Part 5 – Point to Point Wiring and Testing

A project log for Dirt Cheap Tube Guitar Amp Build

Building my first tube amplifier, on a tight budget.

electroidiot_electroidiot 11/19/2023 at 18:000 Comments

Being a vintage buff, I decided to construct the entire circuit using point-to-point wiring on tag-strips riveted onto the chassis. I followed a wiring diagram found online but made some changes to improve the grounding scheme. The layout is still not ideal but worked out well in the end. After building the 12AX7 preamp stages, I had some trouble with excess plate current. This turned out to be due to either faulty or mis-labelled valves, so the project was delayed until I could get another set from a different source. I tested each stage as I built the circuit, there were a few hiccups that had to be dealt with along the way, but in the end the amplifier works well and sounds great. For more details on each part of the build, please refer to my 4-part vlog videos on YouTube:

Part 1, chassis fabrication and planning, power supply:

Part 2, filament wiring and power supply updates:

Part 3, wiring the amp stages and some problems with biasing:

Part 4, some tweaks, checking gain and power output, final test: