Others who've noted the amplifier/speaker matching issue as the key one are pointing you in the right direction. Having tried Atma-Sphere OTL's (both M-60's and MA-1's) with Coincident, Super Eclipses. I could not imagine attempting to power the Silverline Sonatinas with a set 20-watt OTLs. Unless Graaf does something really special with its design (I am not familiar with it), OTLs really do like high impedance, sensitive loads.
Unless you get one of the ZERO box auto-formers (available from Paul Speltz through the ASOG [Atma-Sphere User's Group]) to aid in impedance matching, I don't think you will have much success driving the Silverlines very well.
I had a 16 x 26 room and much preferred the A-S MA-1 MkII's over the M-60 on the Coincident Super E's (92 dB, not-below-10 Ohms). (My current smaller room would favor the M-60's, but that's another story....) If that gives you any idea of the task your Graaf amps will have, I hope it helps.
My only contact with Silverline was completely negative, but it could have been an anomaly and not worth going into. From direct experience with my Coincident Super E's, I can say that they are revealing, nearly full-range, and quite musically engaging. They take a long time to break in and some of my earlier complaints about them turned out to be cabling or room related, not the speakers. If the Victorys are anything like the Super E's but easier to drive and perhaps more intimate, you are in for a treat! Coincident speakers and OTL amps really are a good match.
Unless you get one of the ZERO box auto-formers (available from Paul Speltz through the ASOG [Atma-Sphere User's Group]) to aid in impedance matching, I don't think you will have much success driving the Silverlines very well.
I had a 16 x 26 room and much preferred the A-S MA-1 MkII's over the M-60 on the Coincident Super E's (92 dB, not-below-10 Ohms). (My current smaller room would favor the M-60's, but that's another story....) If that gives you any idea of the task your Graaf amps will have, I hope it helps.
My only contact with Silverline was completely negative, but it could have been an anomaly and not worth going into. From direct experience with my Coincident Super E's, I can say that they are revealing, nearly full-range, and quite musically engaging. They take a long time to break in and some of my earlier complaints about them turned out to be cabling or room related, not the speakers. If the Victorys are anything like the Super E's but easier to drive and perhaps more intimate, you are in for a treat! Coincident speakers and OTL amps really are a good match.