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HandClap Neg Voltage a bit low

Posted: Mar 10th, '14, 06:56
by discodisco
Hello All,

I have built everything up to the HandClap circuit.

So far, all the voltage test points match my power supply voltage (+/- 0.25v) (i'm getting +15v, +5v and - 14.52 on the power supply rails)

On the handclap however, i'm getting +15 v, but only -13.92 for the neg rail.

Can anyone confirm if they too have a slightly lower negative rail on the handclap circuit.

p.s - I've checked the correct orientation of all the transistors and capacitors, and also checked a few spots where the solder pads are close together - so far everything matches the eagle / schematic.

Is this a problem?

Cheers

Re: HandClap Neg Voltage a bit low

Posted: Mar 11th, '14, 07:31
by discodisco
Hello all,

Just an update:

I replaced the -15v regulator (lm7915) and now all my voltages check out exactly, except for the handclap circuit, i'm still down half a volt (-14.5v)

I guess this is okay (3% out), but I will double check all my components with eagle soon.

If anyone else is checking their voltages, i'd be curious to know what they are getting for their -15v in the handclap circuit.

Cheers

Re: HandClap Neg Voltage a bit low

Posted: Mar 18th, '14, 01:23
by misa
Hi,

I am getting - 13,59 V on the AN 6912 on the handclap, but -14,57 on the power pad.

Where are you measuring your "negative rail"?

Re: HandClap Neg Voltage a bit low

Posted: Mar 18th, '14, 05:50
by discodisco
Hi,

You're getting the same measurements as I am so I guess it is meant to be this way.

I'm measuring on the test points shown in the build guide,
I have finished building and everything sounds good I think (just waiting to borrow a real 808 to compare and adjust the trimpot for the correct decay sound.