Link Audio Design

SLQ51X Equalizer


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Classic console equalizer with new features and modern signal path.

Link Audio has recreated the classic E-series and G-series console equalizers for the 500-series. Each version of the SLQ51x is based on a specific revision of the original EQ with the addition of high- and low-pass filters.

The Brown was the earliest EQ built into the E-series desks. It is a four-band, shelving EQ with a switchable "Bell" mode for the LF and HF bands. Each band provides up to +/-15dB boost/cut. The mid bands have an adjustable Q factor, and the boost/cut amount is fixed relative the Q.

The Orange is a variation of the Brown with broader curves modeled on the Pultec EQs. The Link Audio version features +/-18dB boost/cut on each band. Unlike the Brown, the maximum boost/cut changes based on the Q.

The Black version is almost identical to the Brown but with +/-18dB boost/cut on each band. This version is known for saturating nicely when the boosts are cranked.

The Pink version removes the "Bell" switches and adds "3x" and "/3" switches on the HMF and LMF bands. This means that all of the bands operate only in shelving mode, but the LMF and LMF bands have twice as many frequency options. This version features the most boost/cut available per band at 21dB. The Pink is also unique in that the bandwidth of the filters increases with boost/cut.

Brown Orange Black Pink
HPF 80Hz, 24dB/oct 80Hz, 24dB/oct 80Hz, 24dB/oct 80Hz, 24dB/oct
LPF 8kHz, 24dB/oct 8kHz, 24dB/oct 8kHz, 24dB/oct 8kHz, 24dB/oct
LF 30-450Hz 45-450Hz 30-450Hz 30-450Hz
LMF 0.2k-2kHz 0.2k-2kHz 0.15k-2kHz 0.2kHz to 2 kHz, "/3" mode
HMF 0.6k-7kHz 0.6k-6kHz 0.6k-9kHz 0.6-6kHz, "x3" mode
HF 1.4k-16kHz 1.4k-16kHz 1.4k-16kHz 1.4k-16kHz
LF/HF mode Bell or shelf Bell or shelf Bell or shelf Shelf
Q Adjust Max gain constant w Q Max gain changes w Q Max gain constant w Q Max gain changes w Q
Max Cut/Boost 15dB 18dB 18dB 21dB

Full Features

  • High-quality pots (TT Electronics and Alps Alpine)
  • THAT 1246 input and THAT 1646 output stages
  • Runs on +/-16V in the 500 or in the GDIY 51X rack

Customer Reviews

Based on 5 reviews
Dillon Mckee
Amazing sound

Built 6 of these and man they sound way good. Thanks again for working with great companies

Too easy!

The kit is an easy enough build thanks to some very straightforward instructions, but the real MVP here is the amazing service by the DIYRE team! They definitely went over and above with my order. Fixing a late addition to my order AND a weird shipping error. Couldn’t ask for better service!

Black - Incredible EQ!

Is it magic? I think it might be.
Good instructions make a build like this possible for anyone, just take your time and double check. The finished product is well worth it!

Matthew Hatfield
Excellent EQ!

Built this module over the weekend and I’m very impressed with the instructions, high quality components and overall ease of the build. First test and everything works perfectly, sounds amazing too!! I’m very happy and will be purchasing another for a stereo pair soon!! :) Thank you!!

Eric Hernandez
Better than plugins for sure

I was actually surprised how good this eq sounded. I shot it out next to a plugin and this won pretty convincingly. I made a YouTube video about it if you’re curious. YouTube video placeholder

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