TWO59 VCO module (Building Thread) by FEEDBACK

From circuitbending to homebrew stompboxes & synths, keep the DIY spirit alive!

Moderators: Kent, Joe., analogdigital, infradead, lisa, parasitk, plord, sduck

User avatar
strat-1
Wiggling with Experience
Posts: 490
Joined: Wed Jun 03, 2015 8:58 am
Location: Romania
Contact:

Post by strat-1 » Mon Dec 19, 2016 8:23 am

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
Learning to Wiggle
Posts: 50
Joined: Thu Dec 12, 2013 3:39 am

Post by acilator » Mon Dec 19, 2016 2:42 pm

Sorry talking about the sine ampl adjust, vr6. I made a mistake looking the schematics, offset and r6 are wrong..

User avatar
strat-1
Wiggling with Experience
Posts: 490
Joined: Wed Jun 03, 2015 8:58 am
Location: Romania
Contact:

Post by strat-1 » Mon Dec 19, 2016 3:44 pm

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
Learning to Wiggle
Posts: 50
Joined: Thu Dec 12, 2013 3:39 am

Post by acilator » Tue Dec 20, 2016 2:20 am

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?

User avatar
strat-1
Wiggling with Experience
Posts: 490
Joined: Wed Jun 03, 2015 8:58 am
Location: Romania
Contact:

Post by strat-1 » Tue Dec 20, 2016 3:35 am

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 :)
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.
Last edited by strat-1 on Tue Dec 20, 2016 6:53 am, edited 1 time in total.

acilator
Learning to Wiggle
Posts: 50
Joined: Thu Dec 12, 2013 3:39 am

Post by acilator » Tue Dec 20, 2016 4:26 am

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.

User avatar
strat-1
Wiggling with Experience
Posts: 490
Joined: Wed Jun 03, 2015 8:58 am
Location: Romania
Contact:

Post by strat-1 » Tue Dec 20, 2016 6:52 am

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 :)

User avatar
fuzzbass
Super Deluxe Wiggler
Posts: 2015
Joined: Thu Feb 06, 2014 6:08 pm
Location: Florida, USA

Post by fuzzbass » Tue Dec 20, 2016 7:48 am

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
Wired for weird

User avatar
batank
Learning to Wiggle
Posts: 50
Joined: Mon Feb 29, 2016 2:55 pm
Location: New Haven, CT

Post by batank » Tue Dec 20, 2016 1:33 pm

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.

User avatar
strat-1
Wiggling with Experience
Posts: 490
Joined: Wed Jun 03, 2015 8:58 am
Location: Romania
Contact:

Post by strat-1 » Tue Dec 27, 2016 9:14 am

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)

User avatar
fuzzbass
Super Deluxe Wiggler
Posts: 2015
Joined: Thu Feb 06, 2014 6:08 pm
Location: Florida, USA

Post by fuzzbass » Wed Dec 28, 2016 9:13 am

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...
Wired for weird

pawluszyn
Learning to Wiggle
Posts: 6
Joined: Fri Oct 28, 2016 3:17 pm

Post by pawluszyn » Mon Jan 16, 2017 5:02 am

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

User avatar
strat-1
Wiggling with Experience
Posts: 490
Joined: Wed Jun 03, 2015 8:58 am
Location: Romania
Contact:

Post by strat-1 » Mon Jan 16, 2017 5:29 am

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
Learning to Wiggle
Posts: 6
Joined: Fri Oct 28, 2016 3:17 pm

Post by pawluszyn » Mon Jan 16, 2017 11:47 am

thanks for the answer!

User avatar
geh2oman
Common Wiggler
Posts: 200
Joined: Thu Mar 26, 2015 4:52 pm
Location: Philadelphia, PA
Contact:

Post by geh2oman » Sun Feb 12, 2017 9:55 pm

Small potatoes, but I did notice also the LEDs are not in the BOM.

User avatar
strat-1
Wiggling with Experience
Posts: 490
Joined: Wed Jun 03, 2015 8:58 am
Location: Romania
Contact:

Post by strat-1 » Mon Feb 13, 2017 12:53 am

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.

User avatar
sduck
experimental use of gravity
Posts: 13278
Joined: Wed Feb 18, 2009 6:03 pm
Location: Vortepexaion, TN, USA

Post by sduck » Sun Mar 26, 2017 9:41 pm

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.

User avatar
strat-1
Wiggling with Experience
Posts: 490
Joined: Wed Jun 03, 2015 8:58 am
Location: Romania
Contact:

Post by strat-1 » Mon Mar 27, 2017 1:04 am

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.

User avatar
sduck
experimental use of gravity
Posts: 13278
Joined: Wed Feb 18, 2009 6:03 pm
Location: Vortepexaion, TN, USA

Post by sduck » Tue Apr 11, 2017 7:53 pm

Got these done... now onto the shaper

Image

Image

TheSlowGrowth
Common Wiggler
Posts: 158
Joined: Tue Apr 05, 2016 11:44 am

Post by TheSlowGrowth » Fri Apr 14, 2017 12:30 pm

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.

Image
Image
[/img]

User avatar
brandonlogic
Super Deluxe Wiggler
Posts: 2285
Joined: Tue Jan 27, 2015 9:17 am

Post by brandonlogic » Sun May 21, 2017 8:26 am

Edit

Jarno
Super Deluxe Wiggler
Posts: 2756
Joined: Mon Nov 15, 2010 6:34 am
Location: Rosmalen, NL

Post by Jarno » Fri May 26, 2017 3:46 pm

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
Common Wiggler
Posts: 99
Joined: Tue Sep 27, 2016 10:28 am
Location: Chicago

Post by NiteEagle » Fri May 26, 2017 6:49 pm

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?

User avatar
strat-1
Wiggling with Experience
Posts: 490
Joined: Wed Jun 03, 2015 8:58 am
Location: Romania
Contact:

Post by strat-1 » Sat May 27, 2017 9:34 am

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.

User avatar
strat-1
Wiggling with Experience
Posts: 490
Joined: Wed Jun 03, 2015 8:58 am
Location: Romania
Contact:

Post by strat-1 » Sat May 27, 2017 9:38 am

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 :)

Post Reply

Return to “Music Tech DIY”