I had the Berkeley and very definitely preferred it with a preamp in the chain, in my case a Tube Research Labs DUDE. Very nice combination.
Of course, if you love the sound you already have, it might be prudent to just leave it at that. As an audiophile, I've never been able to do that myself, but it seems like good advice in general.
Of course, if you love the sound you already have, it might be prudent to just leave it at that. As an audiophile, I've never been able to do that myself, but it seems like good advice in general.