ASft21C _ ADSR and others... TL071 question

[marvkaye]

Regarding the TL071 used in the ADSR from Thomas' Synth for the 21st Century... is it necessary / required / desirable to ground or otherwise terminate the input offsets (pins 1 & 5) or can they simply be left to float? I didn't see anything mentioned in the datasheet but I confess that I may have missed something, even if it was there. Your thoughts??

<marv>

[bubzy]

http://electro-music.com/forum/post-94183.html

might clear it up a little, from looking at a few pages it doesnt seem necessary

[marvkaye]

Thanks for the pointer to that thread.. I thought I remembered reading something about it here somewhere. I also recollect the general admonition that said unused pins on certain chips needed to be grounded and was wondering if this was one of those cases. It looks like apparently not.

<marv>

[Tim Servo]

Hey Marv,

In most cases the offset is so small that you don't need to worry about it, and you can leave those pins unconnected.

What you may be thinking of are CMOS inputs. THOSE should never be left unconnected or "floating." Hook them to +V or GND instead. While it's probably not a bad idea to ground unused op-amp pins, it's not absolutely necessary.

Tim (ground round) Servo

[marvkaye]

Hi Tim (typically parenthetical variable mid-nomenclature) Servo,

Thanks for the tip. I've stripboarded this guy and am ready to start testing... I'll see if clipping those offsets to ground has any noticeable effect and can always solder in an extra connection or two if required. I'll try to remember the admonition about CMOS, though... at least I knew something was not supposed to be left hanging.

<marv>