I'm sure I'm asking this poorly but here's what I mean. If I run my Mc50 from the 8 ohm tap into an 8 ohm load, I'm golden. But what if I ran instead:

1. from the 8 ohm tap into a 4 ohm load? -or- 2. from the 4 ohm tap into an 8 ohm load?

If it were a vintage Fender or Traynor amp, I wouldn't give it second thought. But a Mc'I's so different, I really have no idea if this is safe with one.

And my question, I'm embarrassed to admit, isn't purely hypothetical. My MC50 has been modded to have a pair of 1/4" outs, one is supposed to be 4 ohms, the other 8. Unfortunately, they're not labeled, and though I was told upon receiving the amp back which one is supposed to be 4 ohms out and which is supposed to be 8 ohms out, it took a couple of emails back and forth to get a response and I've always had a nagging wonder as to whether I got it straight. Anyway ...

Until this past weekend, I ran out from what I'd thought is the 8 ohm out into an 8 ohm load (1X12 w/a E120). Sounded great.

This weekend, I added a second 8 ohm cab (K120) in parallel (4 ohm total load). This sounds even better! BUT the sound from what I'd think is the 4 ohm out into the 4 ohm load surprised me by being less loud than I'd anticipated. And when I switched to what I think is the 8 ohm out with the same 4 ohm load, it's louder and I actually like the tone better this way.

So I guess my precise questions are, first, would 8 ohms out into a 4 ohm load be expected to be louder than 4 ohms out into the same 4 ohm load (same power amp and all other things being equal)? AND can I safely continue to run out of what I think is the MC50's 8 ohm out into my 4 ohm load, since I like the way it sounds better this way, without damaging the MC50?

Whew, I'm wiped just thinking about and typing this! Thanks for whatever insight y'all can provide.