Dude why would you get the SV20 NON MASTER VOLUME if in your original statement the 4103 was way too loud. So is the SV20.
A Jubilee shouldn't, and doesn't sound like a JCM800, which was whole point of the post. You should really try reading, at least the OP's original post/question, before posting comments about the responses. In response to the OP's original post/question, I referred to the SC20, as coming closest (of the 3 amps) to a JCM800. From the OP's original post... "I wanna get that JCM800 sound back but at a bit more reasonable volume. Something with an effects loop. What do you recommend out of these 3?"
Yeah. I gigged an 800 in the 80s. This thread is months old. The OP's question sounded like an SC20 was the obvious one out of his choices to me.