monitor board
for allRevox B77


1.177.261-2022 new development
The circuit has remained Revox. What do you want to improve there?
The headphone amp is still one of the best that can be found in a tape machine! The switch-on delay with voltage monitoring is ingenious and has been copied several times by us from revox-online.

Nevertheless, some optimizations have also been made here.
Support capacitors on the ICs, no electrolytic capacitors, bypass capacitors, buffer electrolytic capacitors for the circuit board, current and procurable relays, peak displays on the rotary controls!
the technique

The circuit

Bypass

A total of only 4 electrolytic capacitors with 3 bypass capacitors.
If we cannot do without electrolytic capacitors, then the electrolytic capacitors get bypass capacitors. We only use high-quality electrolytic capacitors from Panasonic.
Electrolytic capacitors with bypasses Revox B77 monitor board
1/2 UB separate for right and left Revox B77 revox-online

1/2 UB separated


We at revox-online expect even better channel separation if half the operating voltage is separated for the right and left. There is less crosstalk, the spatial resolution increases. A measure that doesn't cost much, but makes more sense than using outrageously expensive cable!

operating voltage

We at revox-online expect even better channel separation if half the operating voltage is separated for the right and left. There is less crosstalk, the spatial resolution increases. A measure that doesn't cost much, but makes more sense than using outrageously expensive cable!
Buffering monitor circuit board revox-online
Old Revox B77 monitor card revox-online

Original

Very tidy and airy!
Due to the arrangement of the connections and trimmers, the new assembly is largely predetermined. The new relays, the 4 LED displays and the SMD assembly make the biggest difference.

the new board

The first version still has a hole grid area for any changes or extensions. 4 LEDs indicate the operating voltage, the release and the peak ( 6 dB) for left and right.
new monitor circuit board for Revox B77 from revox-online
Ground plane monitor circuit board Revox B77 from revox-online

ground plane

Separate ground planes, shielding planes for the right and left headphone amplifier, the mute switch and the measuring amplifier for the VU meter and peak display. The UB also come separately from a central point to the individual amplifiers. The new monitor circuit board has wide and 70 µm thick conductor tracks.
All amplifiers have their own voltage source. The current does not have to come from the distant power supply via additional strands, conductor tracks and various soldering points and is immediately available to the consumer.

adjustment

You cannot avoid a comparison of the VU meter and the peak display! Even if we check and preset the monitor board, this cannot replace the adjustment. You will need a 1kHz signal source and an accurate AC millivoltmeter to calibrate.
ATTENTION! Never lay the tape machine on its front!

Studer Revox B77, revox-online

Monitor circuit board from revox-online

We at revox-online have used all technical possibilities to guarantee the best monitoring of the audio signal.

if you want the best!

brand new monitor-PCB
1.177.261-2022

for all Revox B77 can be found in our shop
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