Ground loop with Miyajima Premium mono

You have the answer with Aesthetix Rhea or Io. They have already provided a thoughtful solution built into these units. (unfortunately not in the Aesthetix owners manual) Contact Glenn at Aesthetix and he has a complete solution. 

Essentially, you need to run a single signal wire off the (internally bridged, single coil course) the Miyajima Zero, to the #1 input of the Rhea, followed by a dual single-ended RCA cable from #1output on the Rhea. Hence you have avoided the ground loop with the use of one cable containing one +/-  source on the input. Also you have given yourself a dual mono output to send to your stereo preamp. Simple and perfect. 1 = mono. 

Great thread. I have same cartridge and this is helpful.

Hi to all,
I have resolved the question with a Lyra Helikon Mono
cartridge.No hum. I think the problem is the Rhea,
on masses configuration.The doubled coils allow to function
without troubles respect a single coil.Also in agreement with what was said in the Lyra website.

Here's a question: Is there any difference at all between the "BE" version and the plain Premium version, other than the species of the wood that is used? Miyajima website says nothing to indicate any other difference. A US vendor says there are indeed some internal differences between the two models, to justify the $250 price differential. Thanks.

Whoops!!!! I was wrong indeed. I looked on the Miyajima website, where it says, "When it played a stereo LP with this cartridge, a sound is that a distortion and a needle do not work lengthwise, and there is the thing that a needle injures the ditch of the LP." I could not have said it better myself. Thanks for your insight, Salectric.

Salectric, I know nothing about this subject (whether and why a mono cartridge could damage a stereo LP), but just empirically it seems to me that any cartridge with a conventional cantilever has "vertical compliance" to one degree or another. What the mono cartridge does not have is merely the ability to translate vertical motion into electrical output. So if a mono cartridge of the Miyajima type does have the capacity to damage a stereo LP, it should not be due to total lack of compliance in the vertical plane. If I am wrong in this idea, I hope someone will correct me. Thanks.

My Miyajima BE Mono should be arriving this week and I look forward to hearing what all the fuss is about. I'll be using mine on a Schick 12" arm.

Lula, I think I can answer your question. Some mono cartridges (such as the Miyajimas) are "true mono" designs that do not have vertical compliance. This type of cartridge will damage a stereo record. Some other mono cartridges DO have vertical compliance and those should be able to play a stereo record without damaging it. From what I have read, Grado monos are in the second group but there are probably others as well.

Somaxx, I get that this is the explanation on two different sites. Despite that, its not correct.

A ground loop is formed when there is a gain stage that shares a ground with another gain stage, such that it can amplify the currents in the ground circuit.

A classic example might be if a preamp and an amplifier are both have their circuit grounds connected together with their respective chassis, both of which get their grounds from the ground prong of the AC outlet.

In this case, there is no such gain stage; IOW, the cartridge is a passive device. If there was a gain stage between the cartridge and the phono section, then it would be possible, without one you don't have the conditions for a ground loop.

I know ground loops can be mysterious, and recalcitrant hums can be frustrating, but they are not the same thing. I can think of other scenarios that are far more likely:

1) If there are 2 windings in the cartridge, one could be defective

2) A wiring error is occurring in the process of connecting the inputs of the preamp together.

3) the tone arm ground and the minus outputs of the cartridge have become confused

4) if the cartridge has a metal body (or employs for some unknown reason, a ground tab) and is grounded to the arm, you will get hum pickup as the arm is no longer able to shield the cartridge signal.

Sorry to change the subject somewhat....but I've been considering purchasing a mono cartridge and am concerned as to whether or not playing it on a stereo recording will cause groove damage. Besides playing mono recordings, I sometimes switch to mono on my preamp to play stereo recordings from the mid-sixties that have that ping-pong extreme left-right separation as well as stereo 45s to remove (to a certain degree) extraneous noise.

I have tested a Torlai mono cartridge with single coil too.
Mr. Roberto Torlai is a Italian cartridge maker.
Same hum from speakers and the same answer that has given Mikelavigne on as to resolve the problem.Mr. Lukaschek,Benz Micro chief,says that the problem is greater with low output mono
cartridges.Dynavector and Lyra monos has double coils to avoid
loop (this is written on respective websites).
Matter more intriguing for me.

Thanks, Ralph. I had the suspicion that this was the case, but actually forgot to mention it in my post. But, hum is hum and must be eliminated when possible.
It would not surprise me to learn that the hum issue has much more to do with the circuit design of the particular phono stage than with the cartridge itself.

Mike, thanks for the detailed response.

This hum is bad news to me. I have a Kansui, which I like alot, and I was very close to buying the Premium BE Mono but now I think I won't. My Steelhead II doesn't sum through the fixed outputs and my VAC Phi Beta preamp doesn't have a mono switch. I don't want to have to do the summing-splitter IC thing and I certainly don't want to risk hum. Oh well. Seems like the manufacturer could fix this somehow.

I hate to pop the bubble here, but there is no way that one ground in a cartridge is causing a hum on account of a ground loop!

You can prove this easily enough by tying the minus outputs of a stereo cartridge together- no hum will result!

If one channel is responsible for a hum, it is because there is something about that channel that makes it hum, like an open connection or something like that. I'm not denying that the hum exists, just the explanation for it is not a ground loop.

It's wonderful listen fifties and sixties mono jazz LPs!
I have hundreds,so for me is fundamental a mono cartridge.
It's very smart what says Mikelavigne on splitting and suming
interconnect,but it's possible only with a dedicated tonearm and/
or turntable, I think.i have a second tt,a Goldmund Studietto,
but I'm very curious on this question,but it would be beautiful to be able to resolve the thing without working with interconnects cables.

My phono and line stages are fully balanced, so perhaps this would not be an issue for me. Balanced lines typically are less subject to ground loop problems (he said, with his fingers crossed). I would not want to have to build a Y-connector using XLRs. Also, in all cases the use of a Y-connector adds physical connectors into the phono signal path and might slightly degrade sound quality. Not good for those of us like me who suffer from audiophilia nervosa.

In the last two days, I purchased a bunch of very early 50's jazz LPs, all mono, so my appetite for the Miyajima is even more whetted.

ok. Robin said, due to the fact that both sides of the cartridge use the same mono signal; when connecting two stereo outputs it "can" cause a ground loop. this does not always happen. in fact; i've had it when it did not cause a ground loop....and i don't know why it does not always happen.

but if it does; then you get a sum'ing interconnect (where you have 2 rca inputs into one rca output) and plug that into one side of your preamp. and then use the mono switch on your preamp to get 2 channels of mono. you have then defeated the ground loop.

if you don't have a mono switch then you get a splitter (an interconenct with a single rca input and 2 rca outputs) plug the suming single output into the splitter and plug one output from the splitter into each stereo input. you now have a mono signal out of each input (just like a mono switch).

the most elegant solution is to get a friendly cable maker to make you the suming and splitter combo piece and eliminate the extra connectors. it's a simple thing to do.

you can do the same thing with interconnects that a mono switch will do.

Mikelavigne, please explain. Do you mean by using a Y-interconnect or Y-connector? Otherwise, offhand, I don't see how.

Thanks.

Thank you to all for the debate.
One thing is interesting: the same cartridge work fine
throught a EAR 88PB phono stage,without hum problem in
stereo connections.Different construction on phono stages?
Perhaps dual mono or balanced inputs are implicate?

Lew,

you can do the same thing with interconnects that a mono switch will do. so it's not a limitation not having a mono switch.

you simply have to rid yourself of the ground loop.

Robin, Do you mean to say that this is the usual recommended mode of operation for the Premium mono (one channel hooked up and preamp set to "mono")? Does this mean that one would have to tolerate hum (or sound coming out of only one spkr) if one's preamp does not have a mono switch?

obviously Robin is the expert here. i had the same problem with my Miyajima Premium Mono, called Robin, and he gave me the same answer.

i've been listening that way for 6+ months and works great.

enjoy!

stunningly good sounding cartridge.

You resolved it by using one channel as you said and them using the mono switch. Both channels Contain the same
Mono track. Pluging them both in doubles the ground and causes the ground loop hum.