COVID-19 Update Online orders dispatching as normal. Our new Blackburn store is fully open for visits and click & collect
Free Next Day Delivery Over £99
Seen It Cheaper? Get In Touch
Finance Available Over £280* (Subject to Status)

Electro Harmonix Q-Tron Plus Envelope Filter With Effects

Code: Q-TRON+
  • £133.00
  • (Free UK Delivery)
Out of Stock | In Stock

What Electro Harmonix say....

Same design as the original Q-Tron but with extremely useful Effects Loop and an Attack Response Switch.

The Effects Loop gives the musician the ability to place an additional effect, or chain of effects between the Q-Tron Plus's preamp and filter section without changing the envelope drive. This is particularly important with most distortion devices, as most all do not have much of an amplitude envelope. The FX loop will also fire up your creative juices to try all sorts of combinations in the effects loop: try the Micro POG into a Deluxe Memory Man. You can invent all sorts of novel effects.

The added Response Switch selects between a slow, smooth, vowel-like attack and the fast, snaked response of the original Q-Tron.


Gain Control (0-11)- In normal mode the gain control acts as a filter sensitivity control and has no effect on the unit’s output volume. In Boost mode, the Gain control functions as both a volume control and the filter sensitivity control.

Boost Switch (Normal/Boost) - Normal mode passes input signal through the filter at its original level. Boost mode increases the signal gain to the filter according to the Gain control setting.

Response Switch (Fast/Slow) - Changes the sweep response between two optimized settings. “Slow” response creates a smooth vowel-like response. “Fast” response produces a snappy response identical to the original Q-Tron.

Drive Switch (Up/Down) - Selects the direction of the filter sweep.

Range Switch (Hi/Lo) - Emphasizes vowel-like sounds in low position and overtones in high position.

Peak Control (0-11) - Determines the resonance peak or Q of the filter. Turning the control clockwise increases the Q and creates a more dramatic effect.

Mode Switch (LP, BP, HP Mix) - Determines what frequency range the filter will pass. Emphasize Bass with Low Pass, midrange in Band Pass and treble with the High Pass. Mix mode combines BP with the dry instrument signal.

Bypass Switch (In/Out) - Toggles between effect mode and True Bypass. When the Q-Tron+ in bypass the effect loops is also bypassed.

Your Playing Dynamics - The Q-tron’s effect is controlled by the user’s player dynamics. strong attack will yield a more dramatic effect, while a softer playing yields more subtle ones.


The Effects loop allows you to place an additional musical effect between the Q-Tron’s preamp and filter sections without any alteration of the envelope drive. This allows the full dynamic response to your playing while greatly increasing the sound possibilities: Fuzz, soft distortion, echo and chorus, octave divider etc.

When you use an external effect in the Effect’s Loop, the footswitch on the external effect can control whether the signal is “in” or “out”. The Q-Tron footswitch will always switch between the Q-Tron process and the original input signal regardless of the state of the external effect.


Input Jack - Musical instrument signal input. The input impedance presented at this jacks 300 k(.

Effects Out Jack - Output to amplifier. The output impedance is 250 (.

FX Loop Send Jack - Musical instrument signal output to external musical effect in (buffered/amplified). The output impedance is 250 (.

FX Loop Return Jack- From External musical effect output to Q-Tron filter process. The input impedance presented at this jacks 300 k(.

-AC Adaptor-

Your Q-Tron+ comes equipped with a 24 volt DC (inner positive) / 100mA external power adapter. Use only the power adapter that is supplied! Using the wrong adapter can cause serious bodily injury and may damage your unit. This will void the warranty.


Set all controls to minimum. Connect your instrument to the input jack and your amplifier to the effect out jack. Optionally connect an external effect to the Effects Loop. The Unit’s power LED should be lit. Set the Q-Tron’s controls to the following:

Drive Switch: UP

Response Switch: slow

Range Switch: Low

Mode Switch: BP

Peak Control: Maximum

Boost Control: Normal

Gain Control: Variable*

* Vary the gain control until the Overload Indicator LED lights on the loudest notes that you play. If no effect is noticeable, depress the Bypass switch to engage the effect. With this setting the user should be able to approximate the sound of an automatic wah-wah pedal.

Experiment with these settings to see how the Q-Tron reacts to playing dynamics. Adjusting the Gain and Peak controls will vary the amount and intensity of the effect. For tonal variations adjust the Range, Mode and Drive controls.

To attain an effect similar to an original Mu-Tron III, set the Q-Tron’s controls to the following:

Drive Switch: Down

Response Switch: Fast

Range Switch: Low

Mode Switch: BP

Peak Control: Mid Point

Boost Control: Boost

Gain Control: Variable*

* Vary the gain control until the Overload Indicator LED lights on the loudest notes that you play. Increasing gain will saturate the Filter, yielding the famous “chewy” Mu-Tron like sounds. Adjusting the peak control will vary the intensity of the effect. For tonal variations, adjust the Range, Mode and Drive controls.

-Options for use-

The Q-Tron+ can be used with a wide variety of electronic instruments. Here are some setting tips for use with different instrument types.

Range Control - Lo range is best for rhythm guitar and bass. Hi range is best for lead guitar, brass and winds. Both ranges work well for keyboards.

Mix Mode: Works especially well with bass guitar (may require higher peak settings.

Drive Switch: Down drive works well with Bass guitar. Up Drive is best with guitar and keyboards.

The Q-Tron+ can also be used in conjunction with other effects pedals. Here are some interesting combinations.

Q-Tron+ and Big Muff (or tube amp distortion) - Place the distortion device after the Q-tron+ in the signal chain, or effects loop. The use of distortion will dramatically increase the intensity of the Q-Tron’s effect. You can also place the distortion before the Q-Tron+ but this combination tends to flatten the dynamic response range of the effect.

Q-Tron+ into a Q-Tron+ - (or another Q-Tron in effects loop) - Try this with one unit in the up drive position and the other in the down drive position.

Q-Tron+ and Octave Multiplexer - Place the octave divider before the Q-Tron+ in the signal chain or in the effects loop. Use an octave divider, which maintains the natural envelope of the signal. This combination will yield sounds similar to and analog synthesizer.

Q-Tron+ and compressor, flanger, reverb etc in effects loop- create interesting tonal colors while retaining full control of digital sweep.

Try experimenting with other effects and effect placement (before Q-Tron+ or after it in the effects loop) to achieve your own unique sound. When used properly the Q-tron will provide a lifetime of playing pleasure.


Coronavirus Update

Our chosen couriers are currently operating as normal and all orders should be delivered on time. DPD are also now operating a "contact-free" service as a standard process and customers will not be asked to sign handheld units.

Mainland UK Delivery Services

  • Next Working Day - Free for orders over £99, £8.95 otherwise (DPD, Next Working Day)
  • Standard - Free for orders over £99, £4.95 otherwise (DPD, 1-3 Working Days)

Order before 2pm, Monday to Friday, for same-day dispatch of in-stock orders. Very heavy items such as pianos may take longer to deliver. In-stock orders placed over the weekend will be dispatched on Monday. Estimated delivery times for out of stock items are to be used as a guide only, these items may take longer than estimated to arrive. While we try our best to ensure rapid delivery of your order, delays may occur which are outside our control, and delivery of large or bulky items, or to remote or non-mainland addresses may take longer than estimated.

Courier Tracking

Most UK deliveries are shipped by our trusted courier, DPD. You'll receive an email with a delivery day, tracking and a one hour estimated delivery window on the morning of delivery. While we can't specify the time of the delivery, if it's not convenient, you can arrange directly with DPD for an alternative delivery date or request the parcel be left with a neighbour.

For heavier items, we usually ship UK deliveries by TNT. You will receive an email with tracking details when we ship your order. 

Delivery Charges

Delivery to mainland UK addresses is free on all orders over £99. Delivery charges are based on the size and weight of your order and, in some cases, your location. A standard next working day carriage charge for UK mainland addresses is shown on the shopping basket page, but you can change delivery service later in the checkout.

Delivery Couriers

We use a few different delivery couriers, depending on the items being sent, your location, and the delivery service you've chosen:

  • UK inc. Northern Ireland: Most items will be shipped by DPD. Note: all items in your order must be in stock for all of your order to be dispatched on the same day.
  • UK inc. Northern Ireland: Most smaller items will be shipped by Royal Mail Recorded Delivery.
  • UK inc. Northern Ireland: Most very large or heavy items such as pianos are delivered by TNT, or by our in-house delivery service. Orders shipped by TNT are usually on a next working day service, whereas items using our in-house delivery service may take longer. Note: Delivery to non-ground-floor addresses without a suitable lift will cost extra.
  • Europe: Most orders will be shipped by DPD International. Delivery times and charges depend on your location - these charges will be displayed in the order basket.

Most orders will need to be signed for and we advise you make sure to check your parcel/s for any damage before signing. If no-one is available at your address, a card will be left so you can arrange a re-delivery directly with the courier. Redirection of an order after it's been dispatched may incur an extra charge from the courier.

Delivery Areas & European Shipping

Delivery charges displayed apply to most UK mainland addresses. Deliveries to Northern Ireland, UK non-mainland, and European addresses will cost more, and carriage charges will be shown at the checkout before you place your order. Free delivery offers may not apply to some remote/Scottish Highlands addresses.


Coronavirus Update

There are currently delays for all returns processing due to extra safety procedures. Thanks for your patience during this difficult time.

Replacement process for items damaged in transit or faulty items

It doesn't happen often, but occasionally an item can get damaged on the way to you. Don't worry! If your order is received either damaged or faulty, just let us know, preferably using the returns request form within 30 days of receiving the item, and we'll arrange for it its return and for a replacement or refund.

Returning an undamaged item

You can return most items bought online or by phone within 14 days for a refund (provided that it is unused and returned to us in New Condition – including packaging). You will need to return the item at your own expense. When we receive the goods back undamaged and with the correct packaging we will refund the cost of the goods.

Software or products that include software that needs to be registered are not eligible for this 14 day return period if opened and installed, and due to hygiene reasons we can't accept certain used in-ear headphones, microphones or harmonicas.

Faulty items under guarantee

The repair procedure for items which are under guarantee varies from manufacturer to manufacturer - please refer to the documentation which accompanied your purchase or complete the returns request form and we will advise you of the appropriate process.