Siegmund Micro Tube Overdrive

The Nuance of OD
The Nuance of OD

Chris Siegmund is an up-and-coming guitar/amp wizard from Vienna, Austria. A unique type of craftsman, Siegmund is a musician born to a family of architects and furniture makers. He began working with fine woods, and applying the elaborate carving skills of his family’s heritage to building instruments.

In addition to creating beautiful instruments, Siegmund learned to pay careful attention to the tone his designs produced. And his work as a luthier spawned an interest in the electronic side of things, so he recently starting building amplifiers and experimenting with auxiliary items, like preamp pedals.

One of the efforts, the Siegmund Micro Tube Overdrive, is a dual-gain stage, Class A preamp that can be used for a variety of purposes. Housed in an average-size stompbox, the Micro Tube was designed for use with electric or acoustic guitar, electric or acoustic bass, keyboard, or microphone. It can be used with practically any instrument that can be amplified. A true tube preamp, the pedal utilizes a genuine preamp tube – smaller than a 12AX7 – to create its warm tone. Being a small-bottle tube, it produces less gain, so the Micro Tube is a lower-gain unit.

The unit is furnished with four rotary controls for Gain, Treble, Bass, and Volume. Each control is topped with a knurled chrome knob with no markings to indicate positions. However, there is a center detent on the Treble, and the Bass has 10 detents to mark increments. A three-way switch allows selection between Full, Bright, and Normal operation modes. The pedal is AC powered and includes a true bypass on/off switch as well as a light that indicates whether the effect is off (green) or on (red).

The controls are easy to operate and fairly self-explanatory. It takes only a bit of experimentation to find the best settings for each instrument and situation. Unlike some effects boxes, the Micro Tube creates a transparent effect, allowing the guitar’s tone to remain prominent. Subtle differences come through the amp, depending on how the pedal is set, but the instrument’s inherent characteristics shined through, and listeners can distinguish differences between guitars, rather than to have the box make them all sound the same (as many overdrives do).

Depending on settings, the Micro Tube can be used for overdrive, as a simple volume booster (up to 50 dB), or to fatten and warm up the ambience. We found the box very useful in balancing a guitar’s tone. The three-way switch can work like a master presence and tone control. Setting it on the center position is like setting the master control flat. Moved to “Full,” the pedal produces the fattest tones, while “Bright” brings out more sparkle without making the sound thin.

The rotary controls are used to do all the fine-tuning. Gain adds the desired grease and balances the level and boost using the Volume control. When adjusting the Treble and Bass, we started at the mid point and increased or reduced the level to reach the desired sound.

We used a variety of instruments to test the pedal, including a ’78 Les Paul Custom with Seymour Duncan pickups, a stock ’65 Strat, and a ’72 Martin D12-28 with a Barcus Berry bridge pickup. We played them through a mid-’70s 50-watt Marshall head and 4×12 cabinet, as well as through a solidstate Marshall 1×12 combo. We set the tone controls of both flat (at 5).

With the tube Marshall head and 4×12, Normal and Bright worked best with the Les Paul, and any of the three settings worked well for the Strat for creating typical rock sounds. The Full position is more distinguishable with cleaner settings and adds subtle beef to the sound. It’s almost more of a feel than it is a direct tone. When playing the same guitars through the solidstate Marshall, we preferred the sound with the Full setting for all the electric guitars because of the extra warmth and fullness the box added to the straight amp sound. Normal seemed to work best for very clean playing with the electrics. Bright sounded better when we added more mids and bass to the amp’s EQ. For more gain, we tried turning up the amps’ preamps and using a Tube Screamer in line, placed after the Micro Tube. With both amps, these combinations worked out rather well. The Siegmund provided a way to balance and boost the guitar’s signal before anything else.

As for our the Martin, we realize that a standard Marshall half-stack or combo is not the best setup for use with an acoustic guitar. But it is possible to play acoustic through an electric guitar amp with clean settings. When testing the Martin with the Micro Tube, the Normal setting seemed best and helped to bring out the guitar’s natural tone through either the tube or solidstate Marshall. It helped open up the guitar’s amplified sound.

For further experimentation, we tested the Micro Tube by placing it between the guitars and a simple eight-track recording setup – with no amplifier. For acoustic guitar and clean electric guitar, the results were excellent and it really allowed us to manipulate the guitar’s sound for recording. Depending on what kind of sound you’re looking for when playing electric, you may prefer to use an additional overdrive pedal for more dirt and grease.

We have some suggestions for making the Micro Tube more user friendly. Markings on the control knobs would help note preferred settings (a grease pencil or Sharpee marker does the trick, but…). We’d also suggest reversing the positions of the In and Out jacks, to conform with most other effects, so it would be easier to plug in line when using other pedals.

If you aren’t accustomed to working with stompboxes that don’t drastically alter the sound, you’ll need time to fiddle with the Micro Tube to achieve the best results. Although we did not try the box with instruments other than guitars, the manufacturer says it can be used with a microphone or keyboard. We think it would work equally as well accompanying almost any instrument that could be amplified or mic’ed.

For more info, check out Siegmund’s website,, to see the span of his guitars and amp designs.

Siegmund Micro Tube Overdrive
Type Of Effect Overdrive Pedal
Features Gain, Treble, Bass, Volume controls, Full/Bright/Normal switch, true bypass on/off stomp switch, operates on AC power only
Price $249
Contact Siegmund Guitars & Amplifiers, 888-633-6654, (818) 353-0218, (818) 353-5558,, www.Siegmund

This article originally appeared in VG‘s Feb. ’01 issue. All copyrights are by the author and Vintage Guitar magazine. Unauthorized replication or use is strictly prohibited.