crisp@uncecs.edu (Russ Crisp) (04/16/91)
Hello again netlanders. I have need for a low distortion AF preamp, preferably in a IC package, that has frequency response up to around 60 Khz. Power requirements are low, 100mw or less. Does this sound like a good application for an op amp? I have a Tandy semiconductor reference manual, and on page 43 they have a sample application where a 741 linear op amp is set up in a configuration with r1 = 1K and r2 = 9K, which gives a gain of 10 with a 100Khz bandwith. Am I understanding this correctly? Does anyone have any other, hopefully better, ideas on this subject? Thanks! Russ Crisp Western Carolina University
franko@juliet.caltech.edu (Filipanits, Frank J.) (04/17/91)
In article <1991Apr16.131348.9149@uncecs.edu>, crisp@uncecs.edu (Russ Crisp) writes... >I have need for a low distortion AF preamp, preferably in a IC >package, that has frequency response up to around 60 Khz. Power >requirements are low, 100mw or less. Does this sound like a >good application for an op amp? >Thanks! >Russ Crisp >Western Carolina University The 5534 opamp is Ideal for audio frequency preamplification - it's clean, cheap and easy. Also features a high slew for reproducing transients. It comes in an 8 pin DIP from several manufacturers. I can send you details on using it as a mic preamp if you want them.... Frank franko@juliet.caltech.edu
tonyb@titania.juliet.ll.mit.edu ( Tony Berke) (04/18/91)
In article <1991Apr16.131348.9149@uncecs.edu> crisp@uncecs.edu (Russ Crisp) writes:
I have need for a low distortion AF preamp, preferably in a IC
package, that has frequency response up to around 60 Khz. Power
requirements are low, 100mw or less. Does this sound like a
good application for an op amp?
I'm sure someone out there will disagree with me, but I think you
should consider using products from PMI (precision monolithics inc).
They produce several audiophile-grade preamp chips, as well as op-amps
that are tweaked for various audio gain and filter applications.
Their parts find their way into much of the studio gear used to record
much of the music you hear, so you'd better hope you like their sound.
Analog Devices also produces several well-regarded op-amps for audio
use. PMI has a small publication with usefull circuits for their
products, called the 'Audio Handbook' (or something like that), as
well as a giant full-line book with less-detailed ap. notes. I've had
good luck obtaining free data books from both companies (actually, AD
just bought out PMI). Try calling 800 information and get AD's
publications office.
-Tony Berke (tinkerer, certified audio nut) tonyb@juliet.ll.mit.edujgk@osc.COM (Joe Keane) (04/20/91)
The answer to the original question is yes, this is definitely an application for an op-amp. There's not enough information to recommend a specific chip though. I'd say don't use a 741 if you can avoid it, especially if you care about distortion. As a default the LF411 is a good one to use. It can't hurt to stock up on a couple of these. For low noise, low supply current, high output current, or other requirements some other chip would be more appropriate. The PMI SSM chips are quite nice if you want high quality. They're a little harder to find though. -- Joe Keane, amateur electronics hacker jgk@osc.com (...!uunet!stratus!osc!jgk)