Restoration of a Vieta A-225 amplifier
EF184
Vieta is an audio equipment brand created in Barcelona in 1954 by the Vieta brothers, becoming a major reference for high-fidelity audio in Spain at the time. It still exists…
“FRANZIS-Röhrenradio” Radio Kit
I bought this little radio kit during a visit to Berlin, at the gift shop of the Museum of Technology (Deutsches Technikmuseum), a museum with quite interesting exhibitions and well…
Roselson Stereoletta (Part 1)
The Roselson Stereoletta is a radio-record player cabinet manufactured in Spain during the 1960s–70s by the Roselson company, based in Barcelona. It was relatively popular at the time and was…
Optimus Siroco Model 160 (Part 1)
Once again, another Optimus amplifier has fallen into my hands, and this one will be the first I actually own, since unlike other Optimus models, this one was given to…
Building a Superheterodyne Receiver (Part 1)
A few days ago, I was given a French radio from the second half of the 1940s, with the peculiarity that it came completely disassembled—every piece separated. Faced with that…
Analysis of the “Personal AM Transmitter” circuit
A few days ago, a reader of the blog contacted me asking for help figuring out why a vacuum tube AM transmitter circuit he had built—following the instructions from an…
Restoration of the Iberia T-2161 television, part 2 and conclusion
Once I had tested the tubes (and while waiting to get new ones to replace those that were completely dead, as I showed in the first part), I went ahead…
Design and construction of a high-fidelity stereo amplifier using PCL85 / PCL805 vacuum tubes
As my final degree project, I designed and built a high-fidelity stereo amplifier using common television valves — in this case, the PCL805, although PCL85 tubes or other equivalent versions…
Guitar amplifier with tremolo using ECC81 (12AT7), ECL86 (or PCL86), and EZ81.
This small amplifier project began thanks to a blog reader, Sergio, who contacted me via email to see if I could help him design a small guitar practice amp using…
Restoration of the Iberia T-2161 TV, Part 1
Continuing with the restoration of the television, the first step I take is to check some of its valves using the μTracer3+: EF183 valve: As can be seen in the…