Tube amplifier UL40-S2

Page 1: Friday November 2, 2001

Tubes?

Oh yes, it has happened to me too. A highly coutageous infection is spreading amongst audiophile people: Tubes. And i'm too infected by it.

On various occasions, tradeshows and fairs I have listened to tube amplifiers and I liked the open sound very much. What I was not looking for is the typical "brown"tube sound that a lot of people associate with tube amplifiers. Well, as far as I'm concerned I like my music undistorted, controlled and with much detail.

Annemarie and I had made the decision that the HiFi set in the living room was a perfect match both in music and in ergonomics (remote controll everything) , and it was one of the few amps capable of controlling the Dolce-Vita speakers. So it was there to stay.

But in my study, I work from home on a regular basis, there was sufficient room for improvement. There was a Thorens turntable and an old Philips amp connecte dto two old Magnat speakers. Nothing specials and therefore liked the idea of upgrading the audio in that room in a few steps making use of tube technology for amplification. It was clear from the start that it was going to be one of those long-term plans, and it would take time and money to get where I wanted. Also, I decided to build as much as possible myself in order to learn more about electronics (and tube technology in particular).

At this moment the CDplayer (Philip CCD882) and the Thorens TD166 turntable are connected to the Philips DFA-888 digital amplifier. The philips has an internal MM/MC phono equaliser and an internal DAC for the cdplayer. The DAC is "old" according to todays standards but the Philips cdplayer is very good (built like a tank).

• First I want to upgrade the amplifier and replace it by a tube amplifier. I want to build the amp myself
• In order to be independent from the Philips amp, I will need to buy/build a phono equaliser. I the amp project is successful, I want to build a Scratch Phono Amp from TriodeDick.
• After that, new speakers are on the menu. The present Magnat speakers are large but not really refined in their sound. Being 12 years old and from german origin these speakers suffer from the typical german desease: strong bass and strong treble but lacking mirange detail (bathtub frequency response).
• As the Philips CCD 882 does not have a built-in DAC, I need to either upgrade the cdplayer or buy a separate DAC for this player. The long-term risk for this cdplayer is the availability of spare parts. The build-quality is very good, and everything is made from aluminum. However, Philips ceased support for cd players last year and availability of spare parts may be an issue. 

DIY (Do It Yourself?)

On the University I received a pure digital training. Only recently I started to study the world of tube amplifiers. Something that striked me immediately is the absolute simplicity of tube amplifier designs: It is relatively easy to follow the schematics if you look at the internals of a tube amplifier. The sonic qualities are largely related to the quality of the components used (and of-course the design) and Tube amplifiers are a typical examplle of the slogan "Less is more". Due to the high-quality components good tube amplifiers are not by definition cheaper. Output transformers and high-quality audio capacitors to take a large part of the budget. And in some amps the tube themselves are very expensive.

Also you do sometimes get the impression that tube lovers are always heating their soldering iron, looking for beter components, tweaks in the design. When starting this project I was not ready for that, but from the start I was advised to implement certain upgrades immediately during the contruction phase without having to worry about opening up the housing, remove the parts and get new parts to break in at a later stage.

The UL40

In order to learn more about tube amplifiers, reading schematics etc. I bought a book "modern tube amplifiers"of Menno van der Veen. In the book much attention is paid to design and architecture of tube amplifiers with special focus on output transformers of Amplimo. Also, a section in the book is dedicated to the UL40 (version 1) tube amplifier kit. On the audio forums, this amplifier is discussed several times and the general opinion of readers is favourable. of-course there are more do-it-yourself kits available from for example Rik stoet, AudioNote, Velleman etc. but the UL40-s2 kit is a good kit to start with and it will offer musical pleasure for several years.

Fortunately I was able to test drive the UL40-s2 for a week, and I was impressed with it's sonic abilities. And as the UL40-S2 kit can be assembled by anybody with average technical skills (it contains a short course on soldering) according to Triode Dick I decided to buld my own kit. And should I make a mistake or run into trouble, Amplimo will offer technical support in NL for everybody building the kit.

Yesterday evening therefore I decided to drive to Amplimo in Delden and pick up the large box myself (trading for a box with Dutch Guilders). I received a short instruction from Hans Braam and after 30 minutes I was ready to go home again.

So far my first impessions with the UL40-S2. Below you find a picture of the project so far.

© Maarten&Annemarie, November 2001

last modified 6 January, 2007