Modi + Midgard or Modius + Midgard?

[dreaminALife]

Hey guys I am very new to the schiit world.

I am looking at buying the midgard amp for my planars. I looked at their website and it says the midgard is not a balanced amp.

Another fact is, the modius dac and the modi dac have very similar specs. The chips have similar performance. The only major difference between the two is, modius is a balanced dac while the modi is not.

That raises the question for me: Do I need a balanced dac for an unbalanced amp like the midgard? The price difference between the two dacs is around 100 USD I am not sure if it is worth it.

I don't really care about noise cancellation since the cable would be very short. I am curious if the 4v xlr input would make the amp have more headroom compared with the 2v rca input. And is that something audible?

I hear some people say the amp output would be louder using the 4v xlr input compared with the 2v rac input.
Others say NOPE, the amp usually matches the two inputs signal to make them the same for the amp.

Now I am confused.

To sum up:

1.Do I need a balanced dac for an unbalanced amp like the midgard?

2. Would the 4v xlr input make the amp have more headroom compared with the 2v rca input?

3. will the output be louder using the xlr input?

 

[staticV3]

Hi @dreaminALife! Welcome to ASR.

1.Do I need a balanced dac for an unbalanced amp like the midgard?

You do not.

2. Would the 4v xlr input make the amp have more headroom compared with the 2v rca input?

Yes:

3. will the output be louder using the xlr input?

It can be louder using XLR.

Whether it will be, depends on how high you turn up the volume.

 

[dreaminALife]

Hi @dreaminALife! Welcome to ASR.


You do not.


Yes:
View attachment 413365


It can be louder using XLR.

Whether it will be, depends on how high you turn up the volume.

Wow thanks for the reply! May I ask where you get the chart?

 

[staticV3]

Wow thanks for the reply! May I ask where you get the chart?

Made it

 

[dreaminALife]

Made it

Holy schiit love this place already! But how? Could you please elaborate a little bit about the theory behind it? Or is it just an experimental result? Thanks!

 

[staticV3]

Holy schiit love this place already! But how? Could you please elaborate a little bit about the theory behind it? Or is it just an experimental result? Thanks!

I used Schiit's power numbers for the Midgard:


converted them to Vrms using sqrt(P*R)=V:


then did a curve fit on them to get the Midgard's maximum output voltage vs load behavior:


This is the 100% baseline.

For the output voltage vs load impedance at 2V input curve, I had to figure out the Midgard's gain first.

The spec sheet says 14dB, but to be sure, I checked Schiit's own APx555 measurement report:



It contains gain measurements at 300Ω Halo, 300Ω SE, and the same with 32Ω as well:


Gain[dB]=20*log10(Vo/Vi), and that gave me 13.16, 13.14, 13.16, and 12.62dB for the different configs.

I discarded the 12.62dB result as an outlier and used 13.16dB gain for further calculations.

To get maximum output voltage with 2V in, you do Vi*10^(Gain/20), so 2*10^(13.16/20)=9.1Vrms, so about 60% of the Midgard's voltage limit.

Since we don't hear voltages linearly (60% voltage ≠ 60% perceived loudness), I lastly converted that difference to perceived loudness using dB∆=20*log10(voltage ratio) and loudness ratio=2^(dB∆/10).

Plot that against load impedance and you get:

 

[majingotan]

Aside from specs, if you care about stack uniformity, here’s how a modi / (magni piety footprint on my stack) and modius (bifrost footprint on my stack) would stack with Midgard

 

[dreaminALife]

Thanks everyone. Seems like not a big difference to me. Decided to buy the midgard and pair it with my fiio k11 lineout. Not sure if it is going to be worse than modi though

 

[dreaminALife]

I used Schiit's power numbers for the Midgard:
View attachment 413384

converted them to Vrms using sqrt(P*R)=V:
View attachment 413387

then did a curve fit on them to get the Midgard's maximum output voltage vs load behavior:
View attachment 413386

This is the 100% baseline.

For the output voltage vs load impedance at 2V input curve, I had to figure out the Midgard's gain first.

The spec sheet says 14dB, but to be sure, I checked Schiit's own APx555 measurement report:
View attachment 413388


It contains gain measurements at 300Ω Halo, 300Ω SE, and the same with 32Ω as well:
View attachment 413390

Gain[dB]=20*log10(Vo/Vi), and that gave me 13.16, 13.14, 13.16, and 12.62dB for the different configs.

I discarded the 12.62dB result as an outlier and used 13.16dB gain for further calculations.

To get maximum output voltage with 2V in, you do Vi*10^(Gain/20), so 2*10^(13.16/20)=9.1Vrms, so about 60% of the Midgard's voltage limit.

Since we don't hear voltages linearly (60% voltage ≠ 60% perceived loudness), I lastly converted that difference to perceived loudness using dB∆=20*log10(voltage ratio) and loudness ratio=2^(dB∆/10).

Plot that against load impedance and you get:
View attachment 413392

One more question I saw people saying one could connect the headphone out to the balanced xlr input of the amp via an adaptor since the k11 headphone out should have more than 4v. Is that something valid? Any potential issues? Really trying to avoid buying a balanced dac right now lol

 

[staticV3]

One more question I saw people saying one could connect the headphone out to the balanced xlr input of the amp via an adaptor since the k11 headphone out should have more than 4v. Is that something valid? Any potential issues? Really trying to avoid buying a balanced dac right now lol

IMO, not worth the hassle and risk.

I'm 98% sure that the Midgard will be plenty loud enough, even with 2V RCA input.