Pass Monster?????

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The one and only
Joined 2001
Paid Member
Last I looked, Dave and Casey were still working the
supply and output stage angle, and Grey had made some
sort of commitment to design a tube front end.

The supply and output stages are straightforward construction
projects (or at least should be) and I have a front end in case
Grey finds himself unable to finish it.

So I'm sure that the boys will let me know when they are ready
for more.

I have very few hours of free time and writing takes precedence; it makes me costs money. The old adage about "don't quit your day job" still holds for writers, but as pocket money goes it's really quite a decent hobby in terms of what I make versus the amount of time I put into it. (I'll have a story in the next issue of Analog, if anyone reads SF. I'm not sure which story this will be, probably Give Up the Ghost.)
I've also still got a line stage to complete which will--in theory--make me a penny or two. After that, I will be free to put more time into the Monster front end. As things stand now, I've got the voltage swing that Nelson requested (that was a trivial matter, anyway) but I've got one or two details I want to nail down before going on to the output stage. I'm looking forward to that, as I've got an idea that I want to try. If it works out, I'm going to be very pleased, indeed. I keep threatening to do a solid state mock-up just to see if the principle works, but am so short on time that I haven't even gotten that far. Don't worry, if my oddball idea doesn't work out I've got at least two other ways to approach the problem, although asking current of a tube circuit leads to rather pesky problems.
Part of the problem is that every time I switch from solid state to tube and back I have to tear apart my bench and reassemble everything for the required voltages. If I had more room I could just move from one project to another, but that's just not going to happen. The redo takes me about an hour, all told, and if all I've got is forty-five minutes, then that tears up that day and part of the next. It's just not efficient to spend my time going back and forth. I'm much better off sticking with one sort of circuit and bearing down until it's done.
In other words, no, I haven't forgotten...just the usual time constraints.

By late-January I had everything purchased and kitted (except for some inductors) for the power supply section plus a few thousand IRFP240’s and IRFP9240’s for the output sections. The eighteen ¼-inch thick aluminum plates that would serve as the main structural member in the chassis were dropped off at the CNC shop in preparation for, um, “CNC’ing”. The original Pass Monster thread has several mechanical design renderings (and 3D models if you want to play with them) of the proposed 3-chassis design.

Other than tweaking some mechanical details and re-forming 6 Farads worth of big ol' electrolytics, I have been pretty much in a holding pattern waiting for inductors and CNC funding.

-Casey Walsh
OK, can do… (I think I can, I think I can)

I gave the CNC shop the OK to machine the plates for the bottom chassis. I offered to calibrate some of their older (analog servo) CNC machines to get a respectable price break. Also, I have a 50-lb spool of 14 AWG magnet wire. I can make some 3” ID, 4”-long air-core inductors using PVC formers. I’m sure these will be adequate for big CLC part of the power supply section.

I’ll ping Zero to see if he is in a position to begin contributing to this project. If not, I’m sure I can drum up the time and money to bring four of these beasts to fruition.

Yo Grey: What is ‘SF'?

-Casey Walsh
SmarmyDog said:

Also, I have a 50-lb spool of 14 AWG magnet wire. I can make some 3” ID, 4”-long air-core inductors using PVC formers. I’m sure these will be adequate for big CLC part of the power supply section.

-Casey Walsh

Be carefull with PVC formers for PSU inductors, if they get hot (which such tend to do), the PVC will let go of cloride and that is just about the last thing you want to happen :(

Use POM instead, it's chep and nice to deal with as well, not to forget that it can take higher temp. as well.

Magura :)
Monster CNC.

Hey guys, I have a CNC Mill in my garage. If you have the drawings and material, I would be willing to make a donation in the way of doing some of the machining. My travels are 16x32x17 inches. I have true 4th axis on it also. If you need larger, I work for Haas and I can always do it on the showroom machines!:D
I may have found a power knob for this thing. I will post a picture soon. It came from a Western Electric battery tester. It is a big bakelite item that looks very old high power scary!
I have access to cnc lathes as well if that will help.
I still have the big connectors for speaker outs sitting in a box waiting. Regards, Steve
Well now, no one wants nasty gas do they! :blush:

Magura: I see from your gallery (awesome work BTW) that you made an inductor winding tool – perhaps I’ll flatter you by copying the idea :emoticon:. Alternatively, I once made some 4½” voice coils on slit eight-inch thick aluminum formers for an infra-bass experiment. I suppose I could stack up 8 or 10 layers and call them inductors.

gearheaddruid: Thanks for the offer! The plates are 18” x 28” x ¼” (perhaps a hare too wide), but when we get to the heatsinks for the top chassis I might give you a call… BTW, I‘ll PM you regarding those cool speaker connectors.

-Casey Walsh
Pass monster cnc.

Smarmy, I have access to machines up to 60x120 inch travels! The machine in our showroom is 25 x50 travel. No problem for the larger pieces. I also have connections with a couple of plating and powder coat shops if that would help.

Killowattski, I am a regional service engineer for Haas. Unfortunately, I do not have any real perks other than the use of demo machines and I have a big van to drive. ( The motorcycles fit well on weekends!) I have assembled the complete controls for a machine buying broken parts on EBAY and repairing them. I am getting ready to retrofit this on my lathe so I will have cnc there also! It will be a joy cutting threads electronically. I am also working out live tooling for same machine. I can redrill car axles and such a lot easier that way. Regards, Steve

Still, I have an Enco mill drill that I use for stuff at home (DIY stuff). A neighbor owns a machine shop and I learned on one of his old Bridgeports. It had DRO though. Oh boy, do I love DRO. It makes it a lead pipe cinch. He used to let me come in on Saturdays to do my DIY stuff and in turn I wrote some G Code for him. I bought a Mill Drill because I didn't want to wear out my welcome. One day when he gets rid of the old Bridgeport I will be knocking at his door with a rigger and a fist full of cash. The machine is really taken care of and the ways show no sign of wear. When and if that ever happens, I would love to turn my Enco into a CNC mill.
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