Kevin Kennedy – författare

A guide to finding, selecting, restoring and using vintage tube audio equipment (Acrosound to Scott) from the perspective of the audiophile/music lover as opposed to the collector. Anecdotes, descriptions and caveats for everyday use of this gear. Decription of circuit topologies and classes of operation.

Pre-Amplifier project book using commonly available tubes and easily constructed. Designs often feature 0 feedback topologies (some local feedback is used)and tightly regulated supplies. A variety of line stages and phono stages of varying complexity are featured. The more advanced line stages feature front panel switchable output polarity. (Absolute polarity) Phono stages are all passively RIAA equalized with single stage passive equalization networks.

A 30W pushpull amplifier based on the 300B direct heated triode output tube. Fully differential driver stage topology, no global feedback, fixed bias amplifier with full voltage regulation. Audio tube complement is a pair of 300B, 6SN7 differential driver stage, and 6SL7 input stage. Topology is long tailed pair. Inputs may be operated in fully balanced or unbalanced mode with no degradation in performance. The power supply features tube regulated B+ and bias supplies. Potential builders should have moderately advanced construction skills, and at least a good DVM for successful construction and debug. Scope and audio generator recommended. This amplifier will drive conventional modern speakers systems quite well. This design was originally featured in a VTV article 10yrs ago.

Easy to build SRPP based 3 tube stereo line stage featuring regulated power supplies, and a simple transparent sounding audio topology. Purist design with simple audio path and no tone controls. Tube complement is a single 6U8A and a pair of 6189/12AU7A/12BH7A. This high performance project should satisfy the advanced builder, and yet is simple enough that a careful beginner should be able to complete a unit based on this design successfully. Customizable, and a tube rollers dream. Compatible with a wide range of modern and not so modern audio gear.

Here is a relatively simple, high performance, passively equalized phono stage with regulated supplies. Designed for use with high output MC and almost all MM cartridges. Very customizable. Pure tube audio path.