[sdiy] UA726 was: new Texas ic log102 ? log ratio amp

[Glen]

At 10:03 AM 4/4/02 , pfperry at melbpc.org.au wrote:
>> Chris Crosskey wrote:
>> >I stand with Glen on this...if we could buy UA726's for 20 USD, we'd prolly
>> >all be using them for the added accuracy .....
>
>hey, this is synth-DIY, surely we can make UA726's from surface mount bits 
>for less than 20USD! I can remember when radio hams used to make little 
>ovens to stabilise their oscillators (which, BTW, were of an accuracy & 
>stability that maeks the best analog synth look lie a drunk playing slide 
>trombone)
>
>paul perry melb aust

Some radio hams also constructed crystal filtering stages with several poles,
for a very steep skirt. The several crystals involved, needed to be matched to
each other very closely for best results. I have actually heard of some people
"fine tuning" the frequency of the crystals by dipping the quartz elements in a
vat of acid to slowly etch away some of their size, and slightly increase their
frequency. After this was done, the crystals (and associated circuitry)  might
then be placed in an oven to insure temperature stability,. just as you
mention.


Later,
Glen