A thank you and an aside.

zgrav

Well-known member
I wanted to post a thanks to Nathan for the time he puts into making some of his projects available as DYI. Clearly it is not the profit center for his very successful tube-pedal niche, and when you look at the attention given to making clear build docs with links for the parts it shows his attention to detail and effort to support folks who want to give DIY a try.

And for the comment to go with the thanks, I wanted to suggest that offering a tube pedal based on the Dumble schematics could be very well received. The sparkle from four gain stages combined with the slightly different B/M/T tone stack could be sweet.
 
Well shucks, thanks man :) I got my start doing pedals by scouring forums and reading posts from people much smarter than me, and I've always been grateful for the information shared in the DIY community and for all the amazing projects people put out there, so I like being able to make some more options available that are otherwise difficult to get into.

A Dumble preamp certainly would be a cool project. As you mentioned DIY PCBs aren't my main thing and I don't plan for them to be, so I don't want to get carried away with offering a ton of projects, but I'll give it some thought.

Something else that just popped into my head; as soon as you start doing tube preamps it's easy to say "well what about doing ____" and come up with a LONG list of potentially cool projects. But once you really get the hang of it, you notice that the building blocks of one preamp aren't too different from any other, and once you have power sorted out and a reliable way to mount the tube in the box, it's not hard to do a hundred different preamps, which is how the list of pedals that I offer for sale commercially has grown so much.

So here's what I was thinking:

It would be kind of cool to do a tube preamp development board kind of thing. Like a PCB sized for a certain enclosure with the mounts for tube daughterboards and a few spots for pots to be mounted, and an SMPS somewhere on there to get power, then the rest of the PCB could just be like perfboard. Power is taken care of, tubes are taken care of, pots are taken care of, then you fill in the rest with whatever circuit you want. It's a happy medium between a ready-made project and creating whatever you want. It certainly wouldn't be for everyone, but for intermediate-advanced builders who can read schematics and source components it would be an easy/convenient way to prototype tube circuits or do one-off builds, either following one of the MANY schematics already online or creating a completely new design.

Anyway, I start rambling and I keep going :p Just an idea that popped into my head and spun around for a bit.
 
I'll toss this out for consideration and comment. I built an AB763 preamp pedal while waiting for the Particle Accelerator to hatch. Nathan helped me out immensely with it. I built it on a standard terminal strip board and adhered the pots to the back of the circuit board w/ industrial strength double stick tape so the whole thing would lift in and out of the enclosure as a single unit. I set up the pots on a template so they would align properly with the holes I cut in the enclosure, soldered leads appropriately then placed double stick along the backs of the pots and appended the circuit board to it. You could reduce the size of the terminal strip with a PCB design. Eyelets would have to be big enough to receive two or three leads from components and you might consider adding additional eyelets adjacent (and electrically connected) to each "main" eyelet (like a bread board) to provide opportunities to jumper to other components as needed. But mimicking a terminal strip allows for great flexibility and layouts could be shared for various preamp designs. One of the biggest headaches I had was routing and soldering wires to the tube socket, but with Nathan's tube mount solution the tube PCB could contain soldering eyelets to make this much simpler. Power supply is a head scratcher as I'm not so sure leaving as a separate board to adhere to the side of the enclosure might work best. This approach would require a 1590BB (or BB2, BBS), but that's still a very practical size as far as I'm concerned.

AB763_6.JPG AB763_3.JPG AB763_2.JPG
 
I slapped this together last night. It's just an expansion of the PA PCB to inhabit a 1590BB enclosure. It has 6 sockets for 9mm pots and 7 "terminal strips" w/ extra eyelets provided for jumpers as required. The terminal strips are wide enough to accommodate larger Mallory 150's. The lower portion of the PCB could (hopefully) house the PSU components w/ feeds for HV and 2/ea 9vdc's as currently provided on Sushi's stand alone PSU. I'm not smart enough to know if/where grounding eyelets may be required to make for a more accommodating assembly, but this is a start.
Universal Preamp PCB.jpg
 
Just to prove I've REALLY got nothing better to do, here's one using standard solder lug 16mm pots. The 9mm come in fewer flavors so if you need a more flexibility in values 16mm appears to be the way to go. While not as "elegant" as having 9mm that solder to the PCB you also have more flexibility to position controls on the face of the pedal and it seems that the industrial strength double stick tape works plenty well. I provided "terminal eyelets" every 3/16" so it allows more flexibility in positioning components. Finally, I positioned holes to pass hookup wire thru the PCB to connect to the pots. The main gripe I had with my build was that the conventional terminal board was too bulky and widely spaced. This approach would offer a much more compact and flexible arrangement for mounting components.

Universal Preamp PCB v2.jpg
 
Back
Top