sh101 Subosc help please

isak · Posted: Tue Jun 04, 2013 11:13 pm Post subject: sh101 Subosc help please

Hi guys.

i really need some help to understand why the hell -2 is not working.
i'm using the ody VCO saw as my source for the subosc.
i design a pcb for this and -1 is working great only -2 and -2 pulse is not working.
i actually dont care about -2 pulse, i only want the -2 to work.
i modded the original scheme a bit cause it wont work with the resistors values it haves, its a small change, pics uploaded...

this is the original scheme...

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this is the moded scheme...(the changes are marked with red round)

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this is my pcb design...(already etched)

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please tell me if my design is not good, and if its good why -2 is not working?

cheers,
Isak E.

mrmrshoes · Posted: Wed Jun 05, 2013 3:39 am Post subject:

I think your layout is good.

but i can see one problem. Going from your component placement layout the 2n3904 pinout looks wrong.

You've got the emitter going to pin 3 and the collector to GND.

i would also use 220k to the base. or the closest value you have to it.

hope you find the problem

mrmrshoes

isak · Posted: Wed Jun 05, 2013 5:09 am Post subject:

thank you for your reply.

yes, your absolutely right!, how i missed that? Embarassed

i hope it will fix the problem, thank you very much.

i'll update soon.

isak · Posted: Wed Jun 05, 2013 11:27 am Post subject:

ok, ive fixed the transistor pins.
still no change, i dont get -2.

i put 220k pot instead and tried to play with the pot, up and down, still the same.
no -2

Confused

isak · Posted: Wed Jun 05, 2013 1:33 pm Post subject:

i have found the "problem"!

i was thinking to my self that this circuit is published and must work, i checked and replaced everything except the 68k, i puled it out and put a 100k pot instead, dial the pot up and down hoping to get something and i did Cool

after that i turned off power supply and measure the pot value, it was 6.5k, so i put 6.5k resistor instead 68k and thats it Smile

sound freaking amazing!
love it.

some sound sample (no keyboards just sound)

saw-squ and sub -1 and -2 amazing.wav

Description:

Filesize:

7 MB

Viewed:

1939 Time(s)

defog · Joined: Aug 24, 2011 Posts: 113 Location: Philadelphia

Hi there,

I built both the SH-101 4013 based sub oscillator and a 4024 sub oscillator on a breadboard and found they sounded identical, and implementing a 4024 requires nothing but the chip, a cap, and selector switch. The 4024 also gives you options of much lower octaves that can be used as a repeat gate. I've added sub-oscillators to my soundlab ultimate and my own diy synth this way, they're quick and dirty square wave generators. If you have a 4024 laying around, I'd suggest bread boarding one up.

isak · Posted: Wed Jun 05, 2013 8:22 pm Post subject:

Thanks.

You have a scheme of the 4024 subosc or how to connect guide?

Cheers

defog · Joined: Aug 24, 2011 Posts: 113 Location: Philadelphia

Pretty straight forward. Just put a 10nf cap between pin 14 and gnd. And the reset pin needs to be grounded. Nothing else to it.

isak · Posted: Thu Jun 06, 2013 6:04 am Post subject:

I must try this simple thing.
You sure it's sounds the same as the 101 sub?

tokyomatik · Posted: Tue Jul 23, 2013 11:10 am Post subject:

really interested in trying this little circuit...at the moment i don't have any 1n914 but im full with 1n4148s...it will work anyway???

isak · Posted: Tue Jul 23, 2013 11:54 am Post subject:

Yes it will.

Please note that the 2n3904 is reversed in the parts placement, reverse it.
Another thing..
I advice you to put a trimmer instead of R24 (68k), trim it till you get the -2 to work.

Works like a charm Smile

Cheers and good luck.

wackelpeter · Posted: Mon Jan 25, 2016 3:49 am Post subject:

taking all the Input from this thread i'd had a go on my own Version of an Suboscillator... using the CD4024 and the Input circuitry of the SH101 Subosc...

It can be fed by any waveform reaching at least +/-5V... as my Thomas Henry 555 VCOs do...
Feeding in 5V/gnd Signals.. cause Offset voltages...

on link below there's a sample using the suboscillator...
well it's not a solo demonstration of it as i abused the VCO with syncing and as always heavily used the Yusynth VC Panner (Is life possible without that VC Panner?) I'm heavily obsessed by that sounds Floating from left to right...

Well you can hear only one VCO and the SubOsc Output which is synced to an 2nd VCO
2 Thomas Henry 555 EG's involved... one for feding the VCA the 2nd sometimes modulating the master VCO...
no filtering after that, VCO and Subosc. going straight into VCA then into the panner followed by delay and caught onto tape...

https://soundcloud.com/bastian-j/track0131

TRACK0131.mp3

Description:

Sub Oscillator test

Filesize:

3.34 MB

Viewed:

1635 Time(s)

Ray_Ketamu · Joined: Nov 03, 2014 Posts: 48 Location: Germany

could i implemennt this scematics in eurorack without changes or do i need to change values?
4024 seems fine without changes but the original 101?

isak · Posted: Wed Feb 17, 2016 1:24 pm Post subject:

Hi Ray.

Use the board and info from this link Smile

http://electro-music.com/forum/topic-58533.html

Cheers,
Isak.

Ray_Ketamu · Joined: Nov 03, 2014 Posts: 48 Location: Germany

ah. that was quick Smile

thanks. did you try the 18k resistor to ground aproach for square out? didn´t find it in the pcb design. oh and you forgot to change the 15V to the 12V of euro... but very nice indeed. will pair it with two th-555, barton waveanimator and a ringmod Very Happy

finally its DIY again!

Ray_Ketamu · Joined: Nov 03, 2014 Posts: 48 Location: Germany

oooh... and shouldn´t there be an -12V connection too?

isak · Posted: Thu Feb 18, 2016 2:26 am Post subject:

I didn't try the 18k to ground but it's easy to implant.
Didn't checked with 12V.
And no, there is no need to -12V Smile