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.
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.