Home on Decades of Musings on HiFi

The Edison 60 Kit Amplifier with 300B's

Mon, 12 Oct 2026 00:00:00 +0000

This 300B Parallel Single Ended (PSE) amplifier is based upon the Edison 60 amplifier kit, which is made in the UK. This modified version uses the PCBs from the Edison kit with only minor changes. The biggest changes are in the PSU.

The converted Edison 60 with four 300B output valves.

The Site Is Up

Mon, 12 Oct 2026 00:00:00 +0000

First post: what is here, and what is still coming.

Thermionic Valve Analogue Stages for Digital Audio

Wed, 07 Oct 2026 00:00:00 +0000

Preface and update

The bulk of this article is retained from the original, written in 1999 and published worldwide first in valve 2/2000.

It is perhaps to the credit of the early revival of DIY Valve Audio as embodied by “Valve” and “Sound Practices” that this article (which owes so much to both magazines and the communities that sprang up around them in the early days of the internet) has remained in demand and is still occasionally referenced.

Reading one’s own writings with a decade distance is often an interesting experience. Yet I feel that overall this article has stood the test of time well and remains relevant in today’s world. In the days I wrote the original article I was working by day on doomsday scenarios where all computers would crash on the first of Jan 2000 and destroy civilisation as we know it or worse and how to stop it from happening (that one went with such a fizzle, I expected more after all that build-up).

The article was written quite aggressively, as it was originally published in an extremely limited circulation, privately published newsletter. I let it stand as was for publication nearly a year later worldwide and decided to do so again a decade later. On occasion a spade must be called a spade, not in misguided political correctness a “wood and metal digging instrument of limited application”.

Valve Amplifiers were a comparably rare sight at hifi shows and DACs or CD players with valves could be compared to rocking horse droppings. Nowadays you cannot swing a cat or throw a brick in any hifi exhibition without it destroying several valve amps and so-called valve or valve CD players in the process. Of course the “valve” CD players and DACs rarely are true valve units; usually they just contain a valve buffer after a thoroughly conventional and often not so well designed solid state analogue stage. Still, one has got to give points for effort).

I have taken the liberty to insert comments to account for a world that has much changed in the intervening decade with 9/11 and 7/7, al Qaeda, the long awaited sequel to Operation Desert Storm, the infamous Taliban prowling the streets of the UK and the RIAA mass-suing its customers, the rise and fall of the Piratebay plus a global economical crisis which would not have looked bad as the Y2K disaster that never arrived.

ECC808-ECC88 MM RIAA + 6SN7 line stage

Tue, 06 Oct 2026 00:00:00 +0000

A second phono stage built from a proposal Thorsten posted on the diyAudio forum, paired with a 6SN7 line stage that is also his design. Includes power supply prototype notes and tube substitutions for the line stage.

RCA-RIAA successor

Tue, 06 Oct 2026 00:00:00 +0000

A phono stage built on Thorsten’s cheap valve RIAA design, which he developed to avoid the problems of the classic RCA RIAA circuit: an ECC88 second stage, a semi-split RIAA network, and no cathode bypass capacitor in the first stage. Includes grounding and parts notes.

Some thoughts about singleended Valve Amplifiers

Tue, 06 Oct 2026 00:00:00 +0000

While much practical information exists with regards to the Circuits for such amplifiers, I have noted that very little has been done to systematically research the interactions between Input, Driver and Output stage as well as the power supply. In the end, we want to design and use the best possible circuit for a directly heated triode. This is not a simple or light-hearted undertaking.

From here on it might get a bit mystical, but bear with me….

Contact

Mon, 01 Jan 0001 00:00:00 +0000

Email is the way. I answer when time allows, and not every message gets an answer. Please read the FAQ first, it may already cover your question.

Address hidden from spam robots. Enable JavaScript to use these buttons.

This is a disposable forwarding address that changes every hour (your local date and time) to keep spam down. Each hour’s address accepts up to 20 messages. An address you saved earlier keeps working until its 20 messages are used.

FAQ

Mon, 01 Jan 0001 00:00:00 +0000

Q: I have a product that you designed from Brand X that is not working. I need you to help.

A: Your first port of call is the original manufacturer. They are responsible for service.

If that fails, in many cases I do not retain the relevant documentation.

You can message me and I will look what help is possible, when time allows.

And no, you cannot ship the product to me to fix it for you, sorry, it’s way too much hassle.

Who the Fudge Am I?

Mon, 01 Jan 0001 00:00:00 +0000

Thorsten Loesch, mostly Thor. Audio engineer, based in Thailand.

I grew up in East Germany with a tube radio and a record player that sounded awful, so I rewired the first and built my own system. At 12 it won the school science fair. I studied electronics, built mixing desks for a small private pro-audio firm, mixed bands live, and qualified as a Tonmeister. I then moved to the UK, took a second degree in computer science, and spent years in financial IT while building amplifiers at night.