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As I understand the Rowland 201/501 use the icepower asp modules from B&O respectively. This being the case with the exception of the difference in power is there any difference in terms of performance especially for low efficiency speakers. I am using the MBL 121 bookshelf speakers(SPL 82db, 4 ohms) in an apartment.I have received comments that rowland 501 may be perceived as "warmer" than the rowland 201. Assuming that the only difference internally between the 201 and 501 are the icepower modules (I stand corrected but this is what i understand from my dealer) can there be a difference in terms of sonic characters between these amps.
Follow Ups:
A Taiwanese company, Murano-Audio, offers various monoblocks based on the ICE modules. There model- P1000S Plus uses the current revision of the 1000ASP module with a Lundahl input transformer. This is very similiar
to the Rowland 501 mono amp,although the Murano's transformer is shielded/covered. I have listened to 2 different pairs of Murano P1000S
& both the JRDG 501's & 201's. About the only 2 main differences are the chassis design & build and the pricing. The P1000S & the 501's both sound quite identical & both very good. The P1000S has an attractive, nicely done chassis & the Rowland aluminum machining is state-of-the-art
classy. The bottom line: Murano's @ $1798.00/Pair - Rowland's @ $6900.00/Pair. I'm heading over to the Murano Audio online store (US)...
Check out wryed 4 sound,if you want decent prices
I used to own 201 and then upgraded to 501. They sounded similar in tonal balance, but as you would expect 501 is more dynamic, has more head room, better control in bass and sounded more effortless in loud passage.Actually, my speaker was upgraded to MBL 116. Although I have not tried using 501 to drive them, my strong suspicion was that 501 would not have sufficient power and current to push these low-efficiency speakers, and I sold my 501 as a result.
I am surprised you sold yr amp without trying it on yr MBL.AFAIK, 501 cld drive almost any speakers available. I owned Rowland 8Ti and it drove my 111A with current to spare. You will be surprised what yr 501 can do. It gets warmer sounding after it is broken in and loads of power.
With the rating of 1000w into 4ohms I am surprised if the Rowlands 501 are unable to handle the load of the MBL 116 or 121.Of course the MBL's have a reputation for "eating" up loads of power but the volume, genre of music, room will play a large factor.
With your MBL 121 speakers combining low efficiency and low-ish impedance, they will demand both watts and amps to perform at their best.In the context of your speakers, the differences between the ICEpower 1000ASP modules (as used in Rowland's Model 501's) over 500ASP units (as used in Rowland's Model 201's) lie in two areas:
a) Power (watts into 4 ohms): 1,000 vs 500
b) Current (amps-continuous): 45 vs 35The real overall difference between the two lies in the area of dynamic headroom.
Given a reasonably tricky speaker load/efficiency combination, the additional headroom offered by the 1000ASP units will result in a presentation that is "more effortless" as these units would, in comparison to the 500ASP's, be operating well within their performance envelope. This would be more obvious on recording with a wide dynamic range such as the Grieg Piano Concerto and other similar pieces.
As to whether or not this would result in a "warmer" presentation is debatable.
There are two reviews of the Model 201's here in AA's Product Reviews section - one of which offers some insight into the relative merits of the 201 vs the 501 (by "fiji"). Here are the links:
I have had the Model 201's for 3 years, but driving fairly sensitive speakers (~93dB/w) and find them more than adequate. I did manage to borrow a pair of 501's a couple of years ago for an A:B test and found the difference to be discernible, but not enough to justify the price difference. (In your case, the lowish efficiency will result in a more noticeable gap - particularly on classical music).
If you are interested in the underpinning technology used by B&O in their ICEpower modules, they do have have a website with a fair amount of detail on the background, technology, design, specifications and reviews for products that utilise the technology. The link below will take you to their website:
B&O ICEpower - Audio Amplification Solutions webpage
The Jeff Rowland website has separate webpages for each:
Jeff Rowland Model 201 webpage
Jeff Rowland Model 501 webpage
For some unknown reason, $tereophile has not reviewed any of the Rowland ICEpower-based products and Rowland are not well-represented in the UK, so no reviews from that quarter either.
Another occasional visitor to these electronic halls (Mike Mount) has the 501's and his glowing reports were the trigger that made me switch from Classe' to the 201's - a move I've not regretted for one second.
I've seen a review from Absolute Sound comparing digital amps and interestingly 2 writers (Neil Gader & J Valin) rate the 201 second best in a list that includes spectron, kharma, cary, nuforce, CI audio, audio research, and red dragon. The comment on the rowland 201's were that they had a "problematic treble" as in all class D/T amps. The positives includes an exceptional midband and outstanding bottom octaves.I appreciate your comments and can understand your argument that low efficiency and low impedence would require more watts.
Please excuce me.
Does the information of 35 A continuous for the 500ASP unit come from a reliable source?
If so even the 500ASP module based Rowland's Model 201 should drive effortlessly pretty much any speaker on the market.
I mean, 35 A RMS is an enourmous amount of current.
This topic is extremely interesting to me.
I feel that in the next future there will be more and more switching power supplies in audio power amps.Thanks a lot and kind regards,
Hi Beppe,The source of the specifications was B&O's ICEpower website and a downloaded product datasheet for this module.
I mistakenly added the word "continuous" - this is incorrect usage, as the 35 amp figure is, in fact, quoted as "Maximum current draw from amplifier output" and is, more than likely, the threshold setting for the on-board "Over-Current Protection" circuit.
Based on the Power @ Impedance values quoted of
a) 500 watts into 4 ohms: Current drawn = ~11 amps at ~45 volts
b) 250 watts into 8 ohms: Current drawn = ~06 amps at ~45 voltsBy extrapolation (no figures quoted in datasheet) values for lower impedance loads would look like this:
c) 1000 watts into 2 ohms: Current drawn = ~22 amps at ~45 volts
d) 2000 watts into 1 ohms: Current drawn = ~45 amps at ~45 voltsThe datasheet does quote the acceptable speaker impedance load range as being between 2 ohms and 8 ohms, but no figure is provided for rated power output into 2 ohms.
Given a maximum current level of 35 amps, any load less than 2 ohms is likely to pose a few problems.
BTW, I did include a link to the ICEpower website if you wish to dig any deeper.
Thank you very much for your kind and very valuable explanation.
I did listen the Model 201s (driven by a Jadis preamp and driving B&W Nautilus speakers) at an audio show in Milan some years ago.
I liked very much what I heard.
A nice clean relaxed sound. Very good indeed.Thanks again and kind regards,
beppe, do you feel that switching power supplies are better or worse?
My H2O amps use a linear power supply. Used in conjunction with carefully chosen attending components, the sound is utterly sublime. The same builder makes far cheaper ASP module amps. He will be the first to admit, the sound of the linear power supply amp is solidly better than that of the digital.
Well to be honest I am gathering information on the subject in order to try to understand better.
I notice that the very best power amp, at least in terms of driving ability, still have traditional linear power supply.Going back to the JR Model 201 I feel that the 35A continuous figure is optimistic.
I have at hand an Italian magazine with a test report of the Model 201.
I can see a graph of the power output showing about 18A continuous on a pure resistive 2 ohm load (648 W) and about 12A on a 4 ohm load (576 W).To end I really do not know if there is an overall better tecnology.
Maybe not. It could be just a matter of implementation, construction.Kind regards,
beppe
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