Paul Stubblebine Mastering & DVD (PSM) recently hosted a three-day course on designing and building tube amplifiers at its San Francisco studio facility. The class was led by amplifier designers Dan Schmalley and Paul Jappa of Bottlehead Corporation. In addition, Paul Stubblebine (pictured at right) and engineer Michael Romanowski offered tips and procedures for the process of mastering music to highlight the connection between the equipment and the mastering process.
The amplifiers for Stubblebine’s quad-amped Magico speakers were modified by Schmalley and Stubblebine using design techniques that were shown in the class. "There are three important elements in mastering: listening experience and ears, room acoustics, and the choice of equipment,” Stubblebine says. “I have spent a lot of time comparing and modifying my equipment to allow me to hear and change audio in subtle but important ways. These amplifiers are quite special."
Fourteen participants attended the amp building class, including some who flew in from other states. Worktables were set up with soldering irons, lighted magnifiers and all the components needed to build tube amplifiers. Instructions saved as PDF files were handed out as printouts and also projected on an overhead screen so that the instructors could point to each step and explain.
Each class took place between 9 a.m. and 6 p.m. with a break for lunch. The design process covered the audio circuit, parts, hardware assembly, a soldering demonstration, and detailed design of the power supply components, including transformers, chassis wiring, layout, grounding and shielding. Lecture time was also allotted each day to the basics of audio mastering, format comparisons, and software and hardware. The final day included the all-important “smoke test” to make sure that nothing blew up when plugged in.
At the end of the process, participants were able to listen to their hand-crafted amplifiers in Stubblebine’s studio, listening to first-generation master recordings for source material.
New how-to, hands-on classes on amps and other components are planned for the near future.