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ASR alignment

2018-03-12 by Mike Burnham

Connect a constant voltage to the input. Connect one output to a VCO and the Clock input to an LFO or clock running at a few hertz. You should get a constant tone. If there is a stepped warble, one of your ICs has a different offset to the others. You can work out which chip it is by holding your finger on the pins of each chip in turn. Swap the affected chip for another. Repeat if needed until you get a constant tone. I have only had this happen with LM3140/CA3140 chips.

Hi there

I'm using CA3140 ICs.

When I hold my finger on the pins I get different results. Some slight warbling some more dramatic.

Seems like not one chip behaves the same as the others. Is it better to just replace with 4 LF356 ICs?

Re: ASR alignment

2018-03-12 by Ken Stone

It may well be better to just use LF356, as those are meant to have much smaller offsets. Some 3140 I have since received were so bad I could not trim their offsets at all.

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On Tue, Mar 13, 2018 at 1:21 AM, Mike Burnham mikejburnham@... [cgs_synth] <cgs_synth@yahoogroups.com> wrote:

Connect a constant voltage to the input. Connect one output to a VCO and the Clock input to an LFO or clock running at a few hertz. You should get a constant tone. If there is a stepped warble, one of your ICs has a different offset to the others. You can work out which chip it is by holding your finger on the pins of each chip in turn. Swap the affected chip for another. Repeat if needed until you get a constant tone. I have only had this happen with LM3140/CA3140 chips.
Hi there
I'm using CA3140 ICs.

When I hold my finger on the pins I get different results. Some slight warbling some more dramatic.

Seems like not one chip behaves the same as the others. Is it better to just replace with 4 LF356 ICs?

--
Ken Stone otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>

Cgs synth

ASR alignment

ASR alignment

Re: ASR alignment

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