Doug has upgraded my 248 further w/ better DC converter and EQ chip in addition to the external 12v supply.
Guess we can call it the M248 mkII!
Will take it out for test drive next weekend at DBT shows in ATL - Doug said some of you have reached out about this project and the 148 project so
hopefully will have positive results.
Internal/External battery combo should get me about 10-11 hrs.
Here's email from Doug:
Chris, I decided to replace the +/- 12 volt converter
and the EQ chip. They are the only parts common to both
channels. I saw the converter drop to +/- 10.5 volts, not
enough to cause output to drop but enough to tell me
it's on its way out. I used a new chip that I like a lot
for the EQ circuit. It has the ability to generate a more
impressive 3D soundstage. I'm going to leave the M248 on
for a while but I feel good about it now.
I'll let you know and thanks for your patience....Doug
BTW, I'm now working on making the M148 power
system more efficient.