Sonically all Bryston preamps are very similar and on most systems the differences would be slight, the BP25/26 having a lower noise floor and more options for connectivity would at least for me would be the logical choice given that the OP can purchase them at the same price even though the balanced options would not be used.
BP6
I have the BP25 and a B60R whose preamp section is the BP6 so I have compared the two, the BP25 does have the edge.
Using a BCD-1 as source and the 4BSST the overall presentation with BP25 was smoother with a bit more stage width and depth, which I account to the lower noise floor and the use of an external power supply allowing the smallest details and spacial cues to come through.
Powering my Dynaudio Contours 1.3MKIIs the difference was less obvious but still perceivable but on my Dynaudio Special 25s, which incorporate the more revealing Esotar tweeter; the improvements afforded with BP25 are appreciated.
Please also take into consideration that as there is no way to power down the amp section on the B60R when using just the pre/amp section, a stand alone BP6 may indeed have a better signal to noise level and be closer to the BP25/26.
BP25/26
Musically speaking, I’ll leave that to the musicians and the recording engineers, not the equipment.
For BKM I guess it comes down to trying to make a choice between purchasing something new or going used, either preamp will get the job done.
Robert
