Audvance upgrades for your classic B77

The only board that I offer for Dolby equipped machines is the monitor board.

If you enjoy to listen to your recordings via headphones the new monitor amp is what you need. A high quality class A headphone amplifier is included on this board.

Monitor amp 1.177.900.00

• Class A discrete MOSFET headphone amplifier
• Superior sound quality with short signal path and high quality components
• High power to drive any headphone
• Output impedance <1 Ohms
• Extended bass down to 18Hz (-3dB)
• Pre-calibrated VU meter settings
• Handbuilt in the Netherlands

This all new designed board contains a high quality stereo headphone amplifier. This amplifier operates in Class A for highest sound quality. It is much more powerful than the original amplifier and able to drive any headphone. The extra power comes from a SMPS power supply on this board that has to be connected to the mains. A cable to connect it to the mains entry connector of your Revox is included (soldering is needed by a qualified technician). The amplifier is a simple discrete design without overall feedback, resulting in a transparent sound, with lifelike staging and rich natural tones of instruments and voices. Plug in your headphones and enjoy! This board also contains the electronics to control the VU-meters and peak level indicators. These will all be pre-calibrated but you may wish to fine tune it for your machine. Just pull out the old board and plug in this new one. The board is too large to fit in B77 MKII machines (the tape tension switch PCB is in the way).

Details of this board and instructions can be found here.

Price: € 399

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If you have inqueries please email me at

About Me

Audvance amplifiers and boards are designed and handbuilt by Emile de Vlieger in The Netherlands. He is a specialist in analog electronic circuit design and started his career in 1990 at Philips Electronics, designing electronics for microchips. After 11 years with Philips he started his first audio company. In 2017 he started the brand Audvance Audio.