As many of you know, the basic relationship between the signal transfer (in terms of voltage) ratio to impedance between __o__utput (source) and __i__nput (load) is

Vi / Vo = Ri / (Ri+Ro+cable impedance), where V = voltage and R = impdenace

For a standard 75 ohms interconnect cable, without loss of generality, if your preamp output imp. is roughly comparable to the cable impedance, Vi / Vo = Ri / (Ri+2Ro). As a rule of thumb, it is desirable to have Ri is at least 10 times higher than Ro. The corresponding Vi / Vo = 83%. There will be 17% signal loss, acceptable (see below for the coveat) but not ideal. If Ri is 100 times Ro, the Vi / Vo ratio will be 98%, only 2% signal loss and will be deemed ideal.

In @jpasko01 case, i.e., Freya -> Bryston 4B3, Ri = 100 Ro and therefore the signal loss is only 2%. The pariing should work like charm. In the case of a passive preamp SYS (Ro = 5000 ohms) into my Parasound A23 (Ri = 33k ohms) where the ratio is merely 6.6, the Vi / Vo = 33000 / (33000+5000+75) = 87%. This 13% signal loss is significant enough to cause noticeable sound degradation that I heard. This demonstrates that the ratio of 10 is just a rule of thumb, the ratio should be as high as possible like 100 to be ideal. Since I have not seen a passive preamp impedance is lower than 5k ohms, practically only the active preamp is possible to achieve an ideal impedance match.