AI meets tube amp building, a happy story...

[nuke]

I've been meaning to get to a project for a while. Part of it is designing an adaptor plate to fit a smaller power transformer on a chassis that was cut for a much larger transformer.

I procrastinate on these kinds of projects, mostly because I'm not all that great at mechanical CAD drawing. Then there's all the measuring and looking stuff up to make sure the dimensions are right. And I use freeware CAD because it is cheap, despite often annoying.

Was about to finally get this done, as I've done many such exercises before and I thought, let's get AI to do the work.

So I instead of measuring anything, or looking up data sheets. I just prompted (the paid-for version of) ChatGPT:

Design an adapter plate to fit a smaller power transformer onto a chassis that is cutout for a larger transformer. The existing chassis is cut and drilled to fit a Hammond 290D2X power transformer. The target transformer is a Hammond 290XX and the plate should be cutout and drilled to fit.

That's it. I'd already looked these up as equivalents for the transformers I had sitting on my workbench.

Over the next two minutes, ChatGPT searched the web, found the mechanical drawings from Hammond, analyzed the drawings from PDF, collected the dimensions, then designed the adapter plate.

I already knew the depictions at Hammond didn't indicate the size of the transformers that protrudes through the chassis, just the exterior dimensions, and the mounting stud locations.

ChatGPT got it pretty close to right. It had to guess on the center cutout for the new transformer.

I printed the PDF file, went to the bench, took some physical measurements, scribbled down on the drawing the new desired dimensions for the center cutout, the outside cut, and to increase the bolt holes.

My next prompt:

Thanks, that's pretty close. Make the following revisions: Center cutout opening 2.250 x 1.8750. Revise all holes to 0.250 diameter, outer dimensions 4.125 by 3.3750, and select a suitable exterior radius for the outside corners.

And 13 seconds later, I had a PDF, an SVG and a DXF file.

That's it. Done.

Then we discussed material options and thickness, versus weight and impact resistance, finish options and available vendors.

I loaded the DXF up in LibreCAD and validated the dimensions, then logged into SendCutSend, dropped the DXF file on the quote page and a few clicks later, ordered my adapter plates. The preview was fine, and I ordered them. Should be here in a week.

Took me longer to write this post.

[Dr Tony Balls]

then logged into SendCutSend

Sendcutsend has their own AI assistant on their site, as well.

[martin manning]

Not trustworthy on a first attempt yet, but seems to be getting more and more useful. Creation of a ready to use DXF file saved a step for sure.

[xtian]

Very cool.

For CAD, I'm very happy with OnShape.com. Free to use, as long as you don't mind your models being available to the public.

[nuke]

It is a great tool, but it is not a substitute for knowing what you're doing.

The trick is to think, "what task do I assign it?" Not, "what question am I going to ask it?".

It's kind of like having a junior employee around. Task him with stuff, see how he does, supervise and correct.

I've been doing that with coding for a while now. Also, I have an Nvidia DGX Spark here at home, which can run some pretty decent models locally on my own network. My code environment is pointed at as the back-end with decent results.

[pompeiisneaks]

That's pretty much how I see it. I use it daily at work now, and I ask it to do things and it does them about 80% right first try but if I didn't know what i"m doing, i'd accept it as 'right' and then fail. Instead it does 80% of my work for me and I catch the 20% and work way faster now. It 'can' make the world a better place if they can keep corporate greed out of it (as if).

~Phil

[xtian]

LLM (ChatGPT) was invaluable to me when learning KiCAD and OnShape, when upgrading my Ender 3 to Klipper, cleaning my Wordpress site from infection, and many other iterative tasks. Sure, there were some bumps and backtracking, but it went SO MUCH quicker and easier than other means. Far from making me dumber, it has made me way smarter.

[TUBEDUDE]

Looks like a potentially great tool for complicated issues, but for this i use a machinist rule and hand tools.

[nuke]

And time.

It make more sense for me to send metal work out for fabrication, to someone like SendCutSend. I don't have much in the way of metal working capability, nor do I have any materials in stock. Simple metal fabrication gotten quite fast and cheap these days. Have to send them a drawing though.

The amazing thing here is being able to task a machine with exactly what I wanted it to do, let it go hunt down the parts specs and dimensions and come up with the first rev of the drawing, in about 3 minutes. Then a quick reality check with my machinist rule, since I knew the spec sheet didn't show the dimensions of the transformer where it protrudes through the chassis.

I gave the machine revisions in simple english, and in a few seconds, second rev drawings were done. Printed the PDF and cut it out with scissors and it fits. Check the DXF in freeware CAD, all good.

My parts were fabricated and de-burred in less than 12-hours and are already in a UPS box waiting to be picked up. I'll have them midweek it looks like, depending on UPS.

[TUBEDUDE]

With no hand tools or metal, that's good for a one off.
With a sheet of metal and basic hand tools, this is a 90 minute job start to finished plate installed.
No delay and less than $4 of metal.
$20 of metal on hand allows for fabrication of custom covers, straps, braces or supports to keep the build progressing.
McMaster-Carr has everything imaginable in metal sheets, tubes, rods or plates.
Local big box stores have sheets and rod in Aluminum or steel.

[nuke]

So here's how it came out. I ordered on Friday evening. The parts were produced and packed by Sunday morning SendCutSend.com, and they went out UPS on Monday morning from Sparks NV. They arrived Tuesday evening. They even sent candy in the box, just like Sweetwater does.

They look good, laser cut, fully de-burred.

IMG_1770.jpeg

Did a quick fit check and right smack on the money. Every hole lined up perfectly.

IMG_1771.jpeg

That's the easiest and nicest machine shop part I've ever had made. I'll definitely leverage agentic AI to do the grunt work in the future of collecting data and setting up the drawings for production.

[TUBEDUDE]

Just two screws to mount the plate? Looks like the toggle switch is in the way on the one and the stack on the other. Must be the photo angle.
Looks like a copper finish to help with heat dissipation?

[nuke]

Like I said, just a quick test fit in the chassis, so just two screws to check it. Everything lines up perfectly centered in the same spot the much bigger transformer mounts in.

They are plain aluminum. The tint is just the lighting in the photo.

I may alodine them at some point.

Plenty of room inside the chassis, they don't interfere with anything. It's a Bassman 5F6A style chassis, which normally has a much bigger transformer.