Sovtek Deluxe Big Muff Pi Instructions

Back to Product Page
Sovtek Deluxe Big Muff Pi

Congratulations! You have just purchased the passionate lovechild of our revered Green Russian Big Muff Pi reissue and the Big-Muff-on-steroids Deluxe Big Muff Pi: the Sovtek Deluxe Big Muff Pi! We know what you’re thinking – “Oh, no, they didn’t!” Oh, yes, we did! It’s the beefy, woolly tone you love from the Green Russian Big Muff with all the bells and whistles from the Deluxe Big Muff. Check it out.

Features Include:
Big Muff Knob Layout – familiar Sustain, Tone and Volume controls
MIDS EQ – fully parametric MIDS EQ includes variable frequency sweep, boost or cut level control and switchable Q or bandwidth amount
Footswitch for MIDS EQ – turn on the MIDS EQ circuit with the stomp of your foot
Gate – remove unwanted hiss and hum
Blend – allows you to mix the dry signal with the distortion
Wicker switch – opens up the high end for extra attack
Expression Pedal Input – sweep the frequency of the MIDS EQ with your foot
True Bypass


VOLUME Knob – Works as a master volume control for the entire pedal

BLEND Knob – This mixes between the dry and distorted signals. Turn this knob fully counterclockwise for 100% dry signal and fully clockwise for 100% wet signal. Setting the BLEND knob to noon yields a 50/50 mix of dry/distorted signal.

TONE Knob – Provides a range of sounds from high treble to deep bass. As you turn the TONE knob clockwise, treble increases and bass decreases.

SUSTAIN Knob – As in the original Big Muff Pi, adjusts the amount of sustain and distortion

Wicker Switch – This feature is the same as the switch found on the Big Muff Pi with Tone Wicker. With the switch up, the wicker is engaged and high frequency bandwidth is opened up for a bright and clear top end and more pronounced attack. With the switch down, the effect is disengaged and the Big Muff circuit is back to stock.

GATE Knob – Turning GATE clockwise raises the Gate threshold requiring greater input amplitude to open the noise gate, allowing your notes to be heard and your instrument to pass through. Turn the GATE knob down all the way, to fully counter-clockwise, to disable the noise gate.

MIDS LEVEL Knob – When MIDS is engaged (LED near MIDS Footswitch is lit) the MIDS LEVEL knob either boosts or cuts up to +/- 10dB, at the frequency set by the FREQ knob located below it. Turn MIDS LEVEL clockwise from its center 12 o’clock position to boost the center frequency. To cut, turn MIDS LEVEL counter-clockwise from the 12 o’clock position. This knob has a notch near the 12 o’clock position to help identify the center of the knob’s travel. In the center position, MIDS EQ is flat; it does not boost or cut. The MIDS LEVEL knob has no function when MIDS is bypassed (LED near MIDS Footswitch is off).

MIDS FREQ Knob – Sets the center frequency of the MIDS EQ circuit ranging from 310Hz to 5.0kHz. To hear the range of the MIDS FREQ knob, turn the MIDS LEVEL knob up past 3 o’clock, make sure MIDS is enabled (LED near MIDS Footswitch is lit), then play your instrument while turning the MIDS FREQ knob. This knob has no function if either the MIDS section is bypassed (LED near MIDS Footswitch is off) or the MIDS LEVEL knob is set to its center position.

The MIDS FREQ knob can be controlled by an external expression pedal or control voltage (CV). Connect the external device to the EXP jack on the input side of the Sovtek Deluxe Big Muff. The position of the MIDS FREQ knob sets the toe position of the expression pedal or maximum frequency for CV. The heel position of the expression pedal equals the MIDS FREQ knob’s fully counter-clockwise position. Please see EXP Input below for more on the expression pedal.

MIDS Q Switch (HIGH/LOW) – The Q switch sets the resonance or bandwidth of the MIDS EQ. What this means is in LOW mode the EQ sounds broader or rounder and affects a larger range of frequencies; in HIGH mode the EQ sounds sharper or peakier and affects a narrow range of frequencies.

MIDS FOOTSWITCH / LED – Engages or bypasses the MIDS EQ section. When the white status LED is lit, the MIDS EQ circuit is active and the MIDS LEVEL and FREQ knobs can be used to produce a multitude of different tones.

BYPASS FOOTSWITCH / LED – Toggles between effect mode and true bypass. When the red status LED is lit, the effect is active. When the LED is off, the Sovtek Deluxe Big Muff Pi is in True Bypass mode.


INPUT – Plug your instrument into here. The input impedance presented at this jack is approximately 130k with the input buffer off. The input impedance is 1M with the input buffer on.

OUTPUT – This is the output of the Sovtek Deluxe Big Muff Pi. Connect it to the input of your amp or another effects pedal. The output impedance at the OUTPUT jack is 300 ohms.

EXP Input – Connect an expression pedal with a TRS plug to this jack to sweep the MIDS center frequency with your foot or other extremity. Additionally, the EXP IN jack can be connected to a Control Voltage (CV) source using a TS plug; the acceptable range for the control voltage is 0V to 5V. Some suggested Expression Pedals: EHX Expression Pedal, M-Audio® EX-P, Moog® EP-2, Roland® EV-5 or Boss® FV-500L. The polarity of the expression pedal’s plug must connect the Sleeve to the heel position, Ring connected to the toe position and the Tip connected to the wiper. The nominal expression pedal impedance is 10k but it can accept impedances ranging from 6k to 100k. Please note: if the MIDS EQ section is bypassed, the expression pedal is disabled.

9V POWER – The Sovtek Deluxe Big Muff can run off of a 9V battery or you can use a 9VDC AC Adapter capable of delivering at least 50mA. The optional 9V power supply from Electro-Harmonix is the 9.6DC-200BI (same as used by Boss™ & Ibanez™) and delivers up to 200mA at 9.6 Volts DC. The actual current draw of the Sovtek Deluxe Big Muff is 22mA at 9VDC. The AC Adapter must have a barrel connector with center negative plug. The Sovtek Deluxe Big Muff accepts most BOSS® style AC Adapters. Please do not exceed 12VDC at the power jack. The battery may be left in or taken out when using an AC Adapter.


To change the 9-Volt battery, you must remove the 4 screws on the bottom of the Sovtek Deluxe Big Muff Pi. Once the screws are removed, you can take off the bottom plate and change the battery. Please do not touch the circuit board while the bottom plate is off or you risk damaging a component.

To achieve its long sustain, the Sovtek Deluxe Big Muff Pi has a very high maximum gain. This requires that pickups and cables be well shielded and properly grounded to avoid excessive hum when high sustain knob settings are used.

We have included an internal slide switch to engage a buffer on the input to the Big Muff circuit. Engaging this buffer will increase the high end content of both the distorted and clean signal being blended in. The slide switch is located near the input jack and is set to the “unbuffered” position at the factory. Be careful not to touch any other components when adjusting this switch.

The Sovtek Deluxe Big Muff Pi’s MIDS EQ section has three trim pots for adjusting the following: 1) High Q bandwidth, 2) High Q Output Volume and 3) overall MIDS EQ Output Volume. We set these trim pots at the factory so that 1) HIGH Q mode is very resonant but does not self-oscillate, 2) HIGH Q mode is just a bit louder than LOW Q mode and 3) when engaged, MIDS EQ creates a slight volume boost over MIDS EQ bypassed for most settings of MIDS knobs.

We realize our settings may not be perfect for everyone. If you would like to make adjustments to the trim pots, remove the 4 screws on the bottom of the unit and remove the bottom plate. Place the pedal knob-side-down with the power jack facing away from you. In the upper left area of the printed circuit board you will see three small trim pots.

Before you start: we recommend you photograph or sketch the position of each trim pot as it came to you from the factory in case you want to go back to those settings. The factory trim pot settings vary considerably from unit to unit.

When adjusting the trim pots use a small flat head or slotted screwdriver with a width of 2mm. Please do not touch any other parts of the circuit board while the bottom plate is off or you risk damaging a component.

The signal path through the trim pots goes in this order:


Change HI Q’s bandwidth by adjusting HI Q AMT. The volume level of HI Q mode also changes: increasing HI Q AMT increases HIGH Q’s volume; decreasing HI Q AMT decreases HIGH Q’s volume. Therefore if you adjust HI Q AMT you may also need to adjust the HI Q VOL trim pot.

If you want to change the volume of LOW Q mode: 1) adjust the MID EQ OUT VOL trim appropriately until you are happy with LOW Q’s volume, 2) compare HIGH Q’s volume to LOW Q’s volume and adjust the HI Q VOL trim if necessary.

Please register online at or complete and return the enclosed warranty card within 10 days of purchase. Electro-Harmonix will repair or replace, at its discretion, a product that fails to operate due to defects in materials or workmanship for a period of one year from date of purchase. This applies only to original purchasers who have bought their product from an authorized Electro-Harmonix retailer. Repaired or replaced units will then be warranted for the unexpired portion of the original warranty term.

If you should need to return your unit for service within the warranty period, please contact the appropriate office listed below. Customers outside the regions listed below, please contact EHX Customer Service for information on warranty repairs at or +1-718-937-8300. USA and Canadian customers: please obtain a Return Authorization Number (RA#) from EHX Customer Service before returning your product. Include with your returned unit a written description of the problem as well as your name, address, telephone number, e-mail address, RA# and a copy of your receipt clearly showing the purchase date.

United States & Canada
55-01 2ND STREET
Tel: 718-937-8300

Tel: +44 179 247 3258

mouse over image to zoom
Mailing List
Sign up to receive all the latest EHX news!
To withdraw from this service, e-mail us and action will be taken within 2 weeks.
The EHX Community
Here are a few easy ways to stay informed on the latest news from Electro-Harmonix...
Forums (Discussion & Support)
Have a question, comment, suggestion? Come join the EHX Forums! You'll meet EHX staff and knowledgeable users from around the world.

Show your colors with genuine EHX tee shirts and authentic Electro-Harmonix accessories!
Get this limited-edition Day-Glo poster of the original 1968 art that inspired the Electro-Harmonix logo!

Mike Matthews stated: “The image on our Flashback Poster is of the original artwork that inspired the famous Electro-Harmonix logo. I think players who dig our pedals will also enjoy the chance to own a piece of EHX memorabilia.”
Did you know that Electro-Harmonix makes many of the world's greatest vacuum tubes? The next time you need to re-tube your guitar, bass, or hi-fi amp, be sure to insist on getting authentic Electro-Harmonix tubes.
Our new EHX Strings Electro-Harmonix electric guitar strings are custom-designed to our specifications and made in the USA by a premiere string manufacturer. Each wound string is precision wrapped with round nickel-plated steel onto a high carbon, hexagon-shaped steel core. The plain strings are made from the same high carbon steel as the hex cores. The high quality steel and computer controlled winding process results in strings that intonate accurately, are better at staying in tune and vibrate evenly for maximum sustain.
Dig it, now you can rock EHX in our new heavy-duty black hoodie! It’s emblazoned with the iconic Electro-Harmonix Flashback logo in white on the left chest and back.