CBS Volumax 4110 Stereo Compressor / Limiter


This Volumax is being refurbished. Photos and updated details to follow

The CBS 4110 is a classic broadcast limiter much sought after for its creamy sound & compression characteristics. It was originally used in broadcasting to maximise loudness and helped define the sound of 1970s radio in the USA

The Volumax was often used to partner the CBS Audimax and the pair became known as “The Max Brothers”. The Audimax was the Automatic Gain Control (AGC) part of the duo and the Volumax controlled peak levels to avoid “overs” which would overmodulate the transmitter

The Volumax has four sections: it splits the frequency range into three bands and processes them separately before feeding the signal to an instantaneous limiter for final peak level control. Used with restraint the Volumax can give clean, effective peak limiting but, when hit with higher input levels, it pumps quite dramatically, instantly delivering that classic 1970s radio sound. If you like your compressors mean & gnarly, the 4110 will definitely float your boat

These units were built to extremely high standards to conform to broadcast specifications. As a result they are reliable and well-documented. They’re suitable for modification – they are transistor-based and use through-hole components, the best available in the early 70s

The front panel of the 4110 has input & output level trims. In a broadcast chain these are designed to be set once & left. In a studio they can be tweaked to suit. In the centre is a gain reduction meter with green “Normal” and red “Heavy” sections but, in practice, your ears will tell you what is going on

“The “Max Brothers” of the 60’s and early 70’s gave Top-40 music a sound that, for me, increased the enjoyment of the music. Classic processors”

“I noticed that excessive input creates huge compression density and also makes these things pump like mad! I have heard them called Max Brothers, Audi Axes, Audi Smashers and Maxi Squashes”

“As long as the levels were within the floating window it wouldn’t keep chasing them. Not that it would stop the PD from cranking the input attenuator to make the box compress constantly. 😆 That’s where the gain pumping came in. Adjusted properly, they didn’t”

“A true Top 40 sound was A LA3A + Audiomax (set fast) + Graphic Equalizer + Volumax + Plate Reverb! Dub all the music to cart with a DBX118. Now that was Radio! LA3A”

“The Audimax was meant to gently ride gain and keep levels in the right ballpark to drive the Volumax at its “sweet spot” (much as one might use Ahpex’s Compellor ahead of their Dominator limiter). The idea was to second-guess sloppy board ops”

Inputs & outputs are on barrier strip and accept balanced or unbalanced signals. Supplied with a set of pigtails terminated with XLR connectors wired Pin 2 Hot. Front panel input & output preset controls allow channel matching and compression threshold setting. Standard operating level is +4 dBu and the operating manual has details on matching, time constants and compression characteristics.

The power supply has been rebuilt & upgraded with all new parts - UK 220 Volt transformer, rectifiers, smoothing & decoupling capacitors. The rest of the electronics are original

Deep 19" 1U device suitable for 19" racks. 220 Volt AC supply required

Operating manual,%204110%20Manual.pdf

Gearslutz thread

Broadcast Engineering discussion

Radioworld discussion


Vintage unit dating from the 1970s. In excellent condition electronically. In average condition cosmetically with the usual rack rash and case scratches

Vintage Gear

All vintage gear will have case scratches and marks. It may also have, or develop, noisy pots and switches. I make my descriptions as accurate as possible and note any existing defects. I test each item before shipping but please understand that vintage gear will not be perfect and adjust your expectations accordingly