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Encounters With The Mad Professor

Encounters With The Mad Professor

It’s amazing how unusual circumstances can connect players with great guitar equipment.

It’s amazing how unusual circumstances can connect players with great guitar equipment. And that applies doubly when it occurs in unexpected places! Such was the case when I was visiting Stockholm, Sweden, on a business trip in the winter of 1992-1993. One day, I went downtown to meet a friend. We’d decided to meet at one of Stockholm’s best music stores before going out to dinner. As I was standing at the front counter, peering through the glass display at the pick selection, I noticed this very personable fellow next to me who appeared to be returning a slew of repaired amps to the store. A few minutes later, my friend arrived and off we went to eat.

At that point, I didn’t think too much about my first encounter with the mysterious gentleman who’d been standing next to me. I figured he was an amplifier technician. Well, sort of . . . as I later found out. Fast-forward a decade: I was talking on the phone with one Bjorn Juhl, when he suddenly exclaimed, “You know what? I think we’ve met before.” When I asked him to describe where and when, he told me that he remembered a floor-length submarine jacket and a unique pair of red-on-black Spanish lace boots I wore that day. Those outrageously colorful boots ultimately hooked me up with a new amplifier: The Mad Professor CS-40. Fate you say? Definitely! Because it wasn’t long before Bjorn was making a serious attempt to get a Mad Professor CS-40 amp head to me to get an opinion on it.

At the time, a circle of close gearhead friends and I were getting ready to host our third annual “Tone Fest,” an event we’d started to showcase vintage or boutique amplifiers. The idea was to provide an opportunity for guitarists to get hands-on experience with equipment they might be curious about. And this was precisely where the Mad Professor made its debut— Tone Fest 2004. This particular amplifier has become one of my all-time favorites. Let’s take a look at some of its unique features and see why savvy players love it so much.

The CS-40 is, first of all, in the same category as other fast-response amps we’ve discussed in recent columns (Dumble in July 2010, Vox AC30 in August and December 2010, and Hiwatt in September 2010).

Several controls on the CS-40 are very cleverly designed for maximum versatility. The 4-position Focus control helps you “match” speaker cabinets to the CS-40 head. This control affects the amp’s feel and the sonic textures it produces. In position 1, the CS-40 delivers American-style sounds (think classic Fender tones). Position 2 yields some really amazing, early British sounds (yep, think Vox AC30 here as a reference). At position 3, you’ll easily cop some later British-style tones (thinking classic Marshall isn’t a bad idea). Finally, in position 4, the CS-40 enters the realm of modern British sounds enhanced with top boost. These tones are grittier sounding, but very defined.

The CS-40’s Tonal Balance knob is another deviously designed audio manipulator. Turning it counterclockwise from noon offers a really fat midrange sound that gets close to Dumble territory. Turning it clockwise from noon makes the sound brighter and thinner. However, in this scenario, turning up the Master volume or Channel volume fills things out very, very nicely. It’s clear the CS-40 was designed from the ground up to deliver well-defined, heavy distortion.

Next to the input jack is a 2-position switch labeled Tube and F.E.T. In the latter position, this switch can take weak pickups (such as Danelectro lipsticks) and make them sound much stronger. It’s uncanny! The Tube setting is voiced for hotter pickups, such as humbuckers on a Les Paul. P-90s produce gnarly tones in any of these settings, and this marriage of amp and pickups is one of my favorite—it’s so beautifully rude.

Want more volume, even if you’re already cranked wide open? No problem. Just dial in some boost using the front-panel control, hit the CS-40’s Boost switch, and prepare to be thrown against the nearest wall. Most other amps have nowhere left to go when they’re already cranked, but this is where the Mad Professor really shines. Believe me, it was a big surprise the first time I heard this.

In my experience, this amplifier has no bad sounds in it, and I really like the fact that it can be mean or clean or any shade in-between. Little touches, like having Normal and Abnormal channels, reveal Bjorn’s dry sense of humor. You can also plug your guitar directly into the effects loop and bypass the amplifier’s preamp. This delivers what Bjorn describes as “the secret sound”— where you get more of the power section doing its job. And what a cool sound it is! If you get the opportunity and are inclined toward fast-response amps, I highly recommend you try out the CS-40 designs.


Dean Farley is chief designer of Snake Oil Brand Strings, and his ideas have had a significant influence on contemporary string design. He is also known as a great source of guitar, amp, and gear lore. For more information, visit snakeoilstrings.com.