Quick and easy way to build a great sounding small amp

Posted by Henry S on July 23, 2017 at 2:16pm

I have not posted here in a million years -- been off in Google groups, but last night I had a great time when I surprised a good friend by giving him one of a pair of resonator CBGs I had built. The CBG had a flat humbucker as well so he plugged it into a small amp I had given him about a year ago -- and I was really amazed at how good it sounded.

You see as an old (really old) electronics tech I've been on a quest to build a really good battery powered amp for CBGs. I have designed and prototyped a number of LM386 and a multi-watt LM380 in the past 18 months. Each one having some good features and some issues ... the quest continues. But one of my early tests was taking an off the shelf Honeytone amp ($22) and gutting it and putting it into a bigger enclosure with two 3inch 1watt speakers. So if you are lacking the ability to read schematics - solder - of know which end of a resistor to use ------ you can build one of these for around $30 and a few hours. One of the keys here are the right speakers --- this is a sub 1watt amp so if you use those 3inch 30watt car speakers you have laying around its going to sound poor. This little LM386 powered amp cannot fully actuate those speaker cones. While my quest continues on the design side I'm going to build one of these - again  - for my own use.   I can provide more details if there is interest.

   Here are the parts I used:

Honeytone Amp

http://www.guitarcenter.com/Honeytone/N-10-Guitar-Mini-Amp.gc

Nice 3in speakers

https://www.adafruit.com/product/1313

A cheap $8 hobby wood jewelry box

Here is the finished project

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Replies

  • GARAGE HERMIT August 13, 2020 at 10:43am

    that's a really nice set up,

  • Paul Craig July 23, 2017 at 2:39pm

    Welcome back Henry.

    I've built a couple of Ruby amps, one in a 10watt guitar practice amp cabinet with 6" speaker to replace the amp board that quit working(Behringer). That one worked great.

    Also prototyped a dual 386 chip bridged amp variant of the Ruby with 2 gains. Made a Head version for myself and built a combo version for a member in a pine cabinet with a 10" 8ohm WGS speaker. Those turned out rather good I've been able to drive a 10" or 15" 15watt speaker with the head version. Had to change out the output caps to different value for the combo to work with a bright speaker.

    • Henry S > Paul Craig July 23, 2017 at 3:12pm

      Thanks for the welcome Paul - I am currently working on a bridged LM386 design as well based off of the Little Gem MkII but using a TL072 preamp and clipping distortion design I found on the net. I produced a LM380 based version of that and its really sounds pretty good --- but LM380s can be hard to find and a bridged LM386 setup is more than good for a CBG amp. I've also been using a EDA design source to make actual PCBs --- I can get 5 to 6 boards (out of China) for around $30. You might look into that if you haven't. 

      Looking forward to sharing ideas 

      https://easyeda.com/

    • Paul Craig > Henry S July 24, 2017 at 3:16am

      Thanks for the link. Just been doing mine old school style on a Perf Board from Radio Shack. Haha

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