# **Description:** # MC-5 is a variation of the Custome Audio Electronics (CAE) MC-401 Line Driver and named after a Detroit rock band. My version is adapted from schematic traced by ???(found on a Russian website). The orginal version was based upon 9Vdc oepration. This version uses a supply inverter to provide a bi-polar supply and increase the headroom and allow the output to reach a full +23db. The same could have been done by doubling the +9Vdc, but would have required more pcb real estate. This PCB should fit within a Hammond 1590A enclosure. # **Changes from original MC-401 circuit.** # 1. OPA2134A used instead of LF442. While any dual op amp can be used, the OPA2134 provides the same input and output impedances as the LF442. The OPA2134 available at Tayda electronics. 2. The unused op amp is used as unity gain input buffer. 3. As described above,+/- rail operation 4. The High Pass Filter frequency was lowered a bit to allow the low B of 5 string bass frequencys. **Update** 12.25.2018 - Built this on vero board after being annoyed with Easy EDA Online router constantly timing out and fitted into a Hammond 1590A. 01.02.2019 - originally designed around the OPA2134 op amp, notes were crisp and clear however there was an annoying high frequency oscillation produced that could be faintly heard with gain at full when a note was plucked. Swapped in a TL082 and sounds perfect! **# References: #** Note: Datasheet specifies input impedance as 1k, other spec sheets at 1M https://vidweb.aws.marketlive.com/jimdunlop_vid/text/content/pdp/manuals/MC401.pdf