FR 100 Overdrive

Your Price: $199.00
In Stock
Item #:FR100 A

FR 100 is a dual-mode, stacked overdrive. It has a medium gain drive mode and a stacked, high-gain lead mode. Simple layout and controls make FR 100 easy to dial in for the best overdrive and lead tones ever created. LEAD mode is activated by a silent, momentary foot switch on the top of the pedal. The switch is positioned so that knobs don't get hit when LEAD is activated. FR 100 plays well with Fuzz Faces, wah pedals and most other effects. 

FR 100 Drive mode bridges the gap between clean (bypass) and high-gain. A chunky rock 'n roll tone that will make any decent amp shine. LEAD mode is a creamy, high gain tone with a slightly over-cooked, saturated bite to it. The pick attack and sustain makes it highly addicting!

True Bypass, Rear Jacks, 9V battery (or external power), classic Foxrox-style mini-size enclosure. 


Volume: Controls the overall volume of the pedal. Typical setting around 1:00 

Drive: Controls the amount of gain in the main drive section. Typical setting around 2:00 

Lead: Controls the amount of gain added when the pedal is in Lead mode. Typical setting around 2:00. 

Tone: Turn down for bass, up for treble. 

Voice switch: Three selections for matching FR 100 to various amps and playing situations.

High: Tightens the low end and adds resonance in the mids. Good for helping a guitar cut through the mix on a crowded stage. Useful with amps that have a lot of low end.
Mid: This is the natural tone of the overdrive without additional tone shaping.
Low: Fattens the low end for a warm tone. Useful with small amps and to avoid harshness with bright amps. 

Operating Modes / Lead Foot switch

DRIVE mode: When the pedal is powered up it comes on in Drive mode. The signal is passed through a clear-voiced soft clipping section. This circuit is similar to the VT and CS cards used in the Foxrox ZIM pedal. 

LEAD mode: Pressing the LEAD foot switch turns the Red LED on and inserts an additional overdrive stage before the main Drive section. This overdrive adds more gain, sustain and midrange. The two drive stages work together to create a clear, fluid lead tone. Press again to deactivate LEAD mode. 

- The LEAD overdrive section is identical to the H9 Overdrive card used in the Foxrox ZIM pedal. 
- Both Drive and Lead modes are responsive to your guitar's volume knob and the dynamics in your playing. 
- LEAD mode gives you both a gain boost and volume increase. The volume increase can be adjusted internally. 
- Tone knob and Voice switch let you match FR 100 to different amplifiers and playing situations. 

FR100 Block diagram

Circuit description

From the main foot switch, the signal enters the input buffer. From there it goes to the Lead Drive. The Main Drive gets its signal from one of two places, the Lead Drive or directly from the Input Buffer. This is selected by activating and deactivating the LEAD foot switch. The lead drive has two controls, a front-panel DRIVE knob and an internal volume trimmer, which controls the level that gets passed to the Main drive when Lead is activated. This affects the amount of volume boost in lead mode, and it also affects how the two drive stages (Lead and Main) stack together. Standard setting is for a moderate level increase, around 11:00 on the internal blue trimmer. The Main drive has front-panel Gain and Tone controls. The Tone control is a basic Bass/Treble circuit.  After the Main drive, the signal goes to the Voice circuit. The Voice circuit is comprised of two static phase shift stages. This idea comes from the original Foxrox ZIM pedal - these are the first two voice selections on ZIM's voice selector switch. The Voice switch functions like a bass boost/cut switch, but there is more going on than that. The phase shift stages create a musical shift in tone, giving the low setting a a fat, smooth tone, and the high setting a clear and slightly resonant quality. The middle setting is the output of the main drive with  no voicing applied. Next is the volume control. The output level of FR100 is set to be within a reasonable range, unlike some pedals that are way too loud even with the volume knob barely turned up. A linear taper pot is used, which makes the typical volume range arrive  between 10:00 and 2:00. 

FR 100 Daughter Board


This board contains all of the overdrive circuitry and part of the signal switching circuitry.

Blue Trimmer: This trimmer controls the volume of the lead drive. Lead drive is always going into the main drive, which further clips the signal and compresses the dynamic range. Changes in Lead Drive level affect both the drive characteristics in lead mode and the amount of volume boost. Normal setting is around 11:00. 

Signal switching - A solid state relay is used to switch the Lead Drive in and out of the signal path. The logic circuit that controls the relay is on the mother board. This approach keeps high-gain signal runs to a minimum inside the pedal and makes the Lead mode switching silent.

Overdrive circuit - There are two separate overdrives on the FR 100 daughter board. Dual/double sets of clipping diodes each on each drive maximize the amount of dynamic headroom and allow hotter signals in the circuit before clipping. There's a total of 8 clipping diodes. The Main drive has an inverted mid-range feedback circuit that gives it a clear, natural sound. The Lead drive has a strong mid-range and plenty of gain, which is amplified when stacked with the Main drive.

People wishing to modify the overdrive circuitry can do so by downloading the FR 100 DAUGHTER BOARD SCHEMATIC (coming soon). 

FRDB circuit boards are available for hard-core experimenters who wish to create their own overdrive. 

Plug it into FR 100 and you're in business! Mess the card up? Order another one and you're good as new.

More FR 100 photos

FR 100 with battery installed. Foam rubber on the base of the pedal keeps it snug. 

The mother board has all the controls, along with the tone, voicing and switching circuitry.

The two boards interface nicely. 

It all gets mounted in a Foxrox mini size classic-style box.  The perfect guitar effect enclosure.

The upper foot switch (LEAD) and the lower foot switch (Bypass) are thoughtfully positioned to make activation easy. It may seem from looking at the pictures that it's hard to hit the LEAD switch, or that your foot might alter settings or damage the top panel controls. No worries - the correct amount of room is allowed so that your foot never actually touches the knobs or switches. The switch is very easy to hit on-the-fly. This concept received over two years of testing on my pedal board, playing over 100 gigs. -Dave Fox

5 Stars
FR 100
smooth smooth dual overdrive. I also sing and was worried that the two foot switch layout would be awkward but it's designed perfectly to not hit the wrong one without looking down while singing. Umm, the rhythm sound is a really smooth 808/klon kind of sound; I like it on low gain with fender clean style amps. It is also good for both tele/strats and les pauls . The extra lead setting is perfectly balanced volume, gain and tone wise for leads. Great design, functionality and sound. Really well thought out pedal for the live musician in mind
Did you find this helpful? 
Reviewed by:  from hong kong . on 9/8/2020

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