Review: JDS Labs O2 (Black edition) + O2/ODAC discussion
Jul 21, 2013 at 9:41 PM Post #376 of 543
Because this is Head-Fi, where people need to spend $500+ USD on a portable rig to be considered an audiophile. Forget logic and common sense. XD



The question is rather why bypass an excellent DAC and even great amp in the first place.


Very funny!! I thoroughly enjoy my $60 creative live aurvana cans. Not nearly as comfy as an expensive set, but I still consider them a great value for performance.

I was driving a set of 250ohm cans and had to max the volume on my iDevice. I have since bought an amp, but still in a double amp setup since I haven't gone LOD yet.
 
Jul 22, 2013 at 1:15 PM Post #377 of 543
Quote:
Yeah the Line Out Dock connector bypasses the internal amp only, but it outputs the same volume as maximum volume on the iPhone.

E.g. Set your O2's potentiometer at 9 o'clock, plug in the LOD to your iPhone, connect the LOD to the O2, and play some music. Your music's volume level will be the same as if you had set the iPhone volume level to maximum and double amped with the O2 with the potentiometer still in the 9 o'clock position.

You can bypass both the DAC and amp with a digital out connector with a USB-terminated end to connect the iPhone to a special "Apple certified" DAC. A Line Out Dock connector just has a 3.5 mm-terminated end.

Well, i am puzzled by this:
 
 
Quote:
You can bypass both the DAC and amp with a digital out connector with a USB-terminated end to connect
the iPhone to a special "Apple certified" DAC. A Line Out Dock connector just has a 3.5 mm-terminated end.

 
I don't understand. The signal coming out from any LINE-OUT port on any device, (including the iPhone?)  is an an analog signal.
By design, the   LINE-OUT port outputs only
tongue_smile.gif
 analog signal
.
So, how a 'digital out connector with a USB-terminated end' can still retrieve the digital signal?
 
Perhaps the LINE-OUT port on the iPhone doubles as 
confused_face_2.gif
 a digital-out  port as well???
If this is the case, such a port should be called: LINE-OUT / DIGITAL-OUT.
I don't have any Apple product and that's why I am very confused.
 
Jul 22, 2013 at 1:32 PM Post #379 of 543
I'm a newb, but I'll take a stab at this....
 
They are different connectors......
 
The digital out connector would be a lightning/30 pin connector at one end and a usb connector at the other end.  this would be a digital signal and you'd input this into a DAC device, then to an amp or DAC/amp combo.  
 
The analog out (LOD) would be a specialized module that has a lightning/30pin on one end and a 3.5mm jack at the other.  So after writing this and thinking about it, if these LOD modules DO NOT have a dac chip in them, then the idevice MUST output both A and D signals.  right?
 
Another stab - with lightning devices, the reason why going all digital is so expensive is because Apple is requiring licensing of their tech.  I don't think anyone has stated exactly how much it costs, but everything seems to be absurdly expensive, and most blame this requirement as the reason for cost.
 
Jul 22, 2013 at 2:01 PM Post #381 of 543
Quote:
I'm a newb, but I'll take a stab at this....
 
They are different connectors......
 
The digital out connector would be a lightning/30 pin connector at one end and a usb connector at the other end.  this would be a digital signal and you'd input this into a DAC device, then to an amp or DAC/amp combo.  
 
The analog out (LOD) would be a specialized module that has a lightning/30pin on one end and a 3.5mm jack at the other.  So after writing this and thinking about it, if these LOD modules DO NOT have a dac chip in them, then the idevice MUST output both A and D signals.  right?
 
Another stab - with lightning devices, the reason why going all digital is so expensive is because Apple is requiring licensing of their tech.  I don't think anyone has stated exactly how much it costs, but everything seems to be absurdly expensive, and most blame this requirement as the reason for cost.

 
Quote:
Quote:
Yeah the Line Out Dock connector bypasses the internal amp only, but it outputs the same volume as maximum volume on the iPhone.

E.g. Set your O2's potentiometer at 9 o'clock, plug in the LOD to your iPhone, connect the LOD to the O2, and play some music. Your music's volume level will be the same as if you had set the iPhone volume level to maximum and double amped with the O2 with the potentiometer still in the 9 o'clock position.

You can bypass both the DAC and amp with a digital out connector with a USB-terminated end to connect the iPhone to a special "Apple certified" DAC. A Line Out Dock connector just has a 3.5 mm-terminated end.

Well, i am puzzled by this:
 
 
Quote:
You can bypass both the DAC and amp with a digital out connector with a USB-terminated end to connect
the iPhone to a special "Apple certified" DAC. A Line Out Dock connector just has a 3.5 mm-terminated end.

 
I don't understand. The signal coming out from any LINE-OUT port on any device, (including the iPhone?)  is an an analog signal.
By design, the   LINE-OUT port outputs only
tongue_smile.gif
 analog signal
.
So, how a 'digital out connector with a USB-terminated end' can still retrieve the digital signal?
 
Perhaps the LINE-OUT port on the iPhone doubles as 
confused_face_2.gif
 a digital-out  port as well???
If this is the case, such a port should be called: LINE-OUT / DIGITAL-OUT.
I don't have any Apple product and that's why I am very confused.

Sorry if my post was confusing. >_<
 
If you use a Line Out Dock connector (e.g. FiiO L3 or L9, and is terminated with a 3.5 mm minjack), then you get an analog signal out from the iDevice and the signal gets amplified from your own external amp. The audio signal still goes through the iDevice DAC.
 
If you use a digital out connector (i.e. the ones that come with "Apple certified" DACs, and is terminated with a USB end to plug into the DAC), then you get a digital signal coming out of the iDevice and the signal gets converted to analog and amplified through your own DAC and amp respectively. The audio signal doesn't get processed by the iDevice at all.
 
 
I don't know much about the new Lightning dock connector since I don't have any products that use it, but it sounds like the Lightning dock to 30-pin dock adaptor extracts a digital out from the iDevice and there's actually a DAC built in the adaptor such that you get analog out from the 30-pin adaptor. I'm not 100% sure about this though. Or special Lightning dock connectors such as the one from VentureCraft don't have a built-in DAC which allows you to utilise the digital out of the iDevice to connect to your own DAC and amp.
 
 
In any case, to connect the O2 to the iDevice, you can either double amp it by just plugging in a 3.5 mm to 3.5 mm minijack into the O2 and iDevice's headphone port, or you can use a Line Out Dock connector to bypass the iDevices' internal amplifier and the O2 amplifies the analog signal coming out of the iDevice.
 
Jul 22, 2013 at 8:14 PM Post #382 of 543
Quote:
 
Sorry if my post was confusing. >_<
 
If you use a Line Out Dock connector (e.g. FiiO L3 or L9, and is terminated with a 3.5 mm minjack), then you get an analog signal out from the iDevice and the signal gets amplified from your own external amp. The audio signal still goes through the iDevice DAC.
 
If you use a digital out connector (i.e. the ones that come with "Apple certified" DACs, and is terminated with a USB end to plug into the DAC), then you get a digital signal coming out of the iDevice and the signal gets converted to analog and amplified through your own DAC and amp respectively. The audio signal doesn't get processed by the iDevice at all.
 
 
I don't know much about the new Lightning dock connector since I don't have any products that use it, but it sounds like the Lightning dock to 30-pin dock adaptor extracts a digital out from the iDevice and there's actually a DAC built in the adaptor such that you get analog out from the 30-pin adaptor. I'm not 100% sure about this though. Or special Lightning dock connectors such as the one from VentureCraft don't have a built-in DAC which allows you to utilise the digital out of the iDevice to connect to your own DAC and amp.
 
 
In any case, to connect the O2 to the iDevice, you can either double amp it by just plugging in a 3.5 mm to 3.5 mm minijack into the O2 and iDevice's headphone port, or you can use a Line Out Dock connector to bypass the iDevices' internal amplifier and the O2 amplifies the analog signal coming out of the iDevice.

 
Yes, I've known this:
 
 
Quote:
In any case, to connect the O2 to the iDevice, you can either double amp it by just plugging in a 3.5 mm to 3.5 mm minijack into the O2 and iDevice's headphone port, or you can use a Line Out Dock connector to bypass the iDevices' internal amplifier and the O2 amplifies the analog signal coming out of the iDevice.

 
(By the way, by iDevice you mean any iPod, iPhone, iPad, iMac, ...?)
But I'm still puzzled
tongue_smile.gif
 by the mysterious  
deadhorse.gif
 dual 'digital/analog' port of iPhones, iPads,  ....
 
Jul 22, 2013 at 9:10 PM Post #383 of 543
Quote:
Quote:
 
Sorry if my post was confusing. >_<
 
If you use a Line Out Dock connector (e.g. FiiO L3 or L9, and is terminated with a 3.5 mm minjack), then you get an analog signal out from the iDevice and the signal gets amplified from your own external amp. The audio signal still goes through the iDevice DAC.
 
If you use a digital out connector (i.e. the ones that come with "Apple certified" DACs, and is terminated with a USB end to plug into the DAC), then you get a digital signal coming out of the iDevice and the signal gets converted to analog and amplified through your own DAC and amp respectively. The audio signal doesn't get processed by the iDevice at all.
 
 
I don't know much about the new Lightning dock connector since I don't have any products that use it, but it sounds like the Lightning dock to 30-pin dock adaptor extracts a digital out from the iDevice and there's actually a DAC built in the adaptor such that you get analog out from the 30-pin adaptor. I'm not 100% sure about this though. Or special Lightning dock connectors such as the one from VentureCraft don't have a built-in DAC which allows you to utilise the digital out of the iDevice to connect to your own DAC and amp.
 
 
In any case, to connect the O2 to the iDevice, you can either double amp it by just plugging in a 3.5 mm to 3.5 mm minijack into the O2 and iDevice's headphone port, or you can use a Line Out Dock connector to bypass the iDevices' internal amplifier and the O2 amplifies the analog signal coming out of the iDevice.

 
Yes, I've known this:
 
 
Quote:
In any case, to connect the O2 to the iDevice, you can either double amp it by just plugging in a 3.5 mm to 3.5 mm minijack into the O2 and iDevice's headphone port, or you can use a Line Out Dock connector to bypass the iDevices' internal amplifier and the O2 amplifies the analog signal coming out of the iDevice.

 
(By the way, by iDevice you mean any iPod, iPhone, iPad, iMac, ...?)
But I'm still puzzled
tongue_smile.gif
 by the mysterious  
deadhorse.gif
 dual 'digital/analog' port of iPhones, iPads,  ....

Yeah, iDevice = iPod, iPad, iPod Touch, iPhone, iMac.
 
And yeah iDevices are weird like that. If you have a digital out option, the device needs to be "Apple certified" since the digital signal is signed(?) and verified by Apple? I don't know the specifics of that. I do know you can't jailbreak an iDevice and use an external DAC because the signal becomes unverified(?) or something weird like that. The Camera Connection Kit is an exception for the iPad though so it makes it even more confusing. -_-
 
I'm trying to avoid external DACs with iDevices due to their insanely high price tag for a small increase in sound quality.
 
Jul 23, 2013 at 3:59 AM Post #384 of 543
I've seen mixed results when using the 30p to lightning adapters, so wouldnt this mean that lightning is also dual A&D out?


What? I don't understand that sentence. I just said that iDevices with the Lightning connector only have a digital out. That is an absolute certainty.

it sounds like the Lightning dock to 30-pin dock adaptor extracts a digital out from the iDevice and there's actually a DAC built in the adaptor such that you get analog out from the 30-pin adaptor.


That is absolutely correct.
 
Jul 23, 2013 at 6:38 PM Post #385 of 543
Do you guys think the ODAC will be a significant upgrade over the E07k (just for the DAC section of the Fiio).
 
I am using the Fiio E07K to feed the O2, and as a portable amp, but I can not help wondering if I am missing something. I can tell for sure that the Fiio + O2 is a noticeable upgrade over the laptops sound card + O2.
 
Here is my home set up; please ignore the headphone stand:
 

 
Jul 25, 2013 at 9:31 PM Post #386 of 543
Quote:
Do you guys think the ODAC will be a significant upgrade over the E07k (just for the DAC section of the Fiio).
 
I am using the Fiio E07K to feed the O2, and as a portable amp, but I can not help wondering if I am missing something. I can tell for sure that the Fiio + O2 is a noticeable upgrade over the laptops sound card + O2.

 
Bump because I'm interested in finding out this as well.
 
Sep 13, 2013 at 12:03 AM Post #387 of 543
Pretty late but... Yes, it is an update. This is what I´m hearing right now:
 
- Slightly more neutral (less warmer).
- More detailed. (It does much better in the base and treble department).
- Slightly smoother sounding.
- Larger soundstage.
- Much louder!!
 

 

 
 

 
Sep 13, 2013 at 12:24 PM Post #389 of 543
I'm pretty new to digital audio, so after reading this entire thread, my head is kind of spinning. I have a Fiio E07k that I use just for the amplification, since none of my non-laptop sources (Zune HD, Sansa Clip+, Creative Zen Touch) are capable of putting out a digital signal for conversion to analog by an outboard device (as far as I know), and my laptop won't even recognize my E07k when plugged in via USB. I mostly use IEMs, (although I have a pair of Sony MDR-V900HDs, but I think these are pretty low-impedance, high sensitivity cans, and in fact their impedance is stated as 24ohms, vs. 56 Ohms for my UM3xs, with sensitivity of 107 db spl/watt) and though my iems all will get way more than loud enough without amping, using the E07K amp with any portable source results in significantly better sound, especially when it comes to the sense of space and location (soundstage?). Would there be anything to gain at this point soundwise from either an O2 for use at home, and/or either an ODAC or other DAC for use with my laptop (or trying to figure out how to use the DAC of my E07k)?
 
Sep 13, 2013 at 12:46 PM Post #390 of 543
Ok, I'm gonna try to explain it as I understand it, anybody correct me if I'm wrong...
 
DAC: Digital-Analog Converter. Is the responsible of transforming your digital signal to analog signal and this way allowing you to listen to it through your headphones. The quality of the transformation may be good or bad, depending on the implementation of the DAC itself. Each DAC has its own technical characteristics and resolutions. The DAC is gonna be the first bottleneck between your files and the final sound, therefore if you have a very high quality file but your DAC is not capable enough, you will never get the quality of the original file on your headphones.
 
Amplifier: Initially it only serves two purposes: 1. Amplify the signal to make it louder. 2. Properly feed the later load (your headphones). There are difficult and easy to drive headphones, and it's something that depends of the frequency you are reproducing. Let's say that the prebuilt amplifier of your phone might be able to drive properly between 3k and 7kHz but it's not able to drive properly in the sub 400Hz region, therefore your music is gonna sound weird and muddy. The better the amplifier the better the sound usually.
 
Initially both the amplifier and the DAC should be completely transparent, that means that they should not boost any frequency nor modify their responses (that is what an objective DAC, amp does). In the reality the world is far from being perfect, which means that you are gonna be altering the signal by passing it through several steps. That's why everybody talks about warm or bright DAC's / amps, and even more, some people try to find some sinergy between their headphones and gears (this is something that depends on you, and on what you give the highest emphasis in your equipment).
 
All of this being said, you might not experience an improvement by buying a better amp if your IEMs are already properly driven (amp section). Regarding the DAC section it will depend of your current source. Let's say that the amp should only increase the volume or the way your IEMs are driven, but if your DAC is providing a ****ty sound, your amp is not going to improve that.
 
Hope this helps.
gs1000.gif
 
 

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