Bryston 4BSST or 6BST or 7BST

I have had both the 4B-ST and the 4B-SST in the same system and preferred the SST. It was smoother on highs and middle and retained the solid bottom end Bryston is known for.

I could be wrong but I think as far as the 6B's go the ST is nearly identical to the SST. It was designed just before the new names and corresponding faceplates. Though it would be better to check with Bryston directly.

You will get better separation with the monos and clearly more power. Though I digress, depending on your taste and associated equipment your mileage may very with each unit listed. Personally the 4B-SST was enough.....for now.

I have had experience with the Bryston 7BST on my B&W Matrix 800's in my second system and have tried them on my JMLab Utopias, which used to have Pass X600's. The 7BST's are an excellent match to any speaker that needs a lot of current to control and drive the bass, which any of the large B&W series really needs to keep them from getting "muddy". Overall, having to chose between the Pass X600's and the Bryston 7BST, I would keep the 7BST. They give up very, very little to the Pass X600's in the highs, nothing in the mid and kill the X600's in the bass and overall response. I am switching to Wilson Benesch Chimera's and will probably use the 7BST's on them, unless I switch to tubes. I agree with the comments that the difference between the 7BST and 7BSST is hardly perceptible.
I would also comment for guys getting into B&W to buy the older Matrix series as they are better speakers then the Nautilus series. Since B&W got bought out, they have gone to more mass market, then to keeping their previous quality and sound. A pair of Matrix 800's or 801 series 3 is a much cleaner speaker (in the B&W series) then anything they have new. Look at all the Nautilus series that are for sale and notice that the price on the Nautilus 801's are dropping, there is a reason. Good luck

I recently had the experience of directly comparing the 4B SST to a pair of 7B SST driving the same speakers from the same source. I can say that the improvement over the 4B SSTs was so noticeable and dramatic, that I am getting the 7B SSTs.