Tube Amp Tech & DIY

DiMastro

Guitar Tube Amps

Hands-on tools and guides for restoring, building, and biasing vacuum-tube guitar amplifiers — a full bias calculator, an interactive tone stack calculator and a growing set of must-have calculators, along with diy tools, bench guides and the complete technical manual.

Why DiMastro GTA Exists

This started as my own problem, not a business plan — decades on the bench, a growing pile of scribbled bias calculations and half-remembered resistor codes, and no single place that had it all. Rob Robinette's site came closest, and along with him, I owe a lot to the wider forum and YouTube tech community — creators like Psionic Audio, The Guitologist, and Uncle Doug — that expanded my knowledge on vintage guitar amps — but nothing covered everything I actually needed, day to day, at the bench. So I built the toolkit I wished I'd had, for myself first — and with retirement from my day job getting closer, it's turning into what I do next. I'm glad to finally share it. Read the full story

Tools & Guides

Tube Bias Calculator Pro

Work out safe plate dissipation and dial in idle bias for your power tubes.

 Live tool

Tone Stack Calculator

Solve bass/mid/treble response for Fender, Vox, Marshall, and Baxandall-style circuits.

 Live tool

Tech Manual

The complete engineering, diagnostics & restoration manual — topologies, bench practice, troubleshooting, and bias calibration.

 Manual

Guides

Biasing, startup, recapping, and safe power-supply discharge.

 5 guides

DIY Tools

Build your own bias probes, current limiter, cap discharge stick, and dummy load.

 7 DIY tools

Mobile Apps

Install the bias, tone stack, resistor, and capacitor tools as mobile apps.

 4 apps

More Live Tools

Resistor and capacitor toolkits, tube cross-reference, and a full set of bench calculators.

 16 tools

Amp Restorations

Bringing vintage guitar amplifiers back to life.

 1 Restorations
Trademark & brand notice: product names, brand names, and model designations referenced in this website — including Fender®, Marshall®, Vox®, Gibson®, Mercury Magnetics®, Fluke®, Apple®, Google®, Microsoft® and others — are the property of their respective owners, used here strictly for identification and technical-reference purposes. This is an independent, unofficial technical reference, not affiliated with or endorsed by any manufacturer named.