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3-Band Equalizer DIY Kit

DIY Kits


In Stock

This DIY kit contains all electronics and enclosure materials to assemble a 3-Band Equalizer. The printed circuit board is partially assembled. Simply solder the included capacitors, potentiometers, and jacks to complete the circuit, then install in the included enclosure. 


This fun project has been on the shelf at JDS Labs for more than a year, postponed by long lead times of its high quality film capacitors and rare potentiometers. While you can probably find a software equalizer for your favorite music app, this hardware EQ is fully analog in nature, so it works with every app and avoids digital re-sampling. Kit pricing makes the EQ most affordable.

The JDS Labs 3-Band EQ has a wide adjustment range of about ±15dB for bass, mids, and treble. While the point of an EQ is to color your listening experience, the JDS Labs 3-Band EQ achieves low THD+N with its knobs in their neutral positions.

A muting relay eliminates turn on/off transients, and when the EQ is switched off, the original audio signal passes directly to the RCA output jacks.

3 Band EQ - DIY Assembly Guide
3 Band EQ - Frequency Response Curves

Note: We will ship PCB v1.40 with two relays. The photo above has not yet been updated.


  • THD+N, 20-20kHz 0.0022%
  • Noise (A-Weighted) -104 dBV
  • IMD SMPTE 0.0009%
  • IMD CCIF 0.001%
  • Input Sensitivity >2VRMS
  • Crosstalk (1kHz) -69 dB
  • Bass Control ±16.5 dB
  • Mids Control ±14.9 dB
  • Treble Control ±15.2 dB


  • Case Dimensions (mm) 108.50 x 80.00 x 29.50
  • Case Dimensions (in) 4.27 x 3.15 x 1.16
  • Weight 12 oz


  • Input RCA
  • Output RCA
  • Power 15VAC

Packaged Items

  • 3-Band EQ PCB v1.40 (QTY 1)
  • Aluminum Knobs (QTY 3)
  • Aluminum Enclosure Body (QTY 1)
  • Aluminum Front Plate for EQ (QTY 1)
  • Aluminum Rear Plate for EQ (QTY 1)
  • C1, C5 - BFC237510911, 910pF Film Cap (QTY 2)
  • C3, C6 - FKS2D014701A00KC00, 4700pF Film Cap (QTY 2)
  • C4, C7 - FKP2D006801D00JSSD, 680pF Film Cap (QTY 2)
  • J1 - PJ-002AH (QTY 1)
  • *J4, J5 - PJRAN2X1U01AUX (QTY 2)
  • *RL1, RL2 - EC2-12NU (QTY 2)
  • *S2 - 100DP1T2B4M7QE (QTY 1)
  • *VR1, VR2, VR3 - RK09L122002M (QTY 3)
  • *We may ship alternative, equivalent part numbers as inventory changes.

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