Music City Super Power Amplifier Treble and Bass yay. Bet you will never see one of these again. I hope you do though. Made for the Music City Music Store in the UK by Laney some time in mid 70s. Supposedly very similar to the Laney Supergroup but not an exact copy. This thing has been totally recapped, and even all of the coupling caps have been replaced with orange drops. That’s too bad, because it probably had the old yellow mustard caps originally. Oh well, sounds great and works nice too, who cares.
On loan from Big Iron / Tyrant Tone collective. It uses KT77s for the power tubes. I used it for recording and afterwards I noticed two tubes had blackened JJ logos. Flipping it on after the recording the fuse blew in a few seconds. One of the blackened tubes would intermittently short. Usually pretty quick, like within 10 seconds. Ditching the shorted KT77 and throwing in some old EL34 I saw bias was set around 95%. Not sure if this was just an error or it drifted over the years. There is a tag inside the amp saying it was biased to 26.2mA 5/18/12 which would have been a good setting, Maybe it’s been messed with since. Plate voltage on this amp is in 620-640V range.
Checking out the MATH a little lately which is kind of fun. The amp is run up to 32.6VAC output in the pic but it really starts to clip at about 31V into 8 ohms for 120Wt.
Has high and low inputs for Bass and Treble channels as well as an on/off Boost for each.
Originally made for KT77s but doing it up with some 6550s just to check it out. Front panel in purple, the color of psychedelic power.
The old Partridge transformers you see a lot in UK amps of the era.
Fun stuff. Wish I could provide a schematic but not sure if one exists. Please share if you are in the know…..