Pro Audio Design Forum

I keep waiting for them to go through my garage.

"You know you're old when you're pictured in Archaeology magazine," chuckled Olompali-Barton, now 58, who was profiled in that journal in July along with California State Parks archaeologist E. Breck Parkman.

http://www.montereyherald.com/ci_13290049

Steve -

Have the smoke levels dropped down some since your last report? How close did it wind up getting to you? Your photo only looked to be a couple of miles.

Wayne

Thanks Holger and Paul. We will be operating the forum for support for an indefinite time and I, and hopefully others, will continue to post new ideas here as well as documents for older semiconductors and pro-audio equipment. The MS matrix and bruno2000's upcoming mic preamp serve as an example of ...

Thanks John! Was that a Popular Electronics or TAA schematic?

I could scratch something up this weekend if there is interest, but probably not worth it for a one off.

Particularly since we all have extra power amps laying around. I think the ratio of amp channels to speakers here is at least 5 to 1.

Just had an idea. Take this current booster circuit with a 1646 (shown below) and make it a swinging op amp by voltage bootstrapping the rails as in the MCI drawing: https://www.ka-electronics.com/images/jpg/THAT1646_Current_Boost.JPG This gives you lots of output current, the bootstrap transistors ...

I used to write a column in RE/P so have some old issues laying around. John - Thanks for posting here in this neck of the woods. I think that ad ran in '77 or '78. MCI treated it like a major breakthrough. I think it was a cartoon but everytime I saw it I thought of Little Feat's "Dancing Sho...

Note: the "swinging opamp" if it's what I think it is (common emitter transistors driven by opamp power leads) is a relatively simple way to get there. Yep - that's what it is. Pretty simple circuit with widely available parts. Wished I had an old RE/P or dB magazine with the original MCI...

I'd go with the "MCI Swinging Op Amp" using a solo 5534. You might also try an NJM2114 there. They've got almost twice the output current of a 5532. Parallel the inputs of both sections and ballast the outputs through maybe 10-47R and you should be able to get 100-120 mA. Have the summed o...