[Meremoth]

I currently use ATH-AD900X's for everything.  Don't have any other headphones.  I'm going to purchase a O2+ODAC today for my PC.  Questions:
 
1. Where should I buy it or does it matter?
 
2.  Was looking at JDS Labs website and there are different customizable options:  

1. Rear mounted vs Front mounted power jack.  Any difference/benefit?
2. 3.5mm vs. 6.35mm (headphone jack output)  - I need 3.5mm for both AD900X and TH-900, correct?
3. DAC line-output = Default 3.5mm vs Deadicated read line output 3.5mm vs Dedicated rear RCA line-outputs (I have no idea about any of this)
4. Gain = Medium (1.0x , 3.5x), Standard (2.5x, 6.5x), (1.0x, 2.5x)   (also have no idea what to choose)

 
The O2+ODAC will be used for both my AD900X's and TH-900's.  
 

I have finally decided to pull the trigger and get this amp/dac because I've been listening to my 900X's on my iPad lately and realized how much better they sound on my iPad vs my PC (PC using very old Realtek onboard sound).  
 
Thanks in advance to anyone who can offer any help/advice/suggestions/informations/recommendation/tips/opinions etc.    It will be very much appreciated.  
 
Sincerely,
 
Jeremy (wannabe audiophile)

 

[PurpleAngel]

Both headphones seem to need very little power, so a Schiit Fulla ($79), should offer a fair bit of improvement, over the Realtek, for a lot less cash.
 
Not against you getting the O2/ODAC, if that what you really want.
 
The differences you've listed for the different O2/ODAC, is more personal preferences, then something that effects audio quality.
So 3.5mm vs RCA, both will be the same for practical audio quality, RCA just offers a more robust connection.
Technically RCA offers better separation of the audio signals, but I'm guessing not enough to make a noticeable difference.

 

[Meremoth]

  Both headphones seem to need very little power, so a Schiit Fulla ($79), should offer a fair bit of improvement, over the Realtek, for a lot less cash.
 
Not against you getting the O2/ODAC, if that what you really want.
 
The differences you've listed for the different O2/ODAC, is more personal preferences, then something that effects audio quality.
So 3.5mm vs RCA, both will be the same for practical audio quality, RCA just offers a more robust connection.
Technically RCA offers better separation of the audio signals, but I'm guessing not enough to make a noticeable difference.

 
Just found out, from another member, that the TH-900's are actually 6.35mm and not 3.5.  So I guess I need 6.35mm headphone jack output?  Is there a 3.5mm to 6.35mm adapter I can use for my 900X's?  If so, do adapters degrade sound quality at all?
 
I will be connecting my headphones to the O2+ODAC, and connecting the O2+ODAC to my PC.  Should I go with the RCA line-outputs for the DAC?  
 
What additional items will I need to purchase to hook all this up to my PC properly?
 
Thanks again!  

 

[PurpleAngel]

  Just found out, from another member, that the TH-900's are actually 6.35mm and not 3.5.  So I guess I need 6.35mm headphone jack output?  Is there a 3.5mm to 6.35mm adapter I can use for my 900X's?  If so, do adapters degrade sound quality at all?
I will be connecting my headphones to the O2+ODAC, and connecting the O2+ODAC to my PC.  Should I go with the RCA line-outputs for the DAC?  
What additional items will I need to purchase to hook all this up to my PC properly?
Thanks again!  

 
As one of the headphones has a 3.5mm (1/8") plug and the other has a 6.35mm (1/4") plug, you going to end up using one of the headphones with an adapter, no matter what which jack you order the O2 with.
A 1/4" jack would be considered a little more robust and the "better" headphones (TH-900) do come with a 1/4" plug, so that is two reasons for getting the O2 with the 1/4" jack.
Get the RCA line-outputs, why not.
 
Shure makes a thread 1/8" female to 1/4" male adapter (HPAQA1), I've bought about ten of them.
http://www.sweetwater.com/store/detail/HPAQA1
Not sure if the adapter degrade sound quality (do not think so), but it's not like you have a choice, if you want to use the AD900X with the (1/4") O2.

 

[Meremoth]

@PurpleAngel  -  Awesome, man, thanks for the responses and help.
 

 
I think I'm going to get the O2 and ODAC standalone units and the TH-900.  I think I'll get the 6.35mm headphone jack output on the O2 and the RCA line-outputs on my ODAC.  I don't think I'll be using my AD900X's much after getting the TH-900's, but I'll get an adapter just in case.  I'm wondering if there will be any reason to even use my 900X's anymore.
 
 
I think JDS sells the cables and connections I need to use to wire the O2 and ODAC together, and then wire it to my PC.  Should I get the ones they sell, or should I purchase the cables and whatnot from somewhere else?

 
I'm super ignorant about all of this - Will I be connecting my headphone to the O2, then the O2 to the ODAC, and then the ODAC to my PC?  
 

Thanks again!  

 

[PurpleAngel]

  @PurpleAngel  -  Awesome, man, thanks for the responses and help.
 
I think I'm going to get the O2 and ODAC standalone units and the TH-900.  I think I'll get the 6.35mm headphone jack output on the O2 and the RCA line-outputs on my ODAC.  I don't think I'll be using my AD900X's much after getting the TH-900's, but I'll get an adapter just in case.  I'm wondering if there will be any reason to even use my 900X's anymore.
I think JDS sells the cables and connections I need to use to wire the O2 and ODAC together, and then wire it to my PC.  Should I get the ones they sell, or should I purchase the cables and whatnot from somewhere else?
I'm super ignorant about all of this - Will I be connecting my headphone to the O2, then the O2 to the ODAC, and then the ODAC to my PC?  
Thanks again!  

 
This is were I like to buy my cables.
http://www.monoprice.com/Category?c_id=102

 

[Meremoth]

   
This is were I like to buy my cables.
http://www.monoprice.com/Category?c_id=102

 
Here's the cables/connectors/adapters that JDS sells:
 
https://www.jdslabs.com/store#cables

Are the ones you linked of superior quality, or is there not any difference?
 
 
 
Thanks. 

 

[PurpleAngel]

  Here's the cables/connectors/adapters that JDS sells:
https://www.jdslabs.com/store#cables
Are the ones you linked of superior quality, or is there not any difference?
Thanks. 

 
I'm assuming there is no difference
JDS seems to have good prices

 

[ProtegeManiac]

 
1. Where should I buy it or does it matter?

 
Shipping will depend on where you are and where the maker is. There's one in Switzerland if you're in the EU for example, and quite frankly I like their grey case better.
 
 
 

 

1. Rear mounted vs Front mounted power jack.  Any difference/benefit?

 
Ergonomics. Originally front mounted, which wasn't really a problem if you had the O2 with the battery since it's just a charging port, but once you have them running on the adapter, you'd want to minimize cable clutter out in front. Most other desktop/fullsize equipment put everything but the headphone output on the front; some custom amps have the ports on top, so that means you need right angle plugs and it looks like a Navy ship being repaired in a dry dock.
 
 

 

1. 3.5mm vs. 6.35mm (headphone jack output)  - I need 3.5mm for both AD900X and TH-900, correct?

 
Use whatever is more convenient, plus an adapter. If you get the 6.3mm then any screw-on 6.3mm(male) to 3.5mm(female) adapter will work; if you get the 3.5mm, then if you want to plug in a headphone that only has 6.3mm, then you'd have to use an adapter on a pigtail since you'll end up with a too long and too heavy plug being supported by the short 3.5mm plug shaft.
 
 
 

 

1. DAC line-output = Default 3.5mm vs Deadicated read line output 3.5mm vs Dedicated rear RCA line-outputs (I have no idea about any of this)

 
Doesn't matter, if you use the ODAC section to feed another amp it's just a matter of using an RCA to RCA or 3.5mm to RCA cable. If for example you have an existing system with a TT or CDP, or you might want to get a TT later on, then getting the RCA input option (that bypasses the ODAC) is something to consider.
 

 

1. Gain = Medium (1.0x , 3.5x), Standard (2.5x, 6.5x), (1.0x, 2.5x)   (also have no idea what to choose)

 
That depends on your headphones, but generally 1x and 2.5x is for when you use IEMs and efficient headphones. Standard can take on some less efficient headphones at 6.5x, then efficient headphones at 2.5x, but you might not be able to use IEMs on it (even if you get one later on, would you use it at home? I don't)

 

[K_19]

If you are going to use the O2 with the ODAC as source all the time, then definitely go with the setting of 1x and 3.5x as ODAC's 2V output can potentially clip the O2 amp at any gain settings above the 3.5x. Unless you are going to use underpowered sources often (a mobile phone, etc), the 6.5x gain is totally unnecessary.

 

[Meremoth]

  If you are going to use the O2 with the ODAC as source all the time, then definitely go with the setting of 1x and 3.5x as ODAC's 2V output can potentially clip the O2 amp at any gain settings above the 3.5x. Unless you are going to use underpowered sources often (a mobile phone, etc), the 6.5x gain is totally unnecessary.

 
Thanks for the reply, K_19.
 
Why do you recommend 1.0x, 3.5x instead of 1.0x, 2.5x?
 
Thanks again.   

 

[K_19]

Thanks for the reply, K_19.

Why do you recommend 1.0x, 3.5x instead of 1.0x, 2.5x?

Thanks again.   

I recommend that setting for use exclusively with ODAC as typically, the 1x gain will actually be enough for most headphones out there. 3.5x (I think this may have changed now since they changed the ODAC board) is the highest gain setting you can have without going into clipping, so you may as well have the second gain setting with as much as possible gain just in case you happen to run into something really, really inefficient and have some really lower volume mastered tracks.... Although if you are sure that you will use mostly efficient cans only, 1x/2.5x will be fine as well.