Levinson 432 VS. Bryston 4 BSST

Have you addressed room treatments? - That will make a larger STEP UP if you haven't
Are you running fully balanced Cabling?
Have you dropped in dedicated 20amp circuits?

All of these will make a bigger difference for less money...

If you like the Levinson sound, then the refinement of the Levinson over the BSST will show through and make a fine upgrade after these other tweaks have been accomplished.

While I must agree with Cytocycle about dedicated lines and room treatment, the jump (to me) from a Bryston 4 (a bright amp to my ears) to a ML 432 (I currently have the 433) is a major change, for the better to my ears. The Levinson is a smoother amp, and I personally think it is a huge step up from Bryston....

I just sat in on a demo of the Aerial 20T speakers. Source was the Levinson 390S powered by a Levinson 432 power amp ... I'm still shaking. It was absolutely breathtaking and the best setup I have heard in recent memory, maybe ever. I'm currently running a Levinson No.23.5 and No.27 in a bi-amp configuration, matched with a No.37/360S front end. I couldn’t even bring myself to consider making any change until I heard that setup. I will have to settle for Aerial model 9's and my current setup but that Levinson 432 was a peach. If I had the cash ... I might consider the upgrade. Granted they were $30,000 speakers but my more modest setup matched with Aerial 6's is very, very sweet in my opinion. I feel there is a synergy match between certain power amplifiers and speakers ... and I found a good combo. That being said you may want to seek out a company that is willing to let you demo at home OR buy a used 432 and live with it for 5-6 months. It might be the only way to know for sure. I see the 432's sell pretty fast.

PS .

I whole heartedly agree with Cytocycle; I have done the separate power runs and I have deadened my room as much as possible. It made a significant difference so if you have yet to do make those changes I would consider them first or in conjunction with the amp upgrade. What things do you feel you like/dislike about your current setup? what speakers are you running? Can you describe you listening room?