Oppo HA-1 Impressions Thread
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SharpEars

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  In the HA-1 we are using the TI LM4562 OP-AMP for the single ended analog outputs and the TI LME724 (interchangeable with the OPA1632) OP-AMP for the differential (XLR) analog outputs.
 
After many months of asking this question, we finally receive an answer. However, there is no such part number as the TI LME724. So, once again can we please get a definitive and verified answer to the question of:
 
What op-amp is driving the two balanced outputs on the back of the HA-1?
 
If this was a mistake and you meant the LME49724, which is an actual TI part, then please say so and correct your original response.
 
I don't mean to sound overly critical, but many of us plan to drive high end power amps with the HA-1 via a balanced connection and are very interested in the op-amp(s) that will be used to drive them.
 
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After many months of asking this question, we finally receive an answer. However, there is no such part number as the TI LME724. So, once again can we please get a definitive and verified answer to the question of:
 
What op-amp is driving the two balanced outputs on the back of the HA-1?
 
If this was a mistake and you meant the LME49724, which is an actual TI part, then please say so and correct your original response.
 
Hey... how about exercising a little common courtesy and respectfulness. Oppo has been about as helpful as any manufacturer I've dealt with on this site period. We don't want to start dishing out rudeness to the good ones, right? 
 
Thanks in advance for your cooperation (big smile). 

 
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After many months of asking this question, we finally receive an answer. However, there is no such part number as the TI LME724. So, once again can we please get a definitive and verified answer to the question of:
 
What op-amp is driving the two balanced outputs on the back of the HA-1?
 
If this was a mistake and you meant the LME49724, which is an actual TI part, then please say so and correct your original response.
 
I don't mean to sound overly critical, but many of us plan to drive high end power amps with the HA-1 via a balanced connection and are very interested in the op-amp(s) that will be used to drive them.
 
Thank you for the response, although I would have preferred you were a little more tactful in your reply. Yes, it was a typo. I meant to type LME49724. I have since corrected my initial post.
 
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^^ That's flippin' hilarious. 

 
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SharpEars

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LOL, that was hilarious!! 
 
I want to apologize to OPPO and the rest of this form for being "crude" and impatient in my original post. I am actually a nice guy in general, but after scouring countless pages of this thread looking for a correct and definitive answer to what I view to be a fairly simple, objective and relevant question, I was a bit "peaved."
 
Extra props to HasturTheYellow/OPPO for a speedy response and resolution of my issue.
 
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LOL, that was hilarious!! 
 
I want to apologize to OPPO and the rest of this form for being "crude" and impatient in my original post. I am actually a nice guy in general, but after scouring countless pages of this thread looking for a correct and definitive answer to what I view to be a fairly simple, objective and relevant question, I was a bit "peaved."
 
Extra props to HasturTheYellow/OPPO for a speedy response and resolution of my issue.
 
There you go. Well played. 
 
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FYI, here is a post with (crappy) unboxing pics of the HA-1 stand, also showing the HA-1 on the stand, with the PM-1's on their stand on the HA-1 :):
 
http://www.head-fi.org/t/725993/poll-would-you-buy-the-pictured-amp-stand-from-oppo-for-an-estimated-150-made-for-the-ha-1-but-would-perhaps-fit-other-amps-as-well/15#post_10792918
 
Proper pics to be posted some time in the future...
 
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So, at this point several reviewers/users have noted that connecting a power amp to the headphone jack of the HA-1 is a better way to go than connecting it to the balanced XLR outputs on the back of the unit. I suppose that this is due to the fact that the custom Class A headphone output circuit performs better than going through the LM49724 op-amp that buffers the balanced line-out XLR outputs on the back of the unit.
 
My question is, where do you get a converter from the 4-pin XLR balanced headphone output to two 3-pin XLR balanced outputs that could feed a power amp? Also, how would this even work? You need a total of six connections for a balanced stereo power amp:
 
Left: V+ / Gnd / V-
Right: V+ / Gnd / V-
 
The 4-pin XLR balanced headphone out only offers:
 
Left: V+ / V-
Right: V+ / V-
 
So how would a converter cable even work (i.e., where is the Gnd connection coming from)? I've heard of 5-pin XLR which carries a ground pin and can be split into two 3-pin XLRs via a Y cable. But how in the world do you go from 4-pin XLR into two 3-pin XLR, there just aren't enough pins?
 
And as I polish off my googling skills, lo and behold I find: http://www.audeze.com/products/accessories/4-pin-dual-3-pin-cable 
But how the #$%^ were they able to wire this? Where did they get the Gnd connection?
 
(Update: This cable is a no-go, because it only works in the opposite direction, see post #1423 for details.)
 
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  So, at this point several reviewers/users have noted that connecting a power amp to the headphone jack of the HA-1 is a better way to go than connecting it to the balanced XLR outputs on the back of the unit. I suppose that this is due to the fact that the custom Class A headphone output circuit performs better than going through the LM49724 op-amp that buffers the balanced line-out XLR outputs on the back of the unit.
 
My question is, where do you get a converter from the 4-pin XLR balanced headphone output to two 3-pin XLR balanced outputs that could feed a power amp? Also, how would this even work? You need a total of six connections for a balanced stereo power amp:
 
Left: V+ / Gnd / V-
Right: V+ / Gnd / V-
 
The 4-pin XLR balanced headphone out only offers:
 
Left: V+ / V-
Right: V+ / V-
 
So how would a converter cable even work (i.e., where is the Gnd connection coming from)? I've heard of 5-pin XLR which carries a ground pin and can be split into two 3-pin XLRs via a Y cable. But how in the world do you go from 4-pin XLR into two 3-pin XLR, there just aren't enough pins?
 
And as I polish off my googling skills, lo and behold: http://www.audeze.com/products/accessories/4-pin-dual-3-pin-cable
 
But how the #$%^ were they able to wire this? Where did they get the Gnd connection?
 
First of all, who says that? Secondly, please give a specific example of what you are wanting to do. 
 
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First of all, who says that? Secondly, please give a specific example of what you are wanting to do. 
 
Traditionally, one would connect the 3-pin XLR stereo outputs coming out of the back of the HA-1 to the 3-pin XLR stereo inputs of a power amplifier.
 
Instead, I want to connect the balanced 4-pin XLR headphone output of the HA-1 to the two 3-pin balanced XLR inputs on my power amplifier (which is connected to speakers), as some reviewers have claimed to do. In order to do this, I need a conversion (Y cable) that has a 4-pin XLR input (to connect to the HA-1's front balanced headphone jack) and two 3-pin XLR outputs (to connect to my power amplifier's stereo balanced XLR inputs).
 
Sadly after further research, the Audeze cable at: http://www.audeze.com/products/accessories/4-pin-dual-3-pin-cable works in the opposite direction (dual 3-pin XLR to single 4-pin XLR). It is completely misnamed and should have been called dual 3-pin to 4-pin cable (instead of 4-pin to dual 3-pin), since it is doing a 6-pin (total) to 4-pin conversion (i.e., dropping the ground pins of the two 3-pin XLRs). I need to go from 4-pin XLR to two 3-pin XLRs, though, so the search for an adapter/cable continues.
 
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Hi, guys. I have some problems with my setup. I have my Retina MacBook Pro hooked to the HA-1 via USB cable (5 meters), the headphones are HD800s. There's something wrong with the sound on Mac OS X. First, I thought that the USB cable is the problem, but it's not. The problems are gone when I boot into Windows 8.1 via BootCamp. On Mac OS X there are "pops" and "cracks" in the sound. Are my settings wrong?
 
I'm a total newbie when it comes to the sound formats and what not. I tried to change the sampling frequenzy on Mac OS X from 96kHz (which it was by default when I hooked the HA-1 to my Mac) to 44.1kHz but it didn't help. Why do I have to set this up manually, anyway? When on Windows, HA-1 shows that the sampling frequenzy is 44.1/16 and it works just fine. When using Audirvana, the sampling frequenzy changes by itself but the sound is still cracking and popping.
 
Someone please help, this is driving me nuts!
 
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Is anyone using a dedicated PCIe USB card to connect to their HA-1, such as the SOtM tX-USBexp Audiophile PCIe to USB Audio Card? If you are, do you hear any improvements over the built-in USB ports? Or, is this a waste because the HA-1 does enough filtering of the incoming USB stream to make the card superfluous?
 
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