A Direct-to-Disk Recording Experiment

[jesusfwrl]

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Have you ever wondered to what extent the recording equipment influences the sound of a recording?

Back in the beginning of 2016, we conducted an interesting experiment at Magnetic Fidelity, to answer exactly this question, by using an extreme contrast in equipment.

We were having a recording session of a rock band, who were performing entirely live, the sound being captured by multiple microphones, mixed on the fly on a vacuum tube summing mixer, with a bit of equalization and compression added, before reaching the recording device.

The first recording device was a 1970's Telefunken M15A, 1/4" tape recorder, running at 15 ips, CCIR eq.

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We recorded some tracks to tape at a peak modulation level reaching +15 dB over 500 nWb/m, which is well into tape saturation territory, with ATR Master Tape. The M15A can be very transparent, but at these levels, it is a good example of "tape color".

Then we replaced the M15A with a 1930's Fairchild lathe, discussed in this thread
https://www.lathetrolls.com/viewtopic.php?f=15&t=6142&hilit=fairchild+magnetovolt+riaa
, fitted with a 1930's RCA MI-4896 monophonic magnetic cutter head. The outputs of the recording chain were summed to mono and modulation peaks reached +12 dB over a peak lateral velocity of 7 cm/s at 1kHz. This is a great example of "magnetic cutter head color". We used MyShank blanks and his 468P diamond stylus, heated by 0.6A.

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The tape and disk were digitized at 192 kHz/24 bit, and can be downloaded from here:
https://agnewanalog.com/blog/2018/05/02/direct-to-disk-recording-session-with-naxatras/


The disk reproduction setup was a Thorens TP160 mkII turntable, Thorens TD16 mkIV tonearm, Stanton 881S cartridge and NAD Series 20 phono stage. The cutting stylus was well used, so a bit noisy.

The limitations of the magnetic cutter heads are quite obvious, but so are the strengths of the disk medium. All in all, aside from the obvious stereo vs mono difference it can be heard that the disk version does not automatically sound 1930's just because it was recorded on 1930's gear!

In fact, the overall sound/style is defined to a much greater extent by the music, performance and recording technique, rather than by the recording device/medium.

The band is Naxatras and some of the music from the tape made it to an EP, available directly from the band through bandcamp,

Incidentally, the Fairchild lathe is now available for sale. I will be posting an ad in the next few days.

Enjoy!

[handcut]

Great blog, great post, great band! Thanks for sharing.

[Gridlock]

I love the way those cutting heads sound. What ohmage is it?

[jesusfwrl]

Handcut, thank you! We will try to keep on posting on a regular basis. We are also still adding a lot of content to the website.

Gridlock, they can indeed sound good if in good condition. Fortunately, they are quite simple to rebuilt if needed, several people on here do such work on magnetic heads, myself included.
It is 8 ohm, although this is not critical. I can supply impedance matching transformers for any head impedance.