which turntable or how to convert to balanced phono setup?

Ralph (Atma), thanks for the clear explanation of AES48. Your statement that the XLR inputs on the TEAC offer only MC gain levels makes sense but the owners manual never actually says as much, or maybe I have to re-read it. The device does have selectable gain. Maybe into the XLRs, low gain is not selectable. English translation of Japanese tech jargon is not always the best either. Anyway the OP got his question answered, and I learned something about driving a balanced differential circuit with a SE device.

Funnily enough, I just found a good website that talks about AES48. (To read the actual original language, you have to pay AES for the text.). Here.

In gear that really does offer both a SE and a separate balanced input, the gain claimed by the manufacturer is usually quoted as being different for the two types of input, with the balanced circuit gain being higher.  Why is that or is it a false claim?  In the PE505 owners manual, the data sheet shows the gain is the same via either input type. I took  this to mean that cleeds is correct in his assertion that the RCA inputs are hooked up for balanced operation. This can also be seen in a diagram on page 9 where they show not to drive the PE505 with a SE output from a TT, "for best results". The diagram also suggests the "ground" side of the RCA jacks is not connected to audio ground, in other words RCA hot must go to pin2 and RCA ground to pin 3. However, they never come out and say it.

On your first point, we are actually in agreement. The SE input is grounded (to pin1) in the case where an SE input is provided, like I did say, and like it is on my Atma-sphere amplifiers, except I am wrong about the need for a transformer or some other device to convert the SE input to balanced. Thank you for the correction. (I’ve never driven my amplifiers from an SE source or using the RCA inputs, but I know the circuit quite well.)

Do you know why the owners manual for the PE505 says the XLR inputs are for MC cartridges only?

You often quote AES48. What does AES48 say?

The words you quote in italics are of course correct but have nothing whatever to do with the PE505 specifically and prove nothing.  However, I finally found the owners manual on line. It is very dumbed down, but if you look at the diagrams on the right hand side of page 9 in the English language section, there is a hint that you are correct.  Also, on the page with specs, the gain is not different when you feed the RCAs vs the XLRs. This too suggests you are correct.  Note the caveat on page 9 about feeding the balanced inputs from a TT wherein the outputs are grounded to the TT or tonearm. As they say and I said, this negates the balanced operation.

OMG! Please don’t talk down to me. I originally assumed you were referring to the case where you feed a signal from a SE component (NOT a phono cartridge) to a balanced component. For example, a SE phono stage into a balanced linestage. You can’t directly drive a balanced device in balanced mode with an inherently SE device. As we all know, a phono cartridge is inherently a balanced device, so what I wrote does not apply.

What I am talking about, what you say happens, is feeding a differential amplifier with a single-ended signal where you say the SE signal is converted to balanced mode.  If you don't do anything with the SE input (transformer input or etc), except hook it up to the balanced input via RCA, then you are driving one half of the balanced circuit (typically the positive phase) with the hot input from the SE source, and the other half of the balanced circuit (typically negative phase) is grounded by virtue of being connected to the ground side of the upstream SE input.  It's really not much different from hooking up a phono cartridge in typical SE mode. You would not get the benefit of balanced operation that way. This is even assuming that the RCA input on the TEAC is connected properly to the balanced circuit, rather than being connected so as to drive the balanced circuit in SE mode. You can't create a balanced source by waving your hands over an SE source. Or please tell me what is driving the negative phase of the balanced input, if you are still convinced I am wrong.

"Even unbalanced signal on the conventional RCA input is converted to the differential processing mode right after the input terminals. (Emphasis added.)"

That would be a neat trick indeed, without a transformer to do the job. I suppose it could be done with an active device, too, but that would be suboptimal, because it requires a processing step in the signal path which would inevitably add distortion however minor.  Are you sure the reviewer did not just misunderstand some blurb? The fact that the PE505 is fully balanced does not at all mean that the RCA input jack is not there to receive an unbalanced signal.  Like I said, Atma-sphere and probably BAT, both of which companies make only fully balanced preamps and amps, provide that SE input option.  The PE505 further offers SE outputs. This is done so as not to alienate potential customers who do not want to convert their whole system to balanced op. Anyway, this is important only to potential buyers of the PE505, of which I am not one. I'm out.

Reviews suggest the RCA inputs (and outputs) on the PE505 offer the option of unbalanced operation, as I suggested might be the case. Don’t use them if you want to take advantage of the balanced circuitry.

Do you know for a fact that the RCA jacks on the TEAC offer input to the balanced circuit? More likely the RCAs ground the negative phase of a balanced signal inside the chassis and convert to SE operation. That’s what Atma-sphere does with their amplifiers, so those who have SE components upstream can stay SE in the amplifier.

I realize you love ARC, and I’ve figured out that’s why you keep bringing up RCAs, but most cannot afford ARC Reference, and what they do is unusual. Anyway my concern is not with “ground” but with the shield that might carry RFI. After my last post I realized the shield can be connected to the middle post in a 5 pin DIN and should not then be connected to the RCAs at all. That’s probably what ARC does. So we’re good.

In a typical DIN to RCA cable, the shield would be connected to “ground”, which is also carrying the negative phase of the signal in balanced mode. That’s not a great idea. In a DIN to XLR cable the shield has its own termination isolated from the negative phase. That’s better. Anyway, every balance phono I’m familiar with offers XLR inputs.

Except the general consensus is that the XLR connector is inherently superior to the RCA connector, balanced or not.  I'm just repeating what I have read on other websites populated by knowledgeable hobbyists.  Not to mention that it looks that way to me too. And "he" needs an XLR cable if he is plugging into a balanced phono that offers only XLR inputs. I know there are adapters available but that is not the optimal way to go. I would rather say that an RCA connection is OK in a pinch, in balanced mode, but not the best way to do it. That's only my opinion.

Sorry to be so pedantic, but it is not the turntable (or the tonearm) that is "balanced".  It is the cartridge; any (modern) cartridge can be connected so as to drive the phono stage in balanced mode, if the phono stage has a balanced input. No matter what any manufacturer says, it is a simple matter to convert any cartridge output from SE to balanced. If you can solder, you can do a conversion from SE to balanced yourself.  If your tonearm leads are color coded as is typical, then White goes to pin2 of the L channel XLR. Blue goes to pin3 of the L channel XLR. Red goes to pin2 of the R channel XLR, and Green goes to pin3 of the R channel XLR, once you have removed the RCA plugs. But again, there is nothing to be gained unless you have a balanced phono stage. If you plug an XLR into a single-ended stage, pin3, which would carry the negative phase signal in balanced mode, goes to ground inside the SE phono stage, and you are back where you started.

For my part, I neglected to mention that a feaux balanced input can be implemented using a transformer at the input driving a single-ended circuit. Some commercial components do that. This offers some of the benefits of balanced operation.

Elliott, Is it not the case that your Mac MX110 preamplifier is single-ended, at least the phono stage?  If so, it is certainly no wonder that you heard no improvement with an XLR cable; the benefits if any are to be had if and only if the internal circuitry is balanced. In the case of a phono cartridge, it is a balanced device that we commonly use in single-ended mode by grounding one side of its output. If you connect that grounded side instead to the negative phase input of a balanced circuit, you get the benefits of added gain and noise cancellation.  I do agree that a noise-free and hum free SE connection using SE components, if you can achieve it, is not noticeably inferior to balanced mode, even when the equipment permits it.

The idea that an XLR cable per se gets you into balanced mode is false but it persists. As for using an RCA connection in balanced mode, it can work OK, IF the cable contains two equal conductors, one for SE hot or the positive phase of a balanced signal, and one for SE ground, or the negative phase.  The shield if any should NOT be connected to the ground side (which becomes negative phase) at either end, in the case where you want to use an RCA cable in balanced mode. (Some inexpensive RCA cable use the shield to carry ground and otherwise contain only a single conductor, for the hot side.)