[sdiy] Re:

[dreichert at sympatico.ca]

Milo,

Are you only using a transformer? If so, you probably are powering your circuits with AC power, you need to have a DC power source. You can convert it quite easily using the 7812 and 7912 regulators, a couple of capacitors and diodes.

Many of the list members' pages have power supply circuits on them, they're all basically the same. Check them out.

Dave

> 
> From: Milo Barrowclough <delta_316 at yahoo.co.uk>
> Date: 2003/10/14 Tue PM 06:10:37 EST
> To: synth-diy at dropmix.xs4all.nl
> 
> hello everybody
>  
> I love electronic sound and i am well into all kinds of synthesizers. Recently i have been trying to build my own rudimentary synth. I have made a simple 555 oscillator that works great. Since the then i have been trying more advanced circuits involving op-amps, but without success. I have tried to make r.a. penfold's vco, penfold's filter, and a basic lm3900 VCO. Whenever i try any of these circuits , it either emits nothing or a quiet buzzing noise. I am almost certain that my circuit is correctly built, i've checked the bastard about 50 times. Can anyone help me? I think that the problem may be the power supply, i am using an old scalextric (model car racing) transformer that puts out 12 volts. Is this a common problem with op-amps? Whats going on? 
> Thanks very much
> Milo
> 
> 
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