We thought it was time to look at another classic compressor/limiter in our arsenal. And so, we decided to take an in-depth look into the Neve 2254.

History
In the late 60’s, David Rees worked alongside Rupert Neve as a design engineer. David had worked for BBC previously and allegedly had first come up with the original model (for its predecessor, the Neve 2253) as nails on wood with soldered wires.

This eventually led to the release of the classic Neve 2254 mono compressor/limiter in 1969, which also became the standard unit inside their 80 Series consoles.

Design
The input stage features an input transformer followed by a diode bridge which acts as a level control element. This bridge relies on the dynamic resistance of the diodes changing with current provided by the control voltage.

Due to their non-linearity, diode attenuators tend to have high distortion levels. To combat this problem, the level was dropped about 40dB in front of the diode bridge. Doing this brought the distortion down to an acceptable level. A second transformer takes the output and passes it to an amplifier chain (the BA183/283).

The make up gain element is actually a 20dB attenuator, with the make up gain reducing the amount of attenuation. So in total, there is a 60dB loss and subsequent amplification in the device, which means the noise floor gets raised quite a bit. This is very common for diode-bridge compression designs, and is one of the reasons later compressor designs more often than not featured alternative control elements. Neve quotes the noise floor at being around -73dBm (20Hz – 20kHz), without any gain reduction.

And lastly, a third transformer drives the output from the device.

Sound
The sound of the 2254 is often described as creamy, warm or round. One of the characteristics of this compressor is that it’s quite limited in parameters. Therefore, when choosing a master bus compressor, people tend to go to its brother, the 33609, which has more flexibility.

The 2254, especially if you have them mounted in a stereo rack, is great for thickening up or toning subgroups, such as drums for example.

Functionality and revisions
There are 4 major “revisions” of the 2254. The original 2254, the 2254A, the 2254E and the new replica, the 2254R.

The unit has 2 chains controlling the level control element. One is the compression and another is the limiting, where we will have a quick look into below.

    • Compressor

The compressors’ attack is fixed at 5ms, while the threshold, ratio and release (recovery) are selectable. The possible ratio settings are 1.5:1, 2:1, 3:1, 4:1, 6:1. The threshold goes from -20dBU to +10dBU in 2dB steps. Recovery time is selectable between 400ms, 800ms, 1500ms or auto.

In the auto position, both the Attack and Recovery times are composite and self-adjusting. Speeds are rapid for isolated peaks, while remaining slow for persistently high levels.

    • Limiter

The limiter section has a variable threshold and recovery time. The former can be set between +4dBu to +20dBu in 2dB steps, while the latter is selectable between 100ms, 200ms, 800ms or auto.

The 2254/A has a fixed slow attack time of 5ms, while the 2254/E and later versions have the option for a faster attack time. The latest 2254/R has the option to set the attack time between 100microseconds and 2ms.

Fun-time
And now, as you can expect from us, it’s time for some fun again. What we did? We created a simple drum subgroup without any previous compression and we ran it 3 times through our Neve 2254/A. Once in bypass, then again but with a 2:1 ratio and one last time with a 6:1 ratio. After having recorded the results, we matched loudness levels by ear. Below in our widget you can click on each of the 3 buttons to start/stop playing each specific setting. Have fun!

Written by Abbey Road Institute Amsterdam