Had a little scare this morning.
Fired up the Jolida below. Waited a couple of minutes, cranked her up some and within a minute the amp "cut out", POPPED and the red light came on. In effect it shut itself down. I checked the manual--evidently the JD-303 has a protection circuit and it claims that if you wait and the unit powers up again you're probably OK?
I powered everything down. Turned the unit off (back switch). Disconnected the power cord, made some coffee, read a newspaper then came back upstairs and hooked everything back up after checking my connections.
While I was checking the connections, I DID notice that a couple of the speaker terminals were NOT making complete contact with the wire. In other words, two wire ends were a little loose? I'm using 14 gauge bare copper wire back there. So I tightened everything down turned on the amp and it powered up as normal, tubes started to glow, bias indicator lights turned on one at a time. And, as far as I can tell, we're OK, fingers crossed.
I am, by no means seasoned in the field of tubes (my first excursion BTW..made sometime last year). But I am assuming that the loose wires may have been the culprit because the amp cut out as I tried to increase its power!
What say you tube guys? I know you're NOT supposed to turn a tube amp on if it is not connected to speakers so I was a little nervous when I saw my wires were a bit loose!