Chord Mojo(1) DAC-amp ☆★►FAQ in 3rd post!◄★☆

Oct 11, 2016 at 7:10 PM Post #23,942 of 42,916
No apologies needed. I've seen instances in this thread where clicks meant clicks down from the preset (3Vrms, not max volume). That's why I asked.

Not relevant to the discussion, but I actually prefer the reference to be the 3Vrms with clicks being above or below this value. Each click is a 1dB step, so it makes calculating the nominal output level much easier. Otherwise I have to figure out how many dB down from 3Vrms one click up from mute is and then add the remaining clicks to that.


There is a different volume control at the lower range of the volume and at the upper range of the volume output vs the middle range. IMO it's easier to count from zero if sticking within the lower end of the volume spectrum.

From my review:

http://www.head-fi.org/products/chord-mojo/reviews/14291

"As I mentioned earlier the volume levels have finer resolution than the Hugo and I asked Rob what the volume range is and this is his reply:

“Mojo’s total volume range is -70 dB to +18 dB. The low level range is from -70 dB to -34 dB in two steps per colour change (so each colour has two steps).

Then from +2 dB to +18 dB it’s in one dB step per colour change for the top level range.”


I should point out that in the lower and upper ranges the volume button colours change independently of each other while in the middle range, -34 dB to +2 dB, the volume buttons change colour together. I think it’s a great option to have finer volume control at either end of the spectrum."
 
Oct 11, 2016 at 7:30 PM Post #23,943 of 42,916
There is a different volume control at the lower range of the volume and at the upper range of the volume output vs the middle range. IMO it's easier to count from zero if sticking within the lower end of the volume spectrum.

From my review:

http://www.head-fi.org/products/chord-mojo/reviews/14291


Man, this is a confusing scheme. Why did they need to make it so hard to determine nominal output level?

dB by itself is relative, so is it -70 to +18 relative to the 3Vrms? So 105uVrms to 23Vrms(!!!)... That upper bound can't be right...
 
Oct 11, 2016 at 8:39 PM Post #23,944 of 42,916
Man, this is a confusing scheme. Why did they need to make it so hard to determine nominal output level?

dB by itself is relative, so is it -70 to +18 relative to the 3Vrms? So 105uVrms to 23Vrms(!!!)... That upper bound can't be right...


I just quoted what I was told straight from the horses mouth. The explanation was so that the user can have finer control for sensitive headphones/IEMs at the lower end and also adjusted for control at the upper end.

The upper limit has been measured 7V max peak on a full battery (not confirmed AFAIK) and 5.3Vrms:

http://www.head-fi.org/t/784602/chord-mojo-the-official-thread-please-read-the-3rd-post/6105#post_12124971


The different volume scheme is simply for user friendliness and is also mentioned in the Mojo Manual.

http://chordelectronics.co.uk/mojo/manual/Mojo-User-Manual.pdf

Rob has confirmed a 5.3Vrms from the Mojo. Why not PM Rob Watts with all your questions as he'll be the best one to give you a straight answer about the volume scheme.
 
Oct 11, 2016 at 9:04 PM Post #23,945 of 42,916
I just quoted what I was told straight from the horses mouth. The explanation was so that the user can have finer control for sensitive headphones/IEMs at the lower end and also adjusted for control at the upper end.

The upper limit has been measured 7V max peak on a full battery (not confirmed AFAIK) and 5.3Vrms:

http://www.head-fi.org/t/784602/chord-mojo-the-official-thread-please-read-the-3rd-post/6105#post_12124971


The different volume scheme is simply for user friendliness and is also mentioned in the Mojo Manual.

http://chordelectronics.co.uk/mojo/manual/Mojo-User-Manual.pdf

Rob has confirmed a 5.3Vrms from the Mojo. Why not PM Rob Watts with all your questions as he'll be the best one to give you a straight answer about the volume scheme.


I'm not disputing what you're saying, I'm just trying to understand it.

So if 5.3Vrms is at +18dB, then -4.5dBV is approximately the reference. So -70dB is -74.5dBV or roughly 189uVrms. Much more reasonable numbers.

Here's what I'm not sure I understand correctly now, so please check me on this...

From -70 (-74.5dBV approx) to -34 (-38.5dBV approx) it's half dB steps? (2 steps per color change, assuming color change = 1dB)

Then from -34 (-38.5dBV approx) to +2 (-2.5dBV approx) colors change together... So 2dB steps?

Then from +2 (-2.5dBV approx) to +18 (14.5dBV approx) it's 1dB steps? (taken verbatim)

So if I wanted a roughly -10dBV output, I would start at the max volume and click down 16 times to get to about -2.5dBV then 4 more clicks to approximately -10.5dBV.

If I take into account power conditions, maybe I want to aim one click higher and stop at -8.5dBV nominal? Is a 1.5dB drop a reasonable expectation? How stable will that level be?
 
Oct 11, 2016 at 9:53 PM Post #23,946 of 42,916
yes guys...thanks.
my mojo is zero'd down to as low as can be...then i click the volume + button,
one by one, til the balls light up and start to change colours...
25 was the blue/purple..

and as per xrelic's helpful info:
 the Flc8 is 11 Ohm with a sensitivity of 93 dB/mW


Well I listen to 16ohm iems at double red, I like listening to metal a little louder.
 
Oct 11, 2016 at 10:08 PM Post #23,948 of 42,916
Any mojo owners that use it with HD650, how well do you think it drives them? Some people say it's sounds weak with no life them others say it sounds great and mojo has no problems driving it.
 
Oct 11, 2016 at 10:10 PM Post #23,949 of 42,916
Any mojo owners that use it with HD650, how well do you think it drives them? Some people say it's sounds weak with no life them others say it sounds great and mojo has no problems driving it.

 
IMO, some say it's weak because they prefer a bright amp + warm headphone (HD650) than a warm analog out of Mojo + warm headphone. Double warm = too polite IMO, but YMMV. BTW, Mojo has enough power to make the HD650 sing, but the synergy varies by people's opinion.
 
Oct 11, 2016 at 10:22 PM Post #23,950 of 42,916
Guys, what is THE most portable mojo stack you can think of?
 
The new Sony A30 - WM port to usb - Mojo?
IPod Touch - CCK - Mojo with adaptor?
AK120mk2 - Toslink - Mojo?
AK70 - usb to usb - Mojo (with the nice dignis case)?
Lotoo Paw 5000 - Optical - Mojo?
 
I lean towards the iPod Touch solution but really have no idea how big it actually would be. Need advice! 
 
Oct 11, 2016 at 10:31 PM Post #23,951 of 42,916
  Guys, what is THE most portable mojo stack you can think of?
 
The new Sony A30 - WM port to usb - Mojo?
IPod Touch - CCK - Mojo with adaptor?
AK120mk2 - Toslink - Mojo?
AK70 - usb to usb - Mojo (with the nice dignis case)?
Lotoo Paw 5000 - Optical - Mojo?
 
I lean towards the iPod Touch solution but really have no idea how big it actually would be. Need advice! 

please define portable....is this just about weight, form footprint, cables needed?
i am using the ipod touch 6 and mojo.
weight: 365g...wish it were lighter, slimmer, less bulky for sure.
 
only use the apple cck cable, but it's a bitch...breaks easily enough with all the bending
(anyone else has had issues with the cck cable?)...had one break today...luckily apple replaced
it at the store no cost (only 3 mo old using between dragonfly red and mojo)
 
Oct 11, 2016 at 10:32 PM Post #23,952 of 42,916
Guys, what is THE most portable mojo stack you can think of?

The new Sony A30 - WM port to usb - Mojo?
IPod Touch - CCK - Mojo with adaptor?
AK120mk2 - Toslink - Mojo?
AK70 - usb to usb - Mojo (with the nice dignis case)?
Lotoo Paw 5000 - Optical - Mojo?

I lean towards the iPod Touch solution but really have no idea how big it actually would be. Need advice! 


Look through the gallery of images on the upper right side of the page and look at all the devices being stacked with the Mojo. I believe the smallest would be the Shanling M1 (not pictured yet) or the AK100mk2 (as seen in the pic below), and then the AK70.

 
Oct 11, 2016 at 10:40 PM Post #23,953 of 42,916
I'm not disputing what you're saying, I'm just trying to understand it.

So if 5.3Vrms is at +18dB, then -4.5dBV is approximately the reference. So -70dB is -74.5dBV or roughly 189uVrms. Much more reasonable numbers.

Here's what I'm not sure I understand correctly now, so please check me on this...

From -70 (-74.5dBV approx) to -34 (-38.5dBV approx) it's half dB steps? (2 steps per color change, assuming color change = 1dB)

Then from -34 (-38.5dBV approx) to +2 (-2.5dBV approx) colors change together... So 2dB steps?

Then from +2 (-2.5dBV approx) to +18 (14.5dBV approx) it's 1dB steps? (taken verbatim)

So if I wanted a roughly -10dBV output, I would start at the max volume and click down 16 times to get to about -2.5dBV then 4 more clicks to approximately -10.5dBV.

If I take into account power conditions, maybe I want to aim one click higher and stop at -8.5dBV nominal? Is a 1.5dB drop a reasonable expectation? How stable will that level be?


Yes, I believe the steps are in 1/2 dB increments up to -34, but after -34 it's 1 step per increment, and after +2 it's 2 steps (not sure on this though). I am not the authority on the measurements or implementation. You are asking for figures that I am not qualified to answer accurately, but hopefully I can help point you in the right direction. Rob Watts.

I do believe he's mentioned the power is very stable throughout the power level, but again, I have no data on this.
 
Oct 11, 2016 at 10:43 PM Post #23,954 of 42,916
 
  Guys, what is THE most portable mojo stack you can think of?
 
The new Sony A30 - WM port to usb - Mojo?
IPod Touch - CCK - Mojo with adaptor?
AK120mk2 - Toslink - Mojo?
AK70 - usb to usb - Mojo (with the nice dignis case)?
Lotoo Paw 5000 - Optical - Mojo?
 
I lean towards the iPod Touch solution but really have no idea how big it actually would be. Need advice! 

please define portable....is this just about weight, form footprint, cables needed?
i am using the ipod touch 6 and mojo.
weight: 365g...wish it were lighter, slimmer, less bulky for sure.

 
Slim, slim, slim... Less pressure on the cable when inside pocket
 
Oct 11, 2016 at 10:45 PM Post #23,955 of 42,916
Slim, slim, slim... Less pressure on the cable when inside pocket


For slim scratch my previous post. Not really that slim. Perhaps the Shanling M1 pictured below. Just recently confirmed to work with the beta firmware.

 

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