which power amp for KEF and Bryston preamp

I used KEF 104.2 with Bryston 5BST and 3BSST briefly before I upgraded the KEFs to JM Lab Electra line. It souned very good, especially the sound stage and although the KEF spec says 55hz, the bass was very nice tight fast and very musical.

I think a used Bryston 3B/NRG/ST will be a good match for the money.

There is a Bryston 4B-ST currently for sale here on A-gon. I have been using this amp for about 5 years, and have been extremely pleased with it. There is also a Bryston 8B-ST in the "For Sale" listings (it's essentially a 4-channel version of the 3B-ST), which can be used to bi-amp your speakers if you wish.

If your budget allows, you might also consider upgrading the power supply for your BP-20 preamp. The new MPS-2 power supply is quite a significant upgrade to the stock power supply in the BP-20. I recently replaced the MPS-1 power supply (for my Bryston BP-1.5 phono preamp) with the MPS-2, and found that the MPS-2 provided better transient response and a bit more clarity than the older power supply.

I have a late model BP-20P, with the improved MPS-1 power supply and longer input and output jacks. I use it with a 3B-ST amp. Speakers are the Spendor SP 2/2. The roon is 17' X 14' X 8'. The sound quality is great. Solid, natual, and clear. I feel that using pre-amps and power amps from the same company make a lot of sense. They should mate pretty well!!

Pete