The Siegmund Micro Tube Overdrive is an analog tube preamp and overdrive pedal from Siegmund Guitars & Amplifiers, the company of Chris Siegmund, a guitar and amp builder from Vienna, Austria1. Housed in an average-size stompbox, it is a dual-gain stage, Class A preamp built around a genuine preamp tube smaller than a 12AX72. Because that small-bottle tube produces less gain than a 12AX7, the Micro Tube is a lower-gain unit with a warm tone, aimed at players who want tube warmth and a transparent effect rather than heavy distortion21.
Vintage Guitar reviewed it in the February 2001 issue at a list price of $2492.
A low-gain tube preamp and overdrive
The Micro Tube is a true tube preamp: it uses a real preamp tube, smaller than a 12AX7, to create its warm tone2. That tube choice defines the pedal's character. Being a small-bottle tube, it produces less gain, so the Micro Tube sits at the low-gain end of the overdrive spectrum rather than competing with distortion or fuzz pedals2.
Vintage Guitar's reviewer found the pedal transparent in use:
"the Micro Tube creates a transparent effect, allowing the guitar's tone to remain prominent."2
The reviewer noted that listeners could distinguish differences between guitars, which points to the pedal's strength as a preamp and tone shaper rather than a heavy clipping device2. Used as a simple volume booster, it delivers up to 50 dB of boost2, putting it in boost pedal territory as well.
The pedal was designed for a wide range of sources beyond the electric guitar: electric or acoustic guitar, electric or acoustic bass, keyboard, or microphone21. Vintage Guitar's reviewer found the results excellent for acoustic guitar and clean electric guitar recording without an amplifier1, and when testing a Martin D12-28 acoustic, the Normal mode setting seemed best and helped bring out the guitar's natural tone2.
The controls and the three-way mode switch
The Micro Tube carries four rotary controls, each topped with a knurled chrome knob with no markings to indicate positions1. Vintage Guitar's reviewer noted that markings on the control knobs would help note preferred settings1.
| Control | What it does |
|---|---|
| Gain | Adds the desired drive ("grease")1 |
| Volume | Balances the level and the amount of boost2 |
| Treble | Fine-tunes treble, with a center detent2 |
| Bass | Shapes bass, with 10 detents marking increments2 |
A three-way switch selects between Full, Bright, and Normal operation modes2. Vintage Guitar described it as working like a master presence and tone control1:
- Normal (center): like setting the master control flat2
- Full: produces the fattest tones2
- Bright: brings out more sparkle without making the sound thin2
The pedal also includes a true bypass on/off stomp switch and a light that indicates whether the effect is off (green) or on (red)2.
The Micro Tube's four rotary controls are topped with knurled chrome knobs with no markings to indicate positions1. The reviewer noted that markings on the control knobs would help note preferred settings, so plan on writing down or photographing the settings you like.
Questions
Does the Siegmund Micro Tube Overdrive run on a battery?
No. The pedal is AC powered and operates on AC power only, so it cannot run on a 9V battery like most overdrive pedals. It needs an AC power source wherever you use it.
Can I use the Siegmund Micro Tube Overdrive with an acoustic guitar or bass?
Yes. It was designed for use with electric or acoustic guitar, electric or acoustic bass, keyboard, or microphone. Vintage Guitar's reviewer found the results excellent for acoustic guitar and clean electric guitar recording without an amplifier.
What tube does the Siegmund Micro Tube Overdrive use?
It uses a genuine preamp tube smaller than a 12AX7, in a dual-gain stage, Class A preamp circuit. Because it is a small-bottle tube, it produces less gain than a 12AX7-based design, making the Micro Tube a lower-gain unit.
How much boost does the Siegmund Micro Tube Overdrive give?
Used as a simple volume booster, it provides up to 50 dB of boost. The Gain control sets the amount of drive, and the Volume control balances the level against the boost.
Who designed the Siegmund Micro Tube Overdrive?
Chris Siegmund, described by Vintage Guitar in 2001 as an up-and-coming guitar and amp builder from Vienna, Austria. The pedal was sold under his company, Siegmund Guitars & Amplifiers.
Sources (2)
- Siegmund Micro Tube Overdrive, Vintage Guitar magazine, 2001-05-11
- Siegmund Micro Tube Overdrive, Vintage Guitar magazine, 2005-08-24