Simple Underground Electronics

Posted by John Sims on December 31, 2008 at 9:20am
As an Electronics Engineer, I like to build things. Particularly electronics for my CBG's, lap steel and pedal steel guitars. Here is a simple LM386 Audio Amplifier using the standard LM386 IC chip in a high-gain configuration (gain = 200). For a maximum gain of 20, leave out the 10 uF cap connected between pins 1 and 8. Maximum gains between 20 and 200 may be had by adding a fixed or a variable resistor in series with the same 10 uF capacitor. The 10k potentiometer will give the amplifier a variable gain from zero up to the maximum.

Here's a high gain amp for those who wish to tackle more difficult projects... And a neat little device from GUITAR GADGETS along with some cool GEO EFFECTS. Of course you can become a real HOME WRECKER using these cool boxes...or THESE cool effects kits. OLC makes some neat stuff also...as well as RUNOFF GROOVE. HERE is a powerful amp kit that pumps 7 Watts into 8 ohms. It has aux stereo inputs and combines left and right channels into one mono signal. It also has a microphone or line input selection switch. The Mic input has its own level adjust control and it includes Bass and treble control as well as a volume control. Will operate from 10 volts DC up 15 volts DC. Of course we want to hear what you've built, so use AUDACITY to record your stuff. Post your cool circuits here and have fun!

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Replies

  • Mark October 11, 2009 at 8:03am
    I just started a forum strand on amps because I have some questions about LM386 circuits and I couldn't find an obvious place to post them. By sod's law I then discovered this strand about 5 minutes later. Rather than re-type the questions I figure it might be better to post the following link to what I've just written.

    http://www.cigarboxnation.com/forum/topics/simple-amps
  • John Sims September 18, 2009 at 1:18pm
    Cool. I use them alot, that is a great link for any setup. Thanks for the Part Number
  • RL Mott September 18, 2009 at 1:10pm
    Great links John .
    Noteworthy is the input jack detail on this layout .

    The 3-contact input jack does away with the need for an on/off switch .
    Unplugged , everything is grounded but the battery .
    Plug in , and the plug "turns on" the battery .

    Switchcraft L12B Mouser Part #: 502-L-12B is a little more $ , but does away with a switch and has a .375 bushing for 1/4" thick boxes .
  • John Sims September 13, 2009 at 7:15pm
    I use 500K pots. Alot of people use 250K ohm. I think that 550K sounds better. Here is a site that has lots of diagrams...
    http://www.seymourduncan.com/support/wiring-diagrams/
    HOGS GRUNT said:
    What are the values of the vol/tone controls and the cap please?


    BT Cohosh said:
    What's the best value for the cap in this arrangement? Bear in mind that I'm amazingly ignorant when it comes to electronics. I've built a couple of little amps only because of my ability to slavishly follow directions....


    Thanks for the diagram.

    John Sims said:
    Hamhock, You don't need to use capacitors with piezos unless you add a tone control. Here is a dual piezo setup with a volume and tone control (plus cap) added...

  • HOGS GRUNT September 13, 2009 at 7:11pm
    What are the values of the vol/tone controls and the cap please?
    BT Cohosh said:
    What's the best value for the cap in this arrangement? Bear in mind that I'm amazingly ignorant when it comes to electronics. I've built a couple of little amps only because of my ability to slavishly follow directions....


    Thanks for the diagram.

    John Sims said:
    Hamhock, You don't need to use capacitors with piezos unless you add a tone control. Here is a dual piezo setup with a volume and tone control (plus cap) added...

  • John Sims May 4, 2009 at 7:59am
    You should be able to. Let us know the results!

    Will Carter said:
    Hi John,
    Is it possible to swap one of the piezo with a normal single coil?Pardon my ignorance but I have only ever used piezos and am electronically impaired!
  • Will Carter May 4, 2009 at 4:12am
    Hi John,
    Is it possible to swap one of the piezo with a normal single coil?Pardon my ignorance but I have only ever used piezos and am electronically impaired!
  • BT Cohosh April 16, 2009 at 11:11am
    What's the best value for the cap in this arrangement? Bear in mind that I'm amazingly ignorant when it comes to electronics. I've built a couple of little amps only because of my ability to slavishly follow directions.... Thanks for the diagram.
    John Sims said:
    Hamhock, You don't need to use capacitors with piezos unless you add a tone control. Here is a dual piezo setup with a volume and tone control (plus cap) added...

  • John Sims March 14, 2009 at 1:24pm
    Hamhock, You don't need to use capacitors with piezos unless you add a tone control. Here is a dual piezo setup with a volume and tone control (plus cap) added...

  • Hamhock March 14, 2009 at 12:46pm
    I'm new to the electronics and all and slowly but surely I'm coming around to the concept of the schematic, but my question is, when installing piezo's to a CBG,,, would capacitors be used at all. I've seen wiring diagrams on different sites but they mainly apply to mag pups. Also is it applicable to use more than one piezo pup in a CBG, like maybe 2 or 3 or more?
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