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Low-Cut filter : 80 Hz (24dB/oct) – modifiable
Low frequency band : 30 Hz to 450 Hz – Bell or Shelf mode
Low Mid frequency band : 0.2kHz to 2 kHz – full Q Adjust (Maximum Gain stays constant with every Q Setting)
High Mid frequency band : 0.6kHz to 7kHz – full Q Adjust (Maximum Gain stays constant with every Q Setting)
High frequency band : 1.4kHz to 16kHz – Bell or Shelf mode
High-Cut filter : 8 kHz (24dB/oct) – modifiable

Maximum 15 dB of boost/cut gain per band (center detent)

High quality pots (TT Electronics and Alps Alpine)

THAT 1246 In- and THAT 1646 Outputstages


Its running on +16V/-16V in the 500 API Standard/ VPR Rack or in the GDIY 51X Rack

Here are some listening samples

Soundcloud SLQ51X

Soundcloud SLQ51X Comparison Test


Build Guide
All our Build Guides


GDIY Help Thread
GDIY Help Thread

SLQ51X Brown

PriceFrom €274.84
Excluding Sales Tax
  • The SLQ51X Brown is a must-have for any audio enthusiast who wants to achieve a classic vintage sound. This program equalizer is designed in the 500 API format and is based on the iconic 4000 Brown (E02) Equalizer. Despite being the oldest and most affordable option, it has been used by numerous engineers to achieve incredible results. With its sleek design and powerful capabilities, the SLQ51X Brown is the perfect tool for any DIY audio project.

    Very Flexible and very precise calibration for all needs. We added to this 4 Band Equalizer a Low and High Cut Filter to make it more flexible in Mixing or Recording situations.

    Improved Build - Easy Final Assembly, New Testpoints, BROWN Colour Caps

    • Shipping will be calculated depending on your location
    • Standard Shipping with DHL
    • UPS Express Saver as Option in Checkout
    • Free Standard Shipping in Europe on orders over 100€

    Return of untouched Original Products is possible during a time of 14 days after receiving your article, check our Return Policy



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