Old Wurlitzer organ a friend gave me some years back. Worked for a little bit, then needed a few caps in the power supply replaced to take away the distortion. As cool as distorted organ could sound, it just kept getting quieter and quieter the longer it was on until eventually it cold barely even play for more than a minute or two. Recently I decided to give it another look and I ended up finishing up the recap and any other original capacitors in the power supply and output section were replaced. The 4100A was made from 1959-1963 so they are very old indeed.
The whole back panel folds down so it is very easily service-able.
With the back panel in the normal upright position. It has 28 12FQ8s in the tone generator circuit. Above are dozens of brown .22uF/4000V coupling capacitors for all the tubes. According to Bogus Magnus “this is Wurlitzer’s first electronic spinet organ using vacuum tubes in oscillator circuits for tone generation and also divider circuits.”
Very nice. To the right of the tone generator is the power supply and output section with their respective tubes facing upright. On the left a 5U4GB rectifier tube and to the right two 6L6s in push-pull for the output section. Beneath those are two 12AX7s. I would guess they are a driver and phase inverter for the 6L6s.
Close up of output section and power supply. Massive power transformer supplies current for almost 40 tubes.
Tone generator maze of even more coupling caps and an old Utah “special design for Wurlitzer” speaker
4100A It is a lot louder now and has a fuller sound with more bass. So if you leave your beer on top you can now rattle it off the side onto the floor, spilling it everywhere.
Wurlitzer 4100 schematic. This is not the right schematic, or even the whole thing, but it’s all i could find so maybe it’s useful in some way.