Preamp


Which preamp for a X350.5? The GSPRE or REF 5SE? Mcintosh c2500?
dskinner5
dskinner5 OP
Is the impedence a problem mating the REF 5SE with the Pass X350.5, I`m not understanding the whole thing? Can someone explain this to me?

Manufacturing a product that is dependant on being a good impedance match and having much experience in it now, you should strive for a  output impedance to input impedance ratio of 1 to 20 or higher There is no "written in stone" set ratio, this is just my own observations, some say 1 to 10 is fine, but I think that's cutting it too close. 

The Ref 5se has an output impedance in the bass of 1.447kohm, this multiplied by 20 equals 30kohm the Pass is only 20kohms as advertised.

This is why I said "being transistor the GSPRE should be fine" as it should be far lower that the 5se's 1.447kohm and a better low to high ratio match with the Pass.  

Cheers George 
The 4 preamplifiers that you mention may well be satisfactory. I urge you to explore the Sutherland Engineering model N1 preamplifier. I have been living with mine since January. I wouldn't let it out of my system for anything. It simply gets out of the way. Spectacular!
Is the impedence a problem mating the REF 5SE with the Pass X350.5, I`m not understanding the whole thing? Can someone explain this to me? 
dskinner5

The Ref 5 se has a high output impedance as measured by Stereophile especially in the bass. Steer clear of this pre with the X350.5’s input impedance of just 20k.
" Stereophile: However, at 20Hz the impedance rose to 1447 ohms balanced and 637 ohms unbalanced"

Being transistor the GSPRE should be fine, and I can’t find anything on the Mac’s output impedance at 20hz so being tube it has a ? on it.

Cheers George


What did you have in mind?
We were the first company to produce balanced line preamps, and they are all-tube.

BAT was one of our early customers before they started operations. They make balanced line tube preamps as well.

Aesthetix has long made balanced tube preamps.

IMO the better balanced preamps are also fully differential; if you google 'fully differential tube preamp' and 'balanced line tube preamp' you will get a long list of contenders.
I thought about the Aurender A10 in the front instead of a pre. What are your thoughts?
@dskinner5 if you are looking for a balanced tube preamp, I would not limit yourself to ARC. I'm very sure you can do better and for less $
Okay,good to know, Thank you. If you know anyone looking for a REL R528 in Piano blk in MINT condition with very low hours on it let me know, Thanks again.
The Ref 5se is definitely better than the C2500.  Although I did not compare directly with that particular unit but instead, the comparison was made with the Mcintosh C1100 dual box preamp running through my Pass Labs 160.5 monos and the Ref 5se was still more musical and better in all parameters.  My dealer was informed me that the Mcintosh has a lot more problems with their preamplifiers over the years than Audio Research and my researches over the net had shown that to be true.  Good luck on your preamp searches.
dskinner5, 

C2500 is a nice pre but not in same league as 5SE. In fact, ARC LS28 bettered the C2500 in my system. 

I agree with audioguy recommendation of 5SE if you can’t afford Ref6. But if you can swing the Ref6, you will be set for a good while. 

I am saving up my pennies for Ref6 :-)
I cannot afford the REF 6 unless I could find one for $7500 and in would have to sell my Rel R528 to do that. You say the C2500 is also a step down from the REF 5 SE?
Would recommend the Reference 5se which is definitely quite a step up in performance than both the GSpre (take a look at the interior of both units and you will see the Ref 5se has much more capacitors and beefier power supply) and the Mcintosh C2500.   If you could afford, go for the Reference 6 which is on a whole new level of performance...fast and palpable, even more transparency, more 3D holographic imaging, more deep tight controlled bass.  I would not imagine any other tube preamp under $20K could even compare to the Ref 6.  Especially when running with the Pass Labs amp, the Audio Research will be a match of heaven!