MUFF WIGGLER Forum Index
 FAQ & Terms of UseFAQ & Terms Of Use   Wiggler RadioMW Radio   Muff Wiggler TwitterTwitter   Support the site @ PatreonPatreon 
 SearchSearch   RegisterSign up   Log inLog in 
WIGGLING 'LITE' IN GUEST MODE

TWO59 VCO module (Building Thread) by FEEDBACK
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3, 4, 5  Next [all]
Author TWO59 VCO module (Building Thread) by FEEDBACK
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
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3, 4, 5  Next [all]
Page 2 of 5
Powered by phpBB © phpBB Group