SAW / PULSE Wave Correct ?
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SAW / PULSE Wave Correct ?

by orange_hand on Sat Aug 18, 2012 4:46 pm

Hi Guys,

I am just in the process of building a xoxbox and I have got a question. I have adjusted and checked the power supply on J4 on my main board. I measured 5.34 and 11,80 Volts. I have already assembled the OSC section and check the ware forms with my scope:

OSC Section:

Image

Saw triggered with 3V:

Image

The saw has got an amplitude of approx. 5Vpp.

Pulse triggered with 3V:

Image

As you can see based on the scope settings the amplitude of the pulse wave is just about 1,5 Vpp which seems to be very low. Also the form looks a little bit odd.

I have checked all parts and believe that everything was correctly soldered in. Do I have already a problem or are my measurements ok ?
Last edited by orange_hand on Sun Aug 19, 2012 7:14 am, edited 1 time in total.
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Re: SAW / PULS Wave Correct ?

by substyler on Sat Aug 18, 2012 6:49 pm

hi Orange,

not sure about your scope settings, but I would go on with soldering and didn't worry too much about in this early stage.

cheers,
SubStyler

btw: did you get your kit from x0xsh0p? didn't they ship the kits with SK30A-O, SK118-O and SK30A-Y?
if so, check the SK118-O for Q38 and see what happen.
electronics consists to 80% of superstition and to 20% of fairy tales • DIY or die!

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Re: SAW / PULSE Wave Correct ?

by orange_hand on Sun Aug 19, 2012 6:50 am

did you get your kit from x0xsh0p? didn't they ship the kits with SK30A-O, SK118-O and SK30A-Y?


Yes, I did 8) and yes, received it with those three transistors, as a part of their great service :D

And I replaced the SK30A-O with the SK118-O. In this case the saw wave is cleaner if you like but the pulse wave looks more or less the same. The pulse is generated from the saw, so I assume that the components for the saw are all right. The only thing I could imagine is a faulty capacitor C11, but I will leave it in there and carry on with the filter section in order to see what happens next...

I'll keep you guys posted

Cheers
orange
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Re: SAW / PULSE Wave Correct ?

by orange_hand on Tue Aug 21, 2012 5:59 pm

Hi,

I have now managed to view the pulse wave on my scope after I soldered some additional parts into the PCB. I guess if you follow exactly the instruction, then the pulse wave can't be produced properly. Attached a picture of my pulse wave :-)

Image

I also completed the filter section and did some tests with the filter:

A filtered pulse wave:

Image

A filtered saw wave:

Image

To be continued....
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Re: SAW / PULSE Wave Correct ?

by antto on Tue Aug 21, 2012 6:28 pm

the "square" waveform on the 303 (and thus on the x0x too) is NOT square at all
it can be described as a f*cked up pulse wave with frequency-dependant pulse-width and middle edge softness

all of your scope pictures look fine now, don't worry :mrgreen:
We are here too: irc.freenode.net >>> #x0xb0x
..:: c0nb0x v1.00 ::.. http://forums.adafruit.com/viewtopic.php?f=7&t=29282 (new control app - win/osx)
VCO Tuning: http://forums.adafruit.com/viewtopic.php?f=12&t=24759 (do it the EASY way)
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Re: SAW / PULSE Wave Correct ?

by orange_hand on Fri Aug 24, 2012 7:31 am

Hi,

I am currently at the following stage with my project:

Image

Image

Image

Image

Still a long way to go ....

Cheers
orange
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Re: SAW / PULSE Wave Correct ?

by antto on Fri Aug 24, 2012 12:29 pm

cool, btw, you won't regret using sockets especially around the VCO and VCF
We are here too: irc.freenode.net >>> #x0xb0x
..:: c0nb0x v1.00 ::.. http://forums.adafruit.com/viewtopic.php?f=7&t=29282 (new control app - win/osx)
VCO Tuning: http://forums.adafruit.com/viewtopic.php?f=12&t=24759 (do it the EASY way)
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Re: SAW / PULSE Wave Correct ?

by orange_hand on Sat Aug 25, 2012 4:53 am

After yesterday's soldering job

Image

Image

Not yet tested....
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Re: SAW / PULSE Wave Correct ?

by substyler on Sat Aug 25, 2012 7:48 am

hey Orange... nice and clean solder joints. good job so far!
don't forget to solder the legs of VR3 - VR8 :mrgreen:
electronics consists to 80% of superstition and to 20% of fairy tales • DIY or die!

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Re: SAW / PULSE Wave Correct ?

by MMM on Sat Aug 25, 2012 8:06 am

Is it just me or are the headers J5 and J7 positioned the wrong way?

(Of course this also depends how the headers on the IOboard are soldered.)
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Re: SAW / PULSE Wave Correct ?

by orange_hand on Sat Aug 25, 2012 9:08 am

Hi,

the headers of the connectors are oriented appropriately, of course aligned with the i/o pcb.

The encoders will be finally fixed when everything works as expected.

cheers
orange
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Re: SAW / PULSE Wave Correct ?

by orange_hand on Sun Aug 26, 2012 7:19 am

I managed to do a first sound check of this new xoxbox after I checked the supply voltage of the various IC's in the sequencer section. Everything in the analog section works as expected !

Image

Image

The next decision is quite difficult, which colours will I use for the box ?

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Ok, I think this looks good:

Image

I decided to go with some nice red flat top LED's :-)

Image

Now I have to fit everything in this nice alloy enclosure:

Image

Image

And finally the control surface can be finished:

Image

Image

Image

Image

The box was tuned and works fine.
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Re: SAW / PULSE Wave Correct ?

by orange_hand on Mon Aug 27, 2012 7:38 am

When I wanted to finish up the xoxbox I realized that the original heat sink was too big, as it was touching the transistors underneath. So I decided to come up with a custom heat sink that fits. I also drilled some holes for a better ventilation on the bottom of the case where the heat sink is located:

Image

Image

Image

Image

I also fixed the capacitors my way :-)

Image

Image

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The completed unit:

Image

Image

Now that I am done with it, I am happy that my first box is fully working straight away. Looking back I can say that it was a hell lot of work. Not sure if I want to build another one :mrgreen:
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Re: SAW / PULSE Wave Correct ?

by antto on Wed Aug 29, 2012 5:14 am

...but one never has "too many" 303s :wink: :mrgreen:
We are here too: irc.freenode.net >>> #x0xb0x
..:: c0nb0x v1.00 ::.. http://forums.adafruit.com/viewtopic.php?f=7&t=29282 (new control app - win/osx)
VCO Tuning: http://forums.adafruit.com/viewtopic.php?f=12&t=24759 (do it the EASY way)
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Re: SAW / PULSE Wave Correct ?

by orange_hand on Wed Nov 14, 2012 10:05 am

That's correct. Please find attached The Acids :-)

Image

Image

Image

Cheers
orange
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