[Mython]

Spoiler: Another interesting post from the DAVE DAC thread, today, that applies to Mojo, too

  PC's are very restricted in what they can do for real time signals. You simply can't replicate the processing that Dave does in a PC - simply because PC processors are sequential serial devices with a very limited number of cores. When you are doing a doing a FIR filter (a tap) you need to read from memory the audio data; read from memory the coefficient data; multiply the numbers together;then read the accumulated data and add that to the previous multiplication; then save the result. Lots of things to do in sequence. With an FPGA you can do all of these things in parallel at once, so a single FIR tap can be accomplished within a single clock cycle (obviously pipelined) - you are not forced to do things in sequence.
 
With Dave I have 166 dsp cores running, plus FPGA fabric to do a considerable amount of further processing. You simply can't do that in a PC. To give you another example - converting DSD into DoP. You need a quad core processor to do this manipulation in real time - otherwise you get drop-outs - but in a FPGA I could do this simple operation thousands of times over, and at much faster rates than DSD256.
 
What some people do not understand is how capable FPGA's are and how widespread they are used - the backbone to the internet? FPGA's. Search engines? FPGA's. Why? because an FPGA is fantastic at doing fixed real time processing - it takes small die area, and can do complex operations with very low power. Mojo for example has 44 dsp cores, uses sophisticated filtering to 104 MHz, and noise shapes at this rate - but does all this whilst consuming only 0.45 W. There is no way any PC consuming huge amounts of power can do this.
 
Intel last year acquired Altera (an FPGA company) for $16.7 billion because they understand that the future of processing is with FPGA's
 
A second issue is not what you can do but how you can do it - it is not just about raw power, but how the filter algorithm is designed. I have put many thousands of hours and over twenty years improving and understanding how to make a transparent interpolation filter; and I am still learning things today.
 
And a third point is that a DAC is not simply a data processing machine but it has got crucial analogue parts too. If I dropped the WTA requirement, I would still need the same FPGA in order to do the noise shaping and other functions.
 
Rob

 

 

[Ultrainferno]

   
The reviewer wishes that the Mojo had a balanced output, but Rob Watts has explained on this thread that he did not add a balanced output, because the FPGA renders balanced outputs unnecessary.
Balanced outputs are normally needed, to compensate for some of the inherent problems, caused by designing DACs using ASIC technology.
 

 
I know but I can still wish it had one, no? A lot of my IEMs have balanced termination so it would be handy (even if it technically isn't valid)

 

[maxh22]

is Mojo hot or not? answer by headfonia:

http://www.headfonia.com/review-chord-mojo-hot-or-not/

The reviewer clearly prefers the tonal balance of the Hugo over Mojo. He believes that Hugo is more layered and has a wider soundstage (Crossfeed settings?). I wonder what he would think if he EQ'd the Mojo to sound more like Hugo using @JaZZ's settings?

I was playing around with it today and noticed that the music sounded more peppy than usual.

 

[GreenBow]

   
The box has a round tamperproof sticker. You can just see it on this pic (shiny silver, with Chord writing that delaminates the sticker if it is tampered with):
 

 
Yeah, someone a few pages ago asked if they could buy and try the Mojo. Or they were saying their retailer had a no returns policy.
 
However in the UK at least, you are legally allowed to try any goods under distance selling regulation. The return if not happy. Otherwise you would not be able to try out anything.
 
Even with this in place though I was nervous about opening my Mojo, I was initially not sure whether to go ahead, after I bought it and it had arrived. It's the tamper proof seal that put me off.

 

[jmills8]

The reviewer clearly prefers the tonal balance of the Hugo over Mojo. He believes that Hugo is more layered and has a wider soundstage (Crossfeed settings?). I wonder what he would think if he EQ'd the Mojo to sound more like Hugo using @JaZZ's settings?

I was playing around with it today and noticed that the music sounded more peppy than usual.

less bass equals bigger soundstage.

 

[kinetic758]

Yeah, someone a few pages ago asked if they could buy and try the Mojo. Or they were saying their retailer had a no returns policy.

However in the UK at least, you are legally allowed to try any goods under distance selling regulation. The return if not happy. Otherwise you would not be able to try out anything.

Even with this in place though I was nervous about opening my Mojo, I was initially not sure whether to go ahead, after I bought it and it had arrived. It's the tamper proof seal that put me off.

Ah I've heard about this UK law. So what happens with all the goods that are returned? Are they sold as "new" or "open box"?

 

[maxh22]

less bass equals bigger soundstage.

I don't think that's how it works.

Mojo doesn't have less bass it has a different bass.

 

[maxh22]

Ah I've heard about this UK law. So what happens with all the goods that are returned? Are they sold as "new" or "open box"?

That's a great question, maybe you should contact Sonic Electronix and let us know. They could be building refurbished stock than have a sale later. But how many people do you think would return their Mojo simply because they didn't like it? My guess is not many. The damaged units get sent to Chord.

 

[miketlse]

Ah I've heard about this UK law. So what happens with all the goods that are returned? Are they sold as "new" or "open box"?

 
The culture in the UK is very different to the US.
 
On the HF forum, it seems quite accepted for US enthusiasts to buy 30 headphones a year, try each for a few hours, and then return most of them. So i imagine that how to sell 'open box' headphones, is a big issue for the dealers. The enthusiasts, for their part, seem understandably concerned about the 'returning goods' policy for each dealer.
 
In the UK, there are two protections for the consumer:
 

• UK distance selling regulations, allow the buyer to return goods
• EU consumer law, states that if the buyer discovers a fault with a product, within the first 6 months after purchase, the fault must have been present when the product was purchased, and the dealer must offer a replacement. After 6 months the level of wear and tear gets considered.

 
So the consumer has more distance selling rights in the Uk, and you would expect a lot of products to be returned - but I think the opposite happens. Anything returned is advertised as 'open box'.

 

[jmills8]

I don't think that's how it works.

Mojo doesn't have less bass it has a different bass.

more bass than the perception of a smaller sound stage. In my case I EQ the Mojo for more bass.

 

[kinetic758]

The culture in the UK is very different to the US.

On the HF forum, it seems quite accepted for US enthusiasts to buy 30 headphones a year, try each for a few hours, and then return most of them. So i imagine that how to sell 'open box' headphones, is a big issue for the dealers. The enthusiasts, for their part, seem understandably concerned about the 'returning goods' policy for each dealer.

In the UK, there are two protections for the consumer:

1. UK distance selling regulations, allow the buyer to return goods
2. EU consumer law, states that if the buyer discovers a fault with a product, within the first 6 months after purchase, the fault must have been present when the product was purchased, and the dealer must offer a replacement. After 6 months the level of wear and tear gets considered.

So the consumer has more distance selling rights in the Uk, and you would expect a lot of products to be returned - but I think the opposite happens. Anything returned is advertised as 'open box'.

Yes, I've heard laws like this actually *help* the sellers, since it encourages buyers to try products without risk and most tend to keep them.

 

[kinetic758]

Quick question (that I probably know the answer to but will ask anyway): if I intend to NEVER use the Mojo as a portable device (it will always be plugged in to the power mains and sit on my office desk), are there other options I should be looking at in the Mojo price range? Just want to make sure I have all my bases covered.

 

[miketlse]

Quick question (that I probably know the answer to but will ask anyway): if I intend to NEVER use the Mojo as a portable device (it will always be plugged in to the power mains and sit on my office desk), are there other options I should be looking at in the Mojo price range? Just want to make sure I have all my bases covered.

 
It depends on your requirements:
 
If all you want is a desktop DAC, and the sound quality is not the deciding factor, there are plenty of DACs/headphone amps to choose from.
 
If instead your requirement is for a desktop DAC, with the Mojo sound quality, then I think your choice is rather more limited.

 

[miketlse]

Yes, I've heard laws like this actually *help* the sellers, since it encourages buyers to try products without risk and most tend to keep them.

 
These UK/EU regulations will certainly have helped all those who bought the Beyer AK8i headphones, and have experienced faults within a few weeks of purchase.
 
I think the longer trial period period, also enables users to try a product long enough for 'brain burn in' to allow them to reaalise that they do like the sound of a headphone/DAC etc.

 

[kinetic758]

It depends on your requirements:

If all you want is a desktop DAC, and the sound quality is not the deciding factor, there are plenty of DACs/headphone amps to choose from.

If instead your requirement is for a desktop DAC, with the Mojo sound quality, then I think your choice is rather more limited.

I would be fine with either form factor, with sound quality being the priority. In other words, the mobile factor of the Mojo is not something I would use, so just wondering if there are any competing desktop amps.