BassmanPaul

It looks as though the pre-amp is powered between the positive rail via a regulator and ground. that's a little odd in my mind. The negative rail just seems to drive a couple of lamps. Hmmm!

Connector pin assignment Pin 1 - Ground Pin 2 - Full Positive rail Pin 3 - Audio Signal Pin 4 - Full Negative rail Pin 5 - Not used Pin 6 - Not used

Thank you @bartelby for going to the trouble of supplying the schematic. @prowla if you are wishing to use this pre-amp standalone you'll have to provide a power supply and audio cabling to feed a suitable power amp. Good luck with that!

I'd be looking at it from below!

I have to admit that I'm glad that I don't have to lift those amps though the Class D, which is not in anyway 'Digital', is going to be much lighter. That being said, I hope you derive much pleasure from using them.

I agree that it's for connecting a Trace power amp board. I tried to read the schematic I found on the web and could see the wiring for the socket but the site was flaky so the diagram didn't stay long enough on my screen to be certain. I'm betting that this unit came from a deceased head as it has no connectivity on the back panel.

I'd go to Glasgow to try it out but I can't swim!

It's not a lamp it's an electron tube/valve. No it's not safe to use. GZ34/5AR4 tubes are readily available and are simple to install. Pull the broken one out and push in the replacement tube in it's place rotating the tube as needed to let the key into the socket base. it's that simple. Edit: Apparently the two rectifier tubes are 5U4G. I beg your pardon. Same applies though.

Oh BABY!! LOL

Yes they can be a bit bright but that can be readily tamed by the tone controls. When I got my B15NF it was red plating the output tubes, leaky capacitors were the problem. Having replaced the amps filter caps and the tubes I had several events of flash over of the GZ34/5AR4 rectifier tube. Adding a silicon rectifier, UF5408, to each plate to increase the PIV solved that permanently. On the whole the amp is a pleasure to use and a delight to hear. Incidentally I play six stringed basses.

A thought that struck me was that if the heater winding fed into a rectifier/capacitor to run the heaters at DC Did the designer multiply the current draw by 1.4 to allow safe operation of that supply. That would equate to 630mA . That's much closer to the 800mA limit of the 12V winding.

Just remember that it's not a complete kit. You'll have to find a suitably sized metal chassis that you'll have to have punched holes for tube sockets, controls and other through chassis mounted components. A face plate and control knobs are needed too. All in all not a suitable project for a neophyte to tube amp construction.

Didn't Fal make the Actifry Air Fryer?

If a 100W tube amp is all you can find you could pull the outside pair of output tube and run the amp at 50W.

I looked at the Handbox tube amp and was amused to see it specified 6L6 tubes. The 6L6 is a metal tube and in such an amp would melt in an instant. The correct tube is a 6L6GC, the letters are important. Why do you want a 50W amp for anyway. A 100W amp can be turned down quite simply to the required volume.

Hi Tim, Back atcha from snow covered Toronto!

Fender ACB50 is one.

You're so lucky!

Try here: https://www.ebay.com/itm/204078117395

Didn't we do this already??

Thinking on this it struck me that the Aplex amp you linked to has 50W output. There are a plethora of amplifiers out there with around that level of output. The answer to the question posed by the head title is that there are many, many amps available to meet your requirements.

Sounds a lot better that the Bassman ever did. I wonder what it's like at volume?

Thank you.

Yep Andy is the go to guy for Genz Benz stuff.

Link the Send and Return of the Effects Loop, if it has one, with a signal cable to exclude problems with the normalizing contacts on the jacks.