Topic: Output volume setting question, again ....

I have a Yamaha WXA-50 Amp, at the spec. sheet it states that the AUX RCA max. input signal (1 kHz, 0.5% THD) allows max. 2.4V, and the "input setting" page of the Amp, AUX allows Input Trim +- 6dB.

So the question is: If I set RME DAC RCA output to +13dBu minus 3.5dBr  (2.312V), and leave the Yamaha Input Trim at 0, is it safe for the Yamaha with 6dB headroom left for the RME DAC B/T, EQ switched on?

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2 (edited by KaiS 2021-08-06 21:30:31)

Re: Output volume setting question, again ....

Johannes AU wrote:

I have a Yamaha WXA-50 Amp, at the spec. sheet it states that the AUX RCA max. input signal (1 kHz, 0.5% THD) allows max. 2.4V, and the "input setting" page of the Amp, AUX allows Input Trim +- 6dB.

So the question is: If I set RME DAC RCA output to +13dBu minus 3.5dBr  (2.312V), and leave the Yamaha Input Trim at 0, is it safe for the Yamaha with 6dB headroom left for the RME DAC B/T, EQ switched on?

No, those Yamaha’s really don’t like hot signals, but have a low self noise, so lower ADI-2 levels are supposed.

If you want to use EQ and Bass/Treble, switch on Auto Reference Level.
If you see the volume as dBr you already have it on.

Dial an output where the reference level is shown as +7 dBu while turning the knob. The exact dBr value doesn’t matter.
When using EQ etc. correct the output into this range.
Set the listening level with the Yamaha’s volume control.

Re: Output volume setting question, again ....

Thank you KaiS, this Yamaha WXA-50 is a small class D Amp, the volume control is a rotary encoder, no display, but can read and set via browser or MusicCast App. The volume Max is 0dB and lowest -80dB ....

When I start with the RME, I follow the HiFi setting, assume the RCA Aux input is 2V, but then discover Yamaha aloows maximum 2.4V for AUX input. And I assume the Input Trim is a processing at the power Amp side of the Yamaha .... that mess me up ....

May be I stick with 8dBu (1.95V) first, which should be safe with 0.45V left, and experience it ....

Pacifist, dumb, not stupid
Listen music out from a box which sounds
Reading words on paper/ screen

4 (edited by Johannes AU 2021-08-07 05:48:59)

Re: Output volume setting question, again ....

The Signal flow as follow:

Apple Music playback from Mac Mini to RME via toslink (correct setting at Audi Midi Setup) OR from iPhone with camera kit to USB input of RME > RME RCA output to Yamaha WXA-50 RCA AUX in ...

When the RME arrived, everything works as it is, but sometimes discover some music are too loud, I can see at the DigiCheck, guess it is the problem of the music file itself, so at MacOS, I lower the Music App volume by 10-20%. But after the new 66/41 firmware flash, the problem gone, I am not sure if the firmware 39 has some small bugs or not so I didn't ask because that could be my own fault at set up values. (at firmware 39 I also found the Toslink switches from LOCK to SYNC back and forth but not anymore with 66/41, could be no more Varipitch?)

Now 66/41 works fine and previous problem gone, then I go back and try to redo the volume setting especially when I found out Yamaha max AUX input is 2.4V not 2V, of course I understand not the higher the better, just want to know the correct evaluation.

Pacifist, dumb, not stupid
Listen music out from a box which sounds
Reading words on paper/ screen

5 (edited by KaiS 2021-08-07 09:05:48)

Re: Output volume setting question, again ....

It’s best to use Auto Reference Level, as ADI-2 calculates the correct value for you, taking into account EQ and other settings.
Else you would need significantly more headroom.

With Auto Reference Level on, volume is shown as dBr instead of plain dB.
The “r” means “referenced to the max possible clean volume setting”, which equals a level of +13 dbu = 3.46 V at the RCA out.

In theory -3,2 dBr would equal your Yamaha’s max input (@ 0.5 % distortions, you don’t want that!).
Practically, in reality there are about 3 dB of intersample peaks above that, with modern pop music masters.

So stay away at least another 6 dB for a clean sound, this would be -9 dBr.
ADI-2 DAC will do it’s job to max out it’s dynamic range then.

6 (edited by Johannes AU 2021-08-07 10:18:41)

Re: Output volume setting question, again ....

KaiS wrote:

It’s best to use Auto Reference Level, as ADI-2 calculates the correct value for you, taking into account EQ and other settings.
Else you would need significantly more headroom.

With Auto Reference Level on, volume is shown as dBr instead of plain dB.
The “r” means “referenced to the max possible clean volume setting”, which equals a level of +13 dbu = 5.76 V at the RCA out.

In theory -7.6 dBr would equal your Yamaha’s max input (@ 0.5 % distortions, you don’t want that!).
Practically, in reality there are about 3 dB of intersample peaks above that, with modern pop music masters.

So stay away at least another 6 dB for a clean sound, this would be -13.5 dBr.
ADI-2 DAC will do it’s job to max out it’s dynamic range then.

Good Morning KaiS, thank you for your inputs.

If RME Auto Ref will adjust automatically for EQ and B/T added, it is super.

My current setting is +13dBu minus 4.5dBr, Auto Ref on, Volume Locked, i just wonder if change from minus 4.5dBr to minus 3.5dBr will be harmful of not.

Pacifist, dumb, not stupid
Listen music out from a box which sounds
Reading words on paper/ screen

7 (edited by KaiS 2021-08-07 09:31:44)

Re: Output volume setting question, again ....

Johannes AU wrote:
KaiS wrote:

It’s best to use Auto Reference Level, as ADI-2 calculates the correct value for you, taking into account EQ and other settings.
Else you would need significantly more headroom.

With Auto Reference Level on, volume is shown as dBr instead of plain dB.
The “r” means “referenced to the max possible clean volume setting”, which equals a level of +13 dbu = 3.46 V at the RCA out.

In theory -3,2 dBr would equal your Yamaha’s max input (@ 0.5 % distortions, you don’t want that!).
Practically, in reality there are about 3 dB of intersample peaks above that, with modern pop music masters.

So stay away at least another 6 dB for a clean sound, this would be -9 dBr.
ADI-2 DAC will do it’s job to max out it’s dynamic range then.

Good Morning KaiS, thamk you for your inputs.

If RME Auto Ref will adjust automatically for EQ and B/T added, it is super.

My current setting is +13dBu minus 4.5dBr, Auto Ref on, Volume Locked, i just wonder if change from minus 4.5dBr to minus 3.5dBr will be harmful of not.

Sorry, I miscalculated the dBu, see correction above.

According to Yamaha’s specs @ 2.4 V you already run into 0.5% distortions.
13 dBu minus 3.5 dBr equals 9.5 dBu / 2.31 V, in theory.

But then come the intersample peaks, which in fact raise the peak level by 3 dB to 12.5 dBu / 3.3 V.
This is well ABOVE Yamaha’s max input.

Nothing will break, but a lot of sound quality gets lost.
The golden rule for audio engineering is:
Have a good amount (say, 6 dB) of headroom with Solid State (read: non-tube) electronics for a better sound.

You don’t gain anything good trying to max out the level.


Did you try to use Yamaha’s Digital Optical input?
This would circumvent the DA-AD conversion.

8 (edited by Johannes AU 2021-08-07 12:01:31)

Re: Output volume setting question, again ....

KaiS, thanks again :-)

>>Sorry, I miscalculated the dBu, see correction above.

According to Yamaha’s specs @ 2.4 V you already run into 0.5% distortions.
13 dBu minus 3.5 dBr equals 9.5 dBu / 2.31 V, in theory.

Me: Nevermind, I knew it is a miscalculation, or could be a typo, I got your original meaning.

>>But then come the intersample peaks, which in fact raise the peak level by 3 dB to 12.5 dBu / 3.3 V.
This is well ABOVE Yamaha’s max input.

Nothing will break, but a lot of sound quality gets lost.
The golden rule for audio engineering is:
Have a good amount (say, 6 dB) of headroom with Solid State (read: non-tube) electronics for a better sound.

You don’t gain anything good trying to max out the level.

Me: Yes, this is exactly my concern, I will stay at +13dBu -4.5dBr (2.06V) with Auto Ref Volume Locked. (As stated in RME manual per HiFi setup)


>>Did you try to use Yamaha’s Digital Optical input?
This would circumvent the DA-AD conversion.

Me: For TV only.
AUX input without DSP solely for RME, Yamaha works as a power Amp in "direct mode" alone.

============
P.S. Consulted Yamaha agent, the Input Trim is to add on minus output to the input of the built in ICEpower class D Amp module, it is the same as on their WXC-50 without Amp. That said, if the Pre-Amp input is use for some low level signal, Input Trim can compensate it to have a similar loudness as other inputs.

Pacifist, dumb, not stupid
Listen music out from a box which sounds
Reading words on paper/ screen