It's pretty much a Champ AA764 circuit. It sounds OK for a 6 inch speaker, not much bass of course. I put a jack in the back that cuts out the internal speaker when an extension cab is plugged in. I tried it with my silver faced Champ 8 inch and it sounds better. I've got a couple of 10" Jensons in a Berringer amp I want to try with it at some point. It was one of those "I did it just to see if I could" things.
Very nice conversion. And it looks very neat, too.
Yeah, those small speakers leave a lot to be desired where bass is concerned. You mght be able to tweak the preamp circuit a little to reduce the treble and mids a little so that the bass sounds better. I don't have the knowledge (yet) to be able to tell you how to do that. But there are probably members here who could.
I have in mind a project to convert an "innocent" little Marshall Lead 12 (3005) amp nto a tube amp. It's slightly more complicated with a master volume (just replacing a resistor with a pot, I think) but essentially same type of project.
I need a way to cut holes for the tube sockets in the relatively heavy gauge steel used in the Marshall chassis. I noticed you used a punch (or punches) to cut your holes. Can you tell me where you got the punch(es) and the cost? I'm planning on building more than one tube amp (conversions and from scratch). So a punch or two would sure be handy.
Those punches are items I have collected over the years from various projects other than building amplifiers. They are made by Greenlee and are generally used for punching holes for conduit in electrical panels. I have one that is marked 1/2 inch conduit and it makes about a 5/8 inch hole. The other two I have are marked 3/4 inch and 1 inch and make the holes sizes as marked. I don't remember where I got them, I have seen them at Lowes or Home Depot in the past. I have seen other brands online. Google knockout punch. Good Luck
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