LC4B - NEW INDUCTOR EQ!!

11/28/25 - (3) In Stock. Additional units being built.

NOTICE: IF THIS ITEM SHOWS 'SOLD OUT' ABOVE, CLICK HERE TO PRE-ORDER WITH A $50 DEPOSIT.

Questions: info@resistanceaudio.com

***FULLY BUILT AND TESTED WITH WARRANTY***

NOTICE: The LC4B Requires (1) Opamps to function. Please choose from the list above, or select 'No Opamps' if you are installing your own.

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.

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 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).


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

Note, the LC4B includes the upgraded Litz Wire transformer option.