This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Thursday, March 19, 2015

MXR Micro Amp

The Micro Amp is a classic clean boost circuit first introduced by MXR in the late 70s. It's a great option if you need to stomp on something for solos. Pretty simple op-amp design that should fit nicely in a 1590a.


11 comments:

  1. hey, me again, just made this as well, at first it did not work properly, so i went through tonpad's schem and some others, and managed to see the problem, in your schem from 500kpot legs 1&2 signal going to ground through R 2K7 and C 4.7 in parallel. it SHOULD go to ground in series resistor first and then cup, made that change, and NOW it works wonderful! :] (before the change the pots response was not ok, it turned off in about half way, and the overall level of it was very low.)

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  2. is there any chance you can make this change ? :]

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  3. u the man²!! I made this too, perfect! soon i'll take pics and send.
    thank you one more time!

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  4. works better if we replace the capacitor 15uf for one of 22uf. I used this on mine.

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  5. What is the function of the 47uF capacitor? In some schematics that I saw, it doesn't appears.
    Thanks!

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    Replies
    1. It's for power filtration. Smoothes out any ripples from your power supply.

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  6. Hi!
    I've made two of your pedals as of now and they work great!(Rat and BMP) great site! Just a quick question on this one: other schematics use a 22M resistor for the pull down resitor. Yours uses a 2.2M. Is it a typo or does it have no impact on the input impedance?
    Thank you!

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    Replies
    1. 2.2M will work fine. 22M is overkill.

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    2. OK thanks! I'm off to finishing this one and finding which will be next...

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