McMartin LR-1004C Compressor #1


In prep now…

The McMartin LR-1004C is a vintage diode compressor from the early 70s. Very much a colour compressor, the McMartin is ideal for drum compression & extreme limiting effects

As standard the LR-1004C has fixed attack & release times. I’ve added potentiometers for these controls and modified the release circuit to allow much faster release times. This allows extremely short release times, making compression effects more pronounced

The standard LR-2004C doesn’t always play well with modern gear – it’s a 600Ω device so doesn’t match well and the input pot is extremely touchy. I’ve built a custom switched input attenuator to allow better matching and to give 11 levels of input attenuation from mild compression to total distortion

As the input level is increased the sound from the McMartin becomes more & more dense & saturated. It’s easy to dial in relatively small amounts of compression, but pushing the input, and shortening attack & release times, makes it possible to have massive pumping compression

Modifications include:

  • conversion to 220 Volts for UK / EU
  • upgraded power supply
  • balanced XLR input & output
  • custom input attenuator
  • attack & release controls brought out to the front panel
  • full recap
  • new knobs & pots

I have a pair of LR-1004C compressors modified for sale. Photos to follow


Rackmount diode compressor / limiter from the broadcast industry

Standard 1U device


In excellent used condition. The compressor has been refurbished, modified & recapped in our workshops and is tested & working 100%. Photos to follow