Sunday, August 20, 2017

I Am The Bassman, part three.





I had a chance to put in some quality time with the Bassman ish project this morning.

In no particular order I got the capacitor board wired and mounted, ran wiring inside where it will be terminated, and I think installed the capacitor cake pan for the last time.

I've also started on the internal wiring and I think I'm about 70 per cent complete there.

Some might ask why I've used the waxed cambric pushback wire from Stewmac for everything including the filament wiring and that's because I like it. It conforms nicely, is nicely stranded and tinned, and according to published information, 22 gauge wire-which is what this is-has a reasonable current carrying capacity.

According to published specifications for chassis wiring this is rated at 7 amps and the total computed filament load is 3 amps, which means I've got more than enough capacity here especially as it is not tightly bundled.

You can't see it here but I do have the Alpha pots mounted and when everything's finished I'll add a brass rod for a bus bar ground.

The intention is that when it's ready to go and has proved its worth, then I will dismount the Bassman 50 chassis, swap over the vintage faceplate and other items and then figure out what to do with the carcass. I figure it'll get broken up and sold for parts.

UPDATE: I did enough wiring to test the voltages and the power transformer got kinda hot pretty fast. What I'd done was put a link on the underside of the bias board I'd made. Removing that calmed things down quite a bit. The only thing I'm missing now is filament voltage on V1 and V2 for some strange reason. A couple of better sockets ought to cure that.

When I'm testing preamp sockets for filament voltage I use an oldish RCA cleartop 12AU7. It's easy to see when it's properly lit up.

UPDATE 2: 10/9/2017

I got the Bassman knockoff up and running sweetly this weekend. For some reason the negative feedback kills most of the volume and wiring up the speaker jacks was sort of a pain, so I just wired in a simple Switchcraft type 11 non grounding jack. If I get really ambitious I may swap it into my J.D. Newell cabinet and give it a road test this week. And if that works out, I'll follow through with my plans for the Bassman 50. For that amp, I will probably take out the Super Reverb power transformer that's in it, use the Fender choke and output transformer in the Bassman knockoff and tidy up the cosmetics.

I got a 100w soldering iron from Hobby Lobby today for doing chassis grounds and it's a peach. I'll tidy up the grounds and swap over the blackface cosmetics when all is in order.

Looks ok, dunnit?




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