Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Solid State Amplifiers => Tubes and Hybrids => Topic started by: Gerry Rzeppa on July 06, 2014, 08:33:37 PM

Title: The Coppertone Saga Continues...
Post by: Gerry Rzeppa on July 06, 2014, 08:33:37 PM
All solid state this time -- and it rhymes!
Title: Re: The Coppertone Saga Continues...
Post by: Roly on July 07, 2014, 08:30:06 AM
Very win!   :dbtu:

I like the organ pipe resonator idea.
Title: Re: The Coppertone Saga Continues...
Post by: tonyharker on July 07, 2014, 10:45:01 AM
Brilliant!  What chip does the MAH3 use?
Title: Re: The Coppertone Saga Continues...
Post by: Gerry Rzeppa on July 07, 2014, 02:27:21 PM
Very win!   :dbtu: I like the organ pipe resonator idea.

In this case they don't give "booming" bass -- because the speaker doesn't put much out to begin with -- but they do smooth out the low end nicely. After some experimenting (by ear) I ended up plugging the four longest pipes (to lower their resonant frequency) and leaving the shorter three open. I like mounting the speakers backside-up so the high-frequencies are evenly dispersed. It's really nice being able to walk around while you're playing and not have the tone change drastically.
Title: Re: The Coppertone Saga Continues...
Post by: Gerry Rzeppa on July 07, 2014, 02:38:29 PM
Brilliant!  What chip does the MAH3 use?

It uses a TDA7267A, a 16-pin dip, which is unique because all the pins on one side serve as a heatsink when soldered directly to a big pad of copper on the board. It also has a smaller chip surface-mounted on the back (I couldn't read the number but it's probably a 386 or something similar) that it uses to produce the "blues" and "fuzz" tones.

This little Velleman kit ( http://www.amazon.com/dp/B005VUCT5I/ ) is a minimum-parts version of the TDA7267A circuit and sounds remarkably good all by itself -- even playing clean -- with a 9v battery, a guitar plugged directly into one end, and an efficient speaker (SPL 90 or above) on the other. The better the speaker, the better the sound.