Adding a 3rd Tape Head to (mono) Reel-to-Reel.

[Folderol]

This is almost annoying! I've got a faint memory about something on using a separate head for the bias, opposite the record head, rather than mixing it in the signal.
Ha! Got it
Right here

[James Perrett]

Wow, fascinating stuff Hugh - it's not often that we can retrieve data from the past with greater fidelity than at the time

There are still people working on ways of improving quality from old tapes. I'm currently testing some Dolby A decoding software that claims to retrieve significantly more detail than the old Dolby hardware. There are a huge number of masters that could possibly be improved by using this software.

And of course we have Jamie Howarth's Plangent Process which claims to eliminate wow and flutter using the bias signal or other continuous tones recorded on the tape as a reference.

[Hugh Robjohns]

Yes... I wonder what they'll come up with in the 2060s to improve the reproduction from early digital recordings...

[Elephone]

Yes... I wonder what they'll come up with in the 2060s to improve the reproduction from early digital recordings...

...or really early wax recordings! Could AI actually re-imagine them into pristine renditions?
That's another story.

[Elephone]

"Martin Walker" Wow, fascinating stuff Hugh - it's not often that we can retrieve data from the past with greater fidelity than at the time

Martin

Have you heard what they did with the Robert Johnson recordings? They may have made even further enhancements since then.

[Hugh Robjohns]

I did... and I have some.

[Tim Gillett]

Quoting myself here:

So I'm not sure that even around 1950 they couldn't make a repro head with narrower gap, so much as they didn't see the need to do so, to go above 15 kHz as the upper frequency limit for playback...

I did a few few quick calculations and cross checked another's figures. https://electronics.stackexchange.com/q ... -tape-head
It seems for a tape repro head to reproduce 20 kHz at cassette speed (1.875ips), its gap length must be 1.2 microns or less. But at 15ips, 8 times faster tape speed, that gap length only needs to be 9.5 microns or less.

In the early to mid 60's, Akai was making tape heads for open reel domestic recording with 1 micron gap lengths. I still have an Akai X-IV portable (Germanium transistors!) which claimed 13 kHz upper freq response at 1.875 ips (cassette tape speed). In the late 1950's, or even earlier, that they couldn't construct a repro head with a gap length of 0.374 thou (9.5 microns),
8 times less critical than what Akai achieved in gap lengths the early to mid 60's seems unlikely.

Tim.