Audio Research Preamp Experts?

I would be using it with a Music Reference RM9 Special Edition. Over time, I have noticed great regard for the LS5 series. My understanding is that the LS5 is all balanced inputs and outputs, but my Merlin VSM BAM has simgled-ended outputs and the amp too is single ended - is this a problem? I am looking for bloom, 3-d, and expansive staging from the preamp. I've used the CAT SL1, Lamm LL2, and Joule LA150 Signature Edition. I use a Lightspeed Attenuator with the Music Reference amp in my set-up, but what to have a tube preamp under 3K to throw in every once in a while. I also want to own a "classic" that I can enjoy and admire from an early period.

Impedance matching between components from source through amp is the main technical spec that can be used to determine likely better matches producing better dynamics, lower distortion, etc..

10:1 ratio or higher of input impedance to output impedance upstream is generally considered good.

Tube gear like tube pre-amps has higher output impedances than SS making meeting this goal less guaranteed without checking first.

I suspect Merlin Bam to be tube friendly, so I would not expect a problem in general with tube pre-amps there, but BP would be the one to say for sure.

I recently upgraded to a remote controlled AR REF 3 pre-amp from my SP-11. I was allowed to take home an SP16, 17 model, and I also compared the retubed SP-11 with all of them and other AR LS models along with Boulder's top-of-the line, Krell's and others.

The SP-11 retubed is very close and a wonderful pre-amp. Better than most in AR's line with the exception of the LS model directly below the REF 3 (can't remember the number), REF 3 and above.

So, for the money, the SP-11 and SP-15 would be the way to go. If you have a little extra, the LS model directly below the REF 3 or the REF 3 are better. But, money is always a factor.

system integration is an important factor. However, compare apples to apples and remember, companies make their products and money based on price points. Therefore, "typically" similarly priced components should be compared and swap one component only and listen. don't change cables, tubes, etc. If you are evaluating a pre-amp. Listen to your favorite, most revealing music through your existing system, then swap the pre-amp (Only) and listen to the same music again.

However, if cost is a factor, and a REF 3 or above isn't in the cards, you can't beat an SP-11 or SP-15 for the money and you get a decent phono stage to boot.

enjoy.

So you feel the LS25 or 26 (The ones below the REF series), is better than the line stages from the earlier years? Like LS5s or SP10 or 11s etc. Is there pretty much consensus on the idea that ARC has simply improved over time? Is the LS25KI an improvement over the LS22? Feelings about those two? I understand that many prefer the LS25MKI over the MII (6922 to 6H30?)

How would the line stage in the SP-3c compare to the aforementioned "favorites" ??