Search found 7 matches

by gjohnson
Wed May 19, 2004 6:45 pm
Forum: General Discussion
Topic: Mystery Transistor - is Dr. Sherlock Holmes out there?
Replies: 8
Views: 1826

Re: Mystery Transistor - is Dr. Sherlock Holmes out there?

My apologies - Thanks for the correction, ljbeng. Now if only it was that easy to clear up the confusion! :) <p>The logo is a circle with what appears to be two curvy upside-down 'V's... it's exactly the same as the logo on Motorola's website, so I have to assume it's a Motorola part. I was only pla...
by gjohnson
Tue May 18, 2004 3:12 pm
Forum: General Discussion
Topic: Capacitors
Replies: 14
Views: 2574

Re: Capacitors

I have limited experience with amplifiers, but I'm very interested in the subject, and am currently working on a modest 250W model whose schematic was posted here some time ago. <p>Anyway, in the test link you posted the only reason I can think of for the similarity between the tests is the rating o...
by gjohnson
Tue May 18, 2004 2:41 pm
Forum: General Discussion
Topic: Mystery Transistor - is Dr. Sherlock Holmes out there?
Replies: 8
Views: 1826

Mystery Transistor - is Dr. Sherlock Holmes out there?

Dr. Holmes - I have a puzzle I cannot solve. I recently aquired a number of transistors from an associate whose only accompanying information is the markings on the case itself. All the information I have is as follows:<p>-TO-3 case type -Motorola insignia -markings: (3 lines) 50221700 MEX 8631<p>Th...
by gjohnson
Sun Jan 04, 2004 5:39 pm
Forum: General Discussion
Topic: High Power Amps - guitar, car, PA, etc.
Replies: 14
Views: 3165

Re: High Power Amps - guitar, car, PA, etc.

True enough - 50% is only a theoretical maximum, and even then only if an output transformer is used. The schematics posted above look to be A/B amps though, and if biased correctly I know these can nearly eliminate the dreaded crossover distortion that seems to be the only attractive thing with a p...
by gjohnson
Wed Dec 24, 2003 7:18 pm
Forum: General Discussion
Topic: High Power Amps - guitar, car, PA, etc.
Replies: 14
Views: 3165

Re: High Power Amps - guitar, car, PA, etc.

Thanks again to all who replied. I'm looking at the schematics that were posted and I think I've almost got all the information I need. Dale, thanks for the elaboration on the output resistance coupling between amps and speaker. I noticed something like that in the aforementioned schematics, but did...
by gjohnson
Thu Dec 18, 2003 4:08 pm
Forum: General Discussion
Topic: High Power Amps - guitar, car, PA, etc.
Replies: 14
Views: 3165

Re: High Power Amps - guitar, car, PA, etc.

Thanks so much for all the input - I'll have to sit down and digest it all over a Guinness or something, but one thing that caught my eye was the mention of parallel output stages.<p>I was never told of this idea in my classes, probably because of the foundational nature of the intro material. It wo...
by gjohnson
Wed Dec 17, 2003 12:49 pm
Forum: General Discussion
Topic: High Power Amps - guitar, car, PA, etc.
Replies: 14
Views: 3165

High Power Amps - guitar, car, PA, etc.

I'm an EE student and I'm currently taking a course that covers power amps. I live with two guitar players who would like to have me build them a good amplifier. I'm shooting for something in the 200-400W range for now, with the overall goal being to move into the 1000W neighboorhood. Think 'Back to...