Pass Synergy with Audio Research

[petroengr]

Looking to bring the rest of system into this century by adding a Pass amp (XA160?). All source equipment is AR--LS27, DAC8 and PH8. Realize that there many variables, but does anyone have any thoughts about this combo?

 

[mep]

Looking to bring the rest of system into this century by adding a Pass amp (XA160?). All source equipment is AR--LS27, DAC8 and PH8. Realize that there many variables, but does anyone have any thoughts about this combo?

Curious as to why you don't want to get an ARC amp to go with the rest of your ARC gear?

 

[petroengr]

Don't want to deal with power tubes. That being said, I really haven't given much thought to AR solid state amps. Just starting this upgrade process. The last time I played the game was in the mid-late 90s.

 

[mep]

One of the good things about the REF 75 is you only have to deal with two matched pairs of KT-120 tubes.

 

[joeinid]

What are your speakers?

 

[rockitman]

what's the rule of thumb of pre output impedance to power amp input impedance ? That should better address the OP's original query.

 

[puroagave]

what's the rule of thumb of pre output impedance to power amp input impedance ? That should better address the OP's original query.

amps with high input impedance are an easier load for preamps to drive (50K ohms and above). some SS amps have an input impedance of 10k which pretty much guarantees matching to a SS preamp unless the matching tube preamp has an output impedance well under 500 ohms (not common).

 

[Bruce B]

what's the rule of thumb of pre output impedance to power amp input impedance ? That should better address the OP's original query.

I thought the input impedance of the amp had to be at least 100x that of the output impedance of the pre?

I see the Pass XS series, the pre has an output of 20 ohms and the amp has an input of 200k !!

 

[rockitman]

I thought the input impedance of the amp had to be at least 100x that of the output impedance of the pre?

I see the Pass XS series, the pre has an output of 20 ohms and the amp has an input of 200k !!

That sounds like a good match. The XS Pre is next after my RTR binge coming up...then I am done....

 

[petroengr]

Speakers are ProAc 2.5...sensitivity is so-so at 86dB. Likely to be replaced at some point.

As far as impedance matching; the AR output is 700/350 ohms (balanced/SE) while the Pass is listed as 30K/20K...I assume the 30K ohm figure is balanced. Based on these specs, the ratio for balanced is about 43x and 57x for SE (I'm running balanced ICs). My current amp (Classe CA200) has a stated input impedance of 75K ohms. With the the AR pre, this gives 107x.

I guess my original question re. synergy has to do with these ratios. What impact does the ratio of impedances have on the sound?

Appreciate the input..

 

[Pierre]

I own a set of Pass XA100,5 and have owned a LS17 and LS26.
They sound great with Pass, but the gain is not a perfect match. As i have understand is, Pass have the biggest gain in there power amps and ARC have the gain in there pre amps.