Lmst

This time my #soldering was a fail. This is supposed to be a #keyboard controller for playing my #StackSynth but the sample and hold part needs rework. The output voltage keeps rising. At first I noticed that I used a ceramic #capacitor where I should've used a polymer one, but this bodge didn't help. Maybe the #TL074 are out of spec (most likely fake ones but worked fine in the other modules) or the FETs are bad...
The keys will be attached using a stereo 3.5mm audio jack, and will be extendable like my perfboard version.
#diysynth #synthesizer #sampleandhold

the bottom side with all SMD components soldered in.

the top side with the through hole components soldered in.

the attempted fix for the sample and hold error.

And here it is. The boards arrived today from @aislerhq so I had to solder it immediately and it sounds nice. Even my wife commented, that my annoying experiments start sounding acceptable.
#soldering #StackSynth #VCF #diysynth #synthesizer #LM13700

the back side of the VCF board. there are a couple of SMD resistors and capacitors

the top of the VCF board. the main component is the LM13700

I'm planning another module for my #StackSynth - a #VCF based on the #LM13700 and the Skull & Circuits VCF-3: https://www.skullandcircuits.com/vcf-3/
I already designed the #PCB in #KiCad but wanted to test it on a solderless #breadboard first. It works fine, so I ordered the PCBs.
#diysynth #electronics #synthesizer

the assembled circuit on a solderless breadboard. the inputs and outputs are connected by long jumper cables

One of the final modules for my #StackSynth project: the #noise generator. It outputs white, blue, and pink noise and uses a #3904 and a #TL074 with a lot of resistors and a couple of capacitors.
It is based on Moritz Klein's video: https://youtu.be/0yB_h_wFkh4
I prototyped it on solderless #breadboard and then designed the #PCB in @kicad and let @aislerhq manufacture them again. It turned out quite nice and sounds great.
#soldering #diysynth #synthesizer #KiCad #pcblayout #MoritzKlein

the prototype on solderless breadboard. it's a bit messy and has lots of resistors scattered around.

the finished board from the top. the components are placed in a neat grid and look very orderly.

And here is the #StackSynth power supply board done. It provides dual rail +/- 12 Volt from 12 Volt AC. Stable for at least 300 mA. The diodes D1 and D2 get a bit warm, though. I'll have to see how it performs with my modules attached.
Again, boards were manufactured by @aislerhq and arrived together with the VCA.
My StackSynth tower is almost finished so far. There will be a Noise module coming and maybe I'll add another LFO.
#soldering #diysynth #synthesizer #powersupply

the finished PSU board from above. the components are visible.

the StackSynth tower so far. almost all planned modules are stacked ontop each other.

Finished #soldering another #StackSynth #diysynth module, an important one: the #VCA - together with the ADSR, it makes the output sound much better.
Again, boards were manufactured by @aislerhq and they look nice.
I noticed that I didn't have any 2MΩ 0805 #SMD resistors, but found a couple of larger 1206 2.2MΩ ones in my recycle bin. They don't fit perfectly, but should do until I have the proper ones.
#synthesizer #LM13700 #TL074

bottom of the finished board. the SMD components are visible.

board from the top showing the LM13700 and the TL074.

closeup of the two larger 1206 resistors (R29 and R11). the top one is a bit crooked.

Finished #soldering the #StackSynth #VCO after the missing resistors arrived today. The tuning knobs are a bit close for my taste. The next revision will have a wider gap between.
After tuning it to roughly 1 Volt per octave, I tried it with my #sequencer. The test setup only included VCO, LFO, and mixer, though. The VCA will be the next board.
https://makertube.net/w/xwhPj4tAb2BdmPDmQuVakv
#diysynth #synthesizer

the finished board from the top, without the ICs.

the finished board from the bottom with all SMD components visible.

the test setup with LFO at bottom, mixer in the middle, and the new VCO at the top

closeup of the side potentiometers. the ones of the VCO are very close to each other, the ones of the mixer are better usable.

As announced, I finished the buffer today. Also, I soldered all #SMD components to the #VCO board that I already had. The two missing resistors will follow when they arrive.
It was fun and went better than my previous attempts, since I used a smaller tip.
#diysynth #StackSynth #soldering #synthesizer

the finished buffer. the two inputs and one output are connected. the LED for the second input is lit, since there is some voltage.

the VCO board with almost all SMD components soldered. only R2 at the right and R8 at the top left are missing.

Three new boards for my #StackSynth arrived from @aislerhq yesterday. They are buffer, #ADSR, and #VCO. The VCO is the first with #SMD components on the bottom side. Two resistor values are missing in my SMD collection: 30k and 68k. I already soldered the ADSR and tested it. The buffer will follow tomorrow.
#diysynth #soldering #synthesizer #envelopegenerator

my parts boxes for the new boards. left has the components for the ADSR, right for the buffer.

the parts box for the VCO. it is the first StackSynth board with SMD components. two resistor values are still missing.

the finished ADSR board. it is powered and has a cable in the gate. the LED is lit, indicating the output being active.

capture of the output of the ADSR. you can clearly see the four stages Attack, Decay, Sustain and Release.

a longer demo of the #sequencer. I play around with some controls and have replaced the mixer and LFO with the available #StackSynth modules, mixing sawtooth and triangle waveforms of the perfboard VCO (will be replaced by one of the next StackSynth modules).
#diysynth #synthesizer
https://makertube.net/w/1SoLv9g8bagtud34Muejjk

More #diysynth stuff. Last year, I started experimenting with #analog synthesizers and built VCO, LFO, VCA, mixer, step sequencer, 1V/oct keyboard. A month ago, I had a dream about a #synthesizer that I wanted to build. Here are the first two modules for this project: a #mixer and a #LFO. There will be more coming soon. I'm calling it "Stack Synth".
Again, manufactured by @aislerhq
#soldering #electronics #pcb #StackSynth

#StackSynth

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