Having decided to add the option of silicon and valve rectifiers to my next build, I spent some time looking at how best to arrange the switching, and it is clear that there are several approaches and manufacturers have also varied their preferences over time. I would guess that, for most people, the brand that […]

My speed in turning ideas into amps is not high but I have a few plans based on some components I have accumulated recently. Of particular note is a really nice Woden “universal” output transformer that I picked up for pennies in a job lot from eBay: With a bit of research, this is clearly […]

Having built a simplified modeller for modelling pentodes from their datasheets, I have now added a similar tool for modelling triodes. This has proved illuminating as it makes it easy to visualise how the various model parameters affect the anode characteristics. As a starting point, I re-used the Cohen-Helie triode model as it is not […]

I’ve recently spent a bit of time looking at creating web-based tools to simplify the process of designing valve amplifiers, which naturally follows from my version of the Valve Tester and the Valve Workbench software to drive it. What becomes quickly apparent is that there are a number of potentially competing goals that must be […]

As I work on improving the Valve Designer, I find myself considering different ways of acquiring and using different models. Modelling triodes is easy as you only need a set of anode characteristics. Pentodes and tetrodes are trickier because you really need to model the screen current (you can’t find bias points without this). One […]

Valve Designer started out as (and remains) a Qt application as a companion to the Valve Workbench with the aim of being able to simplify the design process for valve circuits commonly found in audio amplifiers. Giuseppe Amato has generously provided load line calculators on vtadiy.com that demonstrate the principle of what can be achieved […]