Delve-MST - 500 Series Mastering EQ

Shipping Times:

Shipping Methods and Timelines: We offer several shipping methods, primarily utilizing Canada Post for the time being. Customers can select their preferred method during checkout if the option is available, provided they have not reached the free shipping threshold (499.99CAD+). This is available for clients from Mainland USA & Canada Exc. Territories.

Orders within North America typically arrive within 2-4 business days after shipping out. International orders may take longer, averaging between 3-10 days depending on the region and any local transit delays, after shipping out. 


Order Times: We are currently a small operation and are building all items at the time of order. We have the pieces required to build them and they should be shipped out within 5-7 Business days. If there is any delays, you will be contacted.

For more info, read our full shipping policy

We are excited to introduce the Delve-MST analog shelving equalizer from KSJ Audio. Designed for the API 500 series format, this powerful and versatile equalizer offers a range of tone sculpting possibilities. Featuring high and low-shelf filters with 6 selectable frequencies, a gain knob with 12 steps of 0.5dB, and a boost/cut switch for each band. The Delve-MST provides a comprehensive set of shelving options for mixing or mastering engineers seeking a natural and musical sound, built on stepped switches, with low tolerance components throughout the unit.


The perfect frequency values were selected after immense testing. The low-shelf filters have six different frequencies, ranging from 16Hz to 380Hz, while the high-shelf filters offer 6 frequencies from 1.78kHz to 17.9kHz. The 12-step (Grayhill) rotary switches for gain provide precise control over the level of each band. The boost/cut switch lets you switch the action of a band from boost to cut or vice versa, without changing the gain applied. Each band has a boost and cut range from 0 - 5.5dB, in 0.5dB steps.

The Delve-MST is built with high-quality components and has an anodized aluminum front panel with metal knobs with a white indicator. Each unit is carefully handmade in Canada with low tolerance components, ensuring the best possible stereo-matching performance, recall & reliability. Additionally, the Delve-MST features a relay-based bypass switch for easy A/B comparisons - with no level drop! As well as an optional swappable discrete input stage with a 2520 Opamp footprint for added versatility in the tone of your equalizer.