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Is there anyway to change the speed of my reel to reel deck?
Old 5th October 2008
Lives for gear

Thread Starter
Is there anyway to change the speed of my reel to reel deck?

I have an old Sony TC-651 reel to reel unit and I want to be able to make the speed variable. I want to be able to just turn a knob and have the reel motor change speed in real time. I saw that Teac once made a variable speed control unit:

that you could hook up to do this with a teac machine. I'm wondering if that would work with my sony deck or if there is another way of doing it. The sony deck has a built in stereo tape echo and I wanted to be able to control the speed of the echo effect.
Old 5th October 2008
Lives for gear

You would have to tap into the drive circuitry of the capstan motor if the deck uses a DC servo type drive.
This would be a seriously difficult and costly job unless you know electronics really well.
Not many techs will know the circuitry, so it will take some experimentation and that'll cost time and money.

If the deck has a provision for the unit you have pictured then it would be possible.

If the capstan motor is an AC motor you could build a VSO out of a variable oscillator and a power amp.
That doesn't sound too fun or feasible either, does it?

Varying the speed too far on cheaper AC motors will also cause them to fail from heat build up.
The pro decks like Ampexes and Studers where people did use VSO by means of an oscillator and amp DID have fairly robust motors, but when slowed enough they DO get VERY hot! Motors don't like to run hot.

Look for a deck with VSO or a speed control
I just sold a pair of Technics 1500s for $150.00 each and they have VSO or vari-speed.
They are out there and cheap.
Old 5th October 2008
Lives for gear

Thread Starter
ok awesome thanks for the info. I'm just using this as an fx unit and wanted to control the speed of the built in stereo tape delay. Would be great if i could find another old cheap reel to reel that had this effect but also had a variable speed knob. Looks like this Sony deck is an A/C unit with the option to switch between 50 and 60hz. I did see some speed control units on ebay used for tools with A/C motors. Not sure if something like this would be compatible with this Sony deck though:
Variable Speed Rheostat Control Electrical Motor AC/ DC - eBay (item 260295718619 end time Nov-02-08 18:22:09 PST)
Old 5th October 2008
Lives for gear

It is more complicated than looking at the AC mains input for the deck.
Still, that might give you an option.

There were two main types of motors used in tape drives.
AC where the Mains AC frequency determines the speed of the motor and DC servo where a more complicated system provides a DC current to the capstan motor,
The DC servo motor is more stable, but more expensive.
DC servo motors were found on more expensive decks.
I am sure some TEACs had them, but not many.

The 50/60 HZ switch might allow some speed variances though.
Because it won't hurt the deck's electronics to run at 220V/50hz when actually powered by 120V/60hz you might get a speed variance there.
The electronics will be starved, but who knows?
Maybe it'll sound interesting.
I think the deck will run at the wrong setting.
I bet it will run slow, but it might still be locked to the 60 hz line freq.
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