2004 Kevin O'Connor Workshop - Sweden

 Note: this is a copy of a page from an older version of our website - please enjoy the vintage formatting!


~ presented May 29, 2004 in Gnesta, Sweden   We love Sweden!

They wanted us back!

After the great fun everyone had at the 2003 workshop, many participants told us they'd like to have us back in 2004 for another workshop. We were very pleased!! Since we enjoyed our last trip to Sweden so much, we were more than happy to make plans for another event. Once again, our friend Owe Johnson made many of the arrangements. Martin Kuhn found us a nice hall at the Elektron Folketshus not far from Stockholm. The workshop was advertised in FUZZ Magazine and through the GMF Rörtipsplank (a Swedish tube amp newsgroup). We all converged on the Elektron Folketshus on May 29, a beautiful time to be in Sweden among such great folks!

The Workshop

This year's workshop was based upon the material in our newest book: The Ultimate Tone Vol. 5: Tone Capture...specifically, Chapter One, which deals with preamp design and voicing, with optimizing gain structures, and with repeatable methods for adjusting high-gain circuits. The discussion naturally led to the techniques used in Trainwreck amps, Soldanos, and other brands of interest to the group.

Around the table

Although some of last year's participants could not make it to this workshop, we were pleased to see some new faces from the GMF newsgroup and elsewhere, and, as always, part of the fun of this workshop is to meet folks we've only encountered in cyberspace. We believe the cyberterm for this kind of face-to-face contact is "IRL" (in real life). So, our workshop gives the GMF an "IRL" side. It's good to know that none of the members or projects we've seen on the GMF are fakes, (like the moon-landing...).

During the lunch break everyone scattered, but Kevin and Wendy went "uptown" with some of the others (Gnesta was small but it had a hill) to a nice little restaurant that served pasta and burgers. Perhaps they were not expecting a group of 10 for lunch. A few of us received free drinks due to the slow service. (Wendy chose a cider. She says: "I am happy to say I am getting used to Swedish cider, and so far I like the green stuff better than the pink stuff!")


After lunch Kevin continued the discussion started in the morning, covering the interaction of the preamp and the power amp, Power Scaling, tube protection, and other points brought up by the group for discussion. The mood was relaxed, with lots of dialogue between the group and Kevin.

At about 4pm the lecturing was over, and it was time to show off amp projects! We were all treated to an impressive array of home-built amplifiers.


Project Gallery

Not everyone brought projects, but below are some of the highlights of those we saw.

Benny's amp

Benny demonstrated his computer-controlled tube amp, in which the computer monitors each tube's idle condition, the tube balance, and assures a delay of the application of plate supply. There are simpler, but far less entertaining ways to do this! Thanks Benny!




Alex's amp

Alex's Tube Wonder amp was the most photogenic of the group! We loved the yellow! The amp features custom transformers, PCBs designed by Alex, active-EQ (usually found on mixing consoles), and silk-screened panels. And did we say we liked the yellow...?

Johan's amp

Johan brought along a tube amp that sounded good and had a unique construction that allowed easy viewing of all the "interesting stuff". Reminiscent of the "works-in-a-drawer" televisions by RCA.



Sixten's amp

Sixten presented his "Edgar D-Lux" amp, and all were impressed by its clear, rich tone. It certainly looked nice, too! Sixten produces amps that follow vintage approaches, but he offers the choice of either octal or miniature tubes by installing both sets of sockets in the amp. This allows the player to choose how "tweedy" the amp should sound.


Martin's amp

Martin showed off his amp to good effect with his usual virtuoso playing. He had converted last year's "Martin Kuhn Clean Machine" into this year's "Martin Kuhn Crunch Machine". Part of his setup this year was a rotating vane (at bottom), which emulates a Leslie speaker cabinet. Thanks also to Martin for organizing the venue and for making coffee!


Sven Wickström's amp

Sven used an EF86 tube in the front-end to capture some of the "vintage-Vox" tone in his simple but well-tuned amp.


Henrik's amp

After bringing the smallest amp to the workshop last year (the punk-rock amp in radio dress), this year Henrik brought his modified PA chassis set up for raunchy blues tones.


Sven Ericsson's amp

Sven's been working on this amp for a long time, and it shows! The amp is effectively a three-channel, highly portable gigging box, and it sounded great!


Ola's amp

Ola brought a prototype Lehnert amp, designed for real players. Four controls allow access to clean and distorted sounds, with effective EQ-ing. The amp is voiced to complement the speaker, which is in a partially detuned cabinet. An elegant amp, just like its builder!

Burger break...



At suppertime some of us went up the road to this little grill, for health food!




UGG Tone Party

After the Workshop and the "GMF Amp Party", the gang from Ultimate Guitar Gear (UGG) brought in gear (and beer!) for their "Tone Party". Various boutique amps were available to try out, including a couple of Komet amps, a Mystic amp, and vintage Marshalls. Meanwhile, workshop participants also chatted about their projects, and collaborated on ideas.


Thank you Everyone!
As in 2003, we were very touched by the kind comments from workshop participants,
and the hospitality of those who put us up (and put up with us!) in their homes.


Photo Gallery







Related Links

Amp Healer Owe Johnson www.amphealer.se.

Lehnert Amps (Ola Lehnert) www.lehnert-amps.com

Edgar Audio (Sixten Forsén) www.edgaraudio.se

FUZZ Magazine www.fuzz.se

GMF www.GMF.se

LH Musik & Audio (Kalle Norman) www.lh-musik.se

London Power/Power Press www.londonpower.com

MM Magazine www.musikermagasinet.com

Ultimate Guitar Gear (Anders Bergdahl) www.ultimateguitargear.com

See other Workshop Reports here!


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Thunder Bay, Ontario, CANADA  P7B 6T6
Phone: 807-473-0952   FAX: 807-939-1324



About London Power

London Power was founded in 1990 by Kevin O'Connor, after two decades of research into innovative audio amplification techniques. Kevin is an audio designer, author and speaker, known for his proprietary methodology called Power Scaling, and for his eleven books on audio subjects. Whether you seek amps, kits or information, you'll find useful answers here on not just the "how" but the "why" of audio amplifier design. Please enjoy the information on this site, and don't hesitate to contact us with questions.

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