[sdiy] [Slightly OT] Op-amp headroom in synth & audio applications

[Donald Tillman]

> On Mar 10, 2015, at 11:21 AM, Justin Owen <juzowen at gmail.com> wrote:
> 
> I understand that there's a margin for staying away from the rails and for the tolerances of parts like VRegs and what not and maybe part of it is a hangover from the days of less efficient amps - but considering that a good op-amp like the OPA134 will (according to the data sheet) operate down to +/-2.5V and work-horse amps like the TL072 aren't far behind that - why so much headroom?

1. Headroom good.

2. Why constrain the choice of opamp?

3. Discrete circuitry appreciates the wiggle room.

4. Originally ARP, but now MOTM and many other synths run audio at high levels to match the range of control voltages.  So it's less "headroom" and more a high reference audio level.

  -- Don

--
Don Tillman
Palo Alto, California
don at till.com
http://www.till.com