Chord Mojo 2 Thread ___ [product released January 31, 2022 -- starting on page 95 of thread]
Apr 6, 2024 at 2:55 PM Post #10,321 of 11,840
My use case for DSP is with the Dan Clark E3 headphones, and this small tweak really lets the bass texture and detail through, IMO.
20Hz +2, 125Hz -2, 3000Hz +1, 20kHz -3

Here’s what you’ll get as a deviation from the normal frequency response:
1709081981515.png
Would this apply to MrSpeakers Ether Flow?
 
Apr 6, 2024 at 3:07 PM Post #10,322 of 11,840
Would this apply to MrSpeakers Ether Flow?
I don't own either set, but a quick glance at their respective frequency responses shows two very different headphone tunings. So, no.

However, you could pretty easily come up with your own EQ settings on the Mojo 2 with something like oratory1990's DCA Ether Flow measurements and REW. You still need a target though, so that depends entirely on your own listening preferences. For example, to more closely align with the Harman target, it looks like you could just give a couple dB boost to the 125Hz shelf and a healthy boost to the 3kHz shelf (and drop the 20kHz peak filter to re-normalize the upper treble region). But honestly, with just four basic filters on the Mojo 2, there's no reason you can't just EQ by ear.
 
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Apr 6, 2024 at 4:59 PM Post #10,323 of 11,840
I highly suggest the iFi 90 Degree USB-C to USB C
That’s a great cable, but caution, as it doesn’t play nicely with phone cases, as I just found out the hard way… going to try the ddHiFi next…

Inverters can indeed generate noise and do utilize SMPS equipment. As Rob Watts mentioned in the video posted above, SMPS can offer numerous benefits, but they have to be designed well. The quality and implementation of the inverter matters a lot. I most certainly agree with @MarkParity that, when devices allow for a 12VDC input, connecting said devices directly to a battery without a regulator in between is generally preferrable (depending on the regulator, of course! There are some high quality ones out there, and lots of crappy ones).

While I have not tested more than the bluetti inverter I own (it was suggested to me by an audio retailer whose ears I trust), my audio set up sounds markedly clearer using batteries (for DC devices) and the bluetti battery and inverter (for AC devices) relative to the AC power coming out of my wall. I do repeated tests at many times of the day (just to distract from my day-to-day work to make sure).

I can't be certain I know why I'm getting better listening results using the batteries and inverter. Various hypotheses I cannot in any way definitely (i.e., without a doubt) prove:
  • Power quality from grid-linked AC outlets varies by time of day (power usage is higher during daytime hours - coincidentally usually when my the listening experience is worse).
  • Grounding schemes in vary on a home-by-home basis (Michael Fremmer just got his house re-grounded - fun video here). Therefore not all AC lines offer the same performance due to the differences in grounding.
  • The Batteries and AC Inverter are "floating". This "air gap" from shared ground isolates the audio devices from noise generated by other devices (like microwaves and washing machines) that travel on the AC line and ground.
  • Unknown Unknowns - I have no idea, but in my Brooklyn apartment, I could pick up low-level ham radio signals! I have no idea why this was the case. This problem actually led me down the power isolation rabbit hole.
At the end of the day, all I can do is compare my listening experience vs. different set ups I have experienced (either in my house, at CanJams, or at friends' spots). I'm just sharing my experience in the hopes it benefits others!
Sounds like you have researched this a great deal. I have to say, when I saw that video, I had never heard a Chord product… Now hearing what Rob has achieved with the Mojo 2 and Qutest (can only imagine the others are even more impressive), I have upgraded my trust in what that man says to 99.9%. Both of these products are otherworldly…

In that spirit, I’m going to see if my other flagship DAC (Dayzee) and / or my Qutest will perform better with an iFi iPower X, which, based on the limited info I have found on it, appears to be a well-designed SMPS.
 
Apr 6, 2024 at 9:38 PM Post #10,324 of 11,840
That’s a great cable, but caution, as it doesn’t play nicely with phone cases, as I just found out the hard way… going to try the ddHiFi next…


Sounds like you have researched this a great deal. I have to say, when I saw that video, I had never heard a Chord product… Now hearing what Rob has achieved with the Mojo 2 and Qutest (can only imagine the others are even more impressive), I have upgraded my trust in what that man says to 99.9%. Both of these products are otherworldly…

In that spirit, I’m going to see if my other flagship DAC (Dayzee) and / or my Qutest will perform better with an iFi iPower X, which, based on the limited info I have found on it, appears to be a well-designed SMPS.

Thanks - Rob is the man. I take his word up to 75% of the time! He has a vested interest to steer people to his products, and they are high quality products IMO, but I tend to subscribe to using external upsamplers like PGGB over his MScaler.

iFi makes nifty power supplies. I don't have a Qutest, so it's hard for me to say what that power supply's impact will be. If I had a qutest - I'd experiment with different 5 volt battery solutions (something like Fujitsu AA rechargeable batteries combined with a 5V AA battery pack with USB out). I don't think I've seen 5 volt LiFEPO4 batteries, sadly only 12V.
 
Apr 7, 2024 at 12:08 AM Post #10,325 of 11,840
Thanks - Rob is the man. I take his word up to 75% of the time! He has a vested interest to steer people to his products, and they are high quality products IMO, but I tend to subscribe to using external upsamplers like PGGB over his MScaler.

iFi makes nifty power supplies. I don't have a Qutest, so it's hard for me to say what that power supply's impact will be. If I had a qutest - I'd experiment with different 5 volt battery solutions (something like Fujitsu AA rechargeable batteries combined with a 5V AA battery pack with USB out). I don't think I've seen 5 volt LiFEPO4 batteries, sadly only 12V.
I wonder if that would make a difference for the Qutest since it doesn’t have a direct HP out, so I’m going through a mains-connected amplifier anyway. I might be able to get a battery beefy enough to run the V222, not sure how much it draws, but my kill-a-watt says the WA22 draws around 100 watts… Then again, all of the amps I have have internal power supplies, so really they take AC, which I have to assume is a whole other extremely expensive kettle of fish to reproduce with a battery or by other means. So if the amp is on the mains, I assume there’s still a good chance to pick up some noise… I do have a custom AC + DC filter from a tiny company called Pine Tree Audio to filter the mains power in front of a Furman filtering power strip - obviously nowhere near a battery, but still, better than nothing I would think. Just a long way of asking if it even matters much to go to a battery if you still have a mains connection in the chain…
 
Apr 7, 2024 at 1:35 AM Post #10,326 of 11,840
This is the battery / inverter unit I use for my Nitsch x Schiit Pietus Maximus.

I have no doubt it will be sufficient for your V222. I think it should work with the WA22 too... at 100-watts & the Bluetti's capacity of 1,152Wh, I think you'll have decent headroom so long as you charge between sessions.

To help answer your question - maybe a good test would be to take your IE600 or a more sensitive IEM and plug it into your Mojo 2. Make sure your Mojo 2 is fed via optical or USB from a phone (that is fully charged). Do a noise-floor test (max the volume and see if you can perceive / hear noise). Then use your mains powered amps and do the same to test for noise-floor. You could also do music tests (with the volume controlled by Mojo 2 and the amp's volume, in turn, maxed out, taking the volume pot out of the equation). Obviously the Mojo 2's volume should be at a reasonable level when playing music so you don't blow your ears out. How do you perceive noise floor? How do you perceive the music? The third test, which you can't do, would be to do the same but with the amp plugged into a battery / inverter like the Bluetti. You could, however, do this test though with your power filters (Furman and Pine Tree), and see if you can perceive differences.

A caveat: I think the Mojo 2 works better with an amp in between despite most IEM's modest power needs (I think impedance matching plays a role - the Mojo 2 is driving a high-input-impedance amplifier, limiting current requirements on the Mojo 2, vs. Mojo 2 having to drive the lower variable impedance of the IEM... more of the Mojo 2's goodness can be reaped by the amp vs. directly driving an IEM / headphone). Net-net, the Mojo 2 will likely sound best with an amp in between, so the real question is how the amp's sound powered from the wall vs. the power filter vs. the battery / inverter.

I found moving off of AC mains to be really beneficial. My listening experience with the battery / inverter is 1) more consistent and does not vary by time of day and 2) sounds far "cleaner" relative to AC mains power. My migration to full battery isolation is not complete though - I still run my server off a generic multi-purpose laptop running on AC mains when I upsample. My next project is to set up a dedicated, low-latency server I can run off a LiFEPO4 battery. I also want to try out a different amp for my Caldera... so I've got a few spending decisions to make! Of course, this is just my perspective so all the usual caveats apply - I'm sure there are folks out there that think this is a bridge too far but I, at least, am happy with the trade-offs.
 
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Apr 7, 2024 at 2:03 AM Post #10,327 of 11,840
@GoldenSound I noticed that Mojo 2 is giving much better measurements for linearity with bandpass filter on. I tried to google "Mojo 2 bandpass", but didn't find anything that would had given hints for how to utilize this information in practice. Is there something I could do either in Mojo 2 settings or when processing music with PGGB to get the best linearity?
 
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Apr 7, 2024 at 10:59 AM Post #10,329 of 11,840
@GoldenSound I noticed that Mojo 2 is giving much better measurements for linearity with bandpass filter on. I tried to google "Mojo 2 bandpass", but didn't find anything that would had given hints for how to utilize this information in practice. Is there something I could do either in Mojo 2 settings or when processing music with PGGB to get the best linearity?

You sure he wasn't talking about AP settings?

Mojo2 doesn't have a selectable bandpass filter.
 
Apr 7, 2024 at 11:02 AM Post #10,330 of 11,840
You sure he wasn't talking about AP settings?

Mojo2 doesn't have a selectable bandpass filter.
Hmm, would you happen to know how to interpret those results if that is the case? I haven't seen similar comparisons before. Is the bandbass version closer to "real music" or something like that?
 
Apr 7, 2024 at 11:42 AM Post #10,331 of 11,840
Hmm, would you happen to know how to interpret those results if that is the case? I haven't seen similar comparisons before. Is the bandbass version closer to "real music" or something like that?

I don't closely follow measurement parameters. I'm sure Cameron has a FAQ on his measurement methodology. He's pretty solid at explaining his thoughts. You can PM him.

There is no practical value to the AP measurements. I use them as an academic exercise to see if different sources with certain characteristics may fit a sound profile I like.
 
Apr 7, 2024 at 2:59 PM Post #10,332 of 11,840
Hmm, would you happen to know how to interpret those results if that is the case? I haven't seen similar comparisons before. Is the bandbass version closer to "real music" or something like that?
Yeah, it looks like that was with the AP’s bandpass filter or some other external device. The point of the two measurements was to show linearity. You’d never encounter that distortion in regular use.
 
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Apr 7, 2024 at 4:14 PM Post #10,333 of 11,840
@GoldenSound I noticed that Mojo 2 is giving much better measurements for linearity with bandpass filter on. I tried to google "Mojo 2 bandpass", but didn't find anything that would had given hints for how to utilize this information in practice. Is there something I could do either in Mojo 2 settings or when processing music with PGGB to get the best linearity?
The bandpass filter is on the analyzer not the Mojo 2 itself.

The linearity measurement can be run using a bandpass filter which means it filters out/removes noise either side of 1khz, so you are ONLY measuring the accuracy of the 1khz tone itself. Or you can run it without, meaning it's measuring the level of the whole signal, and therefore factoring in noise.

Generally speaking for DACs the one that you're usually wanting to look at is the bandpass filtered one, the non-bandpass result is just of interest to show how noise levels are affecting things and whether any of the linearity errors shown on the bandpassed result are going to be dominated by noise anyway
 
Apr 8, 2024 at 2:55 AM Post #10,334 of 11,840
The bandpass filter is on the analyzer not the Mojo 2 itself.

The linearity measurement can be run using a bandpass filter which means it filters out/removes noise either side of 1khz, so you are ONLY measuring the accuracy of the 1khz tone itself. Or you can run it without, meaning it's measuring the level of the whole signal, and therefore factoring in noise.

Generally speaking for DACs the one that you're usually wanting to look at is the bandpass filtered one, the non-bandpass result is just of interest to show how noise levels are affecting things and whether any of the linearity errors shown on the bandpassed result are going to be dominated by noise anyway
Riiiight, now it all makes sense. This way we can visualize the bottleneck of the device and in case of M2, it's not the linearity. Really nice to have both measurements. This was revealing :)

Thank you @GoldenSound !
 
Apr 8, 2024 at 11:07 AM Post #10,335 of 11,840
Riiiight, now it all makes sense. This way we can visualize the bottleneck of the device and in case of M2, it's not the linearity. Really nice to have both measurements. This was revealing :)

Thank you @GoldenSound !
Yeah in the vast majority of cases the output of the DAC with noise removed will be more linear, especially delta sigma designs. Though there are some exceptions with other approaches. Denafrips DACs are probably the one that first comes to mind, as the results at lower levels is an effect of the converter rather than a slow upward rise due to noise becoming dominant:

1712588846788.png
 
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