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Oppo HA-1 Impressions Thread

Discussion in 'Headphone Amps (full-size)' started by aamefford, May 7, 2014.
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  1. gotoma8
    Hi there, so, the Heimdall 2 has about 2-3 hours on it so far, and well, so far so good.  That worry over SPC tilting the HD800, well, I do get more air and detials (finer details) and even the low end is better with the Heimdall 2 vs Stock, even if I use the Heimdall on the single ended output... It's got a tad more air and details as well as low end....will see how it breaks in.
  2. MattTCG
    Question. I prefer to use optical  from my pc to connect to my dac and not usb. With the HA-1, if I do use optical can still power/connect to a secondary hp amp (BHC) with the dac from the HA-1 without using any usb? 
  3. efeist

    I don't see any reason why you couldn't. Source to HA-1 via optical, DAC in HA-1, HA-1 to amp via analog output. Keep in mind that optical will not pass DSD to HA-1.
  4. MattTCG
    The analogue out doesn't require a usb connection? I'm not able to get sound to the second amp using this configuration. 
  5. Maxx134
    It is not placibo..
    training your mind to open up it's "active filter" is not Brian burn or placibo. .
    It is an actual occurance..

    Think of how someone can sleep with surrounding noises like air conditioning or fan or crickets,
    Then yet suddenly can differentiate the sound of a someone calling his/her name..
    The brain is an active filter. .

    Also I will PM you why I believe you notice a difference with the Gemini Cable that, although redundant, it coicidentally performed a function that helped..
  6. efeist
    No it doesn't.  You should be connecting the HA-1 to the amp using the "pre out" connections on the rear.
    See page 9 of the Owners Manual:
  7. MattTCG
    My understanding is the "pre-amp" section for the RCA out, only works once the USB connection is made and the driver is installed. Please correct me if this is otherwise. 
  8. Smarty-pants

    IF you are only using the USB input then yes... otherwise, no.
    You still have all the AES/EBU, coax, optical, balanced and unbalanced analog inputs.
    Those inputs will work with the analog outputs completely independent of the USB input.
  9. gotoma8
    Ok, been listening to the HA-1 with HD800 and balanced Heimdall 2 cables from Nordost....Things sounds ok but when I turn off the JRiver output format, the combination is almost unbearable!!!! the HD800 is becoming quite extended and becoming bright?  But with the JRiver output format on and every setting with at None or no, things sound better...
    Even with SE listening, it's almost unbearable with the "output format" not checked in JRiver....I know you're supposed to let the DAC do all the work, but this combo is not sounding great...
    With the stock cable...it's still a little hot...with the Nordost, you get a bit more air, details and dynamics...resulting in a bit more tilt in the top...but the base is better too with the Nordost, both with SE or Balanced.  I guess the combo of HA-1, HD800 and JRiver sans output format checked, it's Not Good...
    More to come...
    I don't know if I am going to keep the HA-1 and HD800,...one has to go, probably the HA-1 since I can still return it.  :)
  10. olegausany
    Try foobar2000 and see if it makes any difference before making final decision
  11. zilch0md
    I would encourage you to consider trying a warmer DAC (i.e. Wolfson or PCM1704UK implementations) while hanging onto the HA-1's amp for use with the hard-to-tame HD800.  
    I'm very much enjoying the HA-1 amp, balanced out to the HD800, with this chain (until further notice):
    44.1/16 and 96/24 WAV on SD cards >
    Win 7 laptop >
    Foobar 2000 with WASAPI event mode >
    Moon Audio Blue Dragon USB cable >
    TeraDak USB Y-cable (pulling only data from the laptop and power from a TeraDak 5V PSU)  >
    TeraDak TeraLink X2 USB-to-S/PDF converter, Coaxial Out >
    Beresford Bushmaster MkII, analog out >
    OPPO HA-1 amp, balanced out >
    Toxic Cables Silver Poison >
    Sennheiser HD800
    The HA-1 amp section has so much authority and grainless transparency, balanced out to the HD800.  The bass is absolutely perfect in my opinion - not lacking in any way - not for extension, not for energy, not for control.
    You read a lot about how the Audeze offerings scale up with more power, but I'm convinced that the HD800 bass is also power dependent. I don't get this bass from my iBasso PB2 portable amp into the HD800, even though every other idiosyncracy of the HD800 is dealt with nicely when using the FiiO X5's warm PCM1792A Line Out with the very neutral and transparent OPA1612s that I am running in the PB2.  
    I've posted this graph a couple of times, estimating the mW rms per channel via the 4-pin XLR jack, for headphone impedances other than the values for 32- and 600-Ohm, found in the HA-1 specifications:
    As headphone amps go, 1084 mW of clean power is a lot into a 300-Ohm load.
    The HA-1 limits the current consumption as it sees ever decreasing loads - to prevent the required current draw from overheating the analog circuits.  This explains why the Watts rms into 32 Ohms isn't 18.75 times the Watts rms into 600 Ohms (why it isn't 15,000 mW into 32 Ohms instead of the specified 2000 mW into 32 Ohms.)
    The bottom line is that into 600 Ohms, the HA-1's amp section is running full out, unconstrained, not that 2000 mW isn't spectacular into 32 Ohms, but nobody seems to appreciate just how powerful 800 mW into 600 Ohms really is, nor 1084 mW into 300 Ohms (HD800), for that matter - and I might be wrong, but I'm reaching the conclusion that if you want to hear significant bass coming from the HD800, just give it lots of power. Even the mids are fuller - very smoothly so - it's not as if adding power causes a spike in the bass or anywhere else along the spectrum. Feed the HA-1 with a warm, but very detailed and transparent DAC (Wolfson, PCM1792A, PCM1704UK, etc.) and the HD800 can be "cured" - allowing you to enjoy its massive soundstage, smooth FR, and spectacular resolution, without harshness, brightness, or a lack of bass. 
    These are just my opinions, of course - very subjective - but to help establish a point of reference, I'll add that I've been a big fan of my Audeze LCD-2 for over 3.5 years, now.  And to emphasize that the "problem" you're experiencing is with the HD800, more so than with the HA-1 DAC and amp...
    I consider the following chain to be the best I've ever heard with my LCD-2 rev.1:
    44.1/16, 96/24 WAV, and DSD on SD cards > 
    Win 7 laptop > 
    Foobar 2000 with WASAPI event mode > 
    Moon Audio Blue Dragon USB cable > 
    OPPO HA-1, internal USB reciever + DAC + amp, balanced out >
    Toxic Cables Silver Poison >
    Audeze LCD-2
    The HA-1's more neutral, brighter ESS9018 DAC into the 1817 mW HA-1 amp section is perfect, balanced out to the 50-Ohm LCD-2 rev.1, and feeding it with coaxial input from an external USB-to-S/PDIF isn't necessary because the LCD-2 can't really appreciate the difference in detail - I have to imagine it's there, but I can't really hear it when I go back and forth with the HA-1's internal USB receiver.
    And the LCD-2 bass is still more energetic than my current HD800 chain (above), and thus, more enjoyable, if not as fast (though perfectly controlled by nearly 2 Watts from the HA-1), as what I manage to get from the HD800. But the loss of sound stage haunts me, especially with some songs for which I've had almost euphoric experiences when using the HD800.  
    Of course, my opinions are subject to change at the drop of a hat! 
    Just how much more powerful is the HA-1 for 300 Ohm headphones than some popular heavyweights?
    For 150 Ohm loads, Tyll Hertsens' measurements of the Burson Soloist show that THD%+N remains below 0.1% all the way to an Output Voltage of 9.3Vrms, as seen in this chart:
    Some research has taught me that the HA-1 isn't the only amp designed to limit current into lower impedance loads and unlike the HA-1, some amps have output impedances nowhere near 0%, and thus, it's not safe to assume that the same output voltage can be achieved with a lower impedance load as a measured output voltage for a given higher impedance. We can, however, safely assume that the same or higher output voltage can be achieved with higher impedance loads than the voltages measured at lower impedances.  
    You might have to read that a few times, but all I'm saying is that if you measure 2V rms into a 150 Ohm load, for example, it's safe to assume you'll get at least 2V rms into a 300 Ohm load, but measuring 2V into a 300 Ohm load, you cannot assume that you'll get as much as 2V into a 150 Ohm load - due to the possibility of the amp limiting current at lower impedances and/or the amp's output impedance not being less than or equal to 1/8th the headphone impedance.
    Thus, with Tyll having measured 9.3V rms into a 150 Ohm load (at 0.1% THD+N), it's safe to assume the Burson Soloist delivers at least 9.3V rms output into a 300 Ohm load (but this is likely lower than the actual Vrms into 300 Ohms). Given that the Vrms into 300 Ohm is at least equal to that for 150 Ohm, using the following formula, we can calculate the Watts Rms into 300 Ohm as being at least...
    Burson Soloist Watts rms into 300 Ohm at 0.1% THD+N = (v*V)/Impedance = (9.3*9.3)/300 = 0.2883
    ... so, at least 288.3 mW into 300 Ohm.
    We can get closer to the truth by plotting the measured Vrms at 0.1% THD+N for 16, 32, and 150 Ohm, and extrapolating the Vrms for 300 Ohm via a (best-fitting) polynomial trendline, as shown here:
    ... then, rearranging the polynomial equation to solve for Volts instead of Ohms, getting...
    Volts = (2 (sqrt(334250 Ohms-2223381)+24163))/6685  = 10.192 Vrms into 300-Ohms at 0.1% THD+N 
    Just looking at Tyll's chart, an output of 10.192 Vrms into 300 Ohm "feels" about right, given the measured values of 6.7Vrms for 16 Ohm, 8.1Vrms for 32 Ohm, and 9.3 Vrms for 150 Ohm impedances.
    Going back to the previous formula, we get...
    Burson Soloist Watts rms into 300 Ohm at 0.1% THD+N = (v*V)/Impedance = (10.192*10.192)/300 = 0.3463 or 346.3mW rms 
    If the OPPO HA-1 really can deliver 1084 mW rms (as I calculated previously) into 300 Ohm at 0.1% THD+N, the HA-1 is a whopping 3.13 times more powerful than the Burson Solist, into the HD800 for example.
    Schiit's specifications for the Lyr2 show it delivering 660 mW rms into 300 Ohm (at an unspecified %THD+N, but that's still less than my interpolated estimate for the OPPO HA-1).  Even the solid state Mjolnir, specifies 850 mW rms into 300 Ohm (at an unspecified %THD+N) vs. my calculated 1084 mW rms for the OPPO HA-1 into 300 Ohm, at less than 0.0018% THD+N (and that's at rated power output, not at the oft'-used 1W figure.)
    Please consider all of this to be speculation until we can see Tyll's measurements for the HA-1 (if indeed he plans to take them) and keep in mind that Burson Soloist specs show 4.0 Watts rms into 16 Ohm (at an unspecified %THD+N), with Tyll having measured only 2.8 Watts [(6.7V*6.7V)/16 Ohm] at 0.1% THD+N.    We need measurements that would allow comparison of power output at the same %THD+N, into the same load.
  12. gotoma8
    Mike, thanks for that amazing response...I am amazed at your understanding and technical prowl on the subject matter... I love the HD800 and the Heimdall 2 combo, but I don't know if I can really justify keeping the HA-1 for just the amp section...A good dac would be another $500 at lease, right?
    Maybe I really need something that doesn't have all the bells and whistles of the HA-1, but it's hard to get a nice Class-A balance HP amp for under $1k.  I will take my time and see.
  13. olegausany
    Instead of using another Dac and ading extra device i would recommend to try Annex mod which will allow you to adjust sound signature and is way cheaper than another Dac
  14. craftyhack
    Do you have a reference to the Annex mod?  I googled a bit with no louk, although found some modwright pages for Oppo stuff, but nothing referred to as Annex.
    On another note, it is on my list to send my HA-1 to RWA and Vinnie is ready for it to see if he has any ideas for upgrades... I will report back on what happens there.
  15. WilCox Contributor
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