[peteivan]

The jukebox amp I have is out of a Rock-ola Fireball jukebox made in 1952. I plan on replacing the original woofer with a PM speaker. I plan to run a voltage divider series of resistors from the point that used to supply +300v to the speaker field coil. The jukebox speaker used a 5K field coil. The new voltage divider would load this point, tending to drop the voltage back down to what it would be if a speaker field coil were connected.This would supply all the positive voltages to the receiver chassis. There also some negative voltages required. The 6L6 output stage is already taken care of, as I am using an existing amplifier. This amp uses a separate transformer to supply 6.3 VAC for the amp filaments. There also 2 other windings on this transformer for the jukebox control circuitry. These aren't needed anymore for their original purpose. These 2 windings are (1) 24VAC, and (2) 35VAC. Essentially, the negative bias voltages to the receiver chassis are obtained from the negative 22-24 VDC bias to the 6L6 output stage on the original chassis. Either the 24VAC or 35VAC windings can be rectified and used to generate negative bias voltages through a voltage divider network. On the original amp chassis, the voltage divider network current seems to be about 40 MA. The service literature I have gave no voltage readings. I had to refer to 37-690 service literature which provided voltage readings ( Relevant to the receiver chassis ). I realize that the amplifier chassis is quite different as far as the output stage goes, but the receiver chassis is quite similar except for the DC controlled bass boost circuit. The original mid-range/tweeters are present,as are the 4 passive radiators. I was a senior microwave technician when I retired from DTE Energy, our local electric and gas utility. I also have extensive experience in the mobile radio field. I have been restoring antique radios for many years. Electronics was a hobby of mine since my elementary school days. I used to go out on trash day, and brought many fine radios home. Unfortunately, I didn't know how to fix some of these radios. They got torn down for the parts and hardware, some of which I still have today. My greatest regret was letting a roommate talk me out of moving an Atwater Kent Model 810 cabinet when I moved. (Excellent sound quality, 3 shortwave bands, and was a very sensitive 10 tube console ) This was around 1975-These things had no value then. I still have the working chassis, and am looking for a cabinet and speaker. As far as the tweeters go, I will drive them from the output of the jukebox amp with a 4.7uF cap in series. If the treble response is excessive, I will add a series resistor, or L pad control. The field coils could be driven from the voltages obtained from the amps 25 and 35 VAC windings.