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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
ricred1
2,058 posts
 
Guido,

I love the Aeris DAC's sound, but dislike the way the gain is accomplished. Per your statement, "If you use a preamp between Aeris and amp, you should set the Aeris attenuation to the DAC's equivalent of unity gain: per the Aeris manual, the right volume LED is lit up solid without flashing." I was originally told to set the attenuation on the DAC so that the left and right volume LED's are of equal brightness. I didn't have enough gain, so I settled on 10 clicks below the right volume LED flashing. I reached out to Rowland three days ago and yesterday Mr. Rowland told me to adjust the gain as you stated. What a difference and I was thinking of selling my 625 S2 and getting the 725 S2's for more power...NOT ANYMORE, THE 625 S2 HAS PLENTY OF POWER now that the gain on the Aeris has been correctly set.
pokey77
1,269 posts
 

"Pokey77,  ARC GSi75 is using KT150 and 200iq is 100 wpc with KT88 so my guess it can handle a tougher load??   200iq can roll KT150 and I mentioned to dealer it would be an interesting experiment."

Knghifi, let me say, I'm not all that knowledge about tube gear. I just know what I like. And when I heard that ARC amp the first time, the presenter made a special point of it employing the KT150 tubes; I would guess to imply that the amp is stronger than rated. I can tell you that many at the demo were amazed at the power, grip, resolve, and transparency that the GSi75 demonstrated. To us, it sounded like it had significantly more power than its reported 75 wpc. -I've not heard that much tube gear that really impressed me, and I've heard much more expensive tube gear driving significantly pricier speakers, but the GSi75 integrated with the Sabrina's is, for me, heaven. It has that tube magic with SS resolve and clarity. I have no idea what the VAC and the Rowland in this thread sound like. If I've heard them at a show, I have no real recollection.

guidocorona
4,298 posts
 

Hi Richard, I freely admit that the UI for volume attenuation/gain on Aeris is a little, ahem.... Techno-terse.

I would have prefered an LED with attenuation values, in addition to an independent indicator that would light up when the unity value optimum for direct use into amps is reached.... E.g. same solid LED, but with label "Direct".

In general, you will find the Aeris manual to be a pretty good source of operational info on the device. Volume control for direct use into amps is discussed on page 16.

Delighted that with Aeris at 0dB attenuation, your M625 S2 delivers all the juice you need for your hungry speakers!

Saluti, Guido

almarg's avatar
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almarg
9,670 posts
 
Ricred1 5-23-2016 9:14pm EDT
I was originally told to set the attenuation on the DAC so that the left and right volume LED’s are of equal brightness.
It could be that that setting would be appropriate for use with a preamp providing significantly higher gain than whatever gain your Corus may be set to. (The gain of the Corus is indicated as being "Independently Programmable 0 to 20 dB on each input").

I would guess that part of the rationale for the adjustment Guido and Mr. Rowland pointed you to might be that it would minimize possible sonic side-effects of the DAC’s volume control mechanism. Such as what is referred to as "bit stripping," if the volume control function is implemented digitally.

In any event, glad that the issue is resolved. As I mentioned earlier it would seem, on paper at least, that your 625 S2 can provide much more power than would ever be used with your speakers.

BTW, Guido, I think you may have inadvertently misworded the second paragraph of your post just above. I believe the reference to unity value should be for use with a preamp, not "for direct use into amps."

Best regards,
-- Al

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!! 
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