Classic Audio Products of IL CAPI LC4B-Litz EQ 2025

The LC4B signal path starts with an OPA134 setup as a balanced receiver. Following are 4 mostly identical OPA134 circuits each used for one of the 4 frequency bands. Next we have a 2520-style discrete output amplifier followed by a 2503-stye output transformer wired 1:3 for 9.5dB of gain (in typical API EQ fashion).

Each of the inductor/capacitor filter networks are in the feedback loop of an OPA134 opamp. The peaking curves have a proportional Q as would be expected with an LC filter. The LC4B is not a common "swinging inputs design" like the 553F or the retired LC53A. Due to the filter topology the curves are a bit wider at lower cut/boost amounts.

The LC4B is not a copy or clone of anything but the filter topology is inspired by the middle bands of the old ADM 1540. With this EQ you can expect amazingly sweet musical and forgiving curves. No matter how heavy-handed you get with the LC4B its nearly impossible to ruin a track.

Key Features:
Balanced receiver stage (no 6dB loss when driven electronically)
Custom EP core inductors wound in the USA
Full and complete zinc plated steel enclosure
All stepped controls for definite and repeatable recall
4 overlapping frequency bands
One octave bandwidth
100% VPR compatible

Come with the GAR2520 ver.4.1 Op-amp

API (and compatible) Lunchbox and VPR500 racking systems.

Fully built to perfection in Canada with a 1 year warranty.

These can be also build to order, please visit my website for that, bywaudio.com