From @Relay.CV.COM,@ukgate.cv.com:cbmnjm@jfbi.CV.COM Mon Aug 2 07:35:41 1993 Received: by csd4.csd.uwm.edu; id AA23714; Mon, 2 Aug 93 07:35:29 -0500 Received: from ukgate.cv.com by Relay.CV.COM; 02 Aug 93 08:16:07 EDT Received: from jfbi.CV.COM by ukgate.cv.com; 02 Aug 93 13:16:31 UT Received: from edm3.jfbi (edmclient3) by jfbi.CV.COM (4.0/SMI-4.0) id AA11190; Mon, 2 Aug 93 13:13:32 BST Date: Mon, 2 Aug 93 13:13:32 BST From: cbmnjm@jfbi.CV.COM (Neil Mackie) Message-Id: <9308021213.AA11190@jfbi.CV.COM> To: Info-High-Audio@CSD4.CSD.UWM.EDU Subject: RE: DIY Amplifiers Cc: riggert@seas.ucla.edu Status: R Following my query about amplifier designs suitable for DIY I have been asked by others interested in the same area to forward any information received. Here is a summary of the information I now have. P.S. As a follow on from one of the replys below, has anyone more information on William Snyder? Are the book and pcbs mentioned above still available from his company? From: "James A. Cobbs" -------------------------------------------------------------------------- Welborne Labs in Littleton Colorado sells a 'catalog' for US$10 that contains just the goodies you are looking for. Most of the stuff is sold as kits, etc. Might want to send along a little extra to cover international postage if that is involved; airmail if you want it in this century. Their address is: Welborne Labs Fax: (303) 791-7856 P.O. Box 26198 Tel: (303) 470-6586 Littleton, CO 80126-0198 U. S. A. From: Craig Stark and From: swlee@grip.cis.upenn.edu (Sang Wook Lee) From: Paul Winser From: andrew@alice.att.com (Andrew Hume) -------------------------------------------------------------------------- If you can deal with FETs, TAA has some excellent amps done by Erno Borbely and the parts are available in Europe (he's in Germany). I've built his 60W amp and am using it on my top end. Also in TAA were a 100W DC and a 100W servo which a friend has built. It has come to my attention recently that he has done a number of redesigns and has a few new kits out. I don't know Borbely Audio's number in Germany, but the US distributor is WelbourneLabs. TAA has had a number of excellent pieces including one by Norman Thagard & Nelson Pass of Threshold (Audio Amateur "Build The A-75 Power Amplifier Part I and II", Part 1, number 4, 1992 and Part 2, number 1, 1993). Its a new class A 75W amp fully balanced & complementary 2-stage design (sold assembled by "Pass Labs" for over $3k). He's also got the old favoritePass A40. The best place to call is Old Colony Sound Labs PO Box, Peterburgh Tel: (603)-924-6371 NH 03458-0243 since they are the kit distributor for TAA (they're both run by Ed Dell.) and are about to sell PCB's and matched MOSFET's. They supply full kits (w/o case) and article reprints. Nelson Pass claimed that it sounds as good as multi-grand monster amps such as Krell, Threshold, Mark Levinson,... The only downer is the cost of 48 power MOSFETS! From: cs6h@crab.psy.cmu.edu (Craig Stark) -------------------------------------------------------------------------- Here are some of the amplifier listings from TAA. Pass 40W Class A: 1978 Borbely 60W MOSFET: 1982 Borbely Servo and DC 100: 1984 20W Class A, 500W MOSFET: 1986 40W all MOSFET: 1988 150W hybrid, Regulating amp supplies: 1989 Pass 75W Class A: 1992-1993 From: Gary Gitzen -------------------------------------------------------------------------- Dick Smith Electronics, out of Australia, has what looks like a real nice FET amp parts kit in that power range. They also have stores in New Zealand, and used to have them in the U.S. From: andrew@alice.att.com (Andrew Hume) -------------------------------------------------------------------------- You can also get a book from William Snyder (who designed krell? amps for a while). it costs about $15 and has the stuff you need to design a pure class A amp (up to >100W). For another $90, he will see you high quality PCB boards and stuffing lists for a particular size amp. I think is company is out of business, so he may have run out of materials. New England Analog Three Rundel Park Rochester, NY 14607 The amps I know about already -------------------------------------------------------------------------- The Virtuso appeared in ETI April 88, May 88, June 88, Nov 89. It comes with either Mosfet or bipolar output devices. Designed by Graham Nalty, reprints and kits are available from AP Electronics Tel: 0332 674929 20 Derwent Business Centre Fax: 0332 298836 Clarke St Derby DE1 2BU The kits are available in a veriety of "levels" of components, e.g. in the top level the resistors are almost all bulk foil types. -------------------------------------------------------------------------- The Linsley-Hood Hart Kit. This is a kit produced from a John Linsley Hood design. From my experience with their tuner kit (also a Linsley Hood design) its a well made kit of parts with a comprehensive list of building instructions. Its a 40W MOSFET design with a regulated power supply which incorporates output protection eliminating output fuses. Its also available in monoblock form and there is a matching preamp. Hart Electronic Kits Ltd. Tel: 0691 652894 Penylan Mill Fax: 0691 662864 Oswestry Shropshire SY10 9AF -------------------------------------------------------------------------- RATA produces an amplifier which is available as a kit. Their catalogue of Hi-end components & kits and is well worth getting. Its free but you may feel you are paying for it when you buy their components. Their system demonstrated at the '91' HiFi show in London is a legend. I have been to number of shows and left feeling that the Russ Andrews system was the best. RATA Ltd. Tel: 0539 823247 EDGE BANK House Fax: 0539 823317 Skelsmergh Kendal Westmorland LA8 9AS -------------------------------------------------------------------------- This (new to me, if not completely new) company curreltly sell electronic components concentrating on digital audio parts. Their catalogue claims they will soon have kits for DACs and amps available. Norwood Electronics, Tel: unknown Unit 8, Pinbush Road South Lowestoft Industrial Estate Suffolk NR33 7NL -------------------------------------------------------------------------- I have already ordered by phone a couple of issues of TAA. They were ordered on a Wednesday and arrived by air mail the following Monday!. Paymant was by Visa so I dont know exactly how much they cost me. If you prefer to deal with someone in the UK the person I spoke to at Old Colony confirmed that back issues of Audio Amateur are available in year packs from: Falcon Acoustics Tel:0508 78272 Tabor House Norwich Road Mulbarton Norfolk NR14 8JT I dont know what price Falcon charge, I have their price list but its out of date (but in 1991 it was 13 pounds + 2.50 p&p. -------------------------------------------------------------------------- The magazine HiFi World has started producing a DIY supplement every alternate month. No transistor amps yet but they have featured a number of valve amp designs. Its not the greatest Audio mag but I find myself buying it just for the DIY supplement and get the magazine as a bonus. Based on their DIY work I would rate their opinions and reviews higher than some other respected magazines I could name. The next issue has another valve amp using the 300B valve and if I remember correctly they say Tim de Parvinci (probably misspelt but you know who I mean) designed the output transformers for them. HiFi World Tel: 516 627 3836 PO Box 754 Fax: 516 627 1972 Manhasset $66 for 12 issues NY 11030-0754 ------------------------------------------------------------------------------- None of the above is guanteed correct, but if you think I have mistyped something, mail me and I'll check. Regards, Neil Mackie.