Terraplane Resonator Guitar Co.

Anti-Feedback Device & Gain Maximizer

Terraplane Squeal Killer

Custom manufactured to Terraplane specifications to reduce and minimize undesired feedback, squeal, and howl of amplified stringed instruments when used in combination with high gain vacuum tube amplifiers.


Designed and built by Jason Lockwood, available now exclusively from Terraplane Guitars.

Specifically voiced and recommended for use with tube based guitar amplifiers (15 watts min).

  • Not recommended for use with solid state amplifiers, low wattage practice amps, full range PA type systems, or mixing boards etc.

Works with internal microphone, piezo transducer, and magnetic based pickup systems.

Straight forward operation with a single "Blend" knob leaves you free to concentrate on your performance.

The Terraplane Squeal Killer does NOT run on batteries. The Terraplane Squeal Killer requires a tip negative polarity, 9 volt DC, 300ma power supply.

  • Polarity is center negative and compatible with most aftermarket pedalboards.

Realize 1/3 more volume from your instruments when using the Terraplane Squeal Killer with a tube amp

A simple blend knob allows the user to regulate how much "Squeal Killer" is applied. Turning the knob to the right is 100% squeal reduction, while turning the knob to the left allows less squeal reduction and more gain from the amplifier.

The Terraplane Squeal Killer allows you to tap into the power section of your tube amp without worrying about encountering premature instrument feedback before this critical gain stage can be reached.

Utilizing the Terraplane Squeal Killer, you can set your amp volume about 1/3 higher than previously possible and adjust the onboard blend knob for a perfect balance between the Terraplane Squeal Killer and amplifier volume. Achieve 1/3 higher usable volume levels with the added bonus of a slightly compressed tone by utilizing the upper register of the tube power section!

As with the original "Squeal Killer" designed for harmonicas, 15 watt tube amps are the minimum recommendation. However, while similarities exist between both Squeal Killers; Only the Terraplane version available here is custom designed for use with amplified stringed instruments. Please Note: This Terraplane version is NOT recommended for harmonicas.


  • Point to Point Wiring, Hand Built, and Assembled in the USA
  • 12at7 Vacuum Tube Driver (installed and included)
  • Carbon Comp Resistors
  • Sprague Capacitors
  • Variable Rotary Potentiometer "Blend" Control
  • Switchcraft 1/4" Mono Input and Output Jacks
  • External Center Negative Polarity, 9V DC, 300mA Power Supply Required
  • Stomp Box Effect Pedal Form Factor
  • Dimensions: 4-5/8" Length x 3-5/8 Width x 2" Height (with blend knob)

The Terraplane Squeal Killer is available now

What's Included?

The Terraplane Squeal Killer is available in any color as long as it's PINK (see photos).

Basic Operators Manual Included.

9-Volt Power Supply required and available with purchase (see ordering info below).

This item ships in plain packaging and will arrive as seen in photos.

What's Not Included?

No fancy box or commercial artwork is included.

1/4 inch cables are not included.

Warranty Information:

The Terraplane Squeal Killer carries a one year replacement warranty for the original purchaser (does not cover vacuum tubes, AC adapters, or units that have been opened, modified, subjected to incorrect voltages, or otherwise tampered with). Return shipping costs are non-refundable and must be paid by the owner. To request warranty service, please contact Terraplane Guitars with your proof of purchase, serial number, and contact information to obtain a RMA number.

Terraplane Squeal Killer

Pricing / Ordering Info

Power Supply Included

Power Supply NOT Included

Free Shipping to USA

For sales inquiries outside the USA, please contact us for a quote before purchasing.

Payments accepted online via PayPal, or by US Postal Money Order via traditional mail.

NJ residents subject to sales tax.

Product usually ships within two business days following receipt of your payment.

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Choose Power Supply Option:

Terraplane Resonator Guitar Co.
PO Box 6095
Bridgewater, NJ 08807

Tel: (908) 218-9229

©2017 Terraplane Resonator Guitar Co. • All Rights Reserved.
In the interest of continued product development, the specifications and/or appearance of Terraplane Devices are subject to change without notice.