Wiim Ultra -> 2 x Balanced Amps

[Zed]

I’m exploring using a Wiim ultra to feed to 2 x Hypex NC252 amps (buckeye). This would be rca Y cables, connected to rca-xlr cables. Besides hum potential, is this a bad idea? Assuming there’s some room correction happening, would I end up with less than ideal voltage to the buckeyes?

(I’d rather not add a 4 channel balanced dac if possible.)

Thank you

 

[staticV3]

This would be rca Y cables, connected to rca-xlr cables. Besides hum potential, is this a bad idea?

No.

Assuming there’s some room correction happening, would I end up with less than ideal voltage to the buckeyes?

The WiiM's output voltage will stay the same, no matter if you're driving a single RCA Amp or two XLR Amps.

Optimal input voltage into the Amps depends on numerous factors, so impossible to give a simple answer.

 

[Zed]

No.


The WiiM's output voltage will stay the same, no matter if you're driving a single RCA Amp or two XLR.

The output stays the same, but what voltage arrives to the amps, at MAX, before accouting for headroom management, volume levels, etc…? Doesn’t the rca-xlr cut effective output (input to amp) in half? And then would the y cables degrade that input voltage further? (Sorry if this is kindergarten stuff).

 

[staticV3]

The output stays the same, but what voltage arrives to the amps, at MAX, before accouting for headroom management, volume levels, etc…? Doesn’t the rca-xlr cut effective output (input to amp) in half? And then would the y cables degrade that input voltage further? (Sorry if this is kindergarten stuff).

All Amps will receive 2.0Vrms max, no matter if they have RCA or XLR input and no matter if there's one, two, or three Amps.

Voltage will not be cut in half.

 

[Zed]

All Amps will receive 2.0Vrms max, no matter if they have RCA or XLR input and no matter if there's one, two, or three Amps.

Voltage will not be cut in half.

That's great news. Thank you much for your speedy responses!

 

[DVDdoug]

Doesn’t the rca-xlr cut effective output (input to amp) in half?

No. Typically, an XLR output has twice the voltage of an unbalanced output (from a device that has both) but that depends on the circuit.

But pro Line level is higher than consumer line level so sometimes XLR inputs don't have enough gain. (Both "standards" are rather "loose", home audio is never calibrated, and if there's a volume control that's another variable.)

And then would the y cables degrade that input voltage further?

No. You could probably drive 10 line inputs before anything happens...

Besides hum potential,

You still get most of the noise-rejection benefits from the balanced input.

 

[somebodyelse]

You still get most of the noise-rejection benefits from the balanced input.

So long as you use a correctly wired cable - twisted pair back to the RCA, joining cold and shield at the RCA. If you run coax and join cold and shield at the XLR end you don't get the benefit.

 

[Zed]

Thank you for clarifying. So I don't have to worry about Y cables or RCA to XLR. Assuming the cables will have the correct pinout, the remaining debate in my mind looks like this based on my research:

1. Buckeye needs ~1.7V input to produce full power of 250W.
2. WiiM Output: Max 2.0V.
3. DSP Penalty: Room correction will use headroom to prevent clipping, effectively cutting output by 6-10dB, resulting in max final input of 0.6V – 1.0V.
4. Only 0.6V–1.0V (35% of max) restricts the amp to roughly 35W (35% of 250W), causing clipping/compression (even if volume is adequate), and the system will lack punch, vibrancy, etc.... for my speakers which have sensitivity of 85db (LS50 Meta).
5. If all of that is true, then I may need 2 x bump boxes/DACs/preamps with high output ratings to boost the signal?
   
   CC: @somebodyelse @DVDdoug @staticV3

 

[staticV3]

DSP Penalty: Room correction will use headroom to prevent clipping, effectively cutting output by 6-10dB, resulting in max final input of 0.6V – 1.0V.

On my WiiM Mini at least, I did not measure any automatic preamp reduction when I used its 10-band PEQ for room correction.

It simply boosted and cut what I told it to.
So long as volume is less than 100%, this works fine though at some point, the WiiM should inevitably run into digital clipping.

Also important to consider that PEQ will not simply result in a uniform 6-10dB volume reduction with Peak output voltage reduced by the same amount.

Instead, Peak voltage will remain at 2.0Vrms with just the AVG output voltage being reduced some.

Only 0.6V–1.0V (35% of max) restricts the amp to roughly 35W (35% of 250W)

If 1.7V -> 250W, then:
0.6V -> 31W
1.0V -> 86W

also:
31W -> 55% of perceived loudness of 250W
86W -> 75% of perceived loudness of 250W

causing clipping/compression

This does not cause clipping, or compression.
Just a reduction in volume.

and the system will lack punch, vibrancy, etc...

No.

If all of that is true, then I may need 2 x bump boxes/DACs/preamps with high output ratings to boost the signal?

Simply try it first. A preamp is easy enough to add later, but you likely won't even need one.

 

[Zed]

Simply try it first. A preamp is easy enough to add later, but you likely won't even need one.

Will do. Thank you! Are you using your mini with an external dac? If not, how do you like it audio wise?

 

[staticV3]

Will do. Thank you! Are you using your mini with an external dac? If not, how do you like it audio wise?

I bought the Mini for my Dad after he bought a used Beolab 7 on impulse and didn't know what to do with it.

It's his bedroom setup currently, with the WiiM connected straight via Aux, as AirPlay receiver + room corrector:


No DAC-related complaints there, though if I was using it myself in a proper Stereo setup, I'd likely irrationally switch to an external DAC just for peace of mind.

 

[Zed]

No DAC-related complaints there, though if I was using it myself in a proper Stereo setup, I'd likely irrationally switch to an external DAC just for peace of mind.

Peace of mind (sleep) is totally rational! That aux out would haunt you for sure. I know 2.1vrms would haunt me if I didn't get the level converters. This is my solution btw. Overkill = peace of mind.

 

[bravomail]

I’m exploring using a Wiim ultra to feed to 2 x Hypex NC252 amps (buckeye). This would be rca Y cables, connected to rca-xlr cables. Besides hum potential, is this a bad idea? Assuming there’s some room correction happening, would I end up with less than ideal voltage to the buckeyes?

(I’d rather not add a 4 channel balanced dac if possible.)

Thank you

I have Wiim Ultra connected to 3e Audio A5. could not be happier.