Simon,
As owner of a MkII SA250, I emailed Peter Thomson of Plinius NZ and asked the same question not long ago,having not heard the Mk1V for myself. Although there is no upgrade path to the IV, Peter said that the difference was subtle, but a slightly "faster" sound from the MkIV, mainly due to the two transformers versus the one big trans of the MkII, although the KVA rating is the same for both. He advised that I not worry too much about the difference and use the money to buy cd's and lp's! One thing he recommended very highly was to run higher quality and more Heavy duty dedicated lines to get the most out of the amp, especially in Class A, where some less than substantial or older lines can cause the amps power supply to buzz slightly. I am more and more satisified with the performance of the 250/2 the longer I have it in my system and feel it is a really excellent quality and sounding amp. In class A it indeed sounds like a BIG tube amp.My feeling is that you are fine with the MkII and will really enjoy the sound. This is a monster of an amp, try to have some help getting it set up...and do watch those aluminum heat sink fins,( sharp edges) dont lift the amp by the fins. Best of luck with it. -Ken
As owner of a MkII SA250, I emailed Peter Thomson of Plinius NZ and asked the same question not long ago,having not heard the Mk1V for myself. Although there is no upgrade path to the IV, Peter said that the difference was subtle, but a slightly "faster" sound from the MkIV, mainly due to the two transformers versus the one big trans of the MkII, although the KVA rating is the same for both. He advised that I not worry too much about the difference and use the money to buy cd's and lp's! One thing he recommended very highly was to run higher quality and more Heavy duty dedicated lines to get the most out of the amp, especially in Class A, where some less than substantial or older lines can cause the amps power supply to buzz slightly. I am more and more satisified with the performance of the 250/2 the longer I have it in my system and feel it is a really excellent quality and sounding amp. In class A it indeed sounds like a BIG tube amp.My feeling is that you are fine with the MkII and will really enjoy the sound. This is a monster of an amp, try to have some help getting it set up...and do watch those aluminum heat sink fins,( sharp edges) dont lift the amp by the fins. Best of luck with it. -Ken