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TonyDuell · 15th Sep 2015, 6:09 pm

Re playing mono records with a stereo cartridge

The Decca ffss cartridge (the slide-on one used on the 'professional' arm, etc) doesn't have the normal L and R coils effectively detecting 45 degree motion of the stylus. From the pictures I've seen of the insides it has the 'lateral' coil which generates an L+R signal and a pair of identical 'vertical' coils which are so wired to add and subtract from the lateral coil, thus producing the L and R signals separately.

The cartridge has 4 connections. These are ground, the L output, R output (obvously) and the output of the lateral coil.The instruction leaflet says that when playing mono records to use that last output (only). The instructions for my Leak Varislope Stereo pre-amp give details for using a pickup cartridge with a seperate 'lateral' output (whether the Decca ffss is the only one I do not know), namely by wiring the L and R inputs to the PU 1 input sockets and the lateral coil to one of the PU 2 input sockets. It then says to play stereo records by selecting PU 1 and stereo, and mono records by PU2 and whichever input channel socket was used.

I could never detect the difference between using the lateral output and just paralleling the L and R outputs (as you would do for any other cartridge) but then I am not a good judge of such things. Was there a good reason for using the lateral coil output (only) for mono records? It's rather too early to be an audiophool idea I think.

15th Sep 2015, 6:09 pm	#25
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Restore a Beau Decca Re playing mono records with a stereo cartridge The Decca ffss cartridge (the slide-on one used on the 'professional' arm, etc) doesn't have the normal L and R coils effectively detecting 45 degree motion of the stylus. From the pictures I've seen of the insides it has the 'lateral' coil which generates an L+R signal and a pair of identical 'vertical' coils which are so wired to add and subtract from the lateral coil, thus producing the L and R signals separately. The cartridge has 4 connections. These are ground, the L output, R output (obvously) and the output of the lateral coil.The instruction leaflet says that when playing mono records to use that last output (only). The instructions for my Leak Varislope Stereo pre-amp give details for using a pickup cartridge with a seperate 'lateral' output (whether the Decca ffss is the only one I do not know), namely by wiring the L and R inputs to the PU 1 input sockets and the lateral coil to one of the PU 2 input sockets. It then says to play stereo records by selecting PU 1 and stereo, and mono records by PU2 and whichever input channel socket was used. I could never detect the difference between using the lateral output and just paralleling the L and R outputs (as you would do for any other cartridge) but then I am not a good judge of such things. Was there a good reason for using the lateral coil output (only) for mono records? It's rather too early to be an audiophool idea I think.