Synthesizer Goodies & Music Production
Welcome to NFL´s first SMT DIY module.
As i´m expecting you´re further experienced with the assembly of SMT parts i´m not providing a detailed step by step documentation this time.
The 2164 MUST be an Alfa AS2164D, all the other ones on the market don´t work as expected!!!
I´ve been following the schematic of SSI but the circuit doesn´t work with their own chip as it seems …
The 2 pole 3 positions rotary switch is this one:
Best you use the IBOM for comfortable assembly.
Self oscillation mod:
Change R26 to 27k
The assembly is pretty self explaing if you know how to place the buttons :p
The orientation matters!!! Take a look onto the side parts of em, the side with two holes -> II <- shows to you, or the bottom of the PCB.
As the button holes of the panel are very precise i´m advicing to solder the buttons at last with mounted panel. So you can make sure they glide softly.
You will quickly realize something´s different here this time …
The thonkiconns share their ground pins and this makes em sit very tight and uncool.
To make sure they sit where they should, place em all as good as possible, solder the middle pin of each, put on the panel or better to say squeeze on the panel and reheat the soldered pins. This will force em to get the right position. I´m sure you will get the myth behind 😉
Happy switching 🙂
Best you check the iBOMs for collecting parts! I´m not using any exotic parts, mostly common stuff 😉
All pots are linear “B”
Follow the BOM and its designator “R”. You see, i´m using vertical allignment to save some space. Orientation doesn´t matter.
You got metal film, electrolytic and a polystrene one. Make sure you flatten down the electrolytic ones, else you will have a bad time with attaching the panel! The poly cap can be a metal film as i´ve already seen. This guy is meant to keep tuning stability with changing outer temperature. I think if you don´t travel from the sahara to the north pole constantly, a metal film will be fine.
You can mount ICs directly to the PCB, but i´m highly not advicing to! You will find a mark on the PCB to place the right orientation. Make sure they sit plane and tight where they should. First solder two outer legs and check the fitting. SOCKETS CAN SAVE YOUR LIVE(time)
The 2×8 headers must be mounted in between the PCBs. Which one is female or male doesn´t matter, but make sure you attach them plain and straight.
The 2×5 power header MUST be soldered on the other side! If you use a shrouded one check the orientation!
The footprints are for 3296X, if you use 3296W flip the orientation. Else the trim pots will work inverted!
Before soldering squeeze the two boards together to make sure the headers correspond together! AND put them on the correct layer!
Ok, that´s easy … if you put the long leg of the LED into the round hole … :p
Finally some fun parts 🙂
Due to my chosen design the fine tune pot is a T18 shaft. For the course pot i´m using a 19mm knob. Make sure they´re all placed clean. First solder one leg of each to see if they sit well.
I´m placing the thonkiconns as final step with attached panel. This way there is no glitch that issues the smoothnes of the Song Huei pots and the panel fits softly.
So, here we are. If everything went fine this unit should already do its oscillator thang. If you have placed the ICs 😀
BUT, before powering check the power pins if there is any short!
After powering the LED should glow and nothing should smell like fried banana!
Don´t worry! But you want your oscillator to act in a musical manner, don´t you …!? 🙂
The tuning process of this circuit is “always” the same. Before explaining this for the 1.000.000 time, i´m giving you some content on the hand. Once you got it becomes simple.
All you need is a source that gives CV notes, something like a beatstep or any other sequencer that gives quantized CV. And a tool to measure the frequency of the outputs, something like an OT1 or a Mordax Data or a guitar tuner with audio input. (Euroack Level 🔥!!!)
The clue is to get it stable over 6 octaves at least. This unit should give 7 octaves minimum 😉
Additionally you got two trim pots. One for the initial center position of the course knob. One for the range of the course knob.
With the “octave trimmmer” you can set individual octave sweeps when fully turned up or down 😉
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