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Power Amplifier for 100kHz.

Instead of just bitching about the sims, I replaced both the TL071 subckt and the LM311 subckt with a default OA and an LT1011 from the standard LTspice library so that the thing runs. ( Be sure to remove or terminate the old subcircuits to ensure easy sim startup.)

This ran with low crossover distortion at 100KHz and about 50mA bias current at xover. The bias current could be raised or lowered proportionally through comparator input adjustment.

No big OA slewing requirements.

So the concept could be demonstrated ~accurately in LTSpice.

RL

Reply to
legg
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Thanks, yes I was intrigued too. So this thread doesn't grow unwieldy I am starting a new post on autobias class AB.

piglet

Reply to
piglet

Yeah, I did it too, using 2N3904s and one 2N3906 for the small signal stuff, D44H11/D45H11 for the output stages of the Darlingtons, a UniversalOpAmp2 configured to look like an LF356 (4 MHz, 12 V/us), an RH111 (rad hard comparator from the LTspice 17.1 library) and a 4-ohm load.

Looks pretty good, for a car amp of that vintage. The bias circuit works well, anyway.

Cheers

Phil Hobbs

Reply to
Phil Hobbs

<snip>

JT's original zips and the generic version:

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RL

Reply to
legg

RL

Nice arm waving there, 'Fred'. How exactly do you propose to do that?

Also it's the output current that makes the speaker move.

Gee, thanks. ;)

Not in 1977, it wasn't. The first public release of the original Berkeley SPICE2 program was in 1972, and it was pretty primitive--FORTRAN, punch cards, running on a CDC 6400. SPICE didn't actually become useful until the early '80s.

Cheers

Phil Hobbs

Reply to
Phil Hobbs

RL

Sure it can, but it would take more work than you suggest.

Laurence Nagel's thesis on SPICE2 was a nice piece of work actually.

I seriously doubt that. 1977 was a _long_ time ago--even the semis were still prototyping with kit parts and doing mask design with Rubylith.

Cheers

Phil Hobbs

Reply to
Phil Hobbs

I went do download this, but it wants a login.

Cheers

Phil Hobbs

Reply to
Phil Hobbs

I've emailed it to you. Links posted here will only be active for a few days. If anyone else needs it try :-

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I did actually build a variation of this when it was originally posted.

Reply to
JM

Thanks!

Cheers

Phil Hobbs

Reply to
Phil Hobbs

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