ADSR Problems...

[Rogue Formant]

Hi, I'm just starting out trying to build my first synth and I've hit a bit of a snag. I've built the dual ADSR from the archive section of this site:

 (http://experimentalistsanonymous.com/diy/Schematics/ADSR%20Generators%20and%20Envelope%20Generators/ADSR%20Generator.pdf)

I've connected it to my oscillator but when I trigger the gate input all I get is the signal coming through at a constant low volume.

I've gone through all my connections and it seems to match the schematic, but I think I might have the power connections wrong for the ICs. Like I say I'm new at this so I'm not sure, but I've wired up the Vcc/Vdd pin on each chip to +12v and the Vss pin to ground. Is this correct? If so, then any other Ideas one where I could be going wrong?

Any help or advice would be greatly appreciated, I've been pulling my hair out over this for two days now!

Thanks.

[expanoncolin]

Some tips -

Note that the power pins are all labeled.  Eg, pin pin 8 on IC2 should be grounded, and pin 16 should be connected to 15V.  All power pins are labeled like this.  Note that IC6 is connected to +15V and -15V, not +15V and ground.

It will probably work with 12V instead of 15V, but there's no guarantee.

Make sure you have the pots wired - it is a little confusing how they are drawn.

Some ADSRs expect different gate signals - 0V to 5V, 0V to 15V, etc.

I'm not sure what is being referred to by the V-(?) and REF to the left bottom of the schematic.

If you play with it more and can't get anything to work, we can try to analyze the circuit more closely to figure out what exactly should be happening at different parts of it.

-Colin

[Rogue Formant]

Thanks for the advice! I assumed that the Vcc- would be the same as connecting it to ground so that's definitely where I'm going wrong. How do I go about supplying negative voltages? Do I need a transformer for that?

Thanks again
John

[expanoncolin]

You need a power supply capable of supplying positive and negative voltages (what's your current supply?).  Unless you're running batteries - in which case you need a second battery, whose + end is connected to ground, and whose - end is V-.

-Colin

[Rogue Formant]

I'm using an ÅTX power supply from an old PC, probably not the best thing I know but i've noticed it does actually have -12v! I've abandoned that particular circuit for now though, think I'm gonna focus more on building my VCO before i start messing aroudn with anything else. Thanks for the help!

[alecriss]

Using an ÅTX power supply from an old PC is not a good thing but it doesn't makes any difference any how..That also when you mentioned it actually have -12v!