A reader asked why the power transformer isn’t mounted at 90° to the output transformers in my 1955 build, and whether that close spacing causes induced hum. Here’s why the layout works in practice.
Pair of Mullard 3-3 printed circuit boards designed to simplify assembly of the 1955 Model vacuum tube audio amplifier, including schematics and PCB layouts.
This document aims to serve as a guide for building the 1955 Gen2 vacuum tube amplifier. It can also be used for assembling the simplified wiring version, the 1955 Gen1.
In the original Mullard 3-3 design the operating point of the EL84 tube is highly dependent of the amplification factor of the EF86 valve.
How to calculate a voltage divider to reduce the input to the valve amplifier
It’s now been more than a year and a half since I first put the original 1955-model tube audio amplifier into regular use in my living room, and I’m pleased to report that it has operated reliably every day without a single breakdown. Over this period the amp has typically been in service for two
New performance measurements have been made over the 1955 (Mullard 3-3) tube amplifier. You can see it on the 1955 tube amp measurements page. Published on 8 April 2020