CP554 Diode bridge compressor (mono)

The CP554 is a transformer coupled diode bridge compressor based on the design of legendary British consoles, adapted to the '500' format.

It is the ticket to immediate access to the classic, harmonics-rich sound of the seventies.

The CP554 adds some features to the original such as a variable attack time, one additional 12:1 ratio or a high-pass filter in the side chain with three frequencies.

Highlights

• Three Carnhill transformers in the audio path,
• Same output stage as in the MP573 preamp,
• Variable attack time,
• Additional ratio of 12:1 makes a limiter,
• Side chain EQ with 3 high-pass frequencies,
• External side chain input,
• All stepped controls,
• Analog gain reduction meter,
• High grade electronic components throughout,
• High grade four layers PCB,
• Available assembled or as a full kit (everything included).

Controls

1    STEREO Connects two compressors in stereo. Whichever unit receives the loudest signal at any moment, controls the sidechain

2    Meter displays the gain reduction in DB.

3    THRESHOLD Rotary switch that sets the input level at which compression begins, from -21 to +12 dBu.

4    RATIO Rotary switch that sets the compression ratio from 1.5 to 12.

5    ATTACK Rotary switch that sets the attack time from 0.5 to 16 milliseconds.

6    50-100-200 Hz Inserts a 50, 100 or 200 Hz high-pass filter in the side-chain. Produces a Fat sound and eliminates bass driven pumping.

7    BYPASS Hardware bypass by relay (when button is released).

8    MAKEUP Rotary switch that restores the signal level after being compressed.

9    RECOVERY Rotary switch that sets the release time from 100ms to 1.5 second. The A1 and A2 positions set 2 automatic release times which are program dependent (fast on isolated peaks but slower for the average level).

10    SIDE CHAIN Controls the source for the side chain. It can be INT: internal, OFF: No compression, EXT: the side chain comes from the second input (the module is 2 units wide)

What's in the kit?

Absolutely everything!

• 3 Transformers,
• Passive components (resistors, capacitors),
• Active components (diodes, transistors, IC's),
• Front panel elements (switches, potentiometers, analog meter, knobs),
• Connectors, relays,
• PCB's,
• Front panel and side panels,
• All hardware.

You bring the solder (use good quality solder, 1mm diameter max) and the Lunchbox.

 

 

Difficulty level

The CP554 kit is a medium difficulty kit. Nothing difficult but a large number of components.

The setup is simple but requires using a good quality digital multimeter.

Product Options

XT500 Extender: The XT500 option is a cable extension that allows you to test and setup the module outside the lunchbox while connected.

501 Case: The 501 case option is a standalone, single slot lunchbox with PSU.
The XT500 Extender is not needed with the 501.

Assembled Product: If you prefer not to DIY, choose an Assembled product. It comes fully assembled, ready to use.

Technical specifications

Documents

Media