CAT SL MKIII vs ARC SP 11 or 10

Has anyone compared these two preamps? I have a VT100 MKII and am looking for a good used preamp with phono. I like what I've heard about the CAT and the SP 11 and SP 10. What would you recommend in the used category for upto $2600. Should I go with balance outputs?

I had an SP 11mk2 and a VT100mk2. I replaced the SP11 with a CAT Ultimate. The CAT has a few quirks, the power supply hard wired to the control unit and a volume control lacking in flexibility, but it's sound was a step up. The bass is fuller and tighter. The soundstage is bigger and more percise. The SP 11 is a fine unit and I don't mean to suggest it isn't a good choice. However, it is more colored than the CAT Ultimate. In some systems the SP 11 may be a better fit, but the CAT is more tranparent to the source.
Well, I have a CAT SL1 Sig Mk3 & I really love it. The phono stage is really quiet, dynamic & produces some really good music.
My friend has a ARC SP-6A. Once Richard Gray (of RGPC) brought it up to spec & K & K Audio changed the coupling caps to Kimber + changed the power supply caps to Panasonics + changed the RCA output jacks to Vampire + added an IEC, the SP-6A sounded very good in my system as well. The bass of the SP-6A is not as deep & controlled as the CAT, the CAT has better high freq extension. However the SP-6A has that ARC signature midrange that has bloom that I have not heard in any other product.
I like the CAT better while my friend likes the SP-6A better!
IMHO, you cannot go wrong with any of your listed choices.
I have read many times that maintenance of tubes in the SP-10 & SP-11 is expensive. Each time the owners tried to save money buying less expensive tubes they felt that they had wasted their money (sound degradation) & that they should have paid the extra money for those expensive tubes. No personal experience - just telling you what I have read.
Search the archives of Audiogon & AA. FWIW.
CAT Ultimate or SL1 Sig. Add to the comments above, the CAT offers very good dynamics. Also drives difficult loads beautifully. True, it's more on the "neutral" side than the ARC.
If you want classic tube sound and a great phono stage (OK line stage, but the phono is the real reason to buy it), you should consider the SP-10. If you'd rather have more neutrality and frequency extension, the CAT is likely the ticket for you. All of the choices you listed are fine performers, it just depends on what sound you're looking for.

Let me be a bit of a contrarian here. I have owned (and listed in order of preference) the SP 10, SP 11 and CAT Ultimate. To my ears, the CAT is the most dead piece of equipment I’ve ever heard. That thing was dull, opaque, sterile and lifeless. “Neutral” maybe, but it did not begin to capture the essence of music. I had the SP 11 at the time I bought the CAT and tried for quite a while to convince myself that the CAT was an improvement. Finally, I put the SP 11 back into the system and did a direct comparison. The CAT was listed here on Audiogon the next day.

I bought my SP 10 after that episode and sold off the 11. I lived happily for about a year at which time I began to get interested in digital. Up to this point, I had use primarily analogue sources. The main short coming of the 10 is it’s line stage. It’s not that the line stage is bad, it’s that you have to take the 10 out of by pass mode to access it which in turn puts all of the front panel clap-trap in the circuit. This definitely degrades the sound. Since I had gotten fairly serious about adding a decent digital source, I debated whether or not to send the 10 to Great Northern Sound for modification or to look elsewhere. In the end, I bought the Herron line and phono stages and sold off the 10. I have lived fairly content with these for the last couple of years.

As a footnote, I had a chance to hear a Friends 10 a couple of weeks ago and there is still something very special about that pre-amp. It makes music like none other I’ve heard. It has a liveliness that I’ve not heard elsewhere. It might have something to do with the two 6L6’s in the power supply. I am hopeful that the Aesthetix combo (that I should get to hear in the next couple of weeks ) will combine the best of the 10 and Herrons in one package. This may be my final resting ground for a pre-amp.


I agree with Rcprince, it is a matter of taste with these excellent pre-amps. I have an CAT SL-1 Mk 1, an audio buddy has an SP-10 Mk2. Each have their specific virtues. The 10 has a lovely bloomin midrange with depth that defines the term "musical" it is beguiling but is less extended at either end. The phono stage of this unit is more preferable to me than the CAT or even my current pre-amp for that matter. The CAT is more neutral with better extension. But neutral is a relative term. Compared to the current crop, the old CAT isn't as neutral as many out there.

The SP-11 I haven't listened to for years but it seemed a bit "whiter" sounding and maybe more transparent than the other two. This was my definite impression when compared directly to a 10 in the same system over a relatively extended period. I always liked the 10 better, more romantic and involving, personal choice and a different time. The 10 is a real classic but does require expensive retubing (read good NOS) You need to listen to hear what camp your in or hopefully you can read between the lines and have a better feel for the differences.
If you intend to keep the CAT, I strongly urge you to send it back to the factory to get it upgraded to Mk 3 status. You will change your impressions of the CAT for the better! The Mk 1 (I assume you have the Signature Mk 1) uses 12AU7 in the V1, V2, V6, V7 positions, which are the input stages for the phono & line resp. The Mk 3 uses 6922 in those positions. I believe that the latter is much better sounding than the Mk 1 that you have. Also much quieter. The tubes last much longer too. If I remember correctly, the Mk 1 version "ate" tubes.

I concur that the CAT doesn't have the ARC midrange bloom. However, I FEEL, that this midrange bloom is "beguiling" as Tubegroover put it. It is artificial i.e. not real. Some people prefer their music this way. So be it. So, I agree, you'll have to discover which camp you belong to & accordingly make your choice.

The CAT volume control is a PITA, I agree! 1 click down is too low & 1 click up is too high! However, CAT does offer a volume control called "CD taper" & is designed to be half the volume increment steps than the default factory volume control. I believe that from 6 o'clock to 12 o'clock on the volume control you get volume increase in half the dB increment steps as the default & past 12 o'clock the volume control steps are exactly as the default. FWIW.
Put the CATs Ultimate aside (since I have not heard), I would probably choose ARC SP11 MKII for my setup. There are only 6 tubes (3 for phono and 3 for line stage) in SP11 MKII so the tube cost is relatively cheap.
Depends on match up, the CATS is definitely more opaque than ARC. In my opinion, the CATS is less musical to my ears. However, either one should be a good choice.
These comments are interesting. Years ago some felt the SP 10 was more musically involving than the SP 11, as the SP 11 moved toward more accuracy. Especially in the phono stage, the SP 11 wasn't as bloomy or euphoric. Some of the comments here now are the CAT Ultimate falls flat musically because it isn't as musical as an SP 10. I spent years with an SP 11 and now I've had the CAT Ultimate for a few years. With the CAT it's easier to hear the difference from one recording to the next because it colors the sound less. It exposes more information, good and bad, than the older ARC units rather than wrapping the sound in a euphoric coloration.

Speaking from years of experience Jld1965 should go one of two ways. If the phono stage is all he's going to use he should go with the SP 10 if he's looking for the "golden glow" sound. If the line stage is of material significance, go with the CAT Ultimate or MK 3. The SP11 doesn't have as good a line stage as the CAT and if a euphoric phono stage is what he wants why stop halfway?

Buy gear to enjoy the music! Not to tell which recording is better or worse. That's engineer's boss' job! We are music lover aren't we?
Bombaywalla and Egrady yes, the 10 is euphonic and a bit more than real but what is really telling is that my heart ALWAYS enjoys if my brain is telling me something different.

So far as the CAT is concerned, yes it is murder on tubes, noisy and all that but said and done it is really a nice piece. Excellent line and phono stage. The noise is what is bothersome to me, and the tubes, does it burn through those 12au7's!! Interestingly on this topic Anthony Cordesman did a comparison of these 3 preamps in a 1986 issue of Stereophile that I just revisited, a review of the CAT. His conclusion was quite the same as the comments here with the 10 being the more colored, the CAT being closer to the 11 but the 11 reigning as the SOTA at that time. "If you own a 10 DON'T be so hasty to trade it."

It isn't quite so easy, is it? I can't bring myself to sell the CAT. Maybe I'll try that upgrade Bombaywalla.
Tubegroover -- I never had noise from my CAT, nor did I change tubes for 2 1/2yrs (OK, that's not so long). Maybe that upgrade is indeed in order?!
Greg the noise is definitely from the tubes. Unless they are quiet the noise will come through and they don't seem to last long in that circuit. It has been a continual issue since I've had the CAT. Of course this is the Mk 1

>>I can't bring myself to sell the CAT. Maybe I'll try that upgrade Bombaywalla.

I think the above statement says it all! Case rested.

Please do yourself a favour & get that upgrade! That noise floor will disappear totally & the tube reliability will increase by a huge margin. For ex., I have my Mk3 version since Thanksgiving 2001 with the tubes that came w/ it. Going strong & no need for any replacement at this time.