[Hypops]

Hello! I can’t find in the manual how to run the Mojo 2 strictly as a DAC. The Mojo 1 had a line-level mode by powering on while holding down the two volume buttons. Is there a way to set the Mojo 2 to line-level mode? Thanks for any help.

Also, some amps don't like a full 3V at their RCA input, so the lack of a dedicated line-level mode gives you some additional flexibility to better match your other gear. Worth also knowing that the Mojo 2's cleanest output range is about 3-4.5V, but even at 2-2.5V (more typical for RCA), there isn't that much more distortion. According to both Golden Sound's and ASR's measurements, there's only a difference of a few dB distortion between 4.5V and 2V.

I'd actually be curious if anyone knows (or if Rob Watts has said) why Chord's DACs output at 3V over RCA instead of a more standard ~2V.

 

[Daniel Johnston]

Also, some amps don't like a full 3V at their RCA input, so the lack of a dedicated line-level mode gives you some additional flexibility to better match your other gear. Worth also knowing that the Mojo 2's cleanest output range is about 3-4.5V, but even at 2-2.5V (more typical for RCA), there isn't that much more distortion. According to both Golden Sound's and ASR's measurements, there's only a difference of a few dB distortion between 4.5V and 2V.

I'd actually be curious if anyone knows (or if Robb Watts has said) why Chord's DACs output at 3V over RCA instead of a more standard ~2V.

Why he chose the Mojo 1 to 3V “DAC mode”? I’m sure it’s buried somewhere in the thread.

I only had one amp the 3V was too much and caused distortion. The return to the previous volume setting after resetting mojo 1 was nice. Prevented you from putting 3V into your IEMs.

 

[larcenasb]

Thanks so much for all the replies! I don’t have the Mojo 2 yet, so how do you know what voltage you’re at? Do we know which colors correspond with which voltage? And is 4.5V the max volume? Thanks so much again!

 

[miketlse]

Also, some amps don't like a full 3V at their RCA input, so the lack of a dedicated line-level mode gives you some additional flexibility to better match your other gear. Worth also knowing that the Mojo 2's cleanest output range is about 3-4.5V, but even at 2-2.5V (more typical for RCA), there isn't that much more distortion. According to both Golden Sound's and ASR's measurements, there's only a difference of a few dB distortion between 4.5V and 2V.

I'd actually be curious if anyone knows (or if Robb Watts has said) why Chord's DACs output at 3V over RCA instead of a more standard ~2V.

https://www.head-fi.org/threads/chord-mojo-1-dac-amp-☆★►faq-in-3rd-post-◄★☆.784602/post-12259792
Selecting dac mode was just a short cut to 3V, and the owner could then change the volume if they wanted.
https://www.head-fi.org/threads/chord-mojo-1-dac-amp-☆★►faq-in-3rd-post-◄★☆.784602/post-13730153

 

[miketlse]

Thanks so much for all the replies! I don’t have the Mojo 2 yet, so how do you know what voltage you’re at? Do we know which colors correspond with which voltage? And is 4.5V the max volume? Thanks so much again!

https://www.head-fi.org/threads/cho...ing-on-page-95-of-thread.885405/post-16967755

 

[AussieMick]

Thanks so much for all the replies! I don’t have the Mojo 2 yet, so how do you know what voltage you’re at? Do we know which colors correspond with which voltage? And is 4.5V the max volume? Thanks so much again!

Search the thread, the table has been posted many times

 

[meomap]

Thanks so much for all the replies! I don’t have the Mojo 2 yet, so how do you know what voltage you’re at? Do we know which colors correspond with which voltage? And is 4.5V the max volume? Thanks so much again!

Blue color should be enough.

 

[Hypops]

Why he chose the Mojo 1 to 3V “DAC mode”? I’m sure it’s buried somewhere in the thread.

No, not exactly. I'm wondering why 3V seems to be the fixed and/or optimal output for pretty much all of the Chord DACs (Mojo, Hugo, Qutest, Dave). In the case of Mojo 2, it doesn't have a fixed line-level output (as with Mojo 1), but it does have a lower-distortion sweet spot beginning at 3V--which is Watts' recommended line-level output. It's gotta be a deliberate choice. I just don't know why.

All I could find on the subject was this post:

With a lot of pre-amps or integrated amps 3v will be too hot, with blue being more appropriate. If you find it sounding warmer or smoother with blue, then run with that setting.

So he knows that 3V is often a bit "too hot." Yet, all (or most?) of the Chord DACs have a fixed/optimal 3V line-level output. Gotta be a reason.

 

[BS5711]

No, not exactly. I'm wondering why 3V seems to be the fixed and/or optimal output for pretty much all of the Chord DACs (Mojo, Hugo, Qutest, Dave). In the case of Mojo 2, it doesn't have a fixed line-level output (as with Mojo 1), but it does have a lower-distortion sweet spot beginning at 3V--which is Watts' recommended line-level output. It's gotta be a deliberate choice. I just don't know why.

All I could find on the subject was this post:

So he knows that 3V is often a bit "too hot." Yet, all (or most?) of the Chord DACs have a fixed/optimal 3V line-level output. Gotta be a reason.

Perhaps 3 volts is simply where the DAC is at its best so that is the "line out" voltage that they default to.

If the receiving amplifier isn't happy with the 3 volts that is the problem of the amplifier so why would the DAC setting be compromised.

I am not arguing with you, just stating what I imagine the rationale is.

 

[Hypops]

Perhaps 3 volts is simply where the DAC is at its best so that is the "line out" voltage that they default to.

If the receiving amplifier isn't happy with the 3 volts that is the problem of the amplifier so why would the DAC setting be compromised.

I am not arguing with you, just stating what I imagine the rationale is.

Yeah, I totally get you, but this is also a circular argument ("It's 3V because it's 3V"). Most line-level components output ~2V and most preamps/amps don't like more than that, so 3V is clearly a deliberate choice. And it's not "a problem of the amplifier" because it's an atypical choice. It's not unreasonable for a preamp or amp to expect a 2V line-level input. Contrariwise, I also don't think this is a "problem" with Chord DACs, but it is certainly a peculiar and deliberate choice. I have to imagine there's a reason more than just: "deal with it."

I just figured that since Rob Watts is a regular poster here that he might have said something about this at some point.

 

[BS5711]

Yeah, I totally get you, but this is also a circular argument ("It's 3V because it's 3V"). Most line-level components output ~2V and most preamps/amps don't like more than that, so 3V is clearly a deliberate choice. And it's not "a problem of the amplifier" because it's an atypical choice. It's not unreasonable for a preamp or amp to expect a 2V line-level input. I'm just wondering if there's an advantage or unavoidable necessity in the choice to output at 3V. I have to imagine there's a reason more than just: "deal with it."

My guess is the DAC is designed to do what Rob wanted it to do and the absolutely optimal line out voltage is a byproduct of other design choices.

It isn't like it works badly at 2 volts, just that, as best I understand, it is marginally technically superior at 3 volts.

Perhaps Rob felt that optimising the output to be cleanest at 2 volts limited it for directly driving headphones versus being used as a DAC.

 

[Hypops]

My guess is the DAC is designed to do what Rob wanted it to do and the absolutely optimal line out voltage is a byproduct of other design choices.

It isn't like it works badly at 2 volts, just that, as best I understand, it is marginally technically superior at 3 volts.

Perhaps Rob felt that optimising the output to be cleanest at 2 volts limited it for directly driving headphones versus being used as a DAC.

For sure. I'm just wondering what those "other design choices" are. It's unusual. It's also unusually consistent across the Chord line.

 

[jarnopp]

No, not exactly. I'm wondering why 3V seems to be the fixed and/or optimal output for pretty much all of the Chord DACs (Mojo, Hugo, Qutest, Dave). In the case of Mojo 2, it doesn't have a fixed line-level output (as with Mojo 1), but it does have a lower-distortion sweet spot beginning at 3V--which is Watts' recommended line-level output. It's gotta be a deliberate choice. I just don't know why.

All I could find on the subject was this post:

So he knows that 3V is often a bit "too hot." Yet, all (or most?) of the Chord DACs have a fixed/optimal 3V line-level output. Gotta be a reason.

It’s really not an issue for Mojo or Mojo2 (or Hugo2 or TT2) since the “line out” setting is nothing more than a shortcut to the 3V volume setting. Setting it manually with the volume control results in the EXACT same setting. There is nothing bypassed, added or removed.

 

[Hypops]

It’s really not an issue for Mojo or Mojo2 (or Hugo2 or TT2) since the “line out” setting is nothing more than a shortcut to the 3V volume setting. Setting it manually with the volume control results in the EXACT same setting. There is nothing bypassed, added or removed.

I guess my curiosity isn't translating or something. I'm not criticizing the decision. On the contrary, my Mojo 2 is my most used and most beloved component across all of my audio setups (desktop, mobile, speakers). There are a lot of strange and unorthodox design decisions about this little thing. The 3V output seems like one among many unusual traits. But if no one really knows why, that's fine. Just curious if there was a technical (or subjective) reason.

 

[Rob Watts]

The reason for 3v being Chord standard DAC OP is more historical. Going back to the 90's, it was common to use passive pre-amps (that is a simple analogue volume control and nothing else), and a common complaint was 2v was not enough to drive power amps with quiet CDs - so I added some more voltage to 3v, and that became the standard OP voltage.

But things have moved on considerably since then, notably with my 100% transparent volume controls and the DACs becoming digital pre-amps rather than fixed voltage out DACs. And I found that the 3v was too high a level for some pre-amps - hence why Qutest had 1v, 2v and 3v fixed OP options. And of course, headphones are needing more voltage to drive them, and IEMs are insanely sensitive, so DAC amps are being pulled in two opposing directions.

So if I had a line level OP it would need to be adjustable, and I didn't want to make Mojo 2 more complicated to control, so the line level feature was dropped.