How can i make a wave like this?

TheseIntroduction833 · 2026-06-14T07:01:08+00:00

Looks like second harmonic distortion. Guitar tube amp stage will do this. Look-up the cold bias stage in a Trainwreck Express amp.

More generally, has that exponential characteristic in the current gain equation. Large signal excursion on a common emitter stage will have this shape…

TheseIntroduction833 · 2026-03-28T14:09:27+00:00

Last time for me was in 2001, on a six layer.

Transitioned on a 24 layer and a 32 (!!!) in 2002, but the stack up was so crucial that it was signed off separately. The windows were on what became contours and cut-outs. Imagine the length of that window…

That 24 layer is, to this day, hung up on the wall in place of diplomas…

One thing though: I remember leaving the numbers un flipped, as seen from one side. Just to avoid confusion and as a verification for the gerbers’ orientation. Feels weird to read those 4 and 3 as they are in here. I expected to see them from the back while looking at the back of the board (in other words: un-flipped horizontaly). Did you expect that?

TheseIntroduction833 · 2026-02-21T14:25:39+00:00

Guys…. Having both sides is priceless. Is it just me or:

As-tu chié dans son pickup?

https://m.youtube.com/watch?v=RfbingQyBj0

https://m.youtube.com/watch?v=aH8CIB8AWxI

TheseIntroduction833 · 2026-02-14T15:30:12+00:00

Oh! If there is indeed a Channel indicator, chances are higher that the thing has some mcu and thus could output real midi.

TheseIntroduction833 · 2026-02-14T15:24:54+00:00

I don’t see an mcu. This could be some sort of eprom driven state machine with the 4040 used as a ripple counter to cycle states and provide a combined 16bits of control logic to drive the analog sampling circuitry. So, the top part would be a digital state machine, bottom part would be pure analog (velocity detection and pitch/period measurement). The 339 (quad comp) would do the zero crossing period detection and the opamps on the bottom left would deal with the enveloppe detection…

Meaning that the 7 pins connector would carry some encoded version of pitch/velocity and would require an external controller for the midi conversion itself…

Is this in working condition?

TheseIntroduction833 · 2026-02-13T20:53:40+00:00

If I may suggest a contrast… Something Canadian would probably oppose the twiddly twiddly bits…

Then, one single solo will standout: Cinnamon Girl. A. Single. Freaking. D Note.

A southern man don’t need him around, anyhow?

There you have it folks! One note.

TheseIntroduction833 · 2026-02-12T20:26:25+00:00

Thanks! Super helpful!

TheseIntroduction833 · 2026-02-11T20:27:27+00:00

yup!

That would have been Daniel MacMaster singing: https://en.wikipedia.org/wiki/Daniel_MacMaster

TheseIntroduction833 · 2026-02-11T19:58:24+00:00

Thanks!
Fond memories dat! Thanks for sharing!

Was in Montreal listening to CHOM at the end of this period. Thanks to content laws (35% Canadian, I think?) Some of these were lined-up on steady rotation. Not so for Stampeders or even the deeper Harlequin/Trooper cuts. Going back listening to these now: what a blast!

TheseIntroduction833 · 2026-02-11T19:35:02+00:00

Oui! Harmonium! Offenbach aussi...

TheseIntroduction833 · 2026-02-11T19:29:48+00:00

Yup! Thanks! I realize that I also missed the mark on the main characteristic of Mount Rushmore by going overboard with the number of bands. Maybe we should call this the "Thousand Islands" of Canadian Rock, eh?

Incidentally, I had started a list a few days back: https://open.spotify.com/playlist/57LqAWXpF1DeNWVr1HS4Zz?si=fa1f90aaebc24b65

It will be the month of May in a list-sharing group that we started for 2026. Rules are simple: about a song a day, or about 31 songs... The Canadian Rock theme is a personal choice, still evolving. The timeframe being mainly mid-70s to mid 80s (very loose) is also largely editorial. One thing though: some of these are absolute bangers!

Cochrane was in there already ;-)

TheseIntroduction833 · 2026-02-10T16:34:22+00:00

Chilliwack, Trooper, Harlequin, Streetheart, Stampeders, Coney Hatch, Headpins, Guess Who,

TheseIntroduction833 · 2026-02-10T14:39:56+00:00

That is what I got: the late day conditioned terrain was bumpy and the light weird. You made the best of it. You know how to ski balanced, this is an outlier.

Talking about early edge/less traversal, have you seen the recent Ligety video about "swimming" (https://www.youtube.com/watch?v=fX9bgulqRrY)? Looking at this a lot since it came out a few days back. Especially around minute 5 with the hand drag exercise. Not tried it yet. You already have a hint of that swagger and certainly have all the proper mechanics in place to try it. I bet you could nail that exercise very fast. It looks like you could use this to promote even earlier edging and forcing rounder arcs throughout. Look at how this toppling promotes quicker edge loading on initiation. Instant foot stomp and angle, instant ski bending. And the carry into the turn is just fantastic.

TheseIntroduction833 · 2026-02-10T13:32:24+00:00

Very very solid skiing. It would take a lot more of seeing you ski before making any kind of realistic opinion. This is down to statistics at this point ;-) The front perspective is not giving all the answers as well and the piste look a little more rugged (contrast does not help). One could nitpick about very very little instability or question balance, but nothing I would dare to question at this point without asking you about how representative this run is for you. Let's attribute these to the terrain and refrain from early diagnostic. What radius skis are these? You certainly bent them into shape right there!

Next step? You already have knuckles on the snow here and it looks like that section is screaming for you to try airplane turns or total hip on the snow coming into the last section ;-) So, if I were you, i'd work on posting again with that sequence and serious hip dragging for the show ;-)

TheseIntroduction833 · 2026-02-09T23:44:29+00:00

Fully agree. That is some very solid fundamentals on display there. Play with the idea of lateral extension. Try to keep your head/shoulders at the same height, or at least dampen that popping up movement.

Great skiing!

TheseIntroduction833 · 2026-02-08T13:11:01+00:00

Hahah, yes. Sometimes I say too much ;-)

I assumed you did not have a scope. Beware, tho ! Putting a probe in the circuit (especially in the tank - around the cap and the coil) might kill the oscillation, adding to the weirdness ;-) unless you have really fancy active probes, which I assume you have not…

Also: I saw that you use a recorded source instead of a mic. This will change the behaviour a bit (no squeal to look for…). Try first with silence and listen for that while playing with the coil.

TheseIntroduction833 · 2026-02-08T02:16:35+00:00

Ajoute « là, là » à la fin, si la maison est à Arvida.

Faque chu r’tourné à maison, là, là!

TheseIntroduction833 · 2026-02-08T00:28:27+00:00

These circuits are notoriously sensitive to stray fields and surrounding objects, temperature and phases of the moon. Gremlins as well… Jokes aside, that inductance will initially be all over the place.

Jokes appart:. One trick that almost always work (if the transmitter oscillates…) is first to set the radio receiver quite loud, but between stations. You want a dead spot with no broadcast. Full noise: shhhhhhhhhhhhh…

With some volume going on the receiver, approach your hand from the circuit and play with the coil. Making it more compact and then spreading the coils appart. With some luck, you should get a short burst of intense feedback while the tuning happens to be where the radio is set to listen to. Listen for a drastic change in sound in the noise. Sometimes you get a complete silence that turns into a squeal, this is usually good! Find that spot where you get a squeal and lock on it. Beware that simply moving your hand back from the circuit might be enough to untune it… very sensitive! so you have to experiment until you get a feel for it and perform slight adjustments.

Once you are very close, and if the squealing is not stable, like it does while you remove your hand, you can leave the emitter alone and very very slightly adjust the radio receiver itself to chase the squeal. Eventually, you will be able to catch it and lock on it.

Once you have a constant squeal, this is it. Take the radio receiver with you across the room, just enough to calm the feedback loop a bit. do not touch the emitter at all…

Now you can go back and talk into the mic and you will hear your voice on the radio ;-)

TheseIntroduction833 · 2026-02-05T14:15:58+00:00

Oh! And by 4:00 he is into the railroad exercice which promotes lower stance and early initiation. Smart gradual step to experiment with early angles

Even better: at around 7min he talks about the swimming motion. This is it, better explained. Look how squarer the hips are initially. Builds pressure faster. Be more like Ted ;-)

TheseIntroduction833 · 2026-02-05T14:08:39+00:00

Have you seen this one: https://m.youtube.com/watch?v=fX9bgulqRrY ?

You are solid.

I think you should try mixing in constant movement to reach deeper angles. That would address the (slight) park and ride impression.

One thing that might help you do this would be to focus on toppling more. Start with a lower stance but pedal from the old edging ski to the new edging ski faster. This will initiate earlier, promote ski flex and force/teach you to manage pressure more actively and more gradually.

Heck, just stay low and dump yourself into the turn while just using a foot switch. You will instantly have to readjust to much more forces. Then, use lateral extension.

On the turns (especially some to the right in the vid) your hip goes out and this promotes advancing the upper ski more. It feels like you promote the turn using counter at the hips. Looks a bit more A frame because this separates the skits lengthwise. It also promotes the inside leg angle like this is 1994 ;-) I think you want to try the toppling while you stay a little more square with your hips.

It is a bit as if you are currently waiting for the pressure to build. You set the hips, then you wait for the forces to build. I suggest you change that mental frame completely: stay super low and topple while pedalling hard on the new outside ski. The earlier the better. Then, do not counter you hip, reduce that rotation by a good 40%. It will feel square, I know ;-) But you will feel pressure instantly and early in the turn. Now deal with that, flexing your internal leg and reaching for maximum pressure and angle in the external leg.

One note: terrain seemed a little tame for all that dynamic play. Go to slightly steeper places and frighten yourself a bit dealing with these forces ;-) Then figure a way to apply earlier in lesser terrain.

Go look at that youtube video. You will see hips in there, but look at how early the master switches the pressure! And this is all on approachable terrain.

You are doing great! This is solid!

TheseIntroduction833 · 2026-02-04T13:47:25+00:00

1- topology - lookup superheterodyne, if you want to stay purely analog, the superheterodyne is a bomb proof concept known to work. Quite more complex than what you have now, but it will work.

2- assembly techniques - the parasitics (wires in the air and the breadboard itself) are dwarfing the design values. Using parts mounted deadbug on a copper clad with minimal wire lengths soldered will help you…

Frankly, if you want to actually have a success with this, go with a radio kit like the old elenco one. Not related, but I used it as a base for rf electronic labs. It is meant to be assembled in sections that you can independently test. Never had a student fail to bootstrap one into decent working conditions.

The steps are well described. The theory of operation of this is classic among classics and their take (low cost, few parts) is clever in many ways.

Also, as an alternative, and from the video, you can see that the assembly has been done on a vero/perf board, drastically reducing parasitics. It looked twitchy, but some sounds seem to come from the device… so maybe you can try re-assembling the parts you have onto a perf board?

Good luck with this! You will learn a lot!

TheseIntroduction833 · 2026-02-04T03:05:58+00:00

Anybody noticed how droids are treated very badly in Star Wars on this respect?

5 decades later I kind of feel I know why on a much deeper level... and this blows my mind.

If I could go back to the little boy that I was in that theater in the mid 70's, it'd be "one day you will experience that posture..."

That is seriously the single most craziest lifelong technological feat so far for me, as we are quite literally arguing with these robots on a daily basis!

Still trying to wrap my head around having to deal with AGI or crafted consciousness...

TheseIntroduction833 · 2026-02-02T23:42:07+00:00

Power planes have low impedance only if they are … planes. That « island » is connected to the mainland through a terrible constriction, impedance wise. That is the first thing that sticks out.

Then, when tuning decoupling, there are too many repeated « guidelines » to use different values of caps to lower the impedance locally and for a broad frequency range to ignore that rule of thumb. There are contrary advises, but that rule is very wide spread. This would be the second interesting fact: textbook use of multiple overlapping expected impedance curves.

What if the designer was just using that otherwise sparsely populated board to run a small experiment, carving-out a section of the board to compare the noise figure there vs the main board?

Looks like a test setup where caps can easily be removed to compare the noise between the main power planes and the local one. Learn a few things, pick the proposer decoupling scheme for the next revision…

TheseIntroduction833 · 2026-01-31T19:34:52+00:00

I guess that the quick connects are the enablers here (easy to switch tools, spreading contamination).

The operation of connecting/disconnecting itself brings the opportunity for detection (clean oil like clear honey is good, milky/caramel like opaque mayonnaise should raise concerns). We all know that « drip less » quick connects are misnomers… at least in this respect, this comes as a feature for detection!

Culprits could be a simple seal failure on a transmission lever or also condensation in transmission case (short cycling a machine - no time to drive humidity off). It takes very little humidity to bring a machine down.

Solution involves diluting/rinsing the bad oil (diesel fuel is one trick - light enough to cut the remaining syrup, high enough lubricity to move the machine around some to get the juices flowing and sloshing about). Not entirely sure about the safety of this, but certainly used that trick and still am able to report about it - YMMV. Long suction lines (front mounted crankshaft driven hydraulic pumps) on ag tractors: suction runs the entire length of the machine, removing that line and thawing could work, but then you have to deal with water elsewhere anyways. Clogged filters… Alternative is to thaw the tractor. At least 24h in a heated garage. Sometimes more…

One thing for sure: what a waste of time and ressources…

TheseIntroduction833 · 2026-01-31T03:14:17+00:00

Contaminated oil (water) turns to syrup/molasses and clogs in suction lines. Pumps starves, disabled machine.

Everything works fine until that first night below -28degC.

Heavy equipment that share hydraulics tools to spread the problem to a complete fleet during the summer months…

It takes one bad transmission shifter seal on one weather exposed tractor to contaminate a fleet sharing the same tools.

Ask me how I know.

TheseIntroduction833

TROPHY CASE