I recently bought a used Stax 323s amp/'driver unit' (thanks, Mike!) to upgrade my Stax gear, and have been listening a lot. I thought I would share my impressions.
After a very pleasant morning listening to a variety of orchestral and vocal music along with some 60's-70's rock, the SRM-1 MkII (as it stands now, it's 26 years old) is more 'restricted' than the 323s. The 323s is more powerful in the sense that I have to reduce the volume with the same pair of Stax 407's, also with my original pair of Lambda's. The 323 seems to be reaching deeper, with a shade more bass impact, and greater clarity. The treble range is definitely wider, revealing more detail. Using the same recording (Decca/Solti/Mahler #1, remastered) and the same earspeakers (the 407's), the brass have more bite with the 323 than with the SRM-1. The bass drums have more clarity; by which I mean that you can hear complete sound of the drum - the initial impact as well as the drum head vibrating after. You can hear the bows hit the strings immediately prior to their first notes, something that is missed using the SRM-1. I also hear some faint tape hiss in this remastered recording that I don't hear with the SRM-1, so something is definitely going in with the treble.
With vocals (some opera and Grace Slick/Airplane/Starship), there is less difference. The two sound very much alike, with perhaps a bit more detail with the 323. Probably because of the closer miking, this is more noticeable on the rock selections than in the opera; but in any case, the difference seems very minor.
So, more power, and a greater range, with the differences being confined mostly to the outer edges of the sonic spectrum, with progressively less difference as you approach the mid-range. 'Warmth', to me, is generally a good thing if not overdone. I'm not a great fan of coldly analytical sound, but I do prefer a balance, not cold and harsh, and not overly warm and mushy. Middle-of-the-road, with a slight tilt towards warmth.
BTW, I noticed more differences between the two amps with the newer Signature 407's than I do with the older Lambdas (which had their drivers replaced about 8 years ago). I'd attribute this to the thinner diaphragms of the 407's... what do you think?
After a very pleasant morning listening to a variety of orchestral and vocal music along with some 60's-70's rock, the SRM-1 MkII (as it stands now, it's 26 years old) is more 'restricted' than the 323s. The 323s is more powerful in the sense that I have to reduce the volume with the same pair of Stax 407's, also with my original pair of Lambda's. The 323 seems to be reaching deeper, with a shade more bass impact, and greater clarity. The treble range is definitely wider, revealing more detail. Using the same recording (Decca/Solti/Mahler #1, remastered) and the same earspeakers (the 407's), the brass have more bite with the 323 than with the SRM-1. The bass drums have more clarity; by which I mean that you can hear complete sound of the drum - the initial impact as well as the drum head vibrating after. You can hear the bows hit the strings immediately prior to their first notes, something that is missed using the SRM-1. I also hear some faint tape hiss in this remastered recording that I don't hear with the SRM-1, so something is definitely going in with the treble.
With vocals (some opera and Grace Slick/Airplane/Starship), there is less difference. The two sound very much alike, with perhaps a bit more detail with the 323. Probably because of the closer miking, this is more noticeable on the rock selections than in the opera; but in any case, the difference seems very minor.
So, more power, and a greater range, with the differences being confined mostly to the outer edges of the sonic spectrum, with progressively less difference as you approach the mid-range. 'Warmth', to me, is generally a good thing if not overdone. I'm not a great fan of coldly analytical sound, but I do prefer a balance, not cold and harsh, and not overly warm and mushy. Middle-of-the-road, with a slight tilt towards warmth.
BTW, I noticed more differences between the two amps with the newer Signature 407's than I do with the older Lambdas (which had their drivers replaced about 8 years ago). I'd attribute this to the thinner diaphragms of the 407's... what do you think?
