balanced signal and RCA component

[Hador]

Here is my setup:
I use the balanced TRS output of the DAC, a Topping D50 III, and go into the external EQ (Nubert ATM 381). The EQ only has normal (not balanced) RCA inputs/outputs. From here I move on to the balanced input of the amplifier, a Topping PA5 II.
Now my questions:
1) Is it expected that the EQ will have problems with the balanced signal?
2) Does the balanced signal path even make sense if a component in between processes the signal not balanced? Would it make a difference to also use the RCA connections on the DAC and amplifier?
Thank you very much for your help in advance!

 

[Sokel]

Here is my setup:
I use the balanced TRS output of the DAC, a Topping D50 III, and go into the external EQ (Nubert ATM 381). The EQ only has normal (not balanced) RCA inputs/outputs. From here I move on to the balanced input of the amplifier, a Topping PA5 II.
Now my questions:
1) Is it expected that the EQ will have problems with the balanced signal?
2) Does the balanced signal path even make sense if a component in between processes the signal not balanced? Would it make a difference to also use the RCA connections on the DAC and amplifier?
Thank you very much for your help in advance!

Balanced out turn to unbalanced without a converter or something in between is not the best idea.
The best case if wiring does not include ground is that the noise cancellation is canceled (²)! and the worst if ground is included is that something is shorted at the output.
And it's not good to short outputs,some devices could let magic smoke out in such case.

 

[staticV3]

Hi @Hador! Welcome to ASR.

1) Is it expected that the EQ will have problems with the balanced signal?

No, but it's expected for the D50III to have problems with the single-ended load. See here and here.

In other words: Don't. Use RCA->RCA instead.

2) Does the balanced signal path even make sense if a component in between processes the signal not balanced?

Using a balanced input still makes sense even if the output is single-ended.

If an input is single-ended, then use the single-ended output.

 

[Hador]

Thank you both for the answers.

@staticV3 - so you mean:

(DAC – out RCA) --> (RCA in – EQ – out RCA) --> (Balanced TRS in – AMP)

Can I combine the RCA cable with an adapter (RCA to 6.35mm TRS)? As shown for example in the picture. Or is there a problem because of the lack of grounding? Or are there special adapters specifically for this?

If I really use the balanced input of the amp, won't I have problems with the maximum volume? The single-ended output of the DAC delivers a maximum of 2V. However, a balanced signal has a maximum voltage of 4V. Then I would only have half the power available!

 

[staticV3]

Can I combine the RCA cable with an adapter (RCA to 6.35mm TRS)? As shown for example in the picture. Or is there a problem because of the lack of grounding? Or are there special adapters specifically for this?

See here:


Best approach is to get a regular XLR->XLR/TRS->TRS cable, then snip off one XLR/TRS plug and replace it with RCA, with this pinout:

(Same deal with TRS instead of XLR)

E.g: https://www.audiosciencereview.com/...ments-of-crown-xls-1502-amp.6062/post-2070811

If I really use the balanced input of the amp, won't I have problems with the maximum volume? The single-ended output of the DAC delivers a maximum of 2V. However, a balanced signal has a maximum voltage of 4V. Then I would only have half the power available!

Half the voltage does not mean half the power.

The PA5II has 19.2dB gain with TRS input.
The D50III can output 2.5Vrms via RCA.

That will give you peak output power of (2.5*10^(19.2/20))^2/4=130W @4Ω or (2.5*10^(19.2/20))^2/8=65W @8Ω.

In other words, 2.5Vrms are enough to drive the PA5II to clipping, even with TRS balanced input.
You would not lose any output power.

 

[somebodyelse]

Half the voltage does not mean half the power.

It all depends on the maximum output power and gain of your Amp.

And on whether the amp has different gain for balanced and unbalanced inputs.

 

[Hador]

@staticV3 ... wow, thank you very much for your effort and explanations!

I'm still trying to think about whether the effort of converting the cable myself makes sense for me. In your picture above there is a comparison of the two variants with 0 dB versus >30 dB. This probably refers to reducing possible disruptive influences!? Does the “0 dB variant” have any other negative effects on the actual signal? If not, I could still do it that way. Because between DAC and EQ only a simple RCA cable without shielding is used too.

Using a balanced input still makes sense even if the output is single-ended.

Why actually? Because the signal processing in the balanced input is of higher quality?

 

[somebodyelse]

Why actually? Because the signal processing in the balanced input is of higher quality?

Because it has some common mode rejection, and a better chance of avoiding ground related noise issues.

 

[davmol]

Don't know if it will work for you but I did use this cable to go from a D50III TRS out to a Topping A50s RCA input and it worked fine, until I replaced the A50s with an A50III which has the balanced TRS input:
Amazon link - TRS to RCA cable

If your source is USB then the D50III has an inbuilt 10-band PEQ with multiple configurable profiles. If you use it then you could eliminate the external EQ box and just go balanced TRS dac output to balanced XLR amp input. If you are not using USB then I understand, it was a little frustrating to find that the PEQ only works for USB sources!