I just bought a 1997/1998 Electar 30 Tube Guitar Combo Amp in great condition with a set of 4 Fender Groove Tubes. It sounds great! The instruction pamphlet that was sent with it was very basic and only referenced the “line out” jack as output from the preamp that can be run to a sound board. I assumed that when I plugged a 1/4” cable into it and ran it to the board, that I could still play with full volume through the speaker of the amp. Sadly, the “line out” is acting more like a headphone jack... while it is not cutting the speaker off completely, the sound coming out of the speaker (when a cable is in the “line out” jack) is greatly reduced (almost non-existent). Can anyone tell me why this is happening? There is no explanation in the “brief” manual. Thanks!