Philips Cassette test tape - purpose?

[stevehertz]

I have a few different cassette test tapes that I use. One that I've never been able to use before, a Philips 'Testcassette' 'Service test' TC-S comprises a continuous 6300Hz tone with the occasional (every 60s?) 800Hz pulse. Levels for both are -10dB. What would this be used for?

Actually I've just had to re-house the tape as the original housing had one hub that was nearly devoid of 'teeth' and so wouldn't play or wind (how'd that happen?). That in itself was not an easy task having to open up a glued cassette housing then transfer the tape to the hubs of the new housing, locking the tape ends in place using those minute plastic pins. I also managed to lift off the label using label remover and press it down on to the new housing, dabbing away the remains of the label remover. It plays back perfectly, but as I say, what's its specific purpose? What kind of era is it? I'd say quite early in cassette terms.

[NottsIan]

Sounds like a speed calibration tape. Get it somewhere near by measuring the frequency of the tone then get it spot-on with a stopwatch.

[peterpixel]

I hear bells ringing from the distant past.I think the pulses were used to trigger a 35mm slide projector for a tape/slide programme.This would date from the early seventies as tape slide was a very popular medium for programme presentation then.Best regards all,Peter.

[Mach One]

I have a Sony cassette Azimuth alignment tape that is 6300Hz. So that would suggest to me that that is its primary purpose?

[stevehertz]

Originally Posted by Mach One

I have a Sony cassette Azimuth alignment tape that is 6300Hz. So that would suggest to me that that is its primary purpose?

Yeah, I kind of thought that but in general cassette deck azimuth is set using 8 or 10KHz. Perhaps this was an earlier test cassette where the expectations of the upper frequency of decks was less optimistic and it was deemed that 6300Hz was the correct frequency to use in that case. I'd go with that.

But then there's still that pulse..

[chriswood1900]

Steve
I think you have an azimuth alignment tape there, as the speed tapes were normally at 3,000 or 3,150Hz. 6,300 would be at the upper end of what early 70s basic recorders could do, it was later when the Japanese started development that the frequency response went up and 10Khz became an azimuth test frequency.

[Sideband]

Originally Posted by chriswood1900

Steve
I think you have an azimuth alignment tape there, as the speed tapes were normally at 3,000 or 3,150Hz. 6,300 would be at the upper end of what early 70s basic recorders could do, it was later when the Japanese started development that the frequency response went up and 10Khz became an azimuth test frequency.

Bang on! We had these tapes at Philips and 6.3Khz (with I think a 1Khz pulse at certain intervals) were used extensively with a frequency meter where we could 'zero beat' the tone. The 10Khz tape was used for the Hi Fi decks around.

I think the 1Khz pulse was used for simple speed checking and I remember some people using a stopwatch where the pulses had to appear within a defined interval. Later we had strobe cassettes to adjust the speed.

[peterpixel]

I found this in a manual for a Philips AC560 car radio cassette.It should answer the question.Peter.

[Sideband]

That's it! I seem to recall that 100 seconds was the 'ideal' to go for.

[stevehertz]

Ok, well it looks like it's an early Philips test cassette for use with Ferric tapes to test azimuth at 6.8khz, and an 800Hz pulse every 100 seconds to check tape speed.

Thanks for the input everyone.

[Sideband]

The originals of these were very expensive....back in the 70's when I used them frequently in the Philips workshop they were £50 a pop! The originals had a metal housing I think die-cast aluminum and were quite heavy compared to a normal cassette tape. To complement these there was also a wow and flutter test tape, a torque test tape (for take-up and clutch tests) and a strobe speed test tape.

[TIMTAPE]

In the 80's we serviced Philips dictation machines which by that stage were mini cassette. I remember the speed test cassette. Because mini cassette was rim drive, the speed cassette had no tape in it, just a strobe disc on the take up side. The bench lighting was enough to provide the 50 Hz pulsating light for it.

[Sideband]

We also had a strobe that required a loop of tape around it and a 50Hz light of course. This could be used for reel to reel as well and was suitable for four speeds. However for cassettes we used an ordinary C60 with one side carefully cut away so a loop of tape could be slipped over the strobe.

[factory]

Apparently for checking azimuth & tape speed, cost £8.82 in 1978.
There are a couple of other service/test cassettes too.



David

[stevehertz]

Originally Posted by factory

Apparently for checking azimuth & tape speed, cost £8.82 in 1978.
There are a couple of other service/test cassettes too.

Attachment 211311 Attachment 211312Attachment 211313 Attachment 211314 Attachment 211315

David

Great info, thanks Dave.

[AC/HL]

That 812/MCT tape has a 50Hz tone on the other side. Philips supplied a test unit to go with it. Playback was compared to a mains sample and a centre zero meter allowed the tape speed to be set visually.

[factory]

The 812/MCT cassette was both supplied with the 801/CSS and sold separately.

David