Pass Labs versus Jeff Rowland, Audio Research


As I am considering replacing my trusty pair of Jeff Rowland 7M monoblocks, feeding a pair of MagnePan IIIAs, I am looking at both the current Jeff Rowland lineup, as well as at the latest incarnation of the Pass Labs X series, dubbed the X.5 series, and some Audio Research models.

In the Rowland lineup I am considering the 501 monoblocks, or the 302 stereo amp, while I have already determined first hand that the smaller 201 monoblocks do not drive the MagnePan IIIA pair adequately.

In the Pass Labs lineup I will consider the X-250.5 (already released), the X-350.5 (just out of engineering), and the upcoming X-600.5.

From Audio Research I already discarded the otherwise extremely lovely VT100 as just slightly underpowered for the Maggies, but will consider the VT200 stereo, the new VSM220 monoblocks, as well as the VTM200 monoblocks.

The rest of my system consists of EAD T1000 CD transport and EAD DSP7000 Mk3 (these likely to be replaced by Esoteric X-01, and an Audio Research LS2B.
I most listen to classical, and within it more to solos and small ensambles than to large orchestra.

I'd value all opinions! In particular any comments concerning the relative merits of the newest Pass amps vs the other brands would be very appreciated.
According to Pass and to those dealers that have already the new X.5 models, these new boxes have a more refined and detailed sound than the old X models, and a fuller fleshed-out midrange. But, how do they truly stack up to Rowland and Audio Research?
guidocorona

Showing 7 responses by guidocorona

Eliahu, my experience is somewhat between cursory and extensive. I spent about 4 hours with a dealer and the 201 were among three amps I listen to. I am not sure how much the devices were broken in, but I know they had been running for several days. I loved the 201 monos, but they could not drive the ManePan 3.6 speakers enough. If the recording got a little excited, the soundstage flattened down. I suspect the 501 pair would have done a lot better. It is worth investigating the 201 and 501 chipsets further. the Rowland web site suggests that 302 and 301 are in fact using the IC chipset, which is made by B&O.
Thanks Dave, the info on the X.5 internal changes are still scant. The best info I have found so far seems to suggest changes in the power supply have been included. Here is an extract from an ad for the x-250.5 on audiogon: ". . . addition of single-ended Class A bias, high speed fast recovery rectifiers in the power supply, and some changes to the front end circuitry have been made."
But we won't really know until someone posts a detailed report. have reasons to believe that such changes will be migrated upwards in the product family. I can only guess that the high speed rectifiers may yield improved performance on transient envelope.
And yes, I am tentatively oriented towards the future x-600.5 monoblocks as the MagnePan IIIAs are 4 Ohm bipolars with a low 83Db efficiency.

But transient response is not all that my admittedly fickle self is seeking in this--not just 7-month but long 7-year itch--but also detail, sweetness, delicacy, microdynamics, and overall glow.
In other words, the new am must be the one I want to marry, not the one which I would date once, to yield raving excitement for a hot and stormy one-night-stand.
Thank you so much Dave and Muralman1 for the input.
What is the efficiency of the Apogee Duetta and their impedance?
Please tell me more about the H20 Signature.
I have auditioned the Rowland 201 monoblocks, rated at 250W, also based on the B&O chipset. They sound very magical in many ways, but they did flatten out the soundstage at the minimum excitement while driving MagnePan 3.6, which are just slightly more efficient than mine.
Thank you so much Fernando. I am in fact considering very seriously replacing my EAD T100 + DSP7000 with the Esoteric X-01. In addition I may be able to upgrade either my amplifier or my LS2B preamp.

As you have used both Rowland and Pass Labs amps, what did you find to be the sonic differences between the two brands?
Of course, I am also considering ARC for either the amp or the linestage. Thanks to everyone's input this far. Please keep postings coming!

Guido
Good point RMDH. Have you compared ARC 300.2 with Rowland 501 monoblocks? Excellent idea about Shunyata Anaconda. I have tried this chord at Andy Singer's shoppe in N.Y. recently and I am totally sold on it.
Mfslgold, I'd love to heed your advice, if I were not addicted to MagnePan, that regretably are such unrepentant juice guzzlers.
Could I ask you to comment on the sonic characteristics of the Rowland(s) and ARC(s) that you owned? Thanks, Guido
I have just posted a brief update on the development of the upcoming Pass X600.5. Please see:
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1100367851&openmine&zzGuidocorona&4&5#Guidocorona