Welcome, Guest. Please login or register.

September 28, 2020, 08:48:44 AM

Login with username, password and session length

Recent Posts

 

Author Topic: The Coppertone Saga Continues...  (Read 2403 times)

Gerry Rzeppa

  • Chipper
  • *
  • Posts: 6
  • Chip Points: 0
    • View Profile
The Coppertone Saga Continues...
« on: July 06, 2014, 08:33:37 PM »
All solid state this time -- and it rhymes!

Roly

  • Legendary
  • ******
  • Posts: 2184
  • Chip Points: 288
    • View Profile
    • Australian Valve Amps
Re: The Coppertone Saga Continues...
« Reply #1 on: July 07, 2014, 08:30:06 AM »
Very win!   :dbtu:

I like the organ pipe resonator idea.
If you say theory and practice don't agree you haven't applied enough theory.

tonyharker

  • Elite
  • ****
  • Posts: 149
  • Chip Points: 19
    • View Profile
Re: The Coppertone Saga Continues...
« Reply #2 on: July 07, 2014, 10:45:01 AM »
Brilliant!  What chip does the MAH3 use?

Gerry Rzeppa

  • Chipper
  • *
  • Posts: 6
  • Chip Points: 0
    • View Profile
Re: The Coppertone Saga Continues...
« Reply #3 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.

Gerry Rzeppa

  • Chipper
  • *
  • Posts: 6
  • Chip Points: 0
    • View Profile
Re: The Coppertone Saga Continues...
« Reply #4 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.