Outputs - balanced wiring or not?

Steinberg Hardware UR-C Series
1

I’m really confused by information I’ve seen about the UR-22C and its outputs, regarding whether they are “balanced”.

If I read the product manual, the outputs are described as electronically impedance balanced, and many online reviews simply call the outputs balanced.

So, if the circuit is impedance balanced, like the instruction manual claims, then there would be an advantage in using full TRS wiring to a studio monitor, since there would be an electrical impedance between shield and cold, and there would be some isolation between ground and the signal wires through this impedance.

But, the manual for the UR22C also indicates the TRS jack is shorted between shield and ring (ie no impedance) suggesting it is pointless using balanced wiring to studio monitors.

In another place in the manual, there’s example connection guidance, if you zoom in to the outputs, it’s vague whether you’re looking at TRS or TS connectors, though I’m guessing the pictures show TRS due to the point on the end of the connector.

To make things more frustrating, the UR44C manual suggests fully balanced outputs in its circuit layout - it’s schematic implies differential amps for the outputs.

What is the truth? Does anyone in Steinberg actually know? Or is the marketing speak as misleading as the “32-bit” specification for this UR-C range of products?

If anyone owns a UR-22C and can vouch for the real circuitry, I’d love to know the answer.

This might seem a very “techy” question, but sometimes these things do matter. And if the manual has contradictions, who exactly do you ask these days, in order to make a sensible purchasing decision?

2

The difference from balanced to unbalanced connection on the outputs are marginal for short length cables like the connection to some near-field monitors.

And this has nothing, absolutely nothing to do with the bit depth…

So buy some TRS cables since the price of them is nearly the same as for unbalanced (TS) cables with the same quality.

As far as I remember there are ordinary OP amps shown.

Why sensible? again buy TRS cables, nothing wrong with them.

3

Hi st10ss,

My enquiry is simply to determine the truth, does the UR-22C have balanced outputs or not. Whether the difference is marginal, depends on whether this matters for your needs. If this was not a big deal, why is there balanced outputs on some line devices and not others (e.g. 73 and 88 key Yamaha stage pianos, but not on the 61-key YC model?)

It also has a LOT to do with the bit depth. You see, everywhere on the Steinberg sales literature, the UR-C range says ‘32-bit’, even on the front of the product. Yet, despite this, nobody has ever been able to take 32-bit recordings into their computer from this interface. Because, the literature is misleading - you can’t make 32-bit recordings with these interfaces, the only conclusion anyone has been able to make is that somehow the audio is sampled internally at 32-bit and then downsampled to 24-bit to the computer through the interface. So Steinberg have set a precedent for making bold statements about their products which were, at best, misleading, at worst, lies.

The schematics for the UR-44C, in the manual, have two op amps for each output channel, and a separate ground connection. This usually means differential output. The schematics for the UR-22C have a single op amp and the cold / shield connections on the TRS appear shorted. You can’t have both impedance matching output and a shorted connection.

There are enough issues to navigate around for audio interfaces without manufacturers being vague. There should be no defence for manufacturers being vague about products they design and then sell - it’s easy to make specifications for a product because the specifications are part of the design.

Saying ‘buy TRS cables’ without being able to say whether they provide a material advantage sounds like a “snake oil” salesman approach to me. It’s a flippant answer to a serious question.

All I want to know is if there is a balanced outputs on this device or not, before buying one. It’s a trivial thing for someone to check who owns the interface in question, you’d measure the resistance between shield and ring on the output (using a meter), if this is a dead short then the outputs are unbalanced, otherwise there is some isolation / common mode rejection circuitry on the outputs.

4

I don’t have a 22, I have a 816. But if you use unbalanced cables to your active studiomonitors, chances are high that you willl hear a noise in your monitors coming from the computer. WIth balanced cables this will be quiet.

5

… sorry that is… balanced connections and bit depth… ahmm not related in any way

6

This is simply wrong. Balanced cabling is not the cure to all noise problems.
Balanced cables avoid noise introduced to the cable connection only.

7

What I mean is that unbalanced cables(also short ones) from the interface to the active monitors nearby a computer can pickup interference, unbalanced cables mostly not. That was at least in my case. It’s not indeed not the solution to every problem.

8

That’s correct.

9

I have a 44C and will grab my ohmmeter tomorrow and will make that test for you.
However…
Having a balanced connection for a high-impedance input (like a mic pre-amp) makes a HUGE difference (for noise immunity), while for a lower-impedance input (like on a line out) it makes little or no difference. So unless your cables going to your monitors are long and going around very noisy sources (ex. a frig compressor!), you will never ever hear a difference. I’ll make your test anyway, but it’s irrelevant, aside from answering about it being marketing “fluf” or not.

Now about 32-bit.
Yes the 44C can record in 32-bit, but here again, it’s irrelevant.
The bit resolution says nothing about the usable resolution.
The mic input circuitry has only 102dB of dyn. range, equivalent to about 17 bits.
The Line in 5&6 have 106dB, so about 18 bits equ., about twice better but still quite far from 32b.
This means that when recording at 24b, the lower 6 or 7 bits (LSB) are completely buried in electronic/thermal noise already.
Recording at 32b only gives you 8 more bits of completely random noise - that’s it!
Completely floating in snake oil here.

If recording at 16b only, you’re missing out on some subtle information that might be worth it. But 24b already gives more than enough to capture every iota of significant info. If available, 20b recording would already be overkill, so forget about 32b.

N.B. I’m not talking of bit resolution for the maths/algorithms purposes, only for recording.

There is no value whatsoever in recording 32b instead of 24b, and even with the fanciest 10k$ interface you could find.
To take FULL advantage of 24b, you would need 144dB of dynamics… something NO preamp could ever deliver, unless it’s running in dry-ice or even colder ambiant.

The 44C is a great unit!! But 32bit recording has nothing to do with it.

1 Like
10

Update…
I did the ohmmeter test mentioned previously.
Happy to confirm all 6 outputs support true TRS balanced cabling.
You can of course use also an unbalanced TS cable, which makes no difference for 99.99% of installations.

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11

How do you test balanced sockets with an ohm-meter?
The only information you can get with an ohm-meter is the resistance…

12

Simply plug a TRS to TRS cable in.
Then measure resistance between Ring and Sleeve.
If the output was unbalanced, you would read zero-ohms (or pretty close).
In the present case, it was well above 100kohms, confirming a balanced output.

It’s also clear from the diagram:

image
image713×212 44.2 KB

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13

N.B. : The 32-bit “integer” format of UR-C units is not to be confused with the 32-bit “float” format, esp. when combined with dual ADC converters! Two completely different beasts.
It would be great if the UR-C series supported dual-ADC with 32-bit float… but it sure would be much more $$…

1 Like
14

Putting my engineer’s hat on with a ‘techy’ answer, it’s important to understand what ‘balanced’ and ‘unbalanced’ actually means in the context of audio ground connections between source and load.

We understand that ‘balanced’ generally means differential, so that the load can differentiate source audio from noise in the ground/common between equipment.

For unbalanced signals (i.e. referenced to ground), then any noise current transferred through the ground circuit can effectively manifest in small signal voltage that appears on the unbalanced feed at the load.

It pays to consider that active speakers/amplifiers, computers and USB audio interfaces, have external loops via mains connections to their power supplies, and audio connections between instruments can create impactful ground loops where such noise finds a parallel path along the signal cable ground between connected equipment.

So balanced feeds would appear to be the perfect solution - but not quite, without mention of the ground. Differential (balanced) signals are certainly best in discriminating out common noise on both signal wires, but then there is common-mode voltage range - which isn’t limitless. For example, a common noise spike that exceeds the maximum input signal voltage will manifest as noise on a balanced input regardless.

This is where the ground comes in, effectively binding source and load, keeping common noise within the range that inputs are able to work with.

As a footnote, it is always best to power your audio equipment from a single socket, or adjacent sockets on an extension lead, for example. This helps avoid other noise on mains circuits finding parallel paths through connected audio equipment.