Oops, I almost forgot to mention cosmetics. JRDG is known for their beautiful chassis and this is no different. In one word, it's "stunning". I'm getting the natural finish chassis which as a ¾” machined aluminum face plate. The sides and top have no rough edges and the stepped volume attenuator shows .5dB increments with attractive, blue LEDs. The pre-amp controls are simple with “1”, “2”, “3”, “4” for Source indication, which I think is a good idea, given that there’s a new source component every year or so. Aesthetically this is a really handsome amplifier.
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That's really exciting Dave. . . and -- no surprise -- you discovered there is a magic synergy between JRDG electronics and Vienna speakers. . . isn't that uncanny? By the way, do you happen to know what power chord was on the Continuum and what speaker wire was in use?
Does continuum have a 15A or 20A IEC connector?
I brought it home today and plugged it in. It's too early to go into details, but, even before break-in, it bested the Conrad Johnson CA200 that it replaced. Immediately apparent is increased slam and detail in the bass and more silence in the quiet spots.
The sonic signature is cooler than the C-J's warm overall tone. Mids are rich and complex and the highs are details with no edgyness.
I'll need a few weeks to burn it in.
Oh, BTW, I love the six-button remote. Volume up and down, balance L and R, Mute and Input. It's everything that you need and nothing more. Compact and solid. It seems to be made out of billet aluminum.
The faceplate is stunningly eligant. I was warned not to touch it for a few weeks, lest the finish tarnish where touched. (Apparently it needs a few weeks to cure). My dealer is getting me some cleaning fluid that will not damage the finish.
It uses Cardus-designed binding posts that really give a solid connection with spad lugs and are much easier to connect than individual posts.
My universal player and phono pre-amp are both unbalanced, so I used those inputs. It also has balanced inputs. There's a Line Out bypass for my headphone amp.
I don't remember seeing an XLR on the back of my modded Pioneer universal player, but I'll look again. Right now I'm using a Pro-ject Tube Box SE phono-pre for vinyl, but Rod and I started talking about trying Jeff's phono card in the Continuum, which I will do before too long.
Here are a few other little minor notes:
The power switch is on the back and hard to reach when it's on a high shelf in my equipment armoire, but that's no problem since it's intended to be left on. (At least I think that's the intention. I'll ask Jeff when I tour the factory in May).
When turned off it needs some time to settle back in when you turn it on again. Of course, it was off when I picked it up at Soundings. I rushed home and hooked it up within thirty-minutes of it being turned off. At first it was a little unfocused. Timbres were fine, but it just seemed slightly confused in a timing domain or something. Anyway, it locked in after about thirty to forty-five minutes of play and then got really sweet.
The total hours are now in the 100 to 150 range. Mark of Soundings picked it up at the end of last week and, per my request, played it constantly from then until I picked it up. Like I said earlier in the thread, it's already much better than the Conrad Johnson it replaced, which has several hundred hours on it (approaching 1000, I'm guessing).
The guys at Soundings are a little surprised, saying that their past experience tells them that most JRDG amps need closer to 1000 hours to sound thier best. Perhaps the Power Factor Correction built into the Continuum is speeding that along.
One last thing, as an early adopter I'm doing without a manual right now. No big problem and I'm sure that'll be rectified shortly; however, I thought that I should mention it.
Guido, how many hours did it take your 312 to settle in? That's got PFC also, doesn't it?
Oh Guido, you asked a question, when I heard it in Soundings it was with the stock power cord and that's what I'm using right now.
Crap, I forgot to look at the IEC connector, but give the weight of the supplied cord, I'm thinking that it's 20A. I'll try to remember to double-check this p.m.
The 312 in my system was not at all new, but had probably not been played for a little spell, and had been shipped in a frigid cargo hold. . . it took perhaps 100 hours to settle down.
If the Continuum has a standby switch on the front plate. . . leave that on at all times as well.
Even if the 312 is left completely on, it does take it a good 40 mins to one full hour of playing to sound its best after having idled overnight.
Interesting. There's no standby mode on the Continuum, so it's staying all the way on, all the time.
I sat down today and started serious listening with no wait. I'll pay closer attention tomorrow, to see how it changes over the first hour. I didn't notice a change, but I was playing a wide variety of music. Tomorrow I'll try the same piece.
Switch-mode I think, consistant with the rest of Jeff's product line. See:
Unfortunately, I have no direct literature to support it; however, his use of switch-mode in his other products, the high power, compact size and cool running make me think it's also switch-mode.
BTW, I put in 8-hours of listening today, 5 of which were focused and loud as the cuts played would dictate. I have no fatigue at all.
I swapped out the stock power cord for Coincident Speaker Technologies CST-PC. The difference was very small. When I've put the CST on other pieces it yielded a dramatic improvment, so I'm thinking that the Continuum's internal Power Control Factor processing must reduce sensitivity to upstream improvements. The swap took 15-minutes because the amp is high in an equipment armoire, so that may have reduced my ability to hear a change, if any. Perhaps I should have waited a week or two to make the switch so that I settled into the Rowland more.
Oh, one more revelation; this amp is incredibly quiet. After listening at around the 85dB range I turned off the universal player and put my ear to the tweeter. It was absolutely silent. When I turned the attenuator all the way up to 99.5 (that's the step reading, the dBs would actually be higher if I ever listened at that level. Most digital sources are yielding around 85dB with the attenuator set at 70-75) I could hear a slight hiss. This is very, very quiet.
Listening to a few recordings with very quiet passages, like the very dynamic Reference Recordings "Crown Imperial" CD, the quietness give a greater sense of dynamic and clarity to the quiet voices.
04-26-08: Guidocorona said:
"Rafael, I can confirm that Continuum uses switching power supply(s). What I do not know is if it has one PS serving both channels or twin supplies. Continuum also has a PFC circuit capable of delivering 1500W of DC, which is essentially equivalent to 2 PC1 devices."
I think everything is halved in the Continuum 250. Guido speaks of the Continuum 500, the model discussed in the review. I have no idea if the 500 has two PFC circuits or one bigger one.
04-27-08: Guidocorona said:
"You are correct Dave, what I wrote concerns the 500 model; furthermore the Continuum 250 does not incorporate a PFC circuit."
I should mention that was part of my thought process in chosing the 500. It's around one-thousand dollar more, vs. the 250, but you get the PFC circuit AND 500 more watts into 4-ohms (my nominal speaker load). That seemed like an incredible bargain to me.
The quietness astounds me. I've never such a power and quiet amp before, bar none.
I've got a Rowland Concerto integrated (250 Watts per channel - no PFC). The manual says to leave the power switch on, but you can turn on the mute to shut down the amp outputs (the pre-amp outs stay active all the time). In speaking with Rowland, he said my amp only draws 22 watts when its muted so its simpliest just to leave it on which avoids having to wait for the pre-amp to warm up.
Also, BTW, I asked Rowland about their PC-1 and whether it can be used with a Concerto. The PC-1 puts out 385VDC and there's a switch inside the Concerto that can be set to allow the PC-1 to be used with it (along with a fuse change). What he said you would notice is a lot more base extension (presumably if your speakers can handle it). However, my understanding from something I read that I cannot found now was that all their new monoblocks and integrated amps have PFC - though I'm not positive about that.
BTW - do you know if the Dali Helicon 400 Mk II's you heard had any run in time on them. The Mk IIs are pretty new and I've heard they sound pretty poorly just out the box.
Thanks Ric. I've heard that the Continuum 500 has PFC but not the 250. The Capri pre-amp doesn't have PFC, but it's compatable. Guido reports much improvement to the Capri he's evaluating.
I think it's a sound investment to add a PC-1 in front of your Concerto.
Yes, I read the other manuals online and decided to leave my Continuum on all the time.
I'm certain that the DALIs that I heard have at least 100-hours on them. I'm going back later this week to give them another chance with another amp. (Probably a class AB Conrad Johnson).
In current integrateds Continuum 500 has PFC; 250 does not have PFC but is compatible with PC1. In amps 302, 312, 301 have PFC built in; 201, 501 do not have PFC but are compatible with PC1 through fuse change/repositioning. I recommend 2 PC1 units in 501 for max authority, but JRDG can supply PC1 Y splitter if preferred. Capri pre does not have PFC but is compatible with PC1 without any switches/fuse changes because it has an autosense power supply. I suspect Continuum may also have autosense pS, so PC1 on 2650 may not need any setup.
I'll be running down to Colorado Springs on Monday to have Rowland's phono card installed in my Continuum. I'll add some comments on the phono section after I get some hours on it.
Guido, the Decca/Speakers Corner LPs (two disks) of Solti and the CSO doing Beehtoven's 9th came in yesterday. I didn't have time for the whole thing, so I just listened to the last movement. WOW, it blows away my Riener version. Thanks for the lead.
Hi Dave, not surprised about your reaction to the Soltl perf of Beethoven 9th. . . I heard subtleties and profound understanding of the score in the 2nd movement that I had never heard before. . . now have to find a version of the same on CD or SACD for my collection. . . as for Reiner, I am not usually much taken by his performances/interpretations.
I drove down to Colorado Springs today to have Jeff install the phono stage modules in my Continuum 500. Installing the phono circuits took about 10-minutes but I ended up spending all day with Jeff. He's quite the philosopher and we took turns going off on deep tangents, from the madness of crowds to the Marfa lights.
One of the highlights of the trip for me was seeing inside my own Continuum and marveling at the incredible quality. Most of you know, but for those that don't, the chassis is made out of high quality billet aluminum to tolerances of .003". When I asked about the percentage cost of the chassis vs. total construction cost, Jeff launched to a discussion of how hard it to say because of all the time saved in assembly because the holes always line up, attachment points are machined into the chassis, etc., etc..
Here's an interesting detail, the Continuum is the first (or one of the first) Rowland products to receive a curved faceplate. The faceplate still has the same distinctive machine work ("turning", but way more refined than that), but with a curved front that is more accentuated. Well, the really interesting detail is that each button must be a different length to look "just right". So Jeff went from one button to six buttons in order to achieve the clean, balanced look that he wanted to maintain.
BTW Guido, Jeff's has a curved faceplate for the 300-series. Oh man, it's stunning. It's an easy replacement for the stock plate. Jeff's costs is "hundreds" and he's working out the retail price.
You may expect a review of the phono stage, but it's way too early. I've only listened to one side of Ella. I can say it's first rate and superior to the Pro-ject Tube Box SE that it replaced. The noise level is vanishingly low, like all the stages of the Continuum and the balance seems very neutral and clean, but I need to listen a wider variety of music over a longer period of time. Also, the stage needs burn-in.
As to the Continuum itself, I think it did move into new territor this weekend. It passed 200-hours. Previously I was totally enjoying my SACDs, DVD-As and vinyl, but I was getting tired listening to certain CDs. My Pioneer AV-58DV universal player only has about 300-hours on it since modification by Ric Shultz. I was beginning to think that the CD function wasn't benefiting as much as the hi-rez digital. Well, this weekend I listened to about 8-hours of CDs with no strain at all.
I think it was mainly due to the amp getting better. It had been on constantly for a week. There's little clear cut that I can point to, other than that EVERYTHING seemed better, more transparent, more open, even less stressed.
Poor digital still shows up as poor digital with the Continuum. Remember those Telarc LPs for the late '70s, with Cleveland and Atlanta orchestras. They were recorded with early digital 16-bit technology. Well, I could hardly stand them. Early RCA analog tape-based LPs still sound glorious in comparison.
So, the Continuum is incredibly revealing, yet incredibly transparent, incredibly quiet and easy to listen to for hours and hours IF and only if, you sources are very good and don't add any harshness.
When I was putting the Continuum back into the system after bringing it back from Rowland's shop, I put the Conrad Johnson CA200 control amp into the system for about 30-minutes. Maybe the CJ needed more warm up time, but both amps were cool before I did this final swap. The highs on the CJ seem slightly harder and more brittle in comparison to the Continuum. I put the Continuum back in the system and started right where I left off yesterday, nice and smooth. I'm afraid that the CJ may have needed another hour or two sweeten up, but when I'd used it in my system it was on standby when not in use and needed only a few minutes to start sounding good. Maybe because it had been disconnected for two weeks it wasn't at its best.
I'm going to make no more comparisons to the CJ. It's a fine amp, but the Continuum is the amp for my old age.
OMG, I got the bill for the phono cards and it blew my mind... $355!! They cost $200 less than the Pro-ject Tube Box that they replaced.
I actually think the price is fair, because the little cars are about the size of the last joint of my little finger. Obviously they're well designed and takes advantage of the infrastructure of the Continuum, but it really only two very small cards. (When Jeff brought them out he said, "Don't let the small size disturb you). I guess my point is, ask a couple of other high-end makers how much it'd cost to add a phono section to one of their pre-amps or integrated amp and see how close to $355 they get.
A further thought or two about the phono "section." The background is total quietness. The tonal balance is perfectly neutral. I've got some RCA LPs of the CSO with Reiner and SACDs of the same performances. Well, the cartridge/phono-stage has the same balance as the the SACD.
With new studio style recordings, like Diana Krall, Nora Jones, Herbie Hancock (River), I can listen deeper into the vocals, hearing more nuance and lower level decay of tones. There's no stress and listening is great. Detail, clarity, dynamics, transparency and bass are all there in abundance and proper balance.
Gee, I can't wait 'til it's burned in. It's hard to believe that it might improve.
Given the sonic delights of those old RCAs, you won't be too surprised that I just ordered about 15 SACDs with Reiner, Heifetz, Rubinstein, Monteux, etc. Layton really knew how to capture an orchestra.
So you see, I'm not purely a vinyl hugger.
With both my vinyl and SACDs I'm worried about transfering it all to a server in the next year or two, when a suitable hi rez server comes out. (I think it's near). I've got a 5.6 MHZ DSD recorder, so I might have to convert, via analog output, to a hi rez format like 24/192 or 24/96. It's doable, but only in real time.
Ah, but I digress, these phono cards are fantastic.
Yes, if I fed it that way. Of course, the phono is unbalanced in, but that's not an issue because you ground to the chassis. Also, since it's an integrated, there's no pre-to-power IC. My universal disc player only has unbalanced out, so I'm just using short unbalanced ICs for that. Anyway, there's a full set of balanced and unbalanced inputs and the Line Out is either balanced or unbalanced.
Rafael, the answer is yes, current JRDG designs are completely balanced from the input to the output signal; so much so that the output signal of JRDG amps have active positive and negative phases. This is one of the reasons why they tend to have superior control of bass drivers of certain speakers with difficult loads -- e.g. Vienna Acoustics. . . . speaker cones are apparently both pushed then pulled, rather than simply pushed then released.
Thank you Dave and Guido. As you describe its suberb design. I wish I could listen top of the line Jeff Rowland amp versus Spectron monoblocks.
However, its academic - I am extremely happy with Spectron and you both guys are very happy with your JRDG's and this is what counts !!!!!
Its been a pleasure.
how does the unit compare to the Concentra IIs of yesteryear? I remember quite a few folks around here preferred the Concentra to the Concerto integrated when it came out. i had the 201s for a bit- which did't really thrill me (too cool/stale sounding) although i did like the Concentra II a few years ago which i should have never sold.
ps. I've always found Meridian CDPs to be very complementary to Rowland
KR, sorry but I haven't heard the Concentra II. The pre-amp section is based off the new Capri that's receiving great reviews. (On A'gon, look for Guidocorona's preliminary review of the Capri and comparison to his ARC Ref3).
Sweet is a word that comes to my mind, but it's toward the cool, neutral end of the spectrum IMHO. Without glare, but clear, transparent, sweet and open.
Compared to the 201 and the 501s, the Continuum 500 has the PFC (power factor correction) which I suspect contributes much to the stable effortlessness of the sound.
Here's a follow-up on the little $355 phono stage now that it's got between 150 and 200-hours:
My first impression still holds, it's very transparent, revealing and sweet. The quietness is incredible, no different than the line-stage with the universal player.
Perhaps a not-so-great recording made it most clear how deep that I can look into the music. On the advice of a friend here on A'gon, I bought Decca's Solti/CSO performance of Beethoven's 9th. The performance is indeed amazing, with Solti milking the great orchestra for all it's worth. Unfortunately, the balance is very unnatural, with the chorus dominating the orchestra and the strings dominating the brass. In the real world this doesn't happen. I much prefer the RCA CSO recordings, mostly with Reiner. They've got a concert-like balance.
With my Pro-ject Tube Box SE phono-stage the Solti performance just seemed homogenized and I couldn't really make out the brass with any clarity. With the Rowland I can "listen through" and hear everything in detail. Yeah, Bud Herseth was present blowing his brains out on first trumpet. Farkus was there on horn and Arnold was there on tuba. Of course the balance was still not right, but I could hear every detail through this very dense recording.
Listening to Ella and Joe Pass on the fantastic reissue of the Pablo's "Take Love Easy". The pressings are incredibly quiet 45 rpm. Ella's late-career voice is rich and details. The details of Joe's playing on acoustic guitar (he alternates between acoustic and electric)are incredible, including his fingers on the strings, the air around the strings and the woodyness of the guitar body.
On Eva Cassady's "Songbird" album, the reverb is more etherial. This is a great album, with very mixed production values. Much of it was originally recorded in Eva's home studio (her bedroom, I understand) and then production was layered on after her untimely death. You hear the piezo pickups of her guitar into her prosumer recording deck, then you hear pro-studio effects added on, with strings here, electric guitar there, etc. I heard this stuff with the Pro-ject, but it's now crystal clear, like I'm listening to the master.
Maybe you're worried that something so revealing may be TOO etched and detailed. Well somehow the Continuum's phono-stage stays sweet. The highs are accurate and detailed, but not overly emphasized.
BTW, so you don't have to look up my system, I'm using a Pro-ject RPM10 TT with the Speed Box II and a Sumiko Blackbird high output MC cartridge. This rig is at the point I consider to be entry level high-end, equivalent to say the VPI Scoutmaster.
Here's another follow-up. The top of my C500 is hot to the touch. You can hold your hand on it, but it gets uncomfortable after a few seconds. When we visited his shop in Colorado Springs (see JRDG Tour) I guessed that the temp was 130-degrees and asked Jeff if this was an issue. He said it's not where close to a problem. He said that the C500 runs hotter than the C250, because the PFC units in the 500 generate some heat.
Today I actually measured the warmth at 120-degrees with the armoire door closed.
Lots of ICEpower units are cool to the touch and I've heard stories of one or two Continuum 500 owners being concerned about the heat, so I wanted to discuss this issue here.
I have had the Continuum 500 in my 2nd system for a couple of months now. It replaced an Accuphase E308. All i can say is wow! It was as I had washed the windows. Very revealing. This amp is definately better than a lot of more expensive separates out there! Very musical, dynamic and powerful, but never hard or edgy. Sounds close to the real event.
Other equipment in this system: Modwright transporter, Audio Physic Virgo 5 speakers, Synergistic Research Tesla APEX interconnect and Tesla Precision Reference speaker cables.
I am currently using Burmester 011 preamp with the 301 monos, but I will soon upgrade to Burmester's new reference preamp (model 077). The Burmester add some warmth to the sound, but is also very dynamic and musical and I really like the combo. I have not tried the Criterion preamp, but it should be very interesting... The reason I have ordered the Burmester ref preamp is because I already have the Burmester ref CD player and I got very good deal for trade in of the 011 preamp.
The 501 mono (+PC1 power correction unit) is only used for center channel. Surround processor is Cary Cinema 11.
I have not done a comparison between C500 and Burmester 011/301 in my main system. I am sorry but I think I will have some problems doing that because of cable lengths etc.
I have a listen and wrote a short review on the Continuum 500 recently. Overall, apart from some niggling concerns i throught the amp was pretty impressive.
I wouldn't mind about damping factor. My 301s drive my speakers, Aerial 20T, with ease. Full control! They replaced Theta Citadel monos. The 301s are in comparison more dynamic, open and resolved. The Citadel had a warmer sound though, but with Burmester front end as I have I find the 301s to be a perfect match.
PS: My 501 mono drives an Aerial CC5 speaker. Aerial speakers are not the easiest load, but the 501 was a huge improvement over Cary Cinema line when it comes to dynamics, openness and details. Because very much of the audio in a movie goes through the center channel, the 501 has lifted my movie experience to a new level. I can hear the improvement not only for music, but dialogue as well.
Kiwi's well written review of the Rowland driving his MBLs concerns me just a little, because I don't think that the MBLs are the type of speaker that most users would combine with the Rowland.
I've never heard a truly successful MBL setup, due to my very limited exposure to them rather than their own fault, only in showrooms. I suspect that they can be made to sing, but they had a slight "character" to their sound when I heard them. Thus, I suspect, part of their "voicing" will come from the amp choice. Since Rowland leans toward the very neutral, no compensating voicing can be expected.
With more "traditional" speaker choices, like Vienna Acoustic, Wilson, Sonus Faber, Aerial, DALI, Magico, ProAc, etc., etc. the Continuum 500 will be a very musical match.
Gents (Guido, Mapman, Dave),
In response to your questions here and in the 'best integrated thread' i would concur that the Rowland is an outsiders choice for powering MBL speakers.
Most MBL owners opt for big monoblocks or stereo power amps either from MBL or from other manufacturers such as McIntosh [500 Watt popular], Plinius, Boulder, Pass Labs, Krell or BAT.
That said, the MBL speakers are open, airy, dynamic and superfast and the Continuum 500 is clear match for these attributes plus the Continuum absolutely has more than enough grunt to pull it off. The front end digital is noted [see audiogon site for reviews] for its musicality and warmth so no issue there.
The dealer was unsure how many hours had been clocked on the JR so i'm not able to specifically comment, other than to note that the unit was not brand new.
Comment has been past that the MBL is not a dynamic speaker. Certainly, that true of the mid/tweeter but outside of that the MBL has dual 5.5 inch and dual 8 inch cones to push.
Kiwi, I suspect you may have been reviewing a device that was not fully broken in. Switching amps do very strange and often unpleasant things to the treble until they have stabilized. . . and stabilization may not occur for about 1000 hrs of playing time. May I also ask how many hours of active warm up you allowed before performing critical listening.
Yes, I didn't mean to say that the MBLs are not "dynamic", it's just that much of the midrange comes from an unusual driver (for lack of a better word).
The Continuum 500 does indeed need 150-200 hours to sound it's best, IMHO. (It's less than some other Rowland products, probably due to the heat generated by the PFC units). I've also found that if you unplug it for even a short while, then it needs a full 24 hours to get to "full song." It's very presentable after an hour or two, but doesn't get as fully involving until a full day or so.
When combined with speakers such as Magico, Vienna Acoustics, DALI, Sonus Faber, Wilson, Magico, etc., etc. it should be on the short list with Mac, Plinius, Boulder, Pass Labs, Krell and BAT for consideration. I suspect that properly broken in that it'll work very well with the MBLs, but there may or may not be some special issues there.
Digital sources are the subject of much debate. I'll just say that the Playback Designs MPS-5 is a wonderfully musical match for the C-500.