Max – 1000 watts / Idle – 35 watts, Max – 2000 watts
Power Supply Switch Mode (SMPS) / Switch Mode (SMPS) with active power factor correction (PFC) and universal AC input voltage
Amplifier Weight 41 lbs. - 18.6 kg / 44 lbs. - 20 kg
Overall Amplifier Dimensions (H) x (W) x (D) 5.3" x 15.5” x 15.0” (135mm x 394mm x 380mm)

* * *

Please note that the model Continuum 500 is front ended by a 1500W PFC unit, which is integrated in the device. The Continuum 500 has also implemented a bank of bulk output capacitors not even available on the 312 stereo amp. The additional caps are exp
ected to yield enhanced headroom/authority. G.
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