------------------------------ From: Holm-Kjetil Holmsen Subject: Re: DIY: Phono stages and power amps Date: 3 Feb 1994 10:33:38 +0100 You can try the designs of Erno Borbely. He has published some of his designs have been in The Audio Amature: RIAA-1 and RIAA-2 (a complete phono stage) TAA 3/90 Class-A Lineamp TAA 3/90 Lineamp 388 (originally 1988 ??) TAA 3/90 In adition he has poweramp designes that have been in The Audio Amature. These have since been upgraded. There are two designs: Servo-50: 50 W high current amp. Can be operated in Class A DC-102: DC coupled amp. Up to 100 W. Can be operated in Class A He allse has a line of "High Quality, Low Cost" pre- and power- amplifiers. All his designs are made with FET-transistors. Erno Borbely runs a small company in Germany. He sels his designs in kit-form and allso fully assembled and tested. A 8-page list of what he has (kits and parts as different transistors, heatsinks, wire etc) is free (if I remember correctly) and a complete kit catalog with schematics, parts list, set up procedure and design comments costs 12 DM in Europe and US$ 12 from other countries. The address is: BORBELY AUDIO MELCHIOR FANGER STRASSE 34 A 82205 NEU-GILCHING GERMANY Tel.: +49 / 8105 / 5291 Fax: +49 / 8105 / 24605 DISCLAIMER: I'm not connected with Mr. Borbely in any way I know of. Like you, I'm just a DIY-guy who wants High Quality designs. I have both of the above mentioned catalogs, and am impressed with what I have seen so far. I have not built any of his designs, but many people have, and they are verry satisfied. The kits catalog itself is worth the 12 DM, IMHO Holm-Kjetil Holmsen kjetil@taskon.no (Don't reply to kjetil@ifi.uio.no, as the account will be terminated) ------------------------------ From: mlloyd@ihlpm.att.com Date: Mon, 14 Feb 94 18:20 CST Subject: Re: DIY Borbely Amp, Preamp Kits Ron Dillman asks: : Please tell me more about your Borberly building experience. I am very : interested in building my own amp and preamp. but since I do not have : a machine shop in my basement I am looking for an old time DIY kit. : One with ALL the components you need, the case all drilled, tapped, : painted, and lettered. You supply only simple hand tools and labor : using easy to follow instructions. Does this describe the Borberly kit ? : Is there such an animal ? : Thank you for your input. : Ron : ron.dillman@stlcat2.com Ron (and others that may want to know): The Borbely kits that I've purchased direct from his company in Germany ARE NOT like Heathkits or the old Halfer kits. The PCBS are not silk screened. No hardware is included in the kits, although he does sell some boxes, heat sinks, etc. that you can cut, drill, tap, etc. yourself. No power supply stuff is included, no wire, no solder, etc. I would say that the plans included with the kits are more like suggestions for reasonably experienced electronic constructors than step by step instructions for an inexperienced person. Some things you would have to figure out on your own based on what kind of power output you want, available types of output devices, desired class of operation (class A, AB, etc), etc..... I think the best description is you get the electronics base to build around, not a complete kit. I took a couple of months to build my last Borbely design based amp, a Servo 50. I found a local machine shop to cut aluminum panels for the case. I did all the tapping (have you ever tapped heat sinks for a total of 20 output devices! Grrrrr..........). I shared your problem of not having a metal shop in the basement; I never knew I could do so much with a dremel! Many days (and nights) I did not enjoy the labor (broken taps and other such disasters!), but I had planned to spend at least 4 months so I would not feel I had to rush and get it done. I can't speak for how "Heathkit like" the Borbely amp and preamp kits from Welbourne Labs are as I have never bought any from them. Maybe someone else can say something about that? If this sounds like a lot more work than you want, one of my friends had the idea of buying a couple of Borbely amp driver boards and installing them in an older amp (say a Hafler DH-220, for example). Just an idea. Ron, let me know if you have any more questions. Michael Lloyd ------------------------------ From: randy@ptolemy2.rdrc.rpi.edu (Randall Bradley) Subject: Re: Erno Borbely's Amps Date: 22 Apr 1994 20:30:46 GMT FYI: Erno Borbely's amps are excellent. But, like anything else, they are only as good as you build them. In other words, there is more to building a first rate amplifier than a schematic. Although a schematic is certainly necessary, and a good one is a better place to start,you control the "horizontal" and "you control the vertical." Think of it this way: the schematic is just a guide, you are the artist and sculptor. The results are directly proportional to the time, energy, skill and care that you put into it. Properly executed, and this will cost you $$$ to do, they will beat any commercial amp and have the potential to sound as good as the highly vaunted and touted directly heated pure triode-zero feedback designs! This I know for fact, and can prove it. Any one wanting a demo, let me know! There are lot`s of technical reasons that these amps perform as well as they do. But, again, they are only as good as your execution of the design. Remember, the same thing is true of triode amps as well. Or, any amp, for that matter. There are no panaceas!! Regards, -_-_randy bradley BEAR Labs-_---