The 444 is a clone of a 4-band mastering EQ unit with optional M/S operation. It is 500/51x compatible and can be run at a variety of operating voltages.

Features:

• Transformer-balanced output, hybrid transformer/5532 IC balanced input
• 4-band parametric operation, Hi/Lo Q switches on each band, shelf/bell switches on low/high bands
• Uses Quad8 AM-10 discrete op-amp

Price:

• ~$350-$400 per module, depending upon transformers used
• Circuit is currently (6.29.2014) in final stages of prototyping, however entire project documentation is available below

More Information:

• View the GroupDIY documentation thread