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TWO59 VCO module (Building Thread) by FEEDBACK
MUFF WIGGLER Forum Index -> Music Tech DIY  
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 smile
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.

TheSlowGrowth
Can the lock potentiometer be substituted for 25kB?
Jarno
Looks like an voltage divider, so probably, yes.
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).
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
djamsia
sorry for my stupid question, now i see the squematic and i see the diference betwen 12v and 15v....opssss!!!
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.
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)
Jarno
Small bear electronics?
strat-1
batank wrote:
I regret not asking earlier, but can anyone recommend a source for THAT340?
(other than Newark/Farnell who charge a wicked $20 freight fee)


http://www2.mouser.com/ProductDetail/THAT/340P14-U/?qs=9Udfh7QmL4v%252 bNZRbg%252bkVYQ%3D%3D

http://synthcube.com/cart/that340-matched-transistor-ic-bjt-bag-of-2
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 lol

Jarno wrote:
Small bear electronics?

Thanks! I did check these guys first, but got no results
synthetek
batank wrote:

Jarno wrote:
Small bear electronics?

Thanks! I did check these guys first, but got no results


http://smallbear-electronics.mybigcommerce.com/ic-that-corp-340p/
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.
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.
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.
TheSlowGrowth
You can try out this tuner app. It reduces the time needed to just a few minutes.
CliffordMilk
Thanks, I really should use my eyes more smile

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.
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.
CliffordMilk
Yes. Exactly that.
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.
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.
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 smile
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 smile)
....But if you build the board well, THAT will survive long enough.
strat-1
I forgot to put the switch in the BOM, I will correct that.
Thank you for helping me revise the docs.
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?
strat-1
acilator wrote:
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?


What offset trimmer ?
You are talking about VR3 offset trimm or VR6 sine amplitude trimm ?
acilator
Sorry talking about the sine ampl adjust, vr6. I made a mistake looking the schematics, offset and r6 are wrong..
strat-1
acilator wrote:
Sorry talking about the sine ampl adjust, vr6. I made a mistake looking the schematics, offset and r6 are wrong..


Please explain more the problem. With VR3 offset trimmer you adjust the
starting frequency of the frequency pot, it's not related with the amplitude of the signal. What 4.2Vpp you could not set ?
acilator
The fist line about calibration in the build manual says;
connect a oscilloscoop to pin1 from con2 and adjust sine for a 4.2Vpp amplitude,with vr6 sine ampl adjust. That's the problem,when I turn the trimmer vr6 it only goes down to 4.5Vpp.

The vr3 offset trimmer works correct, the starting frequency of th frequency pot is set to 27.5Hz.

So the only problem is that I can't get the sine ampl adjust down to 4.2Vpp, but only down to 4.5Vpp.
I hope my explanation its clear?
strat-1
acilator wrote:
The fist line about calibration in the build manual says;
connect a oscilloscoop to pin1 from con2 and adjust sine for a 4.2Vpp amplitude,with vr6 sine ampl adjust. That's the problem,when I turn the trimmer vr6 it only goes down to 4.5Vpp.

The vr3 offset trimmer works correct, the starting frequency of th frequency pot is set to 27.5Hz.

So the only problem is that I can't get the sine ampl adjust down to 4.2Vpp, but only down to 4.5Vpp.
I hope my explanation its clear?


Yes, now is clear. So you are talking about the sine amplitude in the end smile
If the sine wave is correct and has nice shape (take in mind you will not have a perfect sine with this module, if it's rounded enough on the edges is good enough), it will not be a problem if could not adjust the wave below 4.5Vpp. The shaper will do the job fine with voltages between 4-5 Vpp.
This "issue" comes from the fet parameters and the sine schematic design.
acilator
Sine shape is near perfect! So everything seems to be ok with the VCO's.
Thanks for the reply! Now lets finish the shaper build.
strat-1
acilator wrote:
Sine shape is near perfect! So everything seems to be ok with the VCO's.
Thanks for the reply! Now lets finish the shaper build.


Good luck smile
fuzzbass
FWIW: I went with full kits where Strat selected the prickly bits. Both of my VCOs came to life with nice rounded sines and needing almost no calibrations
batank
fuzzbass wrote:
FWIW: I went with full kits where Strat selected the prickly bits. Both of my VCOs came to life with nice rounded sines and needing almost no calibrations


Congrats! Great to hear.

Mine is still in the shipping envelope in a drawer until I have more free time.
strat-1
UPDATE : I added the missing switch in the BOM list.
All the boards I sent in the last month are rev1.1 boards. For this boards you don't have to solder together the two pins of the connector, as explained in the manual's errata. Also I changed all the values of the components to the 12v ones on the pcbs.
If you have old rev1.0 boards and you didn't built them yet : all the values on the pcb's are the 15V ones, please use the values in the manual.
(better explained : if you have one value on the board and the manual says another value, the one in the manual is correct)
fuzzbass
Watch carefully when soldering at U1 (TL074) pin 12. The pad for R57 (62K) is very close and it's easy to bridge them. If you do, no output for square wave on panel jack, but square is still present on Shaper connector. Experience talking here...
pawluszyn
Hey, I have a quick question:
Do the resistors need to be 0,6W or is it ok to use regular 0,25W ones?
thanks
strat-1
pawluszyn wrote:
Hey, I have a quick question:
Do the resistors need to be 0,6W or is it ok to use regular 0,25W ones?
thanks


It's better to use 0.5w-0.6w ones. The shaper is a power demanding circuit, some of the resitors will be at limit if you use 0.25w ones.
The VCO will work with 0.25w resistors.
pawluszyn
thanks for the answer!
geh2oman
Small potatoes, but I did notice also the LEDs are not in the BOM.
strat-1
geh2oman wrote:
Small potatoes, but I did notice also the LEDs are not in the BOM.


I will correct that, thank you for your help. I usually revise all the manuals for the modules form time to time, but always something slips the eye.
sduck
Trying to find the DZ4V7 diodes - can't find anything but tiny smts. Does such a through hole part still exist? Or can I sub a 4.7v zener?

Edit: never mind, remembered to look on the BOM - found it.
strat-1
sduck wrote:
Trying to find the DZ4V7 diodes - can't find anything but tiny smts. Does such a through hole part still exist? Or can I sub a 4.7v zener?

Edit: never mind, remembered to look on the BOM - found it.


DZ means zener diode. Any zener will work, buy one with 500-600mw power.
sduck
Got these done... now onto the shaper



TheSlowGrowth
I just finished my two VCOs. After tuning I had a ton of fun FM-ing the two - I can't wait until I receive my vactrols so I can finally unite them with the shaper.

Here's the tuning reports for my two VCOs (made with this tool). Good enough for me.



[/img]
brandonlogic
Edit
Jarno
strat-1 wrote:
UPDATE : I added the missing switch in the BOM list.
All the boards I sent in the last month are rev1.1 boards. For this boards you don't have to solder together the two pins of the connector, as explained in the manual's errata. Also I changed all the values of the components to the 12v ones on the pcbs.
If you have old rev1.0 boards and you didn't built them yet : all the values on the pcb's are the 15V ones, please use the values in the manual.
(better explained : if you have one value on the board and the manual says another value, the one in the manual is correct)


Do you have an overview that shows the value of a resistor for 12v and 15v? Like an idiot I started plugging in resistors without fully reading this thread and am pretty much done cry
If I know which ones to pull, that would make life a lot easier.
NiteEagle
Hi,

Finished both VCOs. One doesn't oscillate and the other fails on the sine amplitude adjustment.

One odd things is the one that doesn't oscillate draws twice as much current from my bench supply. 20mA vs 40mA.

Let's deal with the one that oscillates first.

I can't get the sine wave above 560mVpp. The sine wave gets flat at the peaks as I turn the vr6 trim pot up. I can adjust the voltage below 560mVpp and the sine wave looks like a sine wave should.

What shall I check?
strat-1
Jarno wrote:
strat-1 wrote:
UPDATE : I added the missing switch in the BOM list.
All the boards I sent in the last month are rev1.1 boards. For this boards you don't have to solder together the two pins of the connector, as explained in the manual's errata. Also I changed all the values of the components to the 12v ones on the pcbs.
If you have old rev1.0 boards and you didn't built them yet : all the values on the pcb's are the 15V ones, please use the values in the manual.
(better explained : if you have one value on the board and the manual says another value, the one in the manual is correct)


Do you have an overview that shows the value of a resistor for 12v and 15v? Like an idiot I started plugging in resistors without fully reading this thread and am pretty much done cry
If I know which ones to pull, that would make life a lot easier.


Please look at the schematics, the 12v/15v resistors are highlighted.
strat-1
NiteEagle wrote:
Hi,

Finished both VCOs. One doesn't oscillate and the other fails on the sine amplitude adjustment.

One odd things is the one that doesn't oscillate draws twice as much current from my bench supply. 20mA vs 40mA.

Let's deal with the one that oscillates first.

I can't get the sine wave above 560mVpp. The sine wave gets flat at the peaks as I turn the vr6 trim pot up. I can adjust the voltage below 560mVpp and the sine wave looks like a sine wave should.

What shall I check?


What transistor do you used for sine (do you have one bought from me ? -2n5457).
If you have a scope, please post a picture with the signal before and after c31-100uf. (to see the amplitude of triangle signal feeding the sine section)

PS: I've built tens of oscillator using the pdf manual, and all of them worked from the first time......it's just a statement the pcbs and manual is ok smile
NiteEagle
No need to comment about the your build manuals Andrei. They are one of the best in DIY. That doesn't mean I didn't make a mistake of some kind. The other VCO is probably my fault. More on that later. This one first.

Yes, I purchased all the matching parts from you. 2n5457 etc.

Here's the triangle going into C31.



and coming out.



Here's a shot the resistors that you sent for the 2n5457 for your reference.



Just to explain the double height stand offs are because I socketed the THAT340 with out even thinking. I bought some header extenders so the tempco will clear.
[/img]
strat-1
NiteEagle wrote:
No need to comment about the your build manuals Andrei. They are one of the best in DIY. That doesn't mean I didn't make a mistake of some kind. The other VCO is probably my fault. More on that later. This one first.

Yes, I purchased all the matching parts from you. 2n5457 etc.

[/img]


I know you didn't criticised my manuals, I just made a statement about building many vcos of this project.....this shows the pcbs are not faulty.
They can be faulty from factory, not from design. The producer who I'm working with, have the decency to mark all the defective boards.

The scope picture looks fine, everything in order. It's not clear for me if the voltage refference is correct, before capacitor the signal have to be from 0v to 4v, after the capacitor from approx -2v to 2v.
...So your error is in sine section, look for a short, misplaced value etc.
At the moment I'm in another country at a concert, when I will return I can measure the voltages on a board...if you will not find the error until then.
NiteEagle
Hold off on the voltage checks until I get back to you. Up to you, but I don't want you to waste your time. I have the scope on .1V scale so that triangle is nowhere near where it should be. Let me look at the square wave and check that first part of the oscillator around the THAT340 and then the U4A integrator (right?) and try to see why the voltage level is so low.
groove
What should the frequency range of the VCO be (approximately)? Does it go 20-20k in HF mode? Mine seems to be going from ~50Hz to a few K, I'm wondering if I made a mistake somewhere...

All shapes look good and V/Oct tracking is pretty decent after a pass at calibration.
strat-1
groove wrote:
What should the frequency range of the VCO be (approximately)? Does it go 20-20k in HF mode? Mine seems to be going from ~50Hz to a few K, I'm wondering if I made a mistake somewhere...

All shapes look good and V/Oct tracking is pretty decent after a pass at calibration.


The range is from 27.5HZ - 3000HZ. You should apply cv for high frequencies. So everything is working ok fpr you.
groove
strat-1 wrote:
groove wrote:
What should the frequency range of the VCO be (approximately)? Does it go 20-20k in HF mode? Mine seems to be going from ~50Hz to a few K, I'm wondering if I made a mistake somewhere...

All shapes look good and V/Oct tracking is pretty decent after a pass at calibration.


The range is from 27.5HZ - 3000HZ. You should apply cv for high frequencies. So everything is working ok fpr you.


Great, thanks. Excited to start the second VCO today.
Slomen
On my front pcb´s R45 says 20k, but in the build guide it says 18k. Should I go with the build guide?

EDIT: found my answer in the top post w00t
strat-1
Slomen wrote:
On my front pcb´s R45 says 20k, but in the build guide it says 18k. Should I go with the build guide?


Use the values from the guide. You have the rev1 boards. I updated all the values started with rev1.1 boards. It's the same pcb, so nothing is changed in the sound, I just corrected the printed silkscreen values for the circuit to work at 12v.
If you will look at the schematic you will see I highlighted what parts you need for the circuit to work with 12v and what parts are needed for 15v.
Slomen
Thanks!
strat-1
Slomen wrote:
Thanks!


Cool Armus-skin of evil avatar smile)
Puzzler
I build 2 VCOs and both show similar behavior. Unfortunately I first soldered the 2N5457 wrong so connected was G(pcb)-D D(pcb)-S and S(pcb)-G, inclusive poweruing up. But nothing smoked up or anything.

So all the time its like this:

Switch set to HiFreq gives a very high frequency and the freq pot is not responding at all. As seen in this picture (saw output):



Turning the switch to Lowfreq gives this (saw output):



Freq pot still not responding ofc. Is some IC gone because of the misplaced 2N5457? Or what else did I do wrong?
I checked all the rest but couldnt find any suspicious thing so far.
Any halp would be appreciated!!
strat-1
Puzzler wrote:
I build 2 VCOs and both show similar behavior. Unfortunately I first soldered the 2N5457 wrong so connected was G(pcb)-D D(pcb)-S and S(pcb)-G, inclusive poweruing up. But nothing smoked up or anything.

So all the time its like this:

Switch set to HiFreq gives a very high frequency and the freq pot is not responding at all. As seen in this picture (saw output):



Turning the switch to Lowfreq gives this (saw output):



Freq pot still not responding ofc. Is some IC gone because of the misplaced 2N5457? Or what else did I do wrong?
I checked all the rest but couldnt find any suspicious thing so far.
Any halp would be appreciated!!


The wrongly placed fet will not affect the rest of the circuit, there is a 100u condenser in path of the signal, this condenser will not allow dc voltage to pass to the rest of the circuit.
You say you don't have waveforms at all at the output ?
Puzzler
I do have waveforms, but the frequency is too high on Hi and Low, as seen in the picture.
Switch set to Hi gives a frequency of 5khz minimum.
And ofc the freq, finetune pots are not working.
Sometimes i hear (dont have an oscilloscpope) an unstability in the frequency, it shifts slightlyup and down for a second. Maybe thats connected to the problem.
strat-1
Puzzler wrote:
I do have waveforms, but the frequency is too high on Hi and Low, as seen in the picture.
Switch set to Hi gives a frequency of 5khz minimum.
And ofc the freq, finetune pots are not working.
Sometimes i hear (dont have an oscilloscpope) an unstability in the frequency, it shifts slightlyup and down for a second. Maybe thats connected to the problem.


Please verify if c6 (near u4) is 4,7NF, a smaller value can raise the frequency.
If the value is ok, the mistake is in exponential converter, cv summer section, so you should verify r1-r30. Many wrongly placed resistors from the cv summer (mixer) can raise overall frequency.
Puzzler
Found the problem, VCO is working fine now. Thank you strat-1!
strat-1
3 days work smile



Here is how I solder pn3565 matched transistors. I use thermotube and thermalpaste to keep the transistors in contact.

Swyndger
Hello Strat-1!
You are using 1N5819 in the voltage supply. Not only here, but in almost all your builds (Shaper, Pre-BX, Chorus ...)
Now I have none of them here anymore, but I have a big pack of allmost 100 pc 1N5817.
Can I use them for the VCOs and Shaper, or shall I wait till my order of new 1N5819 arrives?
strat-1
Swyndger wrote:
Hello Strat-1!
You are using 1N5819 in the voltage supply. Not only here, but in almost all your builds (Shaper, Pre-BX, Chorus ...)
Now I have none of them here anymore, but I have a big pack of allmost 100 pc 1N5817.
Can I use them for the VCOs and Shaper, or shall I wait till my order of new 1N5819 arrives?


Yes, without a problem!
jimi23
strat-1 wrote:
3 days work smile



Here is how I solder pn3565 matched transistors. I use thermotube and thermalpaste to keep the transistors in contact.



Will PC CPU thermal paste work in this application? I have some of that left over, I assume its similar stuff. Finishing my VCO's this week, before moving onto the Shaper
strat-1
jimi23 wrote:


Will PC CPU thermal paste work in this application? I have some of that left over, I assume its similar stuff. Finishing my VCO's this week, before moving onto the Shaper


Yes it will work, that's why it's called thermal paste smile
Psy'low
Very well explained manual!
Just noticed it lacks one 2K2 resistor in the BOM.
Will test it this week...
rithma
Is there any quantifiable difference between a 12v and 15v build?
I have both types of supplies, and I heard from several places "you get more bandwidth" from op amps running on +/- 15v, so I am curious why the designer ultimately chose 12v for the guide and BOM.

Which is best?

...btw I've noticed I am tracking my shipment every 15 minutes or so like a madman. Can't wait for this one.

/rithers
strat-1
rithma wrote:
Is there any quantifiable difference between a 12v and 15v build?
I have both types of supplies, and I heard from several places "you get more bandwidth" from op amps running on +/- 15v, so I am curious why the designer ultimately chose 12v for the guide and BOM.

Which is best?

...btw I've noticed I am tracking my shipment every 15 minutes or so like a madman. Can't wait for this one.

/rithers


I chosed 12V, because the kit is designed for eurorack version. I understood also, some builders want to assemble the kit for other formats so I highlighted the 15V values on the schematic.
You can't get more "bandwidth" from the opamps here, there is only 5Vpp signal in the circuit so the 12V power is more than sufficient.
I compared a lot the 12v and 15v version and I heard no difference in the sound.
Think were you want to put the module in your system, it will give you the answer. (what voltage to use)
Slomen
Here is how I solder pn3565 matched transistors. I use thermotube and thermalpaste to keep the transistors in contact.

[/quote]

Am I fine without a thermotube and thermalpaste to keep the matches trans in contact? I have thermal paste, but I dont have that tube. Where can I Get them?
strat-1
Slomen wrote:


Am I fine without a thermotube and thermalpaste to keep the matches trans in contact? I have thermal paste, but I dont have that tube. Where can I Get them?


You don't need thermotube, it was just an example.
Just bent the transistors in a way they will remain in contact and everything will be ok.
Slomen
Does this look ok? Im using a silicon based "Heatsink".
strat-1
Slomen wrote:
Does this look ok? Im using a silicon based "Heatsink".


It's not ok. You have to squeeze the transistors together. They should be in perfect contact. Bent the legs in a way they push the transistors to be in contact. The thermal paste should be a very small quanitity, it's role is to cover the scratches, imperfections etc.
Slomen
Thanks strat-1! So I think I fixed it, at least for now of my modules which is now working w00t Buuut, the other one is not. No sound.

There is one fuck up that I dont know is critical: I managed to use a wrong switch on the non-working module. I used a on-off-on switch. Do I need to swap this for the correct one? Or should it work with that switch and something else is wrong?

EDIT: another noob question.. I dont understand the first line of the calibration: "connect a oscilloscoop to pin1 from con2 and adjust sine for a 4.2Vpp amplitude,with vr6 sine ampl adjust." - How do I use my oscilloscope to do this (I have the O´tool)? How do I connect my oscilloscope to pin 1 con 2? Or do I just measure using the sine output?

This by far my most advanced build, I highly appreciate your help smile
strat-1
Slomen wrote:
Thanks strat-1! So I think I fixed it, at least for now of my modules which is now working w00t Buuut, the other one is not. No sound.

There is one fuck up that I dont know is critical: I managed to use a wrong switch on the non-working module. I used a on-off-on switch. Do I need to swap this for the correct one? Or should it work with that switch and something else is wrong?

EDIT: another noob question.. I dont understand the first line of the calibration: "connect a oscilloscoop to pin1 from con2 and adjust sine for a 4.2Vpp amplitude,with vr6 sine ampl adjust." - How do I use my oscilloscope to do this (I have the O´tool)? How do I connect my oscilloscope to pin 1 con 2? Or do I just measure using the sine output?

This by far my most advanced build, I highly appreciate your help smile


It's not necessary to change the switch, but if you want the module to be made by the book, my advice is to destroy the switch with a clamp tool or something. So you will desolder only the legs of the switch, not the entire switch. If you try to desloder the entire switch, you can destroy the board.
Use a desoldering braid to remove the soldering material, after you desolder the legs.
You can use the jack output for sine calibration.
Swyndger
Just to be sure: The both matched 6k8 Resistors in Kit 3 are R72 and R73, in the build manual decribed as 33k. Yes?
rithma
Yes the Sin shape is achieved by testing a variety of resistances, using
temporary trimmers in place of R72 and R73, with the particular JFET you are using. This combo can vary wildly depending on what slice of silicon was used to forge the roll of JFETS on which particular day, and perhaps the phase of the moon at that time.

See page 20 of the build manual "CHOOSING THE SIN TRANSISTOR"

I personally spent the extra money on the kit so that i wouldnt have to dig through jfets and trimmers to shape the sin.
Ilpolainen
batank wrote:
I regret not asking earlier, but can anyone recommend a source for THAT340?
(other than Newark/Farnell who charge a wicked $20 freight fee)


Mouser 887-340P14-U
Ilpolainen
So I just thought to notice that you can add BOM THAT340 Mouser Part.No: 887-340P14-U.

Thanks for AWESOME job. Module not ready yet though. smile
Ilpolainen
I'm not much of an electrician, so is there any specs I should know about these LED's? I have understood, that they are not all similar, and I can't find any information about them in BOM or build Manual.
sduck
Someone posted part numbers for them - maybe near the front of this thread? I'm not sure. I'll post them here if I find them. I used them, and they work, although they're a bit too bright for my tastes. Not enough for me to dismantle enough to adjust the current resistors though.

Edit: link here - https://www.muffwiggler.com/forum/viewtopic.php?p=2504779#2504779
rithma
Quote:
any specs I should know about these LED's?


I'm not so good at specking out LEDs either, but I took strat's advice and installed little sockets wherever variable parts go. If the LEDs look crappy, just pull out and try some other 5mm parts when you get them.

/E
rithma
Anybody know what the 4V7 diode does in the circuit? Looks to me like it just powers the LEDs; but I'm no engineer.

Will I break anything if I use a different value in its place (maybe a 5V zener?.... its the one part I dont have, and I'M DYING TO HEAR THIS THING!!!!!
strat-1
rithma wrote:
Anybody know what the 4V7 diode does in the circuit? Looks to me like it just powers the LEDs; but I'm no engineer.

Will I break anything if I use a different value in its place (maybe a 5V zener?.... its the one part I dont have, and I'M DYING TO HEAR THIS THING!!!!!


You can use a 5V zener, but no more than this.
It's not powering the led, it's driving the gate for FM modulation located in a CD4066 chip working at 5V.
strat-1
Ilpolainen wrote:
I'm not much of an electrician, so is there any specs I should know about these LED's? I have understood, that they are not all similar, and I can't find any information about them in BOM or build Manual.


They are absolutely common leds, one opaque 5mm red and one opaque 5mm green.
With the new projects I have to prepare, I completely forgot to update the BOM.
rithma
I just finished building my VCOs, and I love them love them love them. Best documentation in DIY!!!

One VCO is working as expected( It's peanut butter jelly time! applause )
However one has
-no square wave output
-and this from the sin output:


I haven't had much time to poke around yet, but maybe somebody has an idea of where to start looking?

In the meantime, I'm off to build the shaper. cool

/E
strat-1
rithma wrote:
I just finished building my VCOs, and I love them love them love them. Best documentation in DIY!!!

One VCO is working as expected( It's peanut butter jelly time! applause )
However one has
-no square wave output
-and this from the sin output:


I haven't had much time to poke around yet, but maybe somebody has an idea of where to start looking?

In the meantime, I'm off to build the shaper. cool

/E


My advice is to use the good vco as a test target. Look at the schematics and read with the scope voltages in various points, repeat the readings on the bad module.
If something is different in a point, look there for a bad solder joint, short, wrong part, defective part etc.
rithma
Got It!!!
After building the troubleshioting wiring harness, and an hour of poking around, i found 1 bad joint (missing square wave) and one backwards JFET(bad sine wave). All works now! Chubby sine waves all around.

Thank sweet baby jeesus for sockets.

/Etienne
StudentsOfTheFuture
Bumped the other thread by mistake oops

First - thank you strat-1, this has been an awesome project!

Just finished my VCOs (from kits), one works 100% and one half works.

The half working one has an issue with the main board (because I can swap front boards and get the same thing) - the pitch fluctuates randomly and the waveforms sound distorted.

Any idea what might be to blame? I messed up installing the low freq linearity trimmer and ripped a trace replacing it, but the connections seem to test okay. And that seems like it would be unrelated...

Waveforms, FM, Frequency, Fine, and Lock all seem to work fine, other than the above. I haven't tested more extensively yet.

e: and to eliminate the obvious, components are where they should be, and caps/diodes/ICs are the direction they're supposed to be.

Per schematic it looks like something upstream of the individual waves, so I re-heated some joints around the transistor pair and IC.

I get good tracking for about a minute after leaving it off for a while. I thought I had fixed it and was just tuning it against the other one to make sure when the weirdness came back. That makes me think capacitors?
StudentsOfTheFuture
Huh, now it seems to be working...

I reflowed some joints based on the schematic and my best guesses and no luck... then went to the movies, came back, plugged them in to do some voltage metering and... that seemed to do it somehow?

Checked the THAT340s and the transistors (basically... the hard stuff to replace) and the readings matched on both, and figured I should do a test run just in case. I was able to tune them within a note of each other without calibration, and I have them out of phase droning now just to make sure it holds - I'm getting normal osc drift, not random jumps! (and gosh they sound beautiful).

All of this has me thinking theres a bad joint somewhere. I'm wondering - any obvious culprits for the pitch fluctuations? I figured it was tempco, THAT, or PN3565s, but they all seem okay (actually, I should check the Tempco). And beyond that I'm not sure where to look (but feel free to direct me to schematic sections or general clusters - I do want to learn!)
sduck
Clean the flux off?
StudentsOfTheFuture
That's usually my first step (pre-power, even). I guess if it ain't broke... On to calibration!

e: okay, I think i'm getting closer: I can get the weirdness for about a minute or two after powering on (30 seconds normal, then 2 minutes of jumpiness, then it goes away). Seems consistent with the other oscillator evening out its tuning as it warms, just way more pronounced til it gets there.

This is making me think its just due to a sloppy application of heatsink gel on the tempco.

Anyway, a very workable problem to have (I was thinking if all else fails, well, I know which one the mod osc is gonna be).
Jarno
Finished the build of the two VCO sections today. But only one of them is working, unfortunately.
I've built them at the same time,so I stuffed components in both boards per value. The only differences are that I used solder straps instead of diodes in the non-working board (and diodes in the other), and that the non-working board has a 2N4339 and the working board has 2N5457, the paired resistors had the same value markings, but everything was packed together, so I couldn't distinguish if one pair of resistors went with the one FET and the other with the other FET, but his should only affect the sine output.
On the non-working board,none of the outputs work, I've isolated the problem to the main board, both control boards are OK. I haven't connected pin 9-10 as discussed in the errata section, but that shouldn't matter, right?
As it doesn't oscillate, I am suspecting U4 to be bad, does that make sense? If I check both sides of the 4n7 cap, I only see DC on the scope and no oscillation.

This is the one that does work grin :


sduck
Why did you skip the diodes? I'd guess that's at least part of the problem. Put the diodes in there.
Jarno
Those are the diodes in the power supply section, and are meant to prevent reverse polarisation of the connector. This is not likely to happen (boxed header), therefore I replaced them by wires. Why do you think this is part of the problem?

Edit:
Mine is running on eurorack-standard voltages, so +/-12v (rather than +/-15v).

Edit2:
By the way, the picture above is of the functioning VCO, the one that does not function does have the polarity protection diodes.
StudentsOfTheFuture
The resistors I got seemed interchangable - they tested the same on my (limited, but usually good for finding 1% tolerances) meter.

I had the same semiconductor for both sine shapers, though - looked like the same batch.

How do the U4 pin voltages compare between the two? That would rule that out, at least.
sduck
Sorry, I misread, and also forgot what those diodes do anyway. Never mind.

Not sure what you mean about the 12v power.

Jarno wrote:
Those are the diodes in the power supply section, and are meant to prevent reverse polarisation of the connector. This is not likely to happen (boxed header), therefore I replaced them by wires. Why do you think this is part of the problem?

Edit:
Mine is running on eurorack-standard voltages, so +/-12v (rather than +/-15v).

Edit2:
By the way, the picture above is of the functioning VCO, the one that does not function does have the polarity protection diodes.
Jarno
Not sure what the maximum voltage spec for the CMOS is, but the forward voltage drop caused by the diodes could keep it to just within limits for +/15v operation, but for +/-12v that's likely to be less of a problem (if it works on +15v with voltage drop, it'll work on +12v).

Well, replaced U2 and U4, and the THAT340, still sweet f*ck all. I guess there was going to be a moment like this, whishing I'd put everything in sockets (at the moment only the THAT340 is). On to the shaper first, I'll come back to this.
sduck
Who's running this on 15v? Why did this come up? Doesn't really matter, as it's a non-issue anyway.

I keep relooking at your pictures, and there are a few solders that look suspiciously like they might be cold solders - it's probably just a trick of the angle of the picture, but I also notice some of those suspicious ones don't have solder flow through on the other side. You might consider doing some reflowing. This may not be the problem at all, but just another idea to consider.
rithma
I hate to be *that* guy, but could you have maybe possibly hooked up the power backwards on the non functioning VCO?

(Im ONLY asking this because I have done it... maybe 15 times... every time searching long and hard for a more complicated answer to my problem...)
pbotsaris
I don't know if anyone pointed this out yet but in the BOM is 2 x 2.2K and it's supposed to be 3 X
strat-1
pbotsaris wrote:
I don't know if anyone pointed this out yet but in the BOM is 2 x 2.2K and it's supposed to be 3 X


Thank you. I will correct the bom list.
strat-1
UPDATE : I Corrected some typos in the manual, like wrong number of pots and other text mistakes.
Cryaaa
[EDIT] I realised that i soldered the JFET the wrong way round, i'll hopefully solve the problem, don't have my own oscilloscope though so I'll report back...... I'll leave this here to help others who might make the same stupid mistake d'oh! [EDIT]
I'm having trouvble with the sine output..... Other outputs look great, but i get a really weird sine shape.... Took pictures of the sine out, the trimpot for the amplitude adjust only affects the wide triangle portion of the wave. Wasn't sure what else to measure so I included pictures from the input of the Tl072 Portion that handles the sine shape, if anybody could give me any hints as to where I should start looking that would be great....... checked all solder joints already... I also have the Oscillator readings as CSV-files if that helps.


Siri
Ilpolainen wrote:
So I just thought to notice that you can add BOM THAT340 Mouser Part.No: 887-340P14-U.

Thanks for AWESOME job. Module not ready yet though. smile


+1, it is not mentionned in the BOM
Kan Kaban
Hi!, congrats for the two59. Just got the board+panel kit from modularaddict but realized I dont have the transistor+matched resistor kit.

Is there any chance to replace the 2N5457 with J105,J106,J107, etc; use trimers to find values, and how do I know when the value is just perfect?

Also, where can I buy just the trans+resist kit?

Thanks thumbs up
mritenburg
Anyone building two59 vco's and shapers to order? PM me if you are building and want some business.
secrethero303
mritenburg wrote:
Anyone building two59 vco's and shapers to order? PM me if you are building and want some business.


PM’d, not exactly building to order, but happy to help out.
rossgrady
Quick question: I ordered PCBs in November & received revision 1.2 boards -- is there still an issue with the incorrect route, and the need to manually connect pins 9 & 10 on connector 2, or was that corrected with this revision?

I looked at the boards I got & didn't see any manually cut traces, so perhaps this was resolved?

Are there any other differences with 1.2 boards that I should be aware of?

Thanks!
mattip
A question about the BOM:
C6 is listed as a 4N7 Polystyrene. But in the parts numbers examples are polypropylene caps. It is also a polypropylene cap in the photos in the build docs.
So should I use the styrene or polypropylene?

this:
https://www.mouser.com/ProductDetail/23PW247

or this:
https://www.mouser.com/ProductDetail/505-FKP24700-63-5

/m
humax5600
I have this part of Reichelt installed.
And it works fine

https://www.reichelt.de/film-capacitor-4-7nf-63v-rm5-fkp2-63-4-7n-p172 413.html?GROUPID=7164&START=0&OFFSET=16&SID=95XH61tqwQATUAAHk44qQ630bd 89e8774407bc0f7e5b85b7c8d52&LANGUAGE=EN&&r=1
mattip
Thank you. I think I order both and see if the styrene is too large. /m
strat-1
mattip wrote:
Thank you. I think I order both and see if the styrene is too large. /m


You can use any precision capacitor 1%-2.5% (capacitance tolerance)
It can be polypropylene or polystyrene.

I prefer Wima because of the price vs size vs results.
mattip
OK, thanks. I thought it was something with styrene and vco:s :-)
strat-1
mattip wrote:
OK, thanks. I thought it was something with styrene and vco:s :-)


It is smile

These capacitors provide high insulation, low leakage, low dielectric absorption, low distortion and excellent temperature stability.
airfrankenstein
hi
I'm about to order two complet TWO59kits and a shaper and would like to know what "expensive" parts I'll have to buy in addition besides the THAT340 ?
I'd built a J3RK 258J; this seems similar enough, but trying to get an idea of what my total build budget will amount two in addition to the the "full" kits purchase price (about 200 euros).

Hope someone can help
thanks
synthetek
airfrankenstein wrote:
hi
I'm about to order two complet TWO59kits and a shaper and would like to know what "expensive" parts I'll have to buy in addition besides the THAT340


The vactrols there are 5 vtl5c3/2 and 3 vtl5c3
windspirit
Hey, hope all is well. I recently built one of these using the rare parts kit (pcbs/ panel + transistors and pre-selected resistors). I am having 1 or two issues with my build:

1) Can't calibrate my VCO to 1v/o, when the trimmer is all the way open it is still too low of a range. Im guessing I can replace R2 with a lower value resistor to increase the range?

2) My sine doesn't look anything like a sine. Kind of a bummer since the kit was supposed to come with the preselected values. Adjusting the trimmer doesn't change anything (including the sine amplitude which I thought was odd). Does this mean that there is possibly an issue with my sine shaper circuit or that I should try the method for picking resistance manually instead? I can post pics of the board when I get to my office, all the other waves look fine.
strat-1
windspirit wrote:


1) I can replace R2 with a lower value resistor to increase the range?

2) My sine doesn't look anything like a sine. .


1) Don't change the value of R2. Something is wrong with the circuit.
2) I've built tens and tens of TWO59 VCOs, and always checking my stock of rare parts. A scope image will be very useful.
astroschnautzer
windspirit wrote:


1) Can't calibrate my VCO to 1v/o, when the trimmer is all the way open it is still too low of a range. Im guessing I can replace R2 with a lower value resistor to increase the range?

a faulty THAT chip was the problem for me... IIRC, it was a while ago I built this...
windspirit
Well, I missed the part about soldering the THAT chip directly to the board but afaik it was just for the spacing because you are supposed to use a large tempco correct? My issue might also be that I used 2 x 2k tempcos in parallel to get a 1k, I have a stash of smaller tempcos (still 3500 ppm) but I figured that the increased surface area would improve reliability with a smaller resistor. However, if there is a chance that the THAT chip could be faulty I would really prefer not to solder it directly to the board. Fortunately I have another one to test it with but Ive included some pics of the board in case there could be another issue.

Also I discovered like the gentleman above that my FET was soldered with the wrong pin orientation and thats what was mucking up my sine shape. Unfortunately I broke a leg on the FET desoldering it. Is it possible to use a J201 instead for the sine shaper? I have a few of them laying around, I know that I will have to use a different resistor pair for them.


windspirit
Scratch that, I put a J201 in the footprint and first one gave me a pretty decent sine wave. You have to redo the transistors legs the same way as the other FET but it seems to work well.

I just put another 68k in parallel with R2 on the front board, hopefully I can get some 1v/o tracking for now until I can hunt down the other problem.
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