[Jukebox-list] MRA5-L6

[Mel Knight]

Hi Jurjen!

               Yes! You can play the amp outside of the jukebox, I do it all the time, I service amps as part of my jukebox business. What you need to do is ground the primary of the power transformer. The 5U4 will not be powered and there will be no DC to power the amp. If you look at the back of the round speaker plug you  will find a cloth covered wire connected to the speaker plug, it runs directly to the large power transformer, jumper that to ground and you should be good to go! The 6SL7 & 6SK7 are for the AVC and squelch circuit, the pins on the round plug are for the mute and squelch circuit. When the mech picks up a record to play and the record is clamped, as the arm lands on the record the mute is released and the squelch circuit allows for a soft start (fade up). If the 2 tubes are not present the squelch function will be disabled, only the mute will function. If you are testing the amp on the bench and the 2 tubes are present you MUST provide a jumper to release the squelch (soft start) circuit in order to have full volume!  Mel