A40 Part Substitutions — Nelson Pass / 2000

After 22 years, it appears that quite a few DIY enthusiasts are still eyeing the A40 Class A amplifier design, but are discovering that not a single transistor from this design is still available. The following information is for those scouting out substitute parts: The Lambda output devices are no longer available, and they weren’t that common to begin with. Lambda appears to still be in business, but not in the business of power transistors. Common everyday complementary power darlington transistors will substitute for these. They need to be rated at 75 watts or higher, 5 amps for higher, and… More...

Soldering Tips — Karen Douglass / 2004

PCBoard Soldering can be a kind of art form, when done properly. The result should be a perfect physical and electrical connection, between the part lead and the solder pad on the board. I recommend that you find some solder with low lead content, and rosin core. This can help reduce the amount of lead being dumped into our landfills. You should also have a good soldering iron. Be sure the tip size is appropriate for the job. I suggest a 1/8” 3mm screwdriver tip. Hold the iron tip on one side of the joint (where the part lead and… More...