VG: How about amplifiers?
"I used one of my venerable Marshall heads and one of my 4x12 cabs.I've had four of my Marshalls since the '80s, two were used by the Sex Pistols when they reformed in '96 and in 2002; they're JCM 800s that were modified by Harry Kolbe in '88, and those are what I've always used live and in the studio ever since."
VG: What did Kolbe do to your Marshalls back in the day?
"He ups the quality of the power supplies, so when you hit the bottom-end, it's loud and doesn't make the amp sound thin. In my experience, on certain Marshalls, the preamps used to sound kind of sizzly. So he just added some kind of black box that you can't take apart." Ward Meeker VINTAGE GUITAR July 2012
I also used a plexi Marshall head, and the JCM 800 I've used onstage since 1988. I had it modified by Harry Kolbe in New York to produce nice, warm overtones. Before the mods, it had this horrible, cheap-sounding distortion if you drove it too hard. You can hear that amp on the Sex Pistols' live album of the 1996 Filthy Lucre tour, because Steve Jones bought a bunch of my gear. I bought it back from him after that tour, and then he borrowed it for the Pistols "Silver Jubilee" show in 2003. He's on his own now, though he's not getting it again! Michael Molinda GUITAR PLAYER Febuary 2008
With years of experience in custom amplifier modifications, the New York based Harry Kolbe has become the latest contender in the guitar preamp wars. The GP-1 is a single rackspace , two channel preamp powered by three 12AX7's. The clean channel has so much headroom that I was unable, in a solid week of abuse, to make it distort. This preamp adds a nice sheen without coloring the original tone of the instrument. I had my doubts when Kolbe assured me that, thanks to what he called the Character Generator , the GP-1's overdrive channel could produce both a Fender and Marshall tone, but my scepticism disappeared as soon after I plugged in. Even with a solid state power amp, the Fender setting will make you swear you're playing through 6L6's into Jensen speakers. Kolbe's Marshall setting provides a convincingly warm early Claptonesque overdrive. The third setting takes the GP-1 over the top, and would be perfect for shredding metal sparks off cement. My only beef is with the switching system, which allows you to move between channels, but not between overdrive tones. To access these settings you have to go to the buttons on the front panel. At $1,400, the GP-1 may be out of range for some players, but it's one hell of a piece of work. Richard Lloyd MUSICIAN November 1993
New York City based Harry Kolbe is well known for his hip tube-amp mods and tech service-just ask clients like Kim Stone, Carmine Rojas, Fernando Saunders or Bernard Edwards. Not surprisingly, Harry's BP-1 is a testament to his vast knowledge of what makes a tube tick. The BP-1 won't win any prizes for aesthetics; the solid black front panel with six knobs and an input jack is as stark as it gets. The mid controls area bit different; their passive-inductor/capacitor design provides +-12db of peak and dip EQ, a design that prevents the sound from becoming "hollow" with more extreme EQ settings. Two tiny push buttons, HI and LO, switch the high and low midrange points from 800hz to 1.6hz and 220hz to 440hz respectively. The BP-1 was the quietist all tube preamp we tested. Even with the treble control dimed, we heard virtually no hum or noise of any kind. We found it good for bread and butter tones with a fair amount of punch and bite. It also delivered the most focused B- string sound we heard; the low mid knob is excellent for clearing up a blurry 5- string. Comments: "Solid chunky tone, not a lot of coloring." Extraordinary, you can crank the mids and move a ton of air." BASS PLAYER Jan/Feb 1995
The Harry Kolbe Silent Speaker is a passive load device designed to link your amp's speaker out directly to a mixer or power amp. The SS is not a resistive box; it uses inductive technology to mimic a speakers varying impedances. It has three 1/4" jacks: an amp input ( 2, 8, 16, and 4 ohm loads are kosher ), a line out and a headphone jack. We connected our Princeton to a recording mixer, using the Silent Speaker. The box did it's job without fuss, delivering the amps many moods to the board and monitor system with plenty of line level output. The tone switches however,, produced such subtle changes that at times, I had trouble discerning them. What's more, all switch settings are unmarked on the faceplate, so your'e forced to consult a rather cryptic spec sheet to determine what's what. We hooked up a pair of Koss Pro /4A sealed phones to test the headphone circuit. Even wide open, it has low output. The signal was audible, but if you require studly amounts of headphone volume, you'll have to either crank your amp (which may not yield the tone you're after, or plug your cans into the board. A companion Soundsmith product, the Attenuator features a multi-tapped transformer and converts Silent Speaker into a reactive load box inserts between your amp and speaker cab. Tested with a Fender Princeton and Matchless Clubman, the pair sounded excellent at all reduced levels - detailed, dynamic and musical. Kolbe has some fine reactive voodoo happening here. Andy Widders-Ellis GUITAR PLAYER August 1993
GP: Your tone is astonishingly heavy, but it also has a glass-like top end with a lot of transients.
PH: My signal goes through a Harry Kolbe preamp into a Marshall 2204S 50-watt head with its preamp all the way up and a Kolbe Silent speaker essentially a dummy load into a Drawner noise gate, then to a Mesa Boogie Simul-class 2.90 amp powering four Kolbe cabinets. It's so saturated that you get all these great harmonics. In the past, I've had problems getting the harmonic sound to come through, because Celestions get tired after a while. But the Kolbe cabinets are loaded with 200-watt EV's, so the dynamic range of my chords is significantly increased. Plus the cabinets are 3/4" thick, so they're very roadworthy. I'd recommend them to anybody. James Rotondi GUITAR PLAYER August 1992
"what I've been favoring for the last few years is a pre-CBS Fender Super Reverb with four 10s that I've had for a long time. It was recently souped up by a guy here in New York named Harry Kolbe. The power's jumped from 40 watts to 65, and it now has a master volume, a much better reverb and heavy duty speakers." A Sonic Youth Axology -- GUITAR WORLD December 1990
Harry Kolbe has done work for Allan Holdsworth, Yngwie Malmsteen, Steve Stevens and Al DiMeola to name just a few of his clients. He's been in the audio business for well over 25 years, and at one time he worked in the stereo audio field and wrote reviews for High Fidelity, Stereo Review, and other publications. In the early 70's he founded S.Hawk Limited, and designed and manufactured Hawk pedal effects. He recontours both channels of the amp to create two channels that are as different as night and day. The rhythm channel is smooth and taut, and would certainly please most Fender advocates. The lead channel requires a bit more explanation. For years I've used a variac to get more performance out of my old Marshall plexiglass tops, which deliver everything I've always liked about Marshalls - just a lot more of it. The transients (attack) are much faster, and it makes the amp distort differently. The problem is it makes the amp work against itself and the head eventually blows up. You also have to use a wireless unit on your guitar because a bad ground wire can result in electrocution. The good news is that Harry has come up with a high - headroom, low noise front end preamp that when combined with his power supply mod, faithfully approximates a variac enhanced Marshall head. In fact it's much better and quieter. The variac sound on the lead channel gives a tight focused feel - the notes seem to explode off the pick. Harry also does a superlative Fender mod reworking the entire unit. This type of modified amp is Al DiMeola's current favorite. Harry sums up his approach: " The things I put particular emphasis on in my work are definition, accuracy, and massive flexibility." Cali Freeman "The Amp Issue" GUITAR PLAYER October 1979