1968 Langevin AM4a Mixing/Summing Console. Photo by Pandemic Studio Shop.
This week's fresh Reverb find is a very special Langevin AM4a mixing/summing console. This console has been heavily modified with upgrades and has gone through a full restoration on top of it. According to the listing, Rob Harvey of World Pro Audio in Los Angeles was the engineer behind the $12,000-worth of work that has been put into this special board.
Here are some of the highlights of the Langevin AM4a console's restoration:
- All pots, switches, and connectors have been given a deep cleaning using WPA Brown Stuff (oxidation remover), CRC QD Electronic Cleaner, compressed air, MS Contact ReNu, and lube
- A brand-new XLR rear panel was fabricated for all inputs and outputs
- An additional power supply, decoupling resistor, and capacitors were added to each module to reduce crosstalk from power supply rails
- Faulty transistors, broken capacitors, and all other needed repairs were made
- All electrolytic capacitors were replaced
- Incandescent lamps in each channel's circuit were replaced or installed in those missing them
- Eight line input transformers were added ahead of already existing line input pots (upgrade of existing passive mixer) and mute toggle switches were replaced on all 8x mixer channels
- Four bus modules were modified for lower hiss and hum—first gain stage was changed to a Jensen JE16A transformer, followed by Hardy 990s
- Slight changes were also made to chassis and summing bus grounding to lower hum
- Bypass switch was added on four bus modules. Sonic differences include noticeably brighter sound when bypassed and a slight improvement in bottom tightness while the frequency response remains the same so that transient-handling is improved
- VU meters were calibrated so that +12 db = 0vu (8db hotter than normal studio level of +4db, as this console sounds best at a hotter level)
With all of its restoration work and upgrades, this console is truly one-of-a-kind. If you'd like to learn more or make an offer, follow the link to check out the full 1968 Langevin AM4a Recording/Summing Console listing on Reverb right now.