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Re: 386 Op-Amp

5/25/2000 9:22 AM
JD Sleep	Re: 386 Op-Amp Charlie, I built a little headphones amp with the 386, but with NO preamp as in the Mims Schematic. It sounds VERY good for as simple as it is. I was suprised how good is sounds: Guitar into pin 3 +9v into pin 6 Pin 5 to a 330uF cap and then to headphones (+ side of cap towards opamp) pin 2 and 4 to ground. Use the volume control on your guitar, it distorts ugly on full volume. If you don't have a "treble bleed" cap on your guitar volume, it might not sound so good. The gain is 20, I've never tried it with a speaker. The Mims setup is better, but this is SO dog-gone simple, I had to try it! I think if you add a few more components for volume control and power protection, you'd end up with a very nice inexpensive Q&D headphone amp. I've been meaning to post a schematic of that...maybe one of these days I will. The little smokey is the same except: 330uF cap is 47uF Another 47uF cap between pins 7 and 4 (+ side to 7) Pins 1 and 8 are connected. (This boosts the gain to 200. You can put resistance between to get variable gain.) How much power does it have? Not much, good for headphones or maybe "bedroom" practice. Best advice is to go buy the chip and try it out, they're so cheap and easy you don't have much to lose...and its all good fun! If you want more power, take a step up to the 384 5w IC amp, or the 7w 383 (Anderton's choice) or the 60w 3886. The circuits get a little bit more complex, but not much. JD

5/25/2000 9:22 AM

JD Sleep

Re: 386 Op-Amp

Charlie,

I built a little headphones amp with the 386, but with NO preamp as in the Mims Schematic. It sounds VERY good for as simple as it is. I was suprised how good is sounds:

Guitar into pin 3
+9v into pin 6
Pin 5 to a 330uF cap and then to headphones (+ side of cap towards opamp)
pin 2 and 4 to ground.

Use the volume control on your guitar, it distorts ugly on full volume. If you don't have a "treble bleed" cap on your guitar volume, it might not sound so good. The gain is 20, I've never tried it with a speaker. The Mims setup is better, but this is SO dog-gone simple, I had to try it! I think if you add a few more components for volume control and power protection, you'd end up with a very nice inexpensive Q&D headphone amp. I've been meaning to post a schematic of that...maybe one of these days I will.

The little smokey is the same except:

330uF cap is 47uF
Another 47uF cap between pins 7 and 4 (+ side to 7)
Pins 1 and 8 are connected. (This boosts the gain to 200. You can put resistance between to get variable gain.)

How much power does it have? Not much, good for headphones or maybe "bedroom" practice. Best advice is to go buy the chip and try it out, they're so cheap and easy you don't have much to lose...and its all good fun! If you want more power, take a step up to the 384 5w IC amp, or the 7w 383 (Anderton's choice) or the 60w 3886. The circuits get a little bit more complex, but not much.

JD

Replies:

paul perry Glad to hear people have had good r... -- 5/25/2000 3:07 PM
Charlie Thanks very much for both of your r... -- 5/25/2000 6:36 PM
Stuart I was about to try one of these. I'... -- 5/25/2000 6:52 PM