Stereo cartrdge now playing mono!!

The hum could be coming from the tonearm too. 

You will likely find your answer here https://www.vandenhul.com/wp-content/uploads/2019/09/Phono_FAQ.pdf

As A.J. explains, many times it is due to the very fine wire from the magnet assembly/transducer to the pins sustaining fatigue-failure. The very fine wire is often not long enough and becomes brittle with use. When it fails there is no repair. The manufacturer just replaces it. At a price. 

this is kinda perplexing since I cannot think of a failure mode that would turn a stereo cartridge into a mono one.  

The fact that you reversed the phase of the right channel (swapping red and green) suggests to me that you were mischaracterizing the sound of one channel with inverted phase as mono but this doesn't explain why the hum would suddenly show up.

glad to hear the new cart is singing.... Enjoy!

dave

The cartridge was replaced with a new one. Very happy!

The first time that I installed the Hana I had to reverse the pins of one channel. they pins are are colour coded. So I can only assume that the problem came with the new cartridge which is rather unfortunate,

Meanwhile I have mounted my old (number 52272) Koetsu black which I had serviced by Vd Hul years back.I wonder what it is worth.

Thank you for the responses. i will post the outcome of the Hana ituation when I recieve it.

@lewm , isn't that something. I can't count the number of times I did something thinking it sounded better only to realize it did not. Expectation bias?

OP, you need to try another cartridge. If it works fine the Hana has shorted out. Please check the cartridge pins again. Are the Hana's color coded. Make absolutely sure beyond a shadow of doubt that you have it hooked up correctly. If the Hana's pins are not color coded it is very easy to make a mistake. 

Thanks, I know that it sounds crazy but I solved the situation by swopping the red and green leads. It then gave me stereo with a hum. I sent it back.

If you have a multimeter check the two hot leads on the cartridge to make sure they are not shorted!

The Decca London had a top that could be removed by sliding it off the cartridge body.  Then you had access to a platform that fixed the position of two of the coils using two set screws that if re-set in unison could move the platform up or down.  By pure ignorance, I and a friend converted our stereo Decca London cartridges to mono, simply by maladjustment of that platform.  No modern cartridge that I know about would by its construction permit the user to do such a thing.  Funnily, both of us thought we had improved the sound, until we each separately realized what we had wrought.

Hello lastperfectdaymusic. Have you found a solution to your problem?

If not, the only thing I can recommend is making sure the problem is with the cartridge and not another part of the playback chain. For example, if you swap the left and right channels at your phono preamp, does the same or a different channel play? What about if you swap the leads at the headshell? Or do you have a back-up cartridge you could swap in to see if it plays on both channels?

Hard to really know what to suggest without knowing your full system or what the moving conditions were. If you have tubes, can you rule out that a tube hasn't gone bad?

I don't have a ton of experience with cartridges, but I'd tend to think that, cantilever notwithstanding, there's not a lot to go really wrong within the cartridge itself. I'd want to work back methodically from the last known good component to see if something else might have been upset in the move.

Best of luck - I'll be curious to hear what you learn.