909HAT

 

Tadaaaa!!! It's a 909 HAT!

This is the final retail version of the 909HAT module! I've got like 20 of them, so as fast as people can get on my case to send them out they'll sell.

Anyway, if you've gotten your hands on a kit (or printed up a PCB if that's a thing anyone ever does) make sure to get help building it by going to this Instructable howto link right here.

VCSlope hardware works!!

 

    This is the VCSlope module I obsessively designed in a week or so. It seems to work correctly, as far as I can tell... the two "Rate" knobs set the rate of the slope rise and fall, and clockwise means "slower" or, I guess, "more time going up or down the slope." So when it's oscillating fast, clockwise means lower, counter-clockwise means higher. This isn't what we're used to in SynthUniverse, but it's probably the way they're supposed to be.

    Installing several of these in one case and patching all over them could be a really interesting exercise is random/automatic sound generation. I'll let you know!!

909CRC

Heyyyy! You've found my post about the 909CRC, the crash/ride/COWBELL module!

For full documentation of this build, go check out the Instructable build guide.

Here's the user manual, also included in the Instructable page but maybe you want it here too...

The top jack labeled Pitch is for a control voltage that sets the pitch of the voice. This control conforms to the 1V/octave standard, so you can play tunes with your 909CRC.

The top potentiometer sets the pitch as well. If you turn the knob lower than 12 o'clock, the sample will play backwards. It's possible to scrub back and forth through the sample if you mess with this knob correctly.

The two LEDs show which sample is being selected, and playing.

The button below selects between the three samples, sample one is crash, sample two is ride, sample three is 808 cowbell. Hold this button for two seconds, and it becomes a way to trigger the module without an external trigger signal.

The jack labeled Accent allows you to control the volume of the voice with a control voltage.

The Level pot controls the volume of the voice.

The Trig jack is for the trigger. Send this a pulse of voltage, the module will trigger!

The Out jack is, well... obvious.

Stanced Sedona

 

    I know in my head that this is a crappy old minivan.

    I know that.

    But when I look at it, I don't see a 15-year-old mom-mobile with rust spots and 340,000 miles and mismatching door handles. It looks cool. It looks tough. I have driven this van all over the Colorado plateau. I've driven it to Kentucky more times that I can count. It's the most powerful car I've ever owned (245HP) and may be the fastest as well, both straight-line thanks to the variable valve timing and 24 valve V6, and maybe even on the twisties since tire technology has come so far (but I don't do twisties anymore because the Midwest is a grid and it's dangerous to drive fast through neighborhoods) (I used to fly through neighborhoods in Texas when I was young and foolish).

    We've bonded.

    So anyway, I just put snow tires on Nissan (rear wheel drive) alloy rims, and slapped them on my van. They're wider than stock, and have a wider offset. So the wheels are pretty flush with the fenders. I would love LOVE to put airbags in the suspension -- the front are basic struts, the back are just coil springs, so there's generic airbag kits out there but I can NOT justify the expense but DUDE, letting all the air out of the bags and driving around just slammed would make my heart so happy.

909 metal voices OUT OF MY SYSTEM!!!

    The 909 voice modules are designed, tweaked, printed, and ready for prime time! I do have a question in my mind about the 909HAT, which has a reverse sample playback, but the amplitude envelope can only go "forward" because it's derived analog.....ly... analogly? Probably not a word. Analogously is a word, but don't think it works there...

    So I've got a new obsession, which may be fruitless. The Make Noise Maths is the best-selling module ever. Never got it... never touched one... it's a slope generator that can be a VCO, a clock, a filter, an LFO, an envelope follower, and an envelope generator. Probably wavefolder, trigger-to-gate generator, gate-to-trigger gener ANYWAY, it's a versatile module that can do so much. I guess I'd rather have all those modules more custom-designed to do like... those things.

    BUT!!!!! The possibilities. The Maths is almost a Serge DUSG -- dual universal slope generator. The Internet is lousy with schematics for the DUSG and VSG (voltage-controlled slope generator), and it's a fascinating circuit with non-exotic parts, so I schematic'ed one up, routed the PCB, and I'm on the cusp of ordering a run of five (single) slope generators. I'm imagining putting all five of them in a case by themselves with a sequencer or two on the left, and a mixer/amp on the right. It may be a Ciat-Lonbarde-level nonsense machine (Peter Blasser doesn't know I exist but he's my pretend nemesis) but it might be really really interesting.

    So anyway, that's what has been happening to me. OH!!! Other stuff too -- my kid Houston threw a rod in his Chevy HHR so I replaced the whole engine, while the car was parked on the street so that was a big job. Had to pull an engine from a car five times (first engine pulled was the wrong type, 2nd engine pulled from Houston's car, 3rd engine pulled was correct type, but after installing it and getting it to run, discovered that it had a thrown rod same as Houston's engine so back out it came for the 4th engine pulled, 5th engine pulled was the correct type AND it runs great) and install an engine twice. I'm glad that job is done, but it was fun to have such a large project to sink my teeth into.

        Finally,  Beth and I went to see Depeche Mode. They make lots of really great sounds like "DOOM DOOM DOOM" and "KSSHHH" and stuff. Synthesized awesomeness! We ate fancy brie cheeses on the way there and back in Beth's Kia Rio, which is such a nifty little car.

Inputs & power

Look! It's a SynthCard with inputs and a power regulator!

This thing even has a USB-C power input, but whooooo boy USB power supplies can be noisy. Use USB at your own risk.

It works well, and I've decided to do build guides over at Instructable, so go over there to build this Synthcard, okay?

ZVHP high-pass VCF build guide!

Edit: I just realized that I've already told most of this story in my July 4, 2023 post. uh..... sorry? I finished that post up by saying "golly I hope the 2HP filter works" and it does, so here's this post:


It's the ZVHP high-pass filter! In PCB form!!!

I met Konstantin (Constantine??) at Knobcon 2017, and one of the pieces of advice he told me was "put your kick drums through a high-pass filter then a low-pass filter." I was like what are you talking about but I took his advice, first scouring the Internet for good high-pass filter designs, rejecting most of them as too harsh.

Sorry..... digression...... the most common variable-state VCFs have insane uncontrollable resonance. Thomas Henry fixed that with his excellent VCF-1 design, but I didn't find that one until later. Notice the 10pF capacitors C1 and C2 -- those are the magic capacitors that stop the filter from becoming uncontrollable. Digression done.

The other design I rejected was the VERY VERY GOOD Polyfusion high-pass filter. Ron Folkman (whom I met at Knobcon 2018)

Mr. Folkman's high-pass filter was very controllable, wonderfully designed, and his hand-drawn schematic... my stars, they are artistically gorgeous. Maybe you can tell I'm sorta crushing on him in that picture. 

Anyway, I rejected Ron's filter for kick drum filtering because it is a four-pole filter, making the cutoff too steep for my ear for that specific purpose. I took the design, cut it in half, struggled mightily with the resonance part of the circuit, and when I finally came got something that worked, I found that it worked very well indeed!

So anyway, here it is. I'm really proud of this design. It's one of the first times I felt like I really understood the functioning of each part of the circuit, and could take ownership of the design as uniquely mine.

Okay, build guide time.

First, break the PCB into pieces.

 Smooth the edges of the PCB where the breakoff bits are, especially on the panel.

Then, install the pins that the perpendicular PCB will slot into.

Jacks. Put the Thonkiconn jacks where they go. Solder them in.

Potentiometers. These are 100K linear Song Huei tall trimmers. I usually buy these from Synthcube. Don't solder these in, just place them on the PCB, and then put the faceplate on, installing the nuts on the jacks to hold the front panel where it needs to be. 

Wiggle the potentiometers around on the PCB until you're happy with how smooth and straight they are. Use some pliers to slightly squeeze the mechanical legs of the potentiometers. This way that metal part should let the module fit in your modular. Finally, solder the electrical and mechanical connections to make stuff all sturdy and tight.

Now it's time to mess with the electronics! 

You'll need three 100K box trimmers and one 10-pin shrouded header for the Eurorack power.

The notch in the power shroud goes away from the electronics side of the PCB. Pin 1 of the cable (the red wire) goes where the PCB says "RED STRIPE" anyway, be careful to get that part right.

The trimmers can lay over so they're in the same plane as the PCB.

Now you get to connect the PCB to the rest of the module!!! Never more to be parted. Forever and ever. Amen.

Now it's time for LEDs. This is optional, but who doesn't want light to shine out of their jack holes! I am not a person who doesn't want that, that's for sure! The long leg goes in the square pad. 

Be careful with the legs of the top LED so they're not touching each other or the resistor that's right under them. 

Okay, calibration time. Your trimmers are probably 25-turn pots, and they're probably from the factory set right in the middle at 12.5 turns. Assuming that's the case, start the calibration process this way:

Range trimmer: counterclockwise 8 turns

Scale trimmer: clockwise 4 turns

Resonance limit trimmer: counterclockwise 8 turns

These trimmer settings are a good starting point. Plug a signal into the In jack (something with rich harmonics, a saw, perhaps), listen to the Out jack, and adjust the trimmers more to get the filter dialed in just right.

The range trimmer sets the center frequency of the cutoff knob on the front of the module. Turn it counterclockwise to get the filter higher pitched, clockwise to get it lower pitched (in Rev. 2 this will be swapped).

The scale trimmer adjusts the exponential response of the frequency. If you're careful with this trimmer, and you've set the resonance to self-oscillate, you can use this filter as a 1V/Octave oscillator. It won't be temperature stable, and the response will change with the resonance knob, but it will probably be within a few percent over a couple octaves at least. I've never tried it myself...

The resonance trimmer sets the gain of the feedback signal -- higher gain, more oscillation. This is easy to dial in -- leave the In jack without anything in it, turn the cutoff knob to maybe 9 o'clock, turn the resonance knob all the way up, and adjust the resonance limit trimmer until you're happy with the sound of the resonance. 

You should have your ZVHP all dialed in, ready to go! I love what this filter can do to kick drums, turning them into monster low boom sounds, muting them up to little clicks, or turning them into a little bongo sound, depending on the resonance and cutoff. I hope you find yours as enjoyable.