[sdiy] Elektor Formant Re: Test / Sequencer / Arduino

[Nantonos]

Hello Harald,

Thursday, March 26, 2015, 10:24:38 AM, you wrote:

> for your resting uA726 this might be of interest:
> http://www.haraldswerk.de/NGF/NGF_VCO_CORE_ONE/VCO_CORE_ONE.html
> I have rebuild the Formant VCO with some modern parts keeping the 
> overall architecture original.

I wish more circuits did what you have done, deriving important
voltages from precision voltage references (REF02Z and REF102AP in
your case).

Its depressingly common even today to see voltages derived from
resistive dividers across the power rails. Op-amps with PSRR of 80dB
being used with voltage sources whose PSRR is less than 10dB.

The circular transparent chamber is to prevent airflow-induced
temperature changes?

-- 
Best regards,
 Nantonos                            mailto:nantonos at epona.net