Wreckman build - Stage 1

[MarkB]

I finally got my Wreck in a Bassman head working. It was making background noise, but no guitar signal. I finally realized that I left out the wire from the first plate to the treble pot. I soldered the wire in, and bingo!, guitar. I can't turn it up until tomorrow night, but after weeks of waiting for parts, and messing with other amps, at least I have something to work on now. It's too hissy now, and there's a little buzz, but at least it's a start. I used the Kelly schematic but did my own layout. Doing the layout is half the fun to me, so it's not an attempt to clone the looks, just the sound. Anyway, a thanks to all those who contribute - I've been through a lot of threads getting good info from many people.

[Omar]

MarkB - Congratulations! How 'bout some pics of your build? I would be interested in seeing your layout. Give us a full report on your findings once you play it. I wonder how much of an effect the layout has on the tone of your build.

Omar

[MarkB]

I don't have a camera, but I"ll try to draw a layout when I get it sounding cleaner. The grounding needs work - it's half Fender and half star grounding. I'll probably put a buss on the board to clean it up.



edit: I got to turn it up. At 2-3, it sounds nice. There's some buzz, but I can use it to practice. By 4, it gets noisier and starts to squeal. I've got the first two grid wires shielded, but the preamp grounding is a mess, so I'll put in a buss and get the multiple preamp chassis connections down to one. That will also clean up some of the wiring, so I can start poking around with a chopstick.
I'm also picking up a local public radio station, even with the grid resistor in there. I'll try a cap on the input jack to get rid of it.

[MarkB]

Dammit! I get a nasty buzz I can't get rid of so far. As I turn it up, it goes into oscillation. I've already reflowed the power supply solder joints and rewired the preamp grounds to a buss with no effect, so I'll have to pull the power supply connections from the board tomorrow and rewire/resolder them all.
That's three amps I have in various states of dead now. Someone stole my Mojo.

[mlp-mx6]

Any chance the power tube grids are reversed?

[PaisleyTube]

Hi Mark

Cool!
Last week I did rebuild a '71 Bassman head using two 6V6s and it's a keeper (or someone gotto offer me something nice ), loud enough for a 200 seater (typo?).
As mentioned before: try reversing the OT primary leads OR the pi-outputwires going to the outputtube-grids.

Hope this helps,

Chris

[MarkB]

I've been bouncing between amps, so I've let this one go for a few days. I'll try swapping the wires.

By the way - 5879 tubes are cool! I put one in place of an EF86, - in another amp - with a little rewiring, and it reined in the noise and microphonics I was getting.