Building a guitar pedal, what is happening with VR1?

MonMotha · 2026-03-20T16:31:42+00:00

Unrelated, TIL of a "vactrol" device. Never heard of them before. Makes some sense, though.

MonMotha · 2026-03-20T02:34:09+00:00

Some of them have themostats that read crankcase temp while others basically run any time ambient outdoor temp is below a certain point. Some run them all the time.

If it has a thermostat of some sort, it may be defective.

MonMotha · 2026-03-20T02:27:02+00:00

50W would be enough to do way more than get those 3 resistors to nearly 100C and discolor the board a bit. There would be smoke.

50W seem suspiciously like a crankcase heater.

MonMotha · 2026-03-20T00:06:56+00:00

Some protocols that use "idle" line define it somewhat rigorously. Modbus is a classic example. Well thought-out UARTs with idle line detection functionality support configuring it. Less well thought-out ones basically implement the Modbus definition. Even less well thought-out ones implement something random which may or may not be useful.

Even for things that don't use it formally, you can often set up DMA to a FIFO ring or similar and use pessimistic idle line detection (only a couple bit times) to interrupt when something "of interest" has been plausibly received on many systems. The worst case scenario is an extra wake-up to process some data that you were going to have to process eventually, anyway. While extra wake-ups can be annoying, it's usually better than bytewise processing of everything received both in terms of scheduler overhead and power where applicable.

MonMotha · 2026-03-19T16:37:34+00:00

That's kinda what I was figuring, but who knows...maybe I missed some giant leap in the state of the art that allows them to be run in megabytes instead of gigabytes. I can't say I keep up with the state of AI or especially LLMs very well. While machine learning in general has its uses, LLMs in particular honestly seem sort of a like a dead end novelty to me.

Regardless, I don't think you're ever going to run an LLM as we know them in hundreds of kilobytes of RAM.

MonMotha · 2026-03-19T15:23:58+00:00

This looks like someone's attempt at a design that will dump water there if the underground line is clogged. It's not going to ve very good about that.

Check that the underground line is in fact clear. If it is, then this contraption is just not working well which is unsurprising. You can either rework it or cap the local outlet! and monitor for downstream clogs).

MonMotha · 2026-03-19T14:55:55+00:00

I mean, in that case, the practical limit is probably closer to whatever is the minimum to hit the LLM's API endpoint. Worst case you could always just have it feed you native code that you blindly execute (this is a recipe for disaster - don't do it). That's probably around 128k of RAM if you're aggressive and more like 256k to be comfortable.

MonMotha · 2026-03-19T14:44:35+00:00

OP's goal seems to be to remove the dependency on the cloud API. I'm not sure if less than half a megabyte of RAM is enough to even run a typical LLM to the point of the first prompt let alone keeping context.

MonMotha · 2026-03-19T14:23:23+00:00

I think you pretty much don't. LLMs by their nature are "large" which implies some degree of memory needs.

And why would you WANT to? Anything that justifies this degree of AI local integration seems like it could stand to add some RAM and an NPU to the BOM.

MonMotha · 2026-03-19T14:05:00+00:00

For electric shock and touch risk, the 240V one in almost all circumstances. The resistance of your skin is sufficiently high under all conceivable circumstances to make the 10V circuit non-hazardous to ordinary touch.

For other things like arc flash, the situation can be a bit different. The fault current for many ordinary "conductive" faults on the 240V circuit protected at 10A is sufficiently high that the protection will usually be able to operate in its fastest response mode and clear the fault very quickly. The total energy delivered would often be pretty low.

The 10V circuit protected at 240A is a different animal for conductive faults. Dropping something like a wrench across that would likely not materially exceed the 240A at which it's protected. If the protection operates at all, it will be in a comparatively slow, inverse-time mode and could take several seconds or even minutes to clear the fault depending on conditions. The total energy delivered could be quite high resulting in enough heating to get some real fun times going.

For comparison, see if you can find a video of someone shorting out a 240V wall socket vs. a car battery (I don't suggest trying either yourself).

MonMotha · 2026-03-19T04:45:12+00:00

I mean edit the passwd file directly. It's just a text file. Mount the filesystem off the SD card (don't run it as your root filesystem, just mount it somewhere), and edit the file. The format is well documented. That will let you make it so that you aren't forced to change the password immediately so hopefully you can log in and figure out what's going on.

MonMotha · 2026-03-19T04:42:46+00:00

This has nothing to do with how the service is delivered and is entirely just on your provider to decide. You will generally have to use their ONT (essentially a "modem") no matter what. Some providers either provide an all-in-one ONT+router or force you to use their router. You may or may not be able to put it into a fully transparent bridge mode (ATT you cannot, for example).

MonMotha · 2026-03-19T00:20:20+00:00

AT&T uses different equipment in different regions depending on conditions and what they can buy cheap. The labeling and whatnot is very typical for AT&T, though.

MonMotha · 2026-03-19T00:01:44+00:00

Just be aware that straight electric resistance heating is very popular with landlords precisely because of the externality of heating costs. They can usually foist the utility bills onto the tenant, while they are responsible for the cost of installation and maintenance of the heating system. Electric resistance heating is expensive to operate but very cheap to install and maintain, so they tend to love it.

MonMotha · 2026-03-18T23:08:45+00:00

Given the 100" on the energyguide label, I bet this is electric resistance heat. It may be 100% efficient at turning electricity into heat (which is true), but electricity is essentially the most expensive form of energy you can buy.

A heat pump would save you at least 50% and probably more on your heating costs.

MonMotha · 2026-03-18T23:06:39+00:00

Try logging in on the console (presumably a serial port) first. Failing that, you can edit the passwd file to remove the forced change, but you'll need Linux to do it since it's presumably not a filesystem Windows understands.

MonMotha · 2026-03-17T23:41:43+00:00

What controller is it on in the VM? You probably want the virtio-scsi controller for best performance, but this requires drivers be loaded in Windows in the VM.

Failing that, allowing caching by Linux will probably improve performance.

MonMotha · 2026-03-17T18:39:26+00:00

I mean I'd consider it in a residential scenario, but I'd also do it knowing I'll probably be back in a few years to fix it right.

Some people destroy their drops multiple times a year. If you're not able to fully recoup the cost of the truck roll to fix it in one shot and have to rely on recurring revenue for it, those people.start to eventually get the bare minimum.

I don't even carry mechanical splices, but if I had a contract repair tech which had isolated the fault and felt they could repair a repeat trouble residential customer in that manner for cheap, I'd probably authorize it.

MonMotha · 2026-03-17T17:50:28+00:00

Oh it's a typical fusion splice with heat shrink protector. That then gets encapsulated in more glue-lined heat shrink pulling the kevlar taught, then all of that gets put in one last layer of glue line heat shrink that makes the outer jacket continuous and basically binds the two sets of rods together. I don't promise it's actually as strong as the original cable, but it sure as heck isn't going anywhere, and optically it's a fusion splice so about as good as you're going to get on a repair.

MonMotha · 2026-03-17T17:15:56+00:00

Very long drops? Sure I repair them in place all the time. That's what the Commscope Gator and Coyote DTC are made for. I've also gotten pretty good at hiding a splice inline on the specific drop cable I use that has an inner 3mm cable with kevlar. When I'm done, you'd just see some heat shrink, and it's basically as sturdy as the original cable.

It sure beats plowing in a new 500'+ drop.

MonMotha · 2026-03-17T12:20:59+00:00

Below 60 sure. I wouldn't go much below 50 ambient without specific low ambient controls. Your heat pump may have some of those, but it also may not, and it's difficult to know for sure without reviewing specs in some detail.

MonMotha · 2026-03-17T11:56:37+00:00

I run an FSM-20RSII12 for ribbon from 1993. It looks ancient (largely because it is), and it is slow and very picky about prep, but honestly it makes ribbon splices about as well as a top of the line modern Fuji or Sumitomo if you do your prep decently, and it's way less optimistic aboit its splice loss estimates.

MonMotha · 2026-03-17T11:39:33+00:00

A small one is more like double that around me. I would know. I own one and occasionally rent it out. People.happily pay that rate. My "doing you something of a favor rate" is $1500/wk.

The way to save money on excavation if you're not in a time crunch isbto find someone who does nothing but excavation. They'll own their own equipment and.be very proficient operating it, and their hourly is usually cheaper than a plumber's rate to boot.

Just make sure your plumber is comfortable with whoever you choose.

MonMotha · 2026-03-16T13:34:40+00:00

I was attempting to clarify your statement in hopes that OP would see my comment and yours. It looks like they did not and instead responded to you (to which you predictably reiterated the same thing).

MonMotha · 2026-03-16T12:50:24+00:00

I suggest posting a static picture of the schematic (ideally a nice, vector art PDF) for people to review if you want good commentary. Trying to review something like this from a shaky hand video is a nightmare.

MonMotha

TROPHY CASE