Stereo cartridge wired as mono & pre-amp

[WayneL74]

Hi all.

I am in the process of restoring a mono vintage disco console. I am installing 2 BSR P182 turntables. One of them came with a Sonotone 3559 cartridge. I will obtain another for the other deck if all goes well.

The console originally had crystal cartridges, which had a lot higher output than the Sonotone. I have therefore built a pre-amp using the circuit here - https://www.vintage-radio.net/forum/...=128765&page=6 (post #102)

After reading this post about input impedance when connecting 2 channels in parallel, I am wondering if any of the component values should be changed to suit? - https://www.vintage-radio.net/forum/...d.php?t=135645

When listening it seems that the sound is a bit bottom-heavy, and treble does seem reduced when compared to just having 1 channel connected.

I know this setup is not "Hi-Fi", but I am just trying to get the best balanced sound from the kit I have.

Anyone have any thoughts?

Regards,

Wayne

[dragonser]

Hi,
I seem to remember seeing somewhere a Stereo cartridge ( of the type with four output terminals ) wired with the two ( left and right ) sections in series to give more mono output.
( this was on a mono piece of equipment ).
But I know that there might be disadvantages to such an arrangement.
regards Peter B

[Edward Huggins]

I'm surprised you needed to build a pre-amp. The output of the Sonotone 3559 should be adequate to load the amplifier as the original cartridge would have also had a medium output type. Notwithstanding the fat that a medium output crystal cartridge will, on average, give about 100mV more than a ceramic type. The pre-amp circuit you have used boosts a 200-250mV output cartridge to 1V and may, or may not, overload the pre-amp stages of your console.