NEWS: Rotel introduces RSP-1576MKII and RAP-1580MKII surround processors

Mark.Yudkin

Distinguished Member
Very disapointed in no eARC!
Where did you find that information? I can't find any manuals with detailed specifications. The news here also doesn't say which HDMI version is used (only HDCP 2.2 is clear).
 

DarkDogZA

Active Member
I would also be interested to know whether it definitely does not support 2 subs.
 

Sab

Active Member
Where did you find that information? I can't find any manuals with detailed specifications. The news here also doesn't say which HDMI version is used (only HDCP 2.2 is clear).
The spec on the Rotel website mentions that the HDMI version is only 2.0b
 

Mark.Yudkin

Distinguished Member
Thanks for the link to the manual; all clear. [Manual states HDMI 2.0a and 2 subwoofers, but not separate L & R subwoofers in stereo].

Rather a pity that Rotel should release a new processor, but not base it on HDMI 2.1.
 

Sab

Active Member
Thanks for the link to the manual; all clear. [Manual states HDMI 2.0a and 2 subwoofers, but not separate L & R subwoofers in stereo].

Rather a pity that Rotel should release a new processor, but not base it on HDMI 2.1.
Looks like the manual and their website spec do not agree as per below. The manual states HDMI 2.0a and the website says HDMI 2.0b. Does not inspire confidence!

Rotel processor hdmi version from website.JPG
 

Isco 3

Active Member
Preout 1.0V and the matching multichannel power amp needs 1.9V for full power?
 

popelife

Active Member
XLR inputs, but all the outputs are unbalanced phono? That's the wrong way around for sure.

I wish AV receiver and preamp manufacturers would standardise on balanced XLR outputs for the subwoofer channel(s). Unbalanced subs are so prone to earth loops.
 

shug4476

Active Member
XLR inputs, but all the outputs are unbalanced phono? That's the wrong way around for sure.

I wish AV receiver and preamp manufacturers would standardise on balanced XLR outputs for the subwoofer channel(s). Unbalanced subs are so prone to earth loops.
Most processors with balanced outputs do not actually have balanced circuitry, so it is a largely pointless gimmick excepting where you need very long cable runs.
 

popelife

Active Member
Quasi-balanced outputs, if that's what the manufacturers are doing, seem to work fine on other equipment, def better than a phono output where the shield of the connector is connected to mains earth. It's really the balanced inputs that are doing the work, but it's not a straightforward task to connect a phono output to a balanced input and get a good result.

Vast amounts of audio kit is permanently connected together in studios using balanced connections, without the slightest hint of an earth loop, so balanced connections - even if they're just quasi-balanced - are far from being a pointless gimmick.
 

dms

Active Member
Most processors with balanced outputs do not actually have balanced circuitry, so it is a largely pointless gimmick excepting where you need very long cable runs.
@shug4476

This is something which is bothering me as I do have long cable runs (15m) and am thinking if I need a processor with balanced XLR to replace my Yamaha 3070 which I connect to my active speakers with RCA->XLR adaptors.

Any chance you can explain this "gimmick" element to me here or in a PM as I don't "get it".

The Anthem AVM60 claims to be true-balanced, whereas I've seen comments other processors at this price point aren't.... but they have balanced output so it must be internally somewhere they are not balanced but what difference does that make?
 

popelife

Active Member
TBH, if you're not hearing any mains hum in your speakers when using the 3070 plus the adaptors, then there's not much to worry about.

But... apologies for the forthcoming tech nonsense... (I'll do my best to keep this simple, but no doubt someone will start debating this explanation)

For me, if I have a device that has a balanced XLR input, I'm always happier driving it with a balanced output, whether it's true-balanced or "quasi-balanced".

The number one most useful thing about balanced connections is that mains earth is not used as a reference for the audio signal. Balanced connections are also far more immune to interference than unbalanced, but for AV people, with our line-level signals and relatively short cable lengths, interference isn't a really concern.

A balanced input (nearly always on an XLR) has three connections, usually called "hot", "cold" and "ground". It measures the difference between the hot and cold connections, and that's what it uses as the audio signal.

The shield of the cable (pin one of the XLR) is connected to mains earth (usually). There's no signal on the shield, it purely helps prevent interference getting into the two signal wires. Because it's not used as part of the audio signal, you can disconnect it on one end of the XLR cable if you really need to... the cable will still be shielded, but now you're not connecting the mains earths of the preamp and the sub together via the XLR cable. Although, since mains earth isn't involved in transmitting the audio anyway, there's often no need to lift the earth at one end of the cable.

TL:DR is - balanced connections almost never result in earth loop hum.

Unbalanced RCA connections can cause earth loops, and subwoofers are great candidates for this. (e.g. my REL Strata 3 <grr>). That's because, for everyone's safety, both the receiver and the sub are connected to mains earth via their power lead. But then the mains earths are connected together again via the shield of the RCA cable, because the RCA connector is usually mounted on an earthed bit of metal casework and/or connected to mains earth internally. This is a good recipe for earth loop hum, especially when both devices are plugged into different mains outlets, and you've got a long signal cable connecting them together as well.

As for different types of balanced output - in simple terms, "true balanced" outputs drive both the hot and cold pins with signal - the cold pin carries the same signal as the hot pin, but with the polarity flipped. A "quasi-balanced" output ties the cold pin to ground via a resistor, but the connection still works since the balanced input is measuring the difference between hot and cold pins, and signal - nothing = signal. It's no biggie which kind of balanced output you have. Mostly you don't know, and don't care.

I hope that made sense.

PS Beware of some older hi-fi equipment with XLR inputs that turn out NOT to be balanced inputs at all. That can be a head-scratcher.
 

Mark.Yudkin

Distinguished Member
But... apologies for the forthcoming tech nonsense... (I'll do my best to keep this simple, but no doubt someone will start debating this explanation).
I wonder why so many people think that "balanced connections" means "differential signalling", and worse still try to explain (incorrectly) that differential signalling is responsible for rejection of external noise (it doesn't), whereas it is actually the balanced transmission line that does this. The two concepts are distinct, the only relationship between the two is that they can be implemented simultaneously over XLR (or TRS) connectors. Balanced audio implements both, even if the equipment at the ends is not an internally balanced design (the balun does this).

Balanced lines are about impedance matching, and it is this property, not the differential signalling, that effects the rejection of external noise. See Balanced line - Wikipedia.

Differential signalling does not effect noise cancellation - this is merely a popular misconception. Rather differential signalling allows lower voltages, or equivalently, yields a better signal-to-noise ratio. See Differential signaling - Wikipedia.
 

popelife

Active Member
True all of that, tho those are mainly concerns with data transmission / networks etc. Worth clarifying that there’s no impedance matching going on in audio connections, balanced or otherwise. Typ output impedance for an audio device is 200 ohm or less. Typ input impedance is 5k - 20k ohm.
 

IWC Dopplel

Well-known Member
Thanks for the link to the manual; all clear. [Manual states HDMI 2.0a and 2 subwoofers, but not separate L & R subwoofers in stereo].

Rather a pity that Rotel should release a new processor, but not base it on HDMI 2.1.
Sounds like one sub and two connections, assume EQ is not available separately ? Juts add a mini dsp HD and use one any way for up to 4 subs
 

Scott_Mac

Distinguished Member
Sadly looks as though it is just an update to the existing model but with Dirac added.

Shame as it was ticking so many boxes for me... if it had eARC i'd have been tempted.

Back to the NAD it is!
 

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