Dictabelt speed

If the Zapruder / Kennedy assassination recording is out there , is there any repeated scratch/molding clicks to take timings off ?

Try posting to r.a.r.p ?

Do you get involved with non-contact vinyl/wax reading via CD laser/tracking/servo technology

That would be rec.antiques,radio+phono or is that a different group you had in mind?

Jeff

--
"Everything from Crackers to Coffins"

yep

To OP, would that use shaded pole motor and then fixed gearing?

Which maker and what model? They followed the same speeds at record platters. ips time 15 15 min 7 1/2 30 min 3 3/4 60 min 1 7/8 120 min However, I'm not sure of the times. There were also versions that offered 4 channels per tape, which decreased the run time. For example, the Kennedy tapes were 4 channel mostly at 3 3/4 ips, but only ran for 15-20 mins.

More:

Scroll down to "Dictabelt 1947".

12" circumference, 15 minutes play time, 3.5" wide. The problem is I don't know how how many tracks per inch across the 3.5" wide belt. If you have a device, you can measure tracks per inch or calculate it from the gearing.

30 rev/min = 0.5 rev/sec. At 12" per revolution, that's: 0.5 rev/sec * 12 in/rev = 6 in/sec. Close enough to 7.5 ips.

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Jeff Liebermann     jeffl@cruzio.com
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Capacitor start/run motor with rubber idlerprimary drive; then pulleys and a flat belt to the final drive roller shaft - so there's plenty of slippage to give measurement errors.

Also, the machines I have seen in the UK have 60 c/s motors adapted for

50 c/s, which have very low torque and a high slip frequency on load.

(The only fixed gearing is between the drive roller and the leadscrew.)

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~ Adrian Tuddenham ~
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I recorded the wax test cylinders for Southampton University's optical reading project; but I don't do any optical playback myself.

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~ Adrian Tuddenham ~
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I think you have misunderstood the type of machine I am enquiring about.

[...]

It issignificantly below 7.5 ips. I need to know the manufacturer's specifications as I am developing a playback machine for archival work, where comparison between the actual speed and the 'official' speed can yield useful historical information.

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~ Adrian Tuddenham ~
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Interesting dilemma you got there. I searched the web but then it would be unreasonable to think you hadn't. I found something called a memobelt which was supposedly the same or similar.

However in thinking about it, being a scribing machine of sorts, and given the time frame I would think two things, well one.....

It is unlikely that the unit used a capstan. Crushing the media would not be desirable.

As such that means the media speed would vary as it accumulates on the reel, which we really cannot call a takeup reel because of the lack of a capstan and pinch roller. I guess it would be called a drive reel then.

I don't imagine alot of problems with this, because some things can just be figured out. Now I have gone into wiki and as you probably know the JFK assassination is recorded on this medium. The article I read also states that there are references due to police calls which do denote the time one way or another, but that data are better used in fine tuning, it seems that you need more of a ballpark figure right now.

As such I would attempt to take a picture of a section of this belt media. In fact I would do it at the beginneing of a reel as well as at the end. Since the information is scribed, like a phonograph record groove, you should be able to figure out the speed by the length of the modulation in the "groove".

It is logical to assume that they used the minimum speed possible for intelligibility, therefore figuring the minimum bandwidth for speech what do we have ? I would think that 600 - 4,000 Hz would be enough. Looking at the groove should then give you an idea. The high frequency limit is the key,. And remember they didn't have high compliance Shibata stylii when this thing was invented. You may need quite a length of it, run it through something for film or whatever, and use magnification. Find the shortest "wavelength" undulations in the groove you can, and assume it's a couple of Khz. Then you can figure the IPS from there.

I wonder how you intend to pick this up really. Optically or with a stylus ? I mean would you somehow fit a magnetic phono cartridge to this whatchamacallit or let some type of LED and optical sensor array do it ?

This intrigues me just because it is different, and the fact that I am stil a Beta dood. I even have a one inch vodeotape hiding in the basement, still waiting for a machine that can play it. I used to own a Cartovision !, but I did buy it used.....

Data preservation and restoration is a real field of endevor, I mean people do devote their carreer to it. I myself would pay money to have what I have recorded on Beta for example in the old days. In fact I even worked on one of those Technicolor VCRs. Actually eight millimeter but not the Sony type that was standardized about a decade or so later......

Aaaa, the good old days.

J

Any chance of there being any power-line hum in the recording? If there is, that's your calibration. If not the fundamental, then maybe harmonics ...

Isaac

Maybe. As I see above, it's called a Dictabelt. I used to fix those in the early 1960's. I may still have a functional blue belt Dictaphone, hand mike, and foot switch, somewhere in my mess.

As I understand it, the machine is something like this:

If this is not the machine, it might be helpful if you would kindly disclose some additional clues such as the maker and model numbers.

Ok, I need to know the manufacturer, model number, and color of the belt (blue or red). Please forgive me for not being able to guess that information from your description.

To the best of my limited knowledge from 45 years ago, the nominal speed of these devices used record speeds per the chart above. The speed was settable and adjustable, but always followed the chart as nominal speeds. If you have physical posession of a machine, you should be able to measure it. If you have a clue as to the runtime of the belt, you should be able to calculate it. The belt speed should not have a huge effect on your playback device. If the belt contains voice, you should be able to simply listen to the belt, and adjust the drive speed until the speech is clear. You'll need to do that anyway because many such dictation machines offer multiple speeds, any of which might have been used for the recording.

Good luck.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831-336-2558
# http://802.11junk.com               jeffl@cruzio.com
# http://www.LearnByDestroying.com               AE6KS

[...]

Yes

This was my set-up which I am now having to replace.

[...]

Dictaphone

Any Dictabelt model

Any belt

I am constructing a playback machine for archival work, which needs to be able to cope with any Dictabelt. There was a standard speed which applied to all the normal models and all belts, so as to allow interchangeability of the belts world-wide.

The basic machine was designed for 60 c/s mains, but there were adaptations to allow the machines to run at the correct belt speeds on

50 c/s. Some special machines were also designed to run at half speed for logging purposes . I have already encountered some belts which were recorded on unadapted half-speed 60 c/s machines working from 50 c/s supplies - and, no doubt, there will be others which were recorded at different non-standard speeds for various reasons.

What I need to know is the manufacturer's specification for the standard belt speed which was supposed to allow interchangeability between all the machines. I can then calibrate the speed control on my machine to show the %age speed variation from the norm, so as to deduce information about the circumstances under which each belt was recorded.

--
~ Adrian Tuddenham ~
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That sometimes occurs and is very helpful as long as the machine was running from stabilised mains supplies. Some Dictabelt machines were battery-powered and some 'in the field' would have been run from inverters or vibrator packs.

I need to know the manufacturer's standard speed in order to measure the variations of individual belts from the norm.

--
~ Adrian Tuddenham ~
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www.poppyrecords.co.uk

This is a belt recording system, it was driven by being tensioned around a pair of parallel rollers.

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~ Adrian Tuddenham ~
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www.poppyrecords.co.uk

For the Kennedy material someone melded the dictaphone audio to the 24? fps of film so if any repeat noise/clicks on the belt would then be synced to the film and a forensically accurate timing to determine the number of shots or echoes

Patent number and then Is the original patent tech info available?

Perhaps Adrian should have said that he has been working on these for some time:- e.g:-

Loads of patents, but I don't suppose any of them would include the meanufacturer's designated belt speed.

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~ Adrian Tuddenham ~
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www.poppyrecords.co.uk

It is better to try to find the original specification, rather than to deduce it from recordings which may have been altered or may not have followed the standard in the first place.

As you can see above, it is not easy to be certain what the standard was supposed to be, even when an actual machine is available.

--
~ Adrian Tuddenham ~
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www.poppyrecords.co.uk