Are MC Cartridges commonly damaged in shipping?

[pderousse]

It's probably not a ground loop. The coils in the cartridge aren't (normally) grounded until you connect the preamp. That's only one ground-point, so no loop. And a ground loop after the phono preamp wouldn't get worse with increased preamp gain.

The cartridge and wiring to the preamp can pick-up electromagnetic hum and some hum can get-into the preamp through its power supply.

You might think about going-back to MM. Moving coil isn't ALWAYS better and in your case it's worse.

P.S.
Back to the original question - It's highly-unlikely that any kind of shipping damage would make it more-prone to hum pick-up unless it was damaged to the point where it didn't function at all.

The cartridge has 4 leads with a green plug out and appears to be grounded at the external PS through a four pin power cable, and presumably that’s why there’s no ground lug on the TT. The noise I got with that MC was not characteristic of EMI, it was 60hz, but from afar I agree that would be a potential concern.

I don’t know enough about this topic, which is why I asked, but are you saying something different than MaxwellsEQ (above) regarding the potential to amplify a ground loop?

 

[pderousse]

Hmm...

Probably your best bet is just to go back to the MM cartridge that works well without ground hum. Your MM cartridge will be just as good as anything else you can buy and if you want to confirm, I would refer your to JP's excellent phono cartridge ABX test here on ASR:

Cartridge ABX

I tried a new cartridge today that struck me as being very similar to one I listened to a few weeks ago, so I did some comparisons, and indeed it did! I should've bought a lottery ticket instead. Here are four ABXs of the two cartridges, each with a different genre of music. I did a quick...

www.audiosciencereview.com

If you want to keep with MC, I would recommend finding the nearest wood chipper, tossing the Rega into it, and buying a quality direct-drive TT with a ground lug like a Technics.

Hmm, kinda forward … We we’re just getting to know each other. Do you often tell strangers where to put their TT?

 

[ban25]

Hmm, kinda forward … We we’re just getting to know each other. Do you often tell strangers where to put their TT?

Maybe take a look at this video:

 

[pderousse]

Maybe take a look at this video:

more productive, thanks This is more of a hack for those not using a phono pre, as explained in the OP.

 

[restorer-john]

Maybe take a look at this video:

Honestly, that video is a waste of time.

The Denon he shows is double insulated and likely has a significant nuisance current already in the chassis, so he'll make any hum worse.

He's actually created a ground loop from chassis to RCA outer with his stupid wire in the second instance. The RCA sockets on the amplifier are already optimally grounded.

The best option is a properly grounded/earthed amplifier and all devices plugged into that being double insulated/non earthed. Turntables run from cheap plugpacks (like the Rega) are essentially floating until earthed via the RCA plugs.

 

[pderousse]

1. You, me and I suspect ban25 all agree.
2. The Receiver and the ‘solution’ are both questionable.
3. Agree and it is kinda scary.
4. You can see my system below. The wiring path is RP3 - RCA - Parasound jc3+ - XLR- McIntosh c49 -XLR- minidsp -XLR- all amps.

 

[MaxwellsEq]

are you saying something different than MaxwellsEQ (above) regarding the potential to amplify a ground loop?

It is generally possible to amplify the current travelling in an earth loop. I answered your general question...

Am I wrong to think that there is no such thing as a tiny ground loop that gets amplified?

... with a general answer...

Grounding and ground loops are tricky, but if the current travelling through the loop is a constant, having a much higher gain can amplify the current more. So it's a mistake to assume ground loops are unaffected by gain.

Now, to be more specific, I've used a low output MC on Rega arm without significant hum. Your description is correct - most arms carry the + and - signal in ungrounded coax (one per channel) and have a flying lead which earth's the armtube etc. Rega does not do this. It binds the earth arm to one of the coax screens. This can work just as well, but is slightly less flexible because you can't make decisions about where ground is, because it's always the outer part of one RCA connection on the preamplifier.

When I was using a low output MC, it was into a Pink Triangle PIP preamplifier and there was only a tiny increase in hum compared to an MM cartridge.

 

[JP]

I didn’t see this asked - is the hum the same if the turntable power is not plugged in?

 

[spiral scratch]

Did you check the phono stage with shorted inputs (no cartridge) on the MC setting before sending the cart back?

Did you try this? This is a good way to remove the cartridge from the equation and check if the problem resides elsewhere.

 

[pderousse]

Did you try this? This is a good way to remove the cartridge from the equation and check if the problem resides elsewhere.

Yes

 

[spiral scratch]

Yes

please share your findings

 

[pderousse]

When the cartridge returns from repair and if there is still hum, I will try again.

 

[spiral scratch]

OK. But you understand you don't need to use a cartridge to perform this test. You short the leads, preferably without the cartridge attached to avoid any incidental contact with the cartridge pins.

 

[pderousse]

OK. But you understand you don't need to use a cartridge to perform this test. You short the leads, preferably without the cartridge attached to avoid any incidental contact with the cartridge pins.

I do, and thanks for your help. Sorry, I misunderstood what John was saying earlier and afterwards (I’ve been out of town) realized that I had done just that. Shorting plugs on the phono pre inputs suggested nothing faulty downstream, but I also knew this for reasons mentioned in the op. A new cart arrives in two weeks. I’ll update when that happens.