The Truth About Tape Recorders

[Pluto]

I wonder why they went digital instead of just using a different playback head.

If you looking for, say, 1 revolution of delay at 33rpm, you need about 1" delay, give or take. Running at 15ips, that's a lot of extra tape to manage on your deck plate. The last generation of tape transports went to some extraordinary lengths to minimize the problem of scrape-flutter, a problem that, broadly, increases with the length of the tape path.

What this comes down to is the need for a highly customized transport if you are looking for the ability to delay by more than a few hundred mS. The right solution was to use the best possible transport (i.e. the shortest possible tape path) in conjunction with the new-fangled digital delay.

 

[srrxr71]

If you looking for, say, 1 revolution of delay at 33rpm, you need about 1" delay, give or take. Running at 15ips, that's a lot of extra tape to manage on your deck plate. The last generation of tape transports went to some extraordinary lengths to minimize the problem of scrape-flutter, a problem that, broadly, increases with the length of the tape path.

What this comes down to is the need for a highly customized transport if you are looking for the ability to delay by more than a few hundred mS. The right solution was to use the best possible transport (i.e. the shortest possible tape path) in conjunction with the new-fangled digital delay.

Yes I wondered about how big that transport would be. I did not consider how much they were focused on flutter but that was a huge thing those days. I’m sure some engineer could have designed something for it but digital is cheaper and easier.

 

[Jim Shaw]

...My late dad was an electrical engineer and I have his wire recorder he made in the late 50s. He recorded Sputnik on it. I remember him playing it when I was younger...

Probably more like 40s than the 50s; the wire recorder disappeared quickly with the advent of analog tape in the early 50s. I had one that an older fellow gave me, years later. It worked, electronically, for speech. But avoiding wire snarls was a fool's errand. After WWII, some wire recorders were used by law enforcement, as I recall. But, oh the tangled life we lead when first we try to use wire.

 

[thorn]

Probably more like 40s than the 50s; the wire recorder disappeared quickly with the advent of analog tape in the early 50s. I had one that an older fellow gave me, years later. It worked, electronically, for speech. But avoiding wire snarls was a fool's errand. After WWII, some wire recorders were used by law enforcement, as I recall. But, oh the tangled life we lead when first we try to use wire.

Got me curious, I'll have to go listen and record those wire spools/reels to see what's on them. I hope it still works. It is large and he might of built it. The wire spools are kept in nice stainless steel containers. Sputnik 1 was orbiting in Oct 1957 so he had it then.

 

[Multicore]

It was not CD that killed cassette, it was CD players in the car, that killed cassette. Once the ubiquitous radio/cassette head unit was replaced with a radio/CD unit, that was the end.

Yes, the vibration resistance in the car and for the portable use was critical. I could ride my bike with a CD Walkman in my pocket. When was that relative to introduction of CDs?

Combined with computer based recording of CDRs and people had all the convenience of making their own recordings, but having a somewhat better sounding and resilient format in the car.

Looking back I don't think burning CDRs was as important. It was certainly a factor but I don't remember many people with collections of CDRs. This was the same time we learned to rip onto a computer and to use iTunes and iPods and Napster etc..

 

[atmasphere]

Interestingly, any LP that was half-speed mastered has had the audio passed through a digital delay line prior to it hitting the cutting head. So it would be A-(master tape) to D-(digital delay) to A-(lathe electronics). So some of the most cherished vinyl would have the dead hand of digital placed upon it, bad luck AAA guys!

This statement is incorrect and is very common myth.

The function of the preview head is to assign a signal level value. This value is then used as to influence the speed of the lead screws on which the cutter head assembly rides. The idea is with greater signal the cutter moves faster so as to provide space between grooves. If that space isn't there, with a loud sound that requires a wider groove, it might overcut into the groove just cut prior (about 2 seconds ago; 1 rotation of the platter).

The audio signal itself is not drawn from the preview head (which has to sit 2 seconds upstream from the playback head); it comes off of the playback head. The preview head signal is often converted to a digital value to run the lead screws but this can be done with an analog voltage as well.

I don't know how the idea that the playback head signal somehow got converted to digital ever got started; perhaps from the 'digital preview head' name used; which was IIRC the name used by the Compucut device that was used to run a lathe with variable groove spacing.

In our studio we used an Arduino to create a motion file by playing the project back to the Arduino and then storing the motion file. Then we would set up the lathe and start the project and the motion file after one platter rotation. This worked quite well and was a lot cheaper than having to find a preview head system.

 

[LtMandella]

Until last year when I bought a new MC cartridge and phono preamp, I used the unit you see in my avatar to transcribe my irreplaceable LPs so I could listen to the music as much as I wanted without wearing down the LPs. Worked great, I could play the Mobile Fidelity Beatles box set weekly for a decade and no added wear to the LPs!

Now I transcribe to DSD - a technology which was not available at the time I purchased 99% of my LPs...

 

[Punter]

This statement is incorrect and is very common myth.

The function of the preview head is to assign a signal level value. This value is then used as to influence the speed of the lead screws on which the cutter head assembly rides. The idea is with greater signal the cutter moves faster so as to provide space between grooves. If that space isn't there, with a loud sound that requires a wider groove, it might overcut into the groove just cut prior (about 2 seconds ago; 1 rotation of the platter).

The audio signal itself is not drawn from the preview head (which has to sit 2 seconds upstream from the playback head); it comes off of the playback head. The preview head signal is often converted to a digital value to run the lead screws but this can be done with an analog voltage as well.

I don't know how the idea that the playback head signal somehow got converted to digital ever got started; perhaps from the 'digital preview head' name used; which was IIRC the name used by the Compucut device that was used to run a lathe with variable groove spacing.

In our studio we used an Arduino to create a motion file by playing the project back to the Arduino and then storing the motion file. Then we would set up the lathe and start the project and the motion file after one platter rotation. This worked quite well and was a lot cheaper than having to find a preview head system.

Thanks for clearing that up and what a great Idea to use an Arduino as a lathe control! Excellent!

 

[JaccoW]

Daft Punk just dropped this short video for the 10th anniversary of Random Access Memories.
That's some big tape!