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Jeff Rowlands Amp and Dac vs. VAC amp and DAC

Hello, I am new to this forum but I have a question. I am trying to pair an amp + DAC with my Wilson Sabrinas. I have listened to Jeff Rowlands integrated with the Aeris DAC. And the VAC Sigma integrated with the Aeris DAC. Price is a factor and so is space. Does the 625 need a pre-amp? Any suggestions or thoughts? 
rinpoche
rinpoche OP
154 posts
 
Again, a lot of good information is arising in this thread. To answer the question about what other speakers I auditioned -- I didn't. I had no intention of even purchasing speakers. I went to a Sabrina audition with Peter McGrath and lo and behold I was hooked. At the time it was used with MacIntosh equipment (not my favourite) but they sounded just great. I loved everything about them. The were refined, warm and yet alive all at the same time. I love the cabinet (also important to me). And by selling my older equipment I could afford them. I haven't listened to anything else. I think they are perfect. I just want to pair them with a good amp and be happy listening!! 
guidocorona
4,298 posts
 

Al, the Aeris volume control is neither purely digital nor purely analog. Per the Rowland knowledge base, it operates by varying the reference voltage in the DAC chip. See:

http://jeffrowlandgroup.com/kb/questions.php?questionid=617

There is a variety of other technical information on the Aeris DAC in the Rowland knowledge base:

http://jeffrowlandgroup.com/kb/categories.php?categoryid=205

Regards, G.

guidocorona
4,298 posts
 
Oops... You are right Al... 0 attenuation / unity gain is for DAC feeding a preamp... I Must be getting old! G.
almarg's avatar
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almarg
9,670 posts
 
Thanks for the references, Guido. I read through the one on "DAC-based Volume Control," and many of the others. All of which seemed to me to be informative, meaningful, and technically persuasive, yet concise and well presented.

A model that would be good for other manufacturers to follow on their websites, it seems to me. Assuming, of course, that they have similarly meaningful and technically persuasive information to present :-)

Best regards,
-- Al

rhljazz
1,255 posts
 

One of the amplifiers used in the Stereophile review of the Sabrina was a Mac 275.  The reviewer first used the 4 ohm tap and thought it sounded fine.  Wilson's Peter McGrath mentioned that Audio Research amps sounded best from the 8 ohm tap.  The Mac was switched to the 8 ohm tap and both McGrath and the reviewer preferred the 8 ohm tap.  Therefore, setting the output tap to correspond to the lowest impedance dip may not result in the best sound.  Even though the reviewer acknowledged the solid state amps provided deeper bass, he preferred the overall sound best with the tubed Mac 275.

Comparing the anechoic frequency response whereby there is a pronounced upper bass hump to the impedance magnitude indicates this is where impedance is lowest.   A tube amp will likely produce less drive in this range which may minimize the bass hump.  It was also noted the Sabrina's bass Q was on the under damped side which a tube amp will tend to make more pronounced which may even things out.

I prefer a quality tube amp for its more natural sound.  Have fun in the auditioning process.  

 

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