Valve Amplifiers

amplifier In our modern electronic world where you can store your entire music collection on your phone as MP3 files, at first glance, the thermionic valve (vacuum tube) looks like a dinosaur that should be extinct. A fragile,vacuum filled glass bulb, that has to warm up, glows when it's working, and operates from a high voltage, is at odds with today's low power, miniaturised electronics.


amplifier However, a lot of those MP3 files couldn't be created without a valve. Although they have been replaced in nearly every field of electronics by solid state transistors, and integrated circuits, one area where they remain dominant in is the electric guitar amplifier. Without the pairing of the guitar and amp, we would never have had Hendrix or Clapton, Led Zep or The Who, ACDC or Pink Floyd, Dire Straits or Guns and Roses, Queen or The Beatles, Bon Jovi or Rolling Stones, the list is almost endless.


amplifier The guitar amplifier doesn't just amplify the sound of the guitar, it shapes it, distorts it and allows the guitarist a far wider musical range. Really they shouldn't be considered as two separate pieces of equipment, they are two halves of one instrument, both of little use without the other. The reason for the valve's popularity in these amps is the 'valve sound' which is most notably defined when the amplifier is pushed into distortion.

Unlike solid state electronics which cuts off with a square edge, valves naturally roll off the sharp edges, producing harmonics we find pleasant to the ear.

Valves are also used in some Hi-Fi amplifiers where a much cleaner sound is required, and whilst the valves inside may be the same, they will usually be running at a lower power level, and the transformers will be considerably larger than their valve amplifier counterparts. Mains transformers may be interchangeable, but an output transformer designed for Hi-Fi will have a wider frequency response, with more lamination increasing the bottom end, and more sections in the winding to increase the top end. The choice of solid state or valve is a personal one, with supporters in both camps.

There is also the nostalgia and charm with valve amplifiers, that solid state can't offer. In much the same way the modern electric locomotive is cleaner, more efficient, easier to operate, more reliable, cheaper to run, and superior in every measurable way to the steam engines they replaced, everyone stops to stare if the Flying Scotsman goes past.

Transformers in Valve Amplifiers.

amplifierValve amplifiers require specialised transformers, with most designs needing at least two. The power transformer converts the incoming mains supply to the required high voltage for the valves to operate, as well as low voltage supplies for the heaters. There may be one or more auxiliary windings too and possibly a bias winding.


The output transformer is required to match the high impedance, high voltage, low current valves to the low impedance, low voltage, high current speaker. It is important to understand the output transformer is in the signal path, and not only matches the impedance of the load to the amp, it also helps shape the sound of the music created.

The design of both the mains and output transformers is critical, not only to the sound of the amp, but to the reliability as well.

amplifier We are here to help you with the design of your valve amplifier transformers, and you can benefit from our wealth of experience in both design and manufacture. We probably produce more audio transformers than anyone else in Europe, supplying some of the biggest names in the business, but we are also happy to work with smaller companies and individuals.


Please note, all of our designs are confidential.

Transformers are designed to each customer's specifications, and we don't offer them to anyone else. Your designs will be treated with the same confidentiality.

Although at this time all of our audio transformers are custom designed, we are working on a standard range of parts to meet the most common requirements.