tape speed otari 5050

[Seditionary]

i'm sadly from the digital generation... so i have an otari 1/2" calibration question.

when i send a click track at say 140 bpm to our otari 5050... and then play it back into the daw... it is a tiny bit sped up.  it will come back in at say 140.2bpm  -- i have a speed knob on the otari... i could always slow it down a tiny bit manually before sending it back to the daw...

but for accuracy sake... is there a way to adjust the whole tape machine so that it doesn't speed up a bit when recording/playing back?  i know this is probably some calibration thing.  would love to know how to tweak it just the slightest bit.  it is pretty close... so maybe i shouldn't mess with it... and just change the bpm once i got back into the daw.  would love to know any tape heads' thoughts though.

thanks! 

 

[RuudNL]

I don't have a circuit diagram of the machine, but after reading this I get the impression that during recording the tape speed is 'fixed', but during playback the speed can be variable. Usually there is a switch to activate variable speed, but I think there will also be a trimpot to set the 'fixed speed' during playback.

Edit: found the schematic: http://analogrules.com/manuals/otari_manuals1.html

 

[nielsk]

The only way to get an analog tape machine to record & playback at a constant speed from head to tails is resolved & synchronized.

 

[Seditionary]

cool.  so i take you to mean... it is tape... it isn't going to play back at an exact speed

 

[david-p]

cool.  so i take you to mean... it is tape... it isn't going to play back at an exact speed

You can adjust the speed for both record and replay at the same time.  If the record speed is right, the replay speed will also be right, however, without a sophisticated system (which the Otari does not have) the speed can vary a little from one end of the reel to the other.  The speed stability of an older machine may benefit from a thorough cleaning.

David

 

[PRR]

> i'm sadly from the digital generation...

The clock on my wall, the big hand comes to the top, the show ends and we go to ads and station ID.

140.0 to 140.2 is 5 seconds in an hour. I expect canned programs to run a few seconds long/short, meaning I'll shave or stretch the fill matter to fill out the hour.

That's good accuracy for a non-synchro tape. The better Ampexes in new condition would do better, but in real use often did worse. I'm sure it is within Otari's specs.