Compatible Disc Playback - DB Magazine 1968

technical documents and audio patents
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JaS
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Compatible Disc Playback - DB Magazine 1968

Post by JaS » 17 Jan 2015 16:14

Download

Thanks again to alecm33 for the scans

tubeactive

Re: Compatible Disc Playback - DB Magazine 1968

Post by tubeactive » 21 Nov 2015 23:40

It is indeed very interesting to note that a Stanton field engineer, circa 1968, recommends playback with a stereophonic cartridge for both mono and stereo discs. Also, he advises the simple parallel channels, mono-summing connection; presumably preferring the channel strapping at the headshell, rather than using a mono/stereo switch on your preamp or amp control unit.

The final mono cartridge by Pickering/Stanton was an excellent sounding mono performer, with 2 gram tracking capabilities, their model 370. Because the typical mono cartridge has little to no vertical compliance, this resistance(impedance) in the vertical plane could easily damage stereophonic grooves.

Just as interesting to me is this engineer's hearty recommendation to use solid state "equalized phono preamplifiers" for playback; suggesting active phono equalization over the passive phono EQ techniques. Today, in 2015, this is a very "hot topic" indeed.

KentT
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Re: Compatible Disc Playback - DB Magazine 1968

Post by KentT » 03 Jan 2016 14:56

This engineer is telling the truth. The old passive networks were fine when we had 10mv and more output cartridges. When this industry dropped to lower output MM and MI offerings, the accuracy of the passive equalizer networks suffered. Tube and SS equalized phono stages became the suitable solution, in broadcasting the SS networks have worked well and accurately. Engineering for a station late in the conversion process, I was new to the job and made that very project a priority. The new records then did not track well on the older mono pickups and could not handle the modulation levels and bass energy of the new records. We went from GE VR II and Shure M3D to new turntables with low vertical rumble and new Micro-Trak tonearms and Stanton 500a cartridges. Record wear dropped, reproduction improved, tracking very improved.

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