[sdiy] BP Electrolytics & Obscure Solina ICs?

[Michael Ruberto]

>
>That's exactly what I did when I first hit the situation where I needed
>a "keyboard op amp" for an ARP 2600,  I built one,  on a small hunk of
>perfboard,  using a pretty standard op amp and a dual FET like I'd seen 
>them
>do in some other stuff (this was back before FET-input op amps were as 
>common
>as they later got to be  :-).
>

That's pretty cool. I think I am going to try this. As I'm working on 
swapping these modules I can see that they are simply programmed by an 
external feedback resistor for the gain needed. By todays standards I don't 
think there's anything special about the HA12017. Any decent audio grade 
opamp should do it's job. Looking at the traces in the broken up module it 
looks like the two transistors were just a high current follower stage for 
driving the output transformer. Seems like the only challenge here is using 
parts that can handle the +/- 22V supply.

M. A. Ruberto

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