Mojo Audio Mystique EVO

After about a month of having the EVO, one morning I heard a significant hum out of my speakers.  

I changed the position of the ground switch on the EVO and that fixed it. I couldn't tell you what the original and current position is, but I can look if you need that info.

No idea what caused this - my house is 55 years old and probably has the original wiring.   

From Mojo Website:  "To optimize system integration the DC signal ground can be floated from the AC, Earth, and chassis grounds with the flip of a switch."

Ideally, a system should have only one ground point to the mains through one mains lead. Because you can get small earth loops happening if everything has a mains earth plug
All equipment are grounded to each other via the interconnects from source to poweramp if the power amp has the earth to the mains.
  
The only time a second mains earth is needed is if cd transport using the optical (toslink) connection to the dac. Then the transport need to have a mains earth as well.

Cheers George 

Actually ground loops occur when one or more components have a different ground potential.

Then the grounds seek to equalize themselves between the components through the path of least resistance, which is most often your low-impedance analog interconnects.

If all the components were at the same ground potential it wouldn’t matter if they were star grounded, daisy chained, or grounds floating, relative to each other.

The ground lift isolates AC/chassis/Earth grounds from the sensitive DC ground in the EVOs circuit boards, and from the signal that runs through the connectors to the interconnects.

And the grounding post provides the option to create a path of lower resistance between components than the AC safety ground in your power cables or your interconnects.

For advanced system grounding I recommend using the same 24AWG OCC UniCrystal silver wire we use in our digital and analog signal path upgrades. That would create the lowest impedance ground you could get. Ideally you would do this with all of your components and then star ground all of the grounding posts together at the AC safety ground at one of your wall receptacles.

I recommend connecting to the screw that holds the face plate on that receptacle and replacing the screw with a pure copper screw.

This will create a path of least resistance between all the AC grounds in your system and not only eliminate ground loops, but also actually lower the noise floor in your entire system.

All the best custom systems I’ve heard...ones owned by the most advanced DIYers I know...ones you can’t buy for love or $$$...use a dedicated OCC UniCrystal silver star ground between components.

Then you may be asking "what about the resistance of that brass grounding post on the EVO...it make no sense to use silver wire with that in the ground path" and you would be correct.

I’ve been looking for a low impedance grounding post for an EVO grounding upgrade option and I can’t find a copper one let alone a silver one.

I’m actually considering using a Furutech low-mass RCA plug in place of the brass ground post for customers who want to do advanced system grounding.

We already use silver plated wire in a low-impedance daisy chain between our AC/chassis/Earth ground star ground point located near the grounding post in the EVO and the shielding grounds on the balanced connectors in the EVO, and the shielding barriers between the circuit boards in the EVO.
And when you get our copper clad shielding upgrade both of the .25" thick ferrous shielding barriers are laminated with pure copper foil so that any EMI or RFI that contact the shielding barriers is dumped through the low-impedance copper foil, to the silver plated daisy chain wire, to the the grounding star point and grounding post.

As part of our advanced grounding upgrade not only will you get a low-impedance grounding post/connector, the silver plated wire in the daisy chain and the wire going from the ground star to the grounding post/connector will be upgraded to the same OCC UniCrystal silver wire I’m recommending to use between your components in your system star ground.

At Mojo Audio we take grounding and shielding very seriously :^P

I'm guessing there might be a few more EVO owners out there now.  Anyone care to provide their experience?

Mine continues to impress, especially the microdetails and realism from top to bottom - but really I'm just sitting back and enjoying the music.

I read that there are new boards and perhaps a new chassis coming out.  The "21" model?  Anyone have details.  Oh, 'just looked at the Mojo website and I see the 21 indicated on the products now.

I'll have to ask Ben what that might mean for my original B4B EVO.

@veroguy - I am glad to hear you are enjoying your EVO.  I am (sort of) an EVO owner....I just haven't received it yet.  Did you previously own a v3?  I would be curious to hear how the EVO improves on the v3 since I will be sending my v3 in to Benjamin as a trade-in, as soon as the EVO gets here - but that is weeks away yet.
To your questions, the 2021 version does indeed have new boards and a new chassis.  I was able to purchase the 2021 B4B model with the new boards, but in the 2020 aluminum chassis, which allowed a bit of a savings.  We did not have any discussion about different DAC chips so I do not know whether he is doing that or not.  I do remember owning a Lector CDP-7TL with the PCM63 chip and I later purchased the newer 7TL that used the PCM1704.  An audio industry insider purchased my older Lector with the PCM63 chip and told me in his opinion it would sound better than the newer PCM1704 version.  I didn't understand his thinking at the time...Duh!
The new 2021 chassis is constructed from ferrous metal, which will provide better shielding on all sides from EMI.  The current aluminum chassis may have better resonance characteristics, which is probably more important for my set-up.
I am curious how you are getting the signal to the DAC and which input you have found to sound the best.  I have the ability to use either USB, S/PDIF-BNC, or AES/EBU and I am considering different network bridge options depending on which input sounds the best.  Of course I will try them all myself but I am still curious what other owners are hearing.