I can't seem to find much information on Van Alstine kits since the product line revamp. Does Audio by Van Alstine still offer kits for those that prefer to sling solder?
Thanks.
Tom
I, too, recently had interest in taking on some electronics projects again. Way back when, I built a PAT 4 kit and a couple electronic digital clocks all of which worked first try. The PAT4 developed 60 hz hum about 6 years later and as I lived in Minneapolis at the time, found out Frank was authorized repair center. Of course he could fix it, "but do you want us to make it better?" and the rest is history. Several updates later I traded for the PAT5 chassis FetValve (circa 1992) and still have it and the Omega 3 (Haflerxl280). Yes, it helps to work all switches and pots vigorously twice a year to keep them clean. Do it when Daylight savings time changes.
Back to topic... I stuck a toe in the water by modding a friend's sacd/dvd player (Samsung 841/Toshiba 3960), mainly by beefing up power supply filter capacitors and a couple other things. It was all through hole PC card stuff, stright forward enough. I love the smell of solder and flux in the morning so I decided to next mod my own Pioneer 563. I figured swapping opamps would provide the biggest improvment so I started in. These were all surface mount devices and, ladies and gentlemen, these are small, about the size of a flat ladybug and 8 little legs. Getting the old ones off was a bear and did pull up one pad in the process but found a work around. Putting the new one on was much, much easier - at least after the first leg is tacked down. Liquid flux is your friend. Anyhoo, all 3 opamps were swapped (put in ad823) and the sound transformation was not subtle. Female vocals are lush, great bass impact , good high end. Some loss of detail however.
I had the bug good. I got another Pioneer dv 563a on ebay and swapped out the front channel opamps for the ad8620 - detail is outstanding without the sibilance of stock unit, big soundstage (like the ad823), bass is a little leaner and cleaner. I just did the 2nd unit so I haven't lived with it long so these are intial impressions. And yes, I checked data sheets onAnalog's website to make sure I was within voltage specs, etc. There was some initial concern because the DV563a has a single rail (+12v only - not a problem for the ad823 because it is rated single or dual rail), but after some digging, learned a single supply is OK (with a few caveats)
Getting back to kits etc, I am now collecting parts to begin a headphone amp. I discovered a forum, headwize.com and there are many projects in active discussion. Some of these are works in progress (design-wise) and others have been around for a while. There is input from folks around the world: USA, Finland, China, Germany, Netherlands, Belgium, UK, u.s.w., truly an international undertaking.
The project I chose is the one referred to as SOHA - a tube opamp hybrid. The 12au7 tube B+ voltage is around 40 volts. The design intended to keep B+ voltage under lethal limits which kept some DIYers from taking on some of the other tube desgins. This is a builders (and designers) community and very helpful people. It is not like the old Dyna kits with all the step by step instructions (at least not the SOHA), so the general advice is to select "noob friendly" project to start if one isnew to the scene. I am really looking forward to this one. I have some Grado 325's that have never been properly driven (my Fetvalve preamp does not have a built in headphone amp and my set up precludes running the Omega 3 output back to it feeding headphone jack thru dropping resistors) and am looking forward to that.
First I have to finish the sacd player, 2 more opamps to go!
G E