Suddenly My Turntable Output Is All Summed MONO. Help!

Over the past day or two something happened to my TT or cart or something...everything is summed mono now.

It took me a while to notice because I'd been playing a bunch of mono records over the past couple of days until this morning when I played a stereo record and it was summed.

So, I started troubleshooting.

First off -- it's only the turntable output. Everything else -- CD, tape, digital from the computer -- is fine. There's stereo output.

Next, I checked cables, switched out cables -- no change. Checked the lead wires to the cart -- all snug and correct.

Phone stages -- I switched out my powered phono stage to a passive step up. Same problem.

With my powered phono preamplifier, its output went into a line input on my preamplifier. Now, with the passive phono stage, its outs are plugged into the phono inputs on the preamplifier, as it's supposed to be. No change.

So it would seem the trouble is likely located in the turntable or cart.

Anyone with any ideas on how I can find the cause of the problem, please let me know.

Thanks in advance...

 

Change the cables so the phono preamp uses the same input you know is stereo for your CD player, for instance. Is it in stereo now?

 

"Summed to mono" can be as simple as the two signal leads touching each other somewhere, whether it is the cartridge pins or wiring bent inward so they touch at the headshell, or as hard to discover as tonearm wiring being pinched bare and shorted in the tonearm pivot.

If you unplug one RCA from the turntable at a time and the corresponding channel goes out, you know it's in the turntable.

If you unplug one (and then try the other), of the + leads (white or red) from the cartridge and you still hear mono in both channels, it's not in the cartridge.

reference:


Finally, one would disconnect both the cartridge (or headshell) and RCA wiring, and probe with a multimeter to see if some wires are shorted.

 

I think the problem might be just that I'm a bloody idiot. Switched carts, changed out the phono-step up, went back to check all the cables at the amps and there was one a bit loose. Got stereo back. Sheesh. Where's that dunce cap?