[johncarm]

My question is about comparing the short USB 3.0 cable that comes with the iUSB3.0, which presumably is not a premium cable (it wouldn't make sense for iFi to put a lot of money into the included cable) to a premium USB 2.0 cable, in particular the Gemini or Mercury.
 
I already compared the included USB 3.0 cable to a Cardas Clear, and the included cable was far better. I am not sure what factor is most important. The Cardas was a 2.0 cable, it was much longer, and maybe it's just not a great cable.
 
Isn't the Gemini usable between the laptop and the iUSB3.0? It would need to be plugged into two of my laptop ports. It seems to me it would still be keeping the data lines separate. Of course, you can debate whether the cable on the input side of the iUSB should make a difference. The iUSB3.0 regenerates the USB data and theoretically would be pretty insensitive to its input data quality. But as I said above, at least cable on the input side of the iUSB3.0 was clearly inferior.
 
Regarding the quality of my system downstream from the iUSB3.0, my DAC and amp are very good. My DAC is the Nano, but it has a custom modded power supply internally and some RF control. The amp is a custom 12AU7/MOSFET hybrid with an over-the-top power supply. My headphones are the Senneheiser HD650 which are a great match for the amp (in fact, in my experience, they are a great match for a number of different 12AU7/MOSFET hybrids).
 
John

 

[technobear]

Isn't the Gemini usable between the laptop and the iUSB3.0?

Yes, of course it is. I'm just saying it is wasted there. It is needed on the output side of the iUSB3.0 to keep the regenerated data separated from the regenerated power.

My headphones are the Senneheiser HD650 which are a great match for the amp (in fact, in my experience, they are a great match for a number of different 12AU7/MOSFET hybrids).

My advice is that you shouldn't be wasting any more money on USB cables until you have some top drawer headphones.

 

[johncarm]

It sounds like you are saying that keeping the data and power separate matters on the DAC side but not on the input side of the iUSB. But I have already discovered that the cable on the input side matters, so I'm not sure why it would be that keeping data and power separate does not matter.
 
Here is what I have found in general about headphones and cables. They are different types of differences. I own the Audeze LCD-2 and LCD-XC and they certainly have more treble speed and deeper bass than the HD650. That's one kind of difference. USB cables have a "different kind" of difference.. primarily a sense of refinement and musical beauty. If the DAC isn't putting out a refined sound, then no headphone can fix that. It will just annoy you as it reveals the problem.
 
I think the HD650 with this 12AU7/MOSFET amp is the best amp/headphone combination I own (I own a few other amps too including a Woo WA6 Special Edition). This combination is quite revealing of the refinement that is noticeable as a change between USB cables.
 
But what I am primarily wondering right now is whether the iUSB stock 3.0 cable is better, in general, on the input side, than an audiophile USB 2.0 cable, in particular the Gemini or Mercury.

 

[hamachan]

  But what I am primarily wondering right now is whether the iUSB stock 3.0 cable is better, in general, on the input side, than an audiophile USB 2.0 cable, in particular the Gemini or Mercury.

I have borrowed nano iUSB3.0 together with Gemini cable from the agency in Japan a few months ago as their promotion program.  My DAC is micro iDAC2.  I also own nano iDSD but I did not try with nano iUSB3.0.  I tried following two chains;
 
1. PC > accessory cable (come with iDAC2) > nano iUSB3.0 > accessory cable (come with iUSB3.0) > micro iDAC2

 
2. PC > accessory cable (come with iDAC2) > nano iUSB3.0 > Gemini cable > micro iDAC2

 
Impression of the first chain was sharper focus, more visible of the instrument position, more detail, BUT more solid feeling.  The second chain gave me more natural feeling, sharp and detail but smooth.  My conclusion was obvious, nano iUSB3.0 with Gemini is better.

 

[theaudiologist]

hey guys i have 4 things to consider:
 
chord mojo
ifi nani idsd
sennheiser momentum
sennheiser hd700
 
can anyone suggest a better dac-headphone combo with these. i didn't put the micro idsd because for that price i could get the better mojo. apparently the mojo has a much higher impedance to drive high impedance headphones, but the nano idsd can only be used as a DAC. so even if i want to buy a low impedance headphone to go with the mojo (because of my money) the mojo is futureproof so i can always get the hd700 anytime

 

[technobear]

i didn't put the micro idsd because for that price i could get the better mojo.

That is very much a matter of opinion and preference. Both have their pros and cons.

apparently the mojo has a much higher impedance

That is generally regarded as a bad thing.

but the nano idsd can only be used as a DAC

Not true. It has a headphone socket and can muster 1.65V into high impedance cans. That's pretty loud into a decent can like the T1.

so even if i want to buy a low impedance headphone to go with the mojo (because of my money) the mojo is futureproof so i can always get the hd700 anytime

The micro iDSD is the future proof one as it can drive any headphone out there.

 

[theaudiologist]

mojo specs of output:

1. TECHNICAL SPECS:
2. 
   Output Power @ 1kHz
3. 
   600 ohms 35mW
4. 
   8 ohms 720mW
5. 
   Output Impedance: 0.075 ohms
6. 
   Dynamic Range: 125dB
7. 
   THD @ 3v - 0.00017%

 

ifi nano idsd output:

 

Dynamic Range:	>104dB
THD &N (35mW)	< 0.005%
THD &N (Line)	< 0.005%
Output Power (16R):	> 130mW
Output Voltage:	>1.65V (>100Ω)
Output ImpedanceZout):	<1Ω
Power Consumption:	< 3W (charging battery and playback together)

 
 
is the mojo drastically better and has more power to drive headphones? or is the nano idsd enough and can drive any headphone? and how is the sound? i heard the nano is a little bright

 

[technobear]

mojo specs of output:

1. 
   TECHNICAL SPECS:
2. 
   Output Power @ 1kHz
3. 
   600 ohms 35mW
4. 
   8 ohms 720mW
5. 
   Output Impedance: 0.075 ohms
6. 
   Dynamic Range: 125dB
7. 
   THD @ 3v - 0.00017%

ifi nano idsd output:

Dynamic Range:	>104dB
THD &N (35mW)	< 0.005%
THD &N (Line)	< 0.005%
Output Power (16R):	> 130mW
Output Voltage:	>1.65V (>100Ω)
Output ImpedanceZout):	<1Ω
Power Consumption:	< 3W (charging battery and playback together)

is the mojo drastically better and has more power to drive headphones? or is the nano idsd enough and can drive any headphone? and how is the sound? i heard the nano is a little bright

So your earlier statement was incorrect then. The Mojo does not have high [output] impedance. It has very low impedance so I don't know where you got the previous idea from. In fact that spec is very good. Anything less than 1 ohm is generally considered good.

There are exceptions to this rule. Some folks say that some high impedance cans sound better from a high impedance source. This isn't a universal view though.

The nano iDSD will struggle to get an HD700 to high volumes. It's really designed for portable cans and IEMs.

If HD700 is the goal, then it's between Mojo and micro iDSD. If you search the forum you will find many comparisons of the two. It comes down to a matter of taste really.

 

[theaudiologist]

so the nano idsd is useless then? well i guess i'll go with the micro. (it also has rca for speakers unlike the mojo). but can you tell me why the nano isn't enough? and btw what is the iusb and idac for? do i need the iusb?

 

[technobear]

so the nano idsd is useless then? well i guess i'll go with the micro. (it also has rca for speakers unlike the mojo). but can you tell me why the nano isn't enough? and btw what is the iusb and idac for? do i need the iusb?

What is the transport here?

Is this a portable system or a desktop system or what?


As for the nano iDSD, it can put out 1.65V to the HD700 which is a 150 ohm can. Using Ohm's law (you remember that from physics lessons I hope), the nano will be able to put about 18 mW maximum into the HD700. Sennheiser quote a sensitivity of 105dB for the HD700 but don't specify how that is measured. Most manufacturers specify sound pressure level at 1mW input but I know that Sennheiser has differed from this convention in the past. If it is 105 dB/mW, then the nano will drive the HD700 to about 117dB. That is actually very loud. It might be all you need. (Does anyone know if the HD700 is really a 105dB can?)


The iUSB3.0 is not essential. It is an enhancement for later on.

The iDAC and iDAC2 are desktop versions of the iDSD. They have no battery.

 

[theaudiologist]

oh ok thanks. and some more stupid questions:
 
1)if you have a micro idsd, can you tell me what the xbass and 3d features are and do they really improve the sound?
 
2)is DSD512 / 768kHz and 2x DXD really useful or just a waste?
 
3) are the stock cables good (USB, RCA) or do i need to buy better ones?
 
4) I figured out the hd 700's are 105dB SPL/V. so can the nano drive the hd 700s? if it can drive the hd 700's really loud, what about the hd600 and hd650 just in case i don't have the money for the hd 700's?
 
5) what are the iCan's for?

 

[technobear]

1)if you have a micro idsd, can you tell me what the xbass and 3d features are and do they really improve the sound?

What they are: http://ifi-audio.com/

They don't improve the sound. They modify it.

2)is DSD512 / 768kHz and 2x DXD really useful or just a waste?

There is no (or very little) material available at these sample rates. However you can use software players which upsample and/or convert to these rates. Some people feel this is worthwhile.

In any case the DAC in the iDSD (and the iDAC2) is a very good one.

3) are the stock cables good (USB, RCA) or do i need to buy better ones?

They are fine to start with. There are other better enhancements to consider before worrying about the cables. The iPurifier2 (or nano iUSB3.0) should be top of the list.

4) I figured out the hd 700's are 105dB SPL/V. so can the nano drive the hd 700s? if it can drive the hd 700's really loud, what about the hd600 and hd650 just in case i don't have the money for the hd 700's?

Ah. That is useful information. So the nano iDSD's 1.65V will get the HD700 to a little over 108dB. That's about the sound level of a decent small monitor speaker at 1m. It will be quite loud but it won't be a full orchestra in full swing.

The HD650 and HD600 are harder to drive than the HD700. For starters they are 300 ohm so our 1.65V will only drive half as much current into them thereby halving the power. Then they are also less efficient.

The micro iDSD has way more power than is needed for any of these cans.

5) what are the iCan's for?

See: http://ifi-audio.com/

They are headphone amps for use with other DACs or as an enhancement to the iFi DACs.

 

[theaudiologist]

108dB volume? if so that's pretty loud...i don't know what you mean by it wont drive an orchestra....it's actually ear-deafening.

 

[technobear]

108dB volume? if so that's pretty loud...i don't know what you mean by it wont drive an orchestra....it's actually ear-deafening.

An orchestra in full flight can hit 120dB peaks.

We're not talking continuous sound pressure levels here. It's the peaks we are interested in for high fidelity. We don't want to chop them off. It doesn't sound good.

I agree with you that 108dB is already too loud but there are many people here who seem to think they need more.

 

[theaudiologist]

ok if it can drive the hd 700s at 108dB how loud will it drive the hd 600 and 650?