Personal Comments
In the 1930s, Crosley designed a tone-volume expander circuit that would, in theory, add fidelity to the music that you were receiving from over-the-air radio AM transmitters. The circuit was said to boost the bass and expand the volume. It was used in some of their better 1930s Crosley console radios that are popular with […]
the Crosley Auto Expressionator circuit Read More »
“Standard Brand“, “Rad-Tel“, “Atomic“, “Cosmic” — what kind of brands are these? I found an interesting tube-related article in the Dec-1955-Jan-1956 issue of NATIONAL RADIO-TV NEWS. The article exposed a supply-chain problem during the 1950s where unscrupulous vendors would buy “pull-outs” (duds or near-end-of-life tubes) from repair shops, then manipulate the tubes in a manner
the Reprocessed Tube Racket Read More »
Recently my longtime trusted Eico 1030 regulated high voltage DC power supply succumbed to a catastrophic failure — a shorted transformer winding. The power transformer has a separate winding that supplies screen voltage to the 6L6 pass tubes. This is a half-wave circuit that was rectified by one original 1N4006 silicon diode. Unfortunately, this old
Transformers can blow in the blink of an eye Read More »
For tube fans, today’s Pluggers comic strip conjures memories of the NATIONAL RADIO NEWS magazine cover, Aug-Sept 1945 issue. The Pluggers comic is in today’s newspaper July 23, 2011, or you can enjoy the comic online at Comic Strip Nation, comic link is HERE. I mention this comic because many fans of old tube gear
Pluggers comic conjures ‘National Radio News’ Read More »
©2011, Bob Putnak. This post examines the performance (directly related to the input impedance) of low-cost meters; specifically, I explore a common multipurpose Colluck PM-128E DPM (digital panel meter) and a bargain-priced Cen-Tech #98025 multimeter. Limitations in the design of these low-cost meters can severely affect measurement accuracy. First of all, I prove that the
Limitations of cheap DPM’s and DMM’s Read More »
