Hello.

I own an old Nagra 4.2 mono machine. It has an accessory input on the side of it that was designed for a device that can control (or 'correct') its speed. I do not have this device and it seems impossible to find, thus I was thinking of making one myself.

Here is a video of the device being used:

https://www.youtube.com/watch?v=BLjeSAPiOek&

And here are the pin designations of the input (it's built for a 6-pin Tuchel input):

https://imgur.com/yDzv2eo

Would this job be as simple as getting some potentiometers and dials, and wiring them according to the necessary designation or is their more to it involved? I'm not necessarily new to soldering or making cables or anything, but there are a lot of gaps in my knowledge.

Alternatively, would there be a way to use CV to talk to this and alter the speed?

Any help is appreciated, thanks!

HAINBACH!
https://www.youtube.com/watch?v=HT2mfuuGDM4

Indeed!

That video was what got me thinking. He's using a different model than I own, his has a nice CV input for controlling speed. My 4.2, which he also owns, has nothing but an empty hole where the "speed" input I guess would be. Unfortunately, I'm not smart enough to do anything with that. But I noticed that there is another input for the speed varier device I mentioned above, which I hope to use to my advantage in some way.

This is a truly beautiful machine. Have you tried the sv mod yet? How did it go?!