[googleli]

On the left - Bottom: 15V Regulator for Stepdance,  Middle: CLAS, Top: Meier Stepdance
In the center - Bottom: Fostex HP-P1, Top: SR71A, Back: iPhone 4
On the right - Audeze LCD2 (Rev 1) with Grado mini to normal headphone jack adaptor and Norse 8-conductor cable
 

 
 
The following tests will be performed:
 
(1) iPhone 4 -> CLAS -> Stepdance -> LCD2
(2) iPhone 4 -> CLAS -> SR71A -> LCD2
(3) iPhone 4 -> Fostex HP-P1 -> Stepdance -> LCD2
(4) iPhone 4 -> Fostex HP-P1 -> SR71A -> LCD2
(5) iPhone 4 -> Fostex HP-P1 (using its internal amp) -> LCD2
 
Although the picture shows different cables, the same cables will be used for the different systems in the actual tests.

 

[googleli]

It has been a busy day and although it is well after office hours I am still working. I just squeezed out a bit of time to try out the Fostex HP-P1 - SR71A - LCD2 combo, switching between Filters 1 and 2.
 
Filter 1 of the Fostex HP-P1 is more natural but a bit grainy in the mid range. Filter 2 is more refined but sounds a bit more artificial. Filter 2 has a bit better imaging but human voice is a bit more backward than Filter 1.  I think the DAC chip of the Fostex needs some burn-in, but so far I think Filter 1 is my favourite. 
 
Then I connected the same SR71A to the CLAS, volume matched. Brighter, wider soundstage, lower mids sound less grainy than Filter 1 of the Fostex. Suitable for those who want a cleaner sound - but to me this now sounds a bit too clinical / analytical after listening to the HP-P1 -> SR71A combo.
 
Next, I tried driving the LCD2 the stock amp in the Fostex. It is quite unengaging and unable to drive the lower bass as good as the dedicated amps even at high gain.
 
Overall, I would say the Fostex with SR71A is a better match for the LCD2 Rev 1. Simply more musical and emotional. But if you are looking for the Rev 2 kind of sound from the Rev 1, the CLAS with SR71A seems to be a better choice. I will test out my ES5 tomorrow as I've still got work tonight.
 
I am not able to compare the two DAC units using the Stepdance, as the Fostex -> Stepdance combo creates some unwanted noise. Not sure how it happens but the noise just appears with this very combo and not any other combination. But suffice to say that my previous favorite combo, namely the CLAS -> Stepdance combo, is now less preferred by me as far as the LCD2 is concerned.

 

[daj523]

@googleli - Excellent comparison I was thinking of adding a Ray Samuels amp to my HP-P1. With your review, I am seriously considering the SR-71A.

I too experienced some grain in the mids and some shrill in the highs with my HP-P1 in the first 10 hours or so. But after 20 hours or so, the mids will definitely become smoother and the highs will settle down.

Glad to see another satisfied HP-P1 owner.

 

[Foress]

can't wait for mine which is arriving tomorrow!

 

[daj523]

can't wait for mine which is arriving tomorrow!

You won't be disappointed. The build quality alone is something to behold. Give it time to settle in then the magic begins

 

[Jalo]

Can the Filter be totally bypassed?  If not, it is a major limitation or shortcoming to the purist.  Just don't like any filter to be in the signal path.

 

[googleli]

No, it cannot be bypassed. I am a purist myself but I find Filter 1 is more natural, or "purer" than the CLAS.

 

[googleli]

With all these iStuff related portable devices, I am starting to think about the possibility of a "portable" atomic clock. But first, there should be something simialr to the CLAS and the HP-P1 but with a word clock input jack (usually BNC). Given the real simplicity of an atomic clock I think someone ought to be able to come up with a portable one and much cheaper than the desktop ones out there such as the Antelope 10M, the Antelope Trinity or the legendary Esoteric G-0Rb rubidium clock which would cost a good 10 grands but hardly portable. I have seen people doing 10M clocks by themselves using GPS. Too bad we don't listen to our speakers outdoor. But with a portable headphone rig the GPS 10M clock may actually be do-able.   

 

[googleli]

Is it just me or does anyone else think that holding the Fostex HP-P1 upright in your hand looks like you are holding a portable wine container like the alcohol addicts you see on TV or in movies?
 
Quote:

You won't be disappointed. The build quality alone is something to behold. Give it time to settle in then the magic begins

 

 

[Foress]

just got mine. I am impressed. Indeed, it's a tank.
works with Apps and Videos too. bypasses the iPhone at the first plug in. no pre-requisite set up required.
excellent.

 

[Sarthak117]

Looking forward to that test with the ES5's

 

[googleli]

I found out that the noise when the Fostex is connected to the Stepdance is somehow caused by the 15V regulator I was using. I switched back to the Energizer 15V setup and the noise is gone. With the cheaper AC-DC variable DC convertor, there wasn't any noise from the Stepdance when it was previously connected to the CLAS though. Strange strange strange.
 
I am using the USB to charge the Fostex (and hence the iPhone) and the other output to power the 15V Stepdance setup simultaneously. Will that cause a problem to the Energizer pack, the Fostex or the Stepdance?
 
Later today or tomorrow I will finally be able to perform the Fostex->SR71A and the Fostex->Stepdance shootout. I will still focus on the LCD2 Rev 1 for the time being. 

 

[googleli]

There is one more advantage of the Fostex HP-P1 over the CLAS. The surface of the the HP-P1 is leather-like and does not scratch against the amp. The CLAS' surface is so coarse and unpolished that it makes a very horrible sound when scratched against whatever amp you are using. The "CL" logo on the CLAS would also gradually fade away with time and especially when in contact and friction with the portable amp. The Fostex simply has a better build than the CLAS.
 

 

[qusp]

Quote:

I found out that the noise when the Fostex is connected to the Stepdance is somehow caused by the 15V regulator I was using. I switched back to the Energizer 15V setup and the noise is gone. With the cheaper AC-DC variable DC convertor, there wasn't any noise from the Stepdance when it was previously connected to the CLAS though. Strange strange strange.
 
I am using the USB to charge the Fostex (and hence the iPhone) and the other output to power the 15V Stepdance setup simultaneously. Will that cause a problem to the Energizer pack, the Fostex or the Stepdance?
 
Later today or tomorrow I will finally be able to perform the Fostex->SR71A and the Fostex->Stepdance shootout. I will still focus on the LCD2 Rev 1 for the time being. 

 
I dont believe this is such a good idea, effectively you are connecting the batteries in parallel to the charger, according to good practice and the info on the battery university site, when connecting 2 or more batteries together in parallel to charge they should be of equal voltage and current capacity
 
 

 

[qusp]

Quote:

Can the Filter be totally bypassed?  If not, it is a major limitation or shortcoming to the purist.  Just don't like any filter to be in the signal path.

 
hehe yeah a bit like wanting your radio signal to contain some of the nearby sidebands, a filter to get rid of ultrasonic junk produced by the dac is highly desirable, i really do not understand the want to go without it considering the frequencies we are after are orders of magnitude lower freqency. I know some people think its not linear, but these same people tend to use transformers or expensive capacitors in the signal output of their dacs. far less linear
 
Quote:

With all these iStuff related portable devices, I am starting to think about the possibility of a "portable" atomic clock. But first, there should be something simialr to the CLAS and the HP-P1 but with a word clock input jack (usually BNC). Given the real simplicity of an atomic clock I think someone ought to be able to come up with a portable one and much cheaper than the desktop ones out there such as the Antelope 10M, the Antelope Trinity or the legendary Esoteric G-0Rb rubidium clock which would cost a good 10 grands but hardly portable. I have seen people doing 10M clocks by themselves using GPS. Too bad we don't listen to our speakers outdoor. But with a portable headphone rig the GPS 10M clock may actually be do-able.   

hm, this is a very long way off and pointless unless all the devices in the chain can accept a synchronous distributed master clock, or rather clocks (for the different sample rate multipliers), while even one device is async, there is no need for such a connection. imo the rubidium and such clocks do not focus on the correct area for accuracy, they focus on long term ppm accuracy over years, great for keeping time, not of any real meaning to audio.