|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
74.130.29.193
In Reply to: RE: Balanced phono cartridge posted by Tidycat1 on September 28, 2015 at 20:02:08
I believe if you use a phono stage with balanced differential inputs and you use balanced cables from the cartridge, you will achieve the same result as having a fully balanced cartridge with centered tapped coils. I don't think it's necessary to have three wires from each cartridge coil because there would be no current flowing in the ground wire. For example, suppose you are using a low-output moving coil cartridge designed to be terminated with 100-ohms and your differential input had a 50-ohm resistor on each leg with one end of each resistor tied to ground, I believe that would work just as well as a fully balanced phono cartridge.
On the other hand, it might not make any difference if the input to your phono stage is unbalanced. My system is fully balanced from the output of the phono stage to the input of the power amplifier and it works just fine. I can't imagine how performance could be improved with a balanced input on my phono stage. What do you think would be the advantage of a balanced input to the phono stage?
Best regards,
John Elison
Follow Ups:
"What do you think would be the advantage of a balanced input to the phono stage?"If the phono stage has a balanced input (or SUT input), then the only advantage would be the CMR of all noise picked up by the cabling between the tonearm and the phono stage. Nothing more.
If the phono stage had balanced circuits all the way through then we have many advantages. Two of them would be the constant current draw and the power supply ripple rejection. There would also be the cancelling of any even ordered harmonic distortion created within the differential stage.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/29/15
I have my toearm wires configured for balanced operation and my phono has a balanced input.
But,after talking to two large equiptment manufacturers,I had to pose this question.As a balanced differential circuit is referenced to ground and the differential mode noise rejection is the difference beteween said connections.It is not "truly" balanced,as it does not have a ground,other than supplying a "ground" via the turntable/tonearm ground.
So yes,it does have the positive/negative portions of the soundwave provided by the transducer,but there is no ground on a phono cartridge.Only in and out of phase connections.
So without the fifth and sixth connections for ground,it is quasi-balanced.
I believe Ralph/Atmasphere and I have the same wiring configuration on our tonearms,from discussions over at AudioGon on the subject of :how to" set-up for a balanced input.
This was just a question resulting from asking a manufacturer whether they were going to offer a balanced input on their phono stages-AYRE AND PASS.
Tom:cat
"As a balanced differential circuit is referenced to ground and the differential mode noise rejection is the difference beteween said connections. It is not "truly" balanced, as it does not have a ground..."I'm not really following you.
All I know is this, in the balanced connection I show, any noise picked up in the cable will not pass to the secondary of the SUT because any noise picked up by the cable will be common in the two wires and transformers only respond to the difference between the two ends of the primary winding.
Most balanced connections in a recording studio are just 2 wires carrying the signal, neither referenced to ground. Those would be the floating secondary of a small signal output transformer of one piece of gear connected to the floating primary of a small signal input transformer of the other piece of gear. The only thing in the cable that's grounded is the shield.
The same goes for microphones. For instance microphones (like a u47 or a sm57) use an output transformer. That output transformer secondary does not have a grounded CT. The secondary is not grounded in any way.
In the balanced connection between those microphones and the balanced input of the micpre, the only thing grounded is the shield of the cable.
The "signal" wires just connect the floating secondary of the output transformer to the floating primary of the input transformer.
So again, I don't understand what you mean by "truly" balanced.
What I have shown is as balanced as anything gets.
Tre'
Have Fun and Enjoy the Music
"Still Working the Problem"
Edits: 09/29/15
For some reason, Pass Labs does not feel the need for balanced cartridge inputs on their phono stages. Nevertheless, my XOno is the quietest phono stage I've ever owned; it's basically noise free.
On the other hand, Ayre seems to feel balanced cartridge inputs are desirable for their phono stage. I don't know how the two compare with each other.
Best regards,
John Elison
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: