JLM Audio GEQ500 / API 2520 / 500-Series Mono EQ – Custom Build

Previously offered as a stereo pair, these custom-built EQs are now available individually. This listing is for ONE mono module.

US$800 per module, including EMS shipping from Japan.
Import duties and taxes are not included.

ABOUT THIS UNIT

Custom-built from the JLM Audio GEQ500 kit, this 500-series 16-band graphic EQ features a genuine API 2520 discrete op-amp manufactured in 2009 and a JLM2503 output transformer.

Built, tested and adjusted by me at Altphonic Studio in Tokyo, Japan.

FEATURES

• 16 frequency bands from 25 Hz to 25 kHz
• Three selectable boost/cut ranges: ±3, ±6 and ±12 dB
• Genuine API 2520 discrete op-amp, manufactured in 2009
• JLM2503 output transformer
• Nichicon audio-grade electrolytic capacitors
• Toshin Kogyo film capacitors and polystyrene capacitors

The ±3 dB range is particularly useful for subtle tonal adjustments, while the ±6 and ±12 dB settings provide more pronounced shaping. A versatile EQ for vocals, bass, kick, snare and other individual sources.

To my ears, the API 2520 and JLM2503 combination adds a pleasing harmonic character. The additional frequency bands and selectable ranges make this a flexible alternative to a conventional 10-band graphic EQ.

BUILD QUALITY & ATTENTION TO DETAIL

The genuine API 2520 is only one part of this custom build. I also carefully selected the resistors and capacitors, and used premium solder throughout the assembly.

Every stage of the build received close attention, including soldering technique and temperature control. After assembly, I tested, measured and adjusted the unit using PluginDoctor.

Taking the component costs and the time spent on assembly, testing and adjustment into account, my total investment exceeds the asking price. The price reflects the complete build and the care involved, with EMS shipping from Japan included.

TESTING & CONDITION

Frequency response and EQ operation have been checked using PluginDoctor. Hardware photos and measurement screenshots are included.

Some measurement images show both modules from the original stereo pair for reference. Only ONE module is included in this listing.

Please review the photos for cosmetic condition and signs of use.

WHAT IS INCLUDED

• One JLM Audio GEQ500 custom-built mono EQ module

A compatible powered 500-series chassis is required and is NOT included.

This is a DIY/custom-built unit based on a JLM Audio kit, not a factory-built API or JLM Audio product.

SHIPPING

Ships from Tokyo, Japan via Japan Post EMS. EMS shipping is included in the asking price.

Please contact me through Reverb before purchasing to confirm shipping availability to your country and any applicable import charges. Import duties, taxes and customs-related charges are not included in the price.

Questions are welcome—please send me a message through Reverb.