I have the K150-2, actually I have three heads and 2 cabinets. One has two 8 ohm early 60's CTS alnico type and the other has a single 8 ohm Altec 421A. I get fantastic volume and tone from the CTS's running the K150-2 at 4 ohms. The single 15 Altec does great but it doesn't have near the bottom or fullness the two twelve has, but then again it has less paper moving air at more resistance and that can be the big difference between them. Getting the Frank sound out of a metal face Kustom would only be posible with a good digital EQ to condition the signal before input. That conditioned signal fed into the Frank would again take you to a whole other guitar heaven. The Franks in my opinion have the warmest of all Kustom heads made. I have like six of them and they all have that same warm, rich, robust sound I look for in an amp. Steve C