Tape tension switch for Studer Revox B77
1.177.138 spool size and speed
If you want to evaluate the selected reel size and speed for the Revox B77 MKI, just like with the MKII, you need this tape tension board. On the Revox B77 MKI up to serial number 53,521, only the spool motor voltage is switched between 43 V and 55 V. The drive control of the earlier units is not aware of this. There is no input on the drive control for tape tension (spool size) or the selected speed. From serial number 53,522 up to serial number 99,999, the drive control evaluates the reel size. In this case, our new tape tension board is sufficient to also evaluate the selected speed.
About solder bridges
the device version can be set
Tin bridges
The tape machine version can be selected using 14 jumpers. We don't know which tape machine you have - this circuit board always fits all Revox B77s!
Super Low Speed
Only at super low speed are two bridges set. Here, the deceleration = 0 and is still too slow! At all other speeds, four bridges are always required!
Low Speed
Place tin bridges at the points marked in red, and that's it. The delay is approximately 20 ms.
Standard
Here, too, four tin bridges are required. The delay is barely noticeable, amounting to a few milliseconds.
High Speed
Here, too, there are four bridges. The maximum delay is 200 milliseconds.
All of this is described in detail in the included instructions. We can also manufacture the tin bridges here on-site according to your specifications.
Evaluation
We at Premium-Hifi do the evaluation not only for the pre-run phase when starting up in Play or Record so that no loops are formed.
We use it to adjust many other parameters. The recording delay, the duration of the electronic braking, and other times are optimally adjusted for any speed!
Connection
cabling
The speed signal must also be routed to the circuit board via ground, and on the B77 MKI up to serial number 53521, the tape tension lines to the drive control must also be routed. Since there is no pin for the S-Speed signal in the machine, soldering is required here. The soldering points are very accessible, however!
Solder
Both connections (green = S-SPEED, black = ground) that need to be soldered are located on the power supply board on the outer connector, making them easily accessible! The board comes with two cable ties and two M3 x 10 screws for securing the board and the wiring harness.
Motorspannung
The 43Vac and 55Vac motor voltage connections can be plugged into the 2.8 x 0.8 flat connectors. These are soldered on older versions of the Revox B77. You can then use the flat connectors as soldering points and solder the connections there. It would also be possible to solder directly onto the switch, but we advise against this!
new tape tension board
To allow you to evaluate both the reel size and the current speed for early series tape machines (Revox B77 MK I up to serial number 99,999), we designed the new Tape Tension PCB 1.177.138-22. Here, too, we have the greatest possible separation between the motor voltages and the operating voltage!
Tape Drive Control
The new drive control
Only for the Revox B77 MKI up to serial number 53521, you need the new drive control to be able to evaluate both the selected speed and the reel size. For the Revox B77 MKI from serial number 53522 up to 99999, the change with the speed evaluation takes effect automatically, thanks to the hardware.
Tape Tension Connection
We adopted the markings from the original drive control (or and vio). Since the new electronics only query the resistance value, the pin assignment is completely irrelevant. Our wiring harness is designed so that the orange wire is slightly longer. The wire colors may also vary. Orange can also be yellow, red, or pink - depending on availability.
the required strands!
brand new tape tension
1.177.138
for all Revox B77 you can find in our shop
