| Author |
TWO59 VCO module (Building Thread) by FEEDBACK |
| strat-1 |
www.feedbackmodules.com
 
 
FOR ORDERING AND PROJECT INFORMATIONS USE THE MAIN THREAD :
https://www.muffwiggler.com/forum/viewtopic.php?t=169990
TWO59 VCO is a triangle core VCO with 4 buffered independent outputs : SINE, TRIANGLE,RAMP AND SQUARE.
As a triangle core VCO, it is very suitable for FM modulations.
2 VCO'S together with one SHAPER unit can work as a complex oscillator.
The connection between the modules is done using two 10 core ribbon cables.
This is a highly complex build, so take your time studying this manual before building,some of the details may help a lot
in the building process.
THE SINE TRANSISTOR (2N4339 OR EQUIVALENT 2N5457) SHOULD BE SELECTED FROM A LOT.
NOT ALL FET TRANSISTORS WILL GIVE A CORRECT SINE SHAPE. ALSO TWO RESISTORS FROM THE SINE SHAPER SHOULD BE ADJUSTED BASED
ON THE TRANSISTOR GAIN. YOU WILL FIND MORE DETAILS IN THE MANUAL.
We tried to make the whole experience as easy as possible and give as much information as needed to avoid confusion.
We also provide additional documents like BOM lists (PDF and XLS), images with part values,
and photos of the construction in various stages.Feel free to download the whole pack and have fun.
Audio demos :
The sound clicks are from computer latency, not from the modules 
Somehow I forgot to record the ramp wave. I will record it soon.
[s]https://soundcloud.com/strat1/two59-square[/s]
[s]https://soundcloud.com/strat1/two59-triangle[/s]
[s]https://soundcloud.com/strat1/two59-sine[/s]
[s]https://soundcloud.com/strat1/two59-shaper-basics[/s]
[s]https://soundcloud.com/strat1/two59-shaper-modulations[/s]
[s]https://soundcloud.com/strat1/two59-two59s-on-the-bread[/s]
This demo uses the power of 2 Full modules and one additional VCO (5VCO's in total)
-The starting bass line panned to the left speaker is a triangle wave passing to a jupiter8 filter module, to know how will sound affected by a VCF.
-The second line panned more to the right is the ouput of one shaper directly to a VCA. I turn the timbre slowly in various points of the song.
-For the other two lines I used some spring reverb.
-The ending is with pitch (fm) modulation ON.
-All the VCO's stayed in tune for a period of 3 hours until I closed the system.
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| TheSlowGrowth |
| Can the lock potentiometer be substituted for 25kB? |
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| Jarno |
| Looks like an voltage divider, so probably, yes. |
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| strat-1 |
| TheSlowGrowth wrote: | | Can the lock potentiometer be substituted for 25kB? |
Yes, without a problem. Also many of the 10KB potentiometers can be substituted with 20KB-50KB (all the voltage dividers). |
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| djamsia |
I'm building TWO59 COMPLEX VCO, I have a question.
In the Main Board, there is a resistance (R38) of 8k2 according to the manual, but the pcb is designated as 4k99 ...and 3x30k are mixed in pcb by 22k (R28) and 24k (R49) which one would be the correct values? ...
thanks and regards |
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| djamsia |
| sorry for my stupid question, now i see the squematic and i see the diference betwen 12v and 15v....opssss!!! |
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| strat-1 |
| djamsia wrote: | | sorry for my stupid question, now i see the squematic and i see the diference betwen 12v and 15v....opssss!!! |
The board was noted with 15V values, but I made the manual for 12V.
All the parts in manual are the correct values. For the next batch I modified all the values for 12V ones to eliminate any confusion. Just respect the values in the manual. |
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| batank |
I regret not asking earlier, but can anyone recommend a source for THAT340?
(other than Newark/Farnell who charge a wicked $20 freight fee) |
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| Jarno |
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| strat-1 |
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| batank |
Much appreciated. Searching for "that340" yielded nothing at mouser, but "that 340" brings it right up. It's amazing what just a space can do 
| Jarno wrote: | | Small bear electronics? |
Thanks! I did check these guys first, but got no results |
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| synthetek |
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| CliffordMilk |
OK - VCOs built and sounding great. Tonight, I have the pleasure of calibrating them all. Any advice on trimming the offset?
I was just going to base this upon my own hearing range. |
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| strat-1 |
| CliffordMilk wrote: | OK - VCOs built and sounding great. Tonight, I have the pleasure of calibrating them all. Any advice on trimming the offset?
I was just going to base this upon my own hearing range. |
Follow the procedure explained in the manual. It's the procedure I use to calibrate all the VCO's I make.
The offset will adjust the starting freq of your freq pot.
If you don't have a freq counter you can use a guitar tuner or a professional chromatic tuner if you have one. |
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| strat-1 |
| CliffordMilk wrote: | OK - VCOs built and sounding great. Tonight, I have the pleasure of calibrating them all. Any advice on trimming the offset?
I was just going to base this upon my own hearing range. |
I don't recommend to trimm the vco only by ear, borrow at least one tuner from a friend. |
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| TheSlowGrowth |
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| CliffordMilk |
Thanks, I really should use my eyes more
Tuning isn't an issue, that was done using a Logic plugin. I was just struggling to find a software frequency counter that could handle very low rates.
Anyway, I reckon I got very close and they work very well - track much better than I was expecting, actually. |
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| fuzzbass |
| I received full kit, and one bag contains 2N5457 and 150K resistors. Are these resistors to be used in lieu of the 2x33K resistors indicated in the build doc with "choose"? Thanks. |
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| CliffordMilk |
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| fuzzbass |
| CliffordMilk wrote: | | Yes. Exactly that. |
Thank you sir.
some errata:
DPDT on-on switch omitted from BOM.
You can socket the THAT340 if you have tempco other than big fat KRL. |
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| CliffordMilk |
| It did feel a bit wrong to solder the THAT340's to the board but I did use the big Tempcos and I'm very impressed by the stability. |
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| strat-1 |
| fuzzbass wrote: | | CliffordMilk wrote: | | Yes. Exactly that. |
Thank you sir.
some errata:
DPDT on-on switch omitted from BOM.
You can socket the THAT340 if you have tempco other than big fat KRL. |
Every lot of 2N5457, will need different resistor values to work properly. The new lot I have requiers 6K8 |
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| strat-1 |
| CliffordMilk wrote: | | It did feel a bit wrong to solder the THAT340's to the board but I did use the big Tempcos and I'm very impressed by the stability. |
It was a tough choice, to design the board in this way, requiring THAT to be soldered directly.
But have in mind, you can't damage THAT like you burn an opamp.
Of course you can burn everything if you put random voltages on the back of the board )
....But if you build the board well, THAT will survive long enough. |
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| strat-1 |
I forgot to put the switch in the BOM, I will correct that.
Thank you for helping me revise the docs. |
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| acilator |
Build mine, sounds great!!
The waveforms are ok, the V/oct is ok!
One problem, the offset trim for 4.2 Vpp is only going as low as 4.5Vpp. Somebody got anny idee whats wrong? Maybe changing R6 is a fix? |
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