Vieta A-215: Restoration and repair
EF184
After the successful repair of the Vieta A-225, I’ve come across a slightly older model, the Vieta A-215. It’s a relatively rare model but very similar in circuitry to the…
Amplifier
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…
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…
Building a Mullard 5-10 amplifier
As a summer project, I set out to build a Mullard 5-10 type amplifier using recycled materials I had in my workshop, and thus this amplifier was born. The chassis…
Optimus Alabama 100W Amplifier
This interesting amplifier was brought to me for general maintenance and a few modifications. Its owner wanted to convert the amplifier for use with guitar and bass, aiming to modify…
ECL80 Pushpull amplifier
Here I present a push-pull amplifier circuit that uses two ECL80 tubes and is quite simple to build. It’s an interesting amplifier because it uses ECL80 tubes, which are inexpensive…