mark@mips.COM (Mark G. Johnson) (05/04/88)
In article <265@gt-eedsp.UUCP> drabik@gt-eedsp.UUCP (Timothy J. Drabik) writes > I'd really like to see some good basic power amp designs as well. > Does anyone have that sort of thing? Are there any back issues > of The Audio Amateur that deal largely with power amps? Here are some notable _Audio Amateur_ power amp articles: 4/78 "The Pass/A40 Power Amplifier" by Nelson Pass (page 4). He's the chief engineer of Threshold, an ultra-high-end company known for its power amps and, more recently, a zippy two chassis preamp. This article constructs a full class-A, 40 Watts per channel power amp. *** kit available *** 4/83 "New Power Amp Alternatives: a 200 Watt amplifier", by Johannes Didden (page 7 and continued in issue 5/83). An interesting design with two output signal paths, depending upon amplitude. 200 Watts RMS per channel. 1/84 "Third Generation MOSFETs: the Servo 100" by Erno Borberly (page 7). A 100 Wpc amp using MOSFET output stage and a DC servo. Discussion of predriver stage traeeoffs is excellent; theorists will have an amusing time trying to concoct a cute name for his topology. Input signal is capacitor coupled, remainder of amp is DC. *** kit available *** 2/84 "Third Generation MOSFETs: the DC 100" by Erno Borberly (page 13). A 100 Wpc amp using MOSFET output stage. No DC servo --- the entire amp is DC coupled, input to output. Text discusses the design problems of a DC amp. *** kit available *** 4/84 "Ampzilla III" by Jim Bongiorno (page 7). Bongiorno has started several well known high- (but maybe not ultra-high-) -end audio companies, notably SAE, Great American Sound {mfrs of GAS Ampzilla I}, and Sumo {whose Polaris amp is currently well received}. A fully differential, push-pull design (i.e. neither of the speaker output terminals is "ground"; each channel operates as a balanced bridge). 200 Watts per channel, all bipolar transistors. 2/86 "The Lang 20W Class-A MOSFET Amplifier" by K. Lang (page 7). Mono design with low output power and full class-A operation, the trendy "in" design point at the moment for buyers of pricey solid state amps like the Levinsons. 4/86 "A 500W MOSFET Power Amplifier" by H. J. Heckert (page 17). 500 Watts per channel using 12 output devices in each channel. Inputs are balanced, differential; outputs are standard single- ended. Something to please or offend most everyone; circuit employs bipolar transistors, MOSFETs, and IC opamps. *** kit available*** above means that you can buy a kit of parts from Audio Amateur's companion enterprise, Old Colony Sound Labs. OCSL has a telephone order service at (603) 924-6371 open 9-4 Eastern time. Back issues are available from Audio Amateur: (603) 924-9464, sold by the year (not by the copy). DISCLAIMER: I have no affiliation with Audio Amateur except as a happy subscriber and cheerleading supporter. As such I don't distribute photocopied articles from the magazine, I instead advise folks to support Audio Amateur and purchase back issues. -- -Mark Johnson *** DISCLAIMER: Any opinions above are personal. *** UUCP: {decvax,ucbvax,ihnp4}!decwrl!mips!mark TEL: 408-991-0208 US mail: MIPS Computer Systems, 930 E. Arques, Sunnyvale, CA 94086