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AMPEX reel tape auto-reversing Tones? DOWNLOAD or info?

bradman16

bradman16

Member
Hi I am trying to track down these test tones that were put on the AMPEX pre-recorded reel to reel tapes. I understand they are a 20Hz rumble of sorts? Can someone provide specific information as to what works exactly - or even better, does someone have a source/link where I could download these tones to add to my home-made tapes? Even if you can't supply a link to download them, can someone be specific with what the frequency is, how long it is etc so I can create the tone myself? I would really appreciate it. I have looked around the Internet, and there is a fair bit of talk about these tones, but no one seems to really know what they are exactly - any help here would be greatly appreciated.

( these are for some ampex decks with the auto reversing system that senses these frequencies on ampex tapes and thereby reverses the tape, similar to how some sense a foil leader, they detect a frequency; I guess I could buy an Ampex tape off ebay right?)
 
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I don't know what the frequencies are but perhaps you could record them from the end of an existing pre-recorded Ampex tape and transfer that recording onto the end of the tape that you want to reverse. I don't know if this would work but its worth a shot. I'd imagine if you record and transfer the tone digitally there would be no signal deterioration so the machine should be able to pick it up, and if you save the recording you could use it over and over again. I wish all reversible reel to reel machines used this system, it's such a logical way to handle the task of triggering a mechanism.
 
If you have a service manual for one of those Ampex auto-reversing decks, it should indicate on the tone decoder schematic what the frequency of the tone is, I would think?

Just a thought.

Dave
 
When my 2050 worked, the tone wasn't generated from an oscillator; instead there was a magnet on some kind of a reed-shaped spring that was plucked by a metal finger when the record selector was rotated. The magnet moved near a coil and the induced currents were fed to the left channel only (and the other signal to the recorder's inputs were muted).
 
JBL GUY said:
IIRC it is 25 Hz.
Click to expand...

Yes, I heard 20Hz, try both? I imagine you thought of the idea of taking the tone off a pre-recorded tape too, right? As mentioned above...but if you are like me, downloading or making a tone is easier if you are not set up to record FROM the reel tape...let us know what you find if you can?
 
Would it not be possible to find the correct test tone and burn it to a cd similar to the ones included in the better speaker refoam kits???..just sayin'
 
I have two "Herb Alpert & the Tijauna Brass" tapes that have the tone. And they are only on the original editions of the tapes. Later editions omitted the tone.
 
breeze73 said:
Would it not be possible to find the correct test tone and burn it to a cd similar to the ones included in the better speaker refoam kits???..just sayin'
Click to expand...

Yes, that's a good plan. That is what I did, I just got an ampex tape and hooked it up, ripped the tone to the PC then to the CD for archival purposes. I was just being lazy and wanted to download the tone rather than have to put the R2R where I could plug it into my sound card etc...thanks for your advice, appreciated
 
Did this actually work? I'd be interested if the tone would trigger the auto-reverse when recorded to PC, burned to CD and then recorded back to tape.
 
It would be really easy to synthesize the pure tone and put it on a CD. If anyone wants to send the tone to me as a file, I can do that and make a pure tone.

Dave
 
Find you a broadcast automation tone encoder and 25 hertz tone creation is no issue, go for a couple of seconds and should work a treat.
 
You don't need a tone encoder. Sound Forge can synthesize tones. I'll bet most audio editing software can, as well.

Dave
 
bradman16 said:
Hi I am trying to track down these test tones that were put on the AMPEX pre-recorded reel to reel tapes. I understand they are a 20Hz rumble of sorts? Can someone provide specific information as to what works exactly - or even better, does someone have a source/link where I could download these tones to add to my home-made tapes? Even if you can't supply a link to download them, can someone be specific with what the frequency is, how long it is etc so I can create the tone myself? I would really appreciate it. I have looked around the Internet, and there is a fair bit of talk about these tones, but no one seems to really know what they are exactly - any help here would be greatly appreciated.

( these are for some ampex decks with the auto reversing system that senses these frequencies on ampex tapes and thereby reverses the tape, similar to how some sense a foil leader, they detect a frequency; I guess I could buy an Ampex tape off ebay right?)
Click to expand...

I had a bunch of the 60's era recorders (and still have one), and an AX-300 - and service manuals (somewhere)...

The 60s-era recorders (e.g., 9xx, 11xx, 21xx) had a pulley (driven by the reel belt) with a round magnet in the gap of a vaguely U-shaped ferrous-metal gizmo with a coil - to generate the signal. It was (supposedly) pretty-much a sine wave. [The 8xx recorder, which didn't have auto reverse, had a pulley without the magnet and no coil/gizmo.] The sensor was a little circuit board that was, essentially, a low-pass filter, mounted on the aluminum casting that held the capstans in (from behind). When it sensed the 20Hz (NOT 25Hz) signal, it energized the solenoid that would change direction. There was a control to disable the sensor when playing in the reverse direction (to cause the tape to just run out) or to loop endlessly. [I think that the loop / play-both-sides-once thing was done with the switches. -One of the switches that was moved by the directional control would connect or disconnect the sensor; the user-control would bypass the switch, connecting the sensing circuit regardless of direction.]

I didn't pay much attention to the AX-300 [because I bought it just to transfer tapes that I owned to digital form], but I THINK that the signal was generated electronically (circuit board with oscillator).

I have a box of spare parts; I probably have some of these things in easily-accessible form - if somebody wants a picture.
 
Neat! Kind of sounds like a tone wheel setup similar to what an organ would use. It makes sense that they would trigger it at such a low frequency to prevent false triggers from low bass notes.
 
audiojones said:
Neat! Kind of sounds like a tone wheel setup similar to what an organ would use. It makes sense that they would trigger it at such a low frequency to prevent false triggers from low bass notes.
Click to expand...
The (late) '60s models had a fairly primitive circuit for sensing the reverse signal - I don't think it was much more than a low-pass filter with a driver for the solenoid.
 
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