Weber Maggie

[Guitarzan]

Very cool looking project there. As a licensed HVAC mechanic myself I have been able to learn so much more in amps because of the electrical understanding needed and all the help given here

I worked in maintenance, and almost every aspect of the building trades most of my working life. But mostly I was an HVAC guy. The maintenance positions I got were offered based on strength in the HVAC field. So yeah, the control wiring on some of those big old rooftops units could be a nightmare and even tho it's miles from audio, it definitely helped to lay the foundation for being able to go into this, starting with basic kits that are pretty much like painting by numbers for an old HVAC guy, right?

[lego4040]

Yep, I worked every single position in a building till I went back to school for my refrigeration ticket. Through the three years of apprenticeship school I spent one year dedicated to electrical and that's where I learned how to read schematics, those old units were a lot different then today's units. Today all the parts are on one board and you swap them out in two seconds, most of the time. Good luck on your Maggie, I have one to build also now that I have the correct variacs for tremolo

[AZJimC]

I too am an old HVACR Tech/Contractor. I still do a little for closest friends, but health allows very little. I've been watching this, and you're doing a really nice job. I am gonna have to do a Maggie too, if I ever get space to do it cleared on the bench.

[Guitarzan]

Okay, here's what I've come up with for the eyelet board. I think I have it all on there but please have a look and let me know what you think. Perhaps you'll have either a better idea for the layout or I've missed something or have the values of the components goofed or whatever. The "boost" channel with use the 6SL7 preamp tube and the "normal" with use the 6SN7. I haven't included all of the other parts of the drawing, so we need to assume at this point that I'll know or be able to figure out how to hook it all up. Tube sockets, outputs, V&T pots, inputs are all assumed at this point as well as the wires on the back of the board, the 2 inputs, and boost switch.

[sluckey]

The board looks neat.

[lego4040]

You could take the 68k off the board completely to free up space, put it right on socket pin and shielded input cable

[Guitarzan]

It's my intention to make it only as large as it needs to be to fit the resistors and caps comfortably. The main one that worries me is the big old 10W one that's prolly gonna get hot. I'll wanna try and keep it a little further away from the stuff around it and also keep it up off the board to allow for good air flow around it. It's either that or find a home for it elsewhere in the chassis.
This was what I had handy to use there. Just a basic resistor with no heat sink or fins or any other bells or whistles.

[Guitarzan]

You could take the 68k off the board completely to free up space, put it right on socket pin and shielded input cable

Excellent point. It'll definitely save space. That's exactly what I'll do.Does it matter which end it goes on? I mean if it "feels" like it'll work out better at the jack end is it OK to put it there or should it positively go at the tube socket end?

[Guitarzan]

Well, the brakes got locked up on this project due to the fact that my mother had a stroke. It was a mild one, but a stroke none the less, and she's 95 years old. She's been living independently to this point and the goal is to get her back to that point but it looks like it's gonna be a long haul. I did manage to make some progress on my drawing, then suddenly realized that the shielded input cable to the 6SL7 for the "boost" channel was going to pin 1 on the tube socket. Correct me if I'm wrong, but I should have drawn that to pin 2 on the 6SL7, right? So I have to look all of it over and see that I didn't do anything else wrong before I post it here for you guys to find whatever other mistakes I'm making on this thing.


I know it doesn't sound like a big deal to correct, and isn't really, it's just that my time has been eaten up by trips to the hospital every day, arguments with the insurance company who just wanted to stick her in a nursing home and be done with it, and running all sorts of other errands like cleaning out her fridge and stuff like that so I just haven't had a chance to get back to it lately. It's on my mind all the time tho and I really hope to post a drawing of at least channel 1 in the next day or two. If you guys look it over and decide I'm on the right track with channel 1 then I'll finish up the rest. I don't think I'm going to go with an impedance selector switch like the Weber drawing shows. I'm thinking of putting in 3 output jacks for the 4, 8, and 16 ohm taps the OT has. There are probably a few other things I'll do differently as well, but they don't come to mind at the moment. Actually, I've got to get up to the hospital but just wanted to let anyone who may be subscribed to this thread know that I'm still here and would actually have gotten a lot further by now if it wasn't for the other personal issues. So please stand by. I'll be posting some stuff of actual substance in the next coupla days.
Thanks guys and have a great day.

[sluckey]

I did manage to make some progress on my drawing, then suddenly realized that the shielded input cable to the 6SL7 for the "boost" channel was going to pin 1 on the tube socket. Correct me if I'm wrong, but I should have drawn that to pin 2 on the 6SL7, right?

If you are talking about the input jack wiring to the 6SL7 then that wire will connect to pin 1.

The 12AX7 and 6SL7 are different tubes and the pin assignments are different. You cannot use the 12AX7 pin numbers found on the Weber layout.

[Guitarzan]

Oh! Then I think I had it right in the first place. I just got back from the hospital. I guess what I should do since it only takes a few seconds is to post what I had when I got the call about the stroke. I maybe be able to work on this some today. Maybe even finish it come close to it by tonite. So anyway, even though it's all half-assed-half-done, it is what it to this point.

[Guitarzan]

I drew that heavy line right thru the 68k resistor on the board to represent the lego4040 suggestion of taking that resistor off the board. The routing of that shielded cable will of course be as short at direct as comfortably possible.