I might as well throw in an idea or two ...
What about the ultra efficient speaker route? Klipsch Belle, K-horn, Altec Model 19? The Aleph 5 should have more than enough power to drive speakers with that high of efficiency. Youre current system is hardly lacking from my perspective.
You might want to ask the question: "What is it you seek?" "What is it that you are looking to improve?" Your post leaves a lot to the imagination.
One other possibility that jumps out at me is adding a tube linestage. An ARC LS-25 with balanced in and out might give you a slightly more relaxed sound. That matched with the horns might be an interesting change. Then again, it might be a little too much switching around. Maybe start with the linestage? I am running a Modwright SWL 9.0 Signature with Proac Responce D Two speakers and I am really happy. That being siad: I am in a small bedroom so there isnt much space to fill. I have a close friend with a Pass Labs X350, an ARC LS-16 and B&W 802's. I found this to be an excellent combination in a fairly large room. The Pass amp and ARC tube pre seemed to match up quite nicely. He went through several combinatione before deciding on the Pass Labs amp. If the Aleph 5 isnt enough to drive whatever speaker you choose, possibly jump to an X150 or X250?
What worked for me was to first choose a speaker that fit my room and musical preference ... then find a linestage/amp combo that gave me what I was looking for in terms of presentation and volume level. Finally I purchased an excelent DA converter and I am very pleased.
My current system :
Modwright SWL 9.0 Signature
Mark Levinson No. 23.5 Amplifier (Low Freq)
Mark Levinson No. 27 Amplifier (High Freq)
Proac Response D Two
Velodyne DD-10 sub
Target Stands
Mark Levinson 360S DA converter
Wadia No 23 CDP
Sony NS 9100ES SACD
Logitech Transporter
ARC PH3 SE Phono stage
Denon DP 62L
Cables are a mix :
Cobalt ultra speaker cable (2 sets)
Signal Cable Silver Resolution IC's
Acoustic Zen WOW IC's
Cardas Crosslink IC's
Signal Cable power cords
Music :
Rock
Jazz
Blues
Hard Rock
Alternative
Good luck ...
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