How useful is a 2v/4v measure for an AVR preout ?

[Gedeon]

I'm just really confused about this.

This is still the best site I've found to help audio consumers-enthusiast in order to take better purchasing decisions regarding to audio "fidelity" from electronics point of view.

And at the same time aiming to those products/builders which fail in publishing reliable specs or to release a minimum quality audio performing machine to use in a medium-to-high quality setup.

I do love this site.

However... I still can't find a typical use case in consumer setups in which a 2v(unbalanced)/4v(balanced) SINAD gives any really useful info for end users setups.

AVRs aren't stereo DACs. As far as I know AVR preouts don't aim to feed integrated amps or pre-amps. Not a single one of them. Those outputs will 99% feed multichannel power amps rated to work 1.2-1.5v/2.4-3v inputs.

And thanks to @amirm we have seen some serious changes in SINADs behaviour when output is limited to those 1.2v/2.4v or, let's say 80% maximum output...

At this point I can't read those reviews and try to guess how those machines could perform in typical setups. I just can't.

There are another tons of issues relates to AVRs, like stability, features....price.... but those are different from what I, firstly, would like to find when looking for @amirm reviews.

What do you think ? Are really those measurements as useful as in DACs ? Am I wrong ?

 

[Liten]

According to this review it's important to reach at least 2v but 4v is great.

 

[Gedeon]

According to this review it's important to reach at least 2v but 4v is great.

¿ balanced (XLR) or unbalanced (RCA) ?

 

[Gedeon]

Just checked the doc and the video

Using HDMI input, I plotted an FFT at 1Vrms via the XLR outputs and the resultant distortion was excellent with the 2nd order -105dB below the fundamental. At 4Vrms out, 3rd order rose substantially to -76db

So 1v XLR really good, while 4v XLR not so good. No surprise.

 

[jomark911]

I would say , it's a typical behavior of a not so good implemented circuit , while the design was far better.
Accountants do their magic very often .

 

[jomark911]

Well he said it , at 06"46 , the DENON AVP-A1HDCI prepro.
That's a prepro that is a leader.

 

[Gedeon]

Just giving more visibility to this thread again.

I still think that AVRs pre-outs shouldn't be measured as standalone stereo DACs.

Those machines aren't designed to feed an integrated stereo, a pre-amp (passive or active), or a stereo power-amp.

And most music, although I could be wrong, played through these machines is nowadays done by its internal DLNA engine and applying the room correction provided by the builder.

I'm not saying @amirm measures are wrong, just saying those measurements doesn't fit the typical use case for those equipments. ¿ HDMI source for stereo or 2v rated multichannel power amp attached ? I don't really think that's the common use case for most AVR owners in 2020.

 

[amirm]

Those machines aren't designed to feed an integrated stereo, a pre-amp (passive or active), or a stereo power-amp.

What is the pre-out for then?

Note that similar issue exists with AV Processors without amp. Surely then you have to use an external amp.

 

[Gedeon]

Some multichannel power-amps:

My old, but still functional, Parasound HC855.
Input Sensitivity
1 V for 28.28 V 1.2 V for full output

Emotiva XPA-5
Input Sensitivity (for rated power; 8 Ohm load): 1.5 V.
Gain: 29 dB.

Krell Theater 7
Input Sensitivity
Single-ended or balanced: 1.50 V RMS

Yamaha MX-A5200
(from the manual)
• Input Sensitivity / Input Impedance
Unbalance (1 kHz, 100 W/8).................................................. 1.0 V/47 k
Balance (1 kHz, 100 W/8)....................................................... 2.0 V/47 k
• Maximum Input Signal
Unbalance (1 kHz, 0.5% THD, 8) .......................................................1.3 V
Balance (1 kHz, 0.5% THD, 8) ............................................................2.6 V

Sure you can find some builders which rate their amps to higher voltages, but most multichannel power amps, as far as I know are designed to accept no more than 1.2-1.5 volts from unbalanced/RCA.

 

[Gedeon]

@amirm, I'd just like to know why a 2v output measurement can be more useful than a 1.2-1.5v one in unbalanced/RCA for most AVR owners.

And also, in which proportion AVR owners use the HDMI input from PCM stereo source instead using the integrated DLNA player or the less prone to carry interferences/issues optical/tos-link (even coax).

And lastly how many AVR owners just use pure-direct, disabling subwoofer, and room correction features for music or movies (so no DSP in the sound path).

This is my point of view.

 

[carlob]

@amirm, I'd just like to know why a 2v output measurement can be more useful than a 1.2-1.5v one in unbalanced/RCA for most AVR owners.

And also, in which proportion AVR owners use the HDMI input from PCM stereo source instead using the integrated DLNA player or the less prone to carry interferences/issues optical/tos-link (even coax).

And lastly how many AVR owners just use pure-direct, disabling subwoofer, and room correction features for music or movies (so no DSP in the sound path).

This is my point of view.

I have a Denon X3600 (coming from a X3500) and I use the preouts to feed L+R channels to my main amp which is an HYPEX one - it needs 2,5V to rated power.

 

[Gedeon]

So you

I have a Denon X3600 (coming from a X3500) and I use the preouts to feed L+R channels to my main amp which is an HYPEX one - it needs 2,5V to rated power.

Hence AVR pre-outs should be designed to feed stereo power amps instead multichannel power amps....?

I'm not claiming 2v measurements in AVRs are useless, just saying 1.2-1.5 are, at least, more useful than 2v.

 

[carlob]

Hence AVR pre-outs should be designed to feed stereo power amps instead multichannel power amps....?

I don't know, everyone is different. Since I'm not going for an all-in-one system I like to have the option to feed L+R channels to my 2-channels system. I'd very much prefer to have the option to feed LCR channels to external amps and use the internal amps for the other channels. By the way multichannel power amps based on hypex modules do exist and need 2,5V to rated power (to be precise the NC500MP needs 2,35Vrms with a 4 Ohm load)

Here is the multichannel Hypex offering from the brand I'm using, you can have up to 8 channels: nord-one-hypex-mp-multichannel

 

[Gedeon]

I don't know, everyone is different. Since I'm not going for an all-in-one system I like to have the option to feed L+R channels to my 2-channels system. I'd very much prefer to have the option to feed LCR channels to external amps and use the internal amps for the other channels. By the way multichannel power amps based on hypex modules do exist and need 2,5V to rated power (to be precise the NC500MP needs 2,35Vrms with a 4 Ohm load)

Here is the multichannel Hypex offering from the brand I'm using, you can have up to 8 channels: nord-one-hypex-mp-multichannel

Could you be so kind to link a specs sheets in which RCA/unbalanced input voltage/gain can be found for those ? I'm unable to find that info.

 

[carlob]

Could you be so kind to link a specs sheets in which RCA/unbalanced input voltage/gain can be found for those ? I'm unable to find that info.

Gain is 26dB (25.6 to be precise), specs are that of the Hypex modules, here the NC500MP: NC500MP 01xx Datasheet - Hypexwww.hypex.nl › download

 

[Gedeon]

Gain is 26dB (25.6 to be precise), specs are that of the Hypex modules, here the NC500MP: NC500MP 01xx Datasheet - Hypexwww.hypex.nl › download

I'm really sorry but still unable to find the 2.5v rated input for unbalanced you are claiming for those multichannel power amps.

 

[carlob]

I'm really sorry but still unable to find the 2.5v rated input for unbalanced you are claiming for those multichannel power amps.

I'm not claiming anything, the 2,35Vrms input sensitivity for NC500MP is in the datasheet

 

[ririt]

Could you be so kind to link a specs sheets in which RCA/unbalanced input voltage/gain can be found for those ? I'm unable to find that info.

You can download the data sheet from the Hypex web site for any kind of module, very informative! Same is true for Purifi (except that it does not take into account additional gain provided by the input buffers designed by assemblers like Nord, Audiophonics or Apollon)

 

[zermak]

I'm really sorry but still unable to find the 2.5v rated input for unbalanced you are claiming for those multichannel power amps.

Page 7 of the datasheet

I'm not claiming anything, the 2,35Vrms input sensitivity for NC500MP is in the datasheet

 

[Gedeon]

I'm not claiming anything, the 2,35Vrms input sensitivity for NC500MP is in the datasheet

Ok I see, but that info is for balanced input signal, not for unbalanced/RCA. If "translated" from balanced to unbalanced that voltage would be 1.2v as far as I know:

Input sensitivity
Below a formula is given to calculate the balanced input signal level for a desired output level. Furthermore an
example is given using PRATED 500W, Load 4Ω, Gain 25.6

So, If I'm not wrong, these power amps are in the same league, when talking about input specs, than most of the multichannel power amps in the consumer market.