Tape speeds up at the end of playback!

[SongJohnn]

Hello everybody,

I just purchased an RT-1050 pioneer 2-track reel to reel recorder from about'75. Seller said the machine was 100% ready to go, callibrated and working perfectly.

The machine has the option to use large NAB 10" hubs or small 7" inch consumer sized reels, and the super small 5 inchers are what I'm using, and I'm running the machine at 15 ips. The reel selector is selected on the smaller on.

I just received it today, the machine seems 100% minty and operational in all other areas, but to have the reels start speeding up at the end is unacceptable in a recording environment, especially for mixing down and using it to make tapes compatiable with the 3340, another machine at 1/4" that runs at 15 ips.

Perhaps, and maybe this is entirely my fault, but the reels might be too small?? They are only small 5" reels as ooposed to the standard 7" inch reel. Is this my issue or should the machine still play the 5" reels at 15ips until the end?

thanks, John

 

[jpmorris]

This may mean that the pinch roller isn't pressing hard enough against the capstan and the reel tension is overpowering it.

 

[Tim Gillett]

It should be the other way around. Normally the tape should slow down towards the end of the reel, not speed up.
As JPM says it's probably a pinch roller condition/ pressure issue which you should check on, but also running 5'' standard reels is pushing your luck. The reel hubs are very small and it creates a lot of back tension at the end of the reel. Some makes like Revox B77 specify a minimum hub diameter which works out to be a 7" standard reel.