- The following article, in English translation (thank you Xebeche!) is presented here
with the permission of FUZZ Magazine. FUZZ Magazine is a Swedish publication -

 

From FUZZ Magazine, September 2003, no 7

 

Kevin O'Connor

MEETING AN AMPLIFIER GURU

By Anders Bergdahl, Ulf Edelönn & Fredrik Heghammar

When we here att UGG [Ultimate Guitar Gear, transl. note] hear that one of the best known profiles in the world of tube amps, Kevin O´Connor, is coming to Sweden and also bringing with him at least one of his own amplifiers, we make sure that we get to meet him, and also get to play with his amp.

Kevin O´Connor has become known among tube amp enthusiasts as a somewhat odd person, who likes to debate with other “self-titled” experts, and who has his own solutions as to how tube amps should be built. He was now about to give a one-day seminar in Eskilstuna, Sweden, aimed at both professional and amateur amplifier techs. Here at UGG we have our hands full with playing our amps, instead of taking them apart, so we thought that instead of attending the seminar we´d like to talk to Kevin and give his amp a shot.

The night before the seminar we meet outside the Balsta Music Castle. It´s a rainy 17th of May and Kevin arrives in shorts and a batique T-shirt! He has long, grey-black hair with a matching beard and vintage pilot shades from the 70´s. In short: he looks like a guru. The reason why he started to build amps in the first place, was because he has never found one that could satisfy him.

POWER SCALING
The secret to many of the classic amp sounds is power amp distortion. An old Marshall dialed to 11 for example. Unfortunately the volume is a problem; it gets too high, far too high for practice and for most venues you´ll ever play. Kevin has a solution that he calls Power Scaling. With this technique you can have power amp distortion at any level of volume.

Another of his own controversial ideas is that you can use unmatched, and even different types of tubes in the power section. Most amp techs claim that you should use matched power tubes. Kevin also has thoughts about using components that are not commonly thought to sound good, but have better durability than the ones traditionally used in tube amps. To summarize Kevin's philosophy, one can say that he likes to achieve the traditional sound of tube amps, but with new and better solutions compared to the ones used in the 50´s and 60´s.

O´CONNOR'S AMP
The amp he has with him is his Studio model, and it´s odd to say the least. First of all, it´s meant to be rack mounted, and that´s why all the connectors etc. are in the back. There´s no lack of pots, but there are no tone controls. Instead there are switches and knobs that control, most of all, how the power section is working.

Probably the most unusual control is the Power Scaling, which makes it possible to adjust the number of watts from zero to whatever the output tubes can deliver. You can also adjust the amount of sag - that is, the amount of negative feedback [* Manufacturer's note: the SUSTAIN control controls sag like a variable rectifier effect; the VIBE control controls the negative feedback] and dialing in any kind of mix of the two output tubes. In other words, everything in the power stage can be controlled. But what does this mean to those of us who play guitar?

We begin with two 6V6´s, Kevin adjusts the bias, and we´re off. He dials in a clean sound that sounds like a Fender Deluxe, and then he shows how to get only pre-amp distortion or only power amp distortion and how to mix them at any volume. The amp is, of course, not very powerful with these valves, but the interesting part is to actually hear what the different connections in the output stage sound like. It is also very impressive to have a delicious distortion at such a low volume. It is a very good sound, but now we want some more power. Said and done - Kevin puts in a pair of EL34´s. What a shock! A completely different sound, more like a Marshall. It´s easy to dial in AC/DC, Led Zep and other classic rock sounds. By turning a few switches you get a more Vox-like sound - very impressive. Never ever before have we been able to hear so clearly the characteristics of the different valves.

Finally, Kevin pulls out one of the EL34 and replaces it with a 6L6. The character of the sound changes immediately, a bit toward a Fender sound. This again gives us infinite variations, due to all the adjustment possibilities.

INFINITE POSSIBILITIES
To conclude, one can say that this is very good sounding amp with almost infinite possibilities for different characteristics of sound. A few hours is obviously too short a time to explore everything. We think that this amp is the POD of the tube world. With this amp in the studio, you have a wide arsenal of very good genuine tube amp sounds.

A genuine professional grade amplifier for anyone who needs much variation and is picky when it comes to sound quality.

© 2003

Thanks to Owe “Amp Healer” Johnson who brought Kevin over to Sweden.
For more information about Kevin O´Connor and his amps: www.londonpower.com
Please visit our site: www.ultimateguitargear.com Contact: info@guitargear.com


Home | Amps | Books | DIY Kits | Tube Amp Faq | Links