I have perhaps a silly question: With harmonics so low on this tube-amp (i.e., below <-100dB in most cases), how can this amp in any way differ audibly from a solid state amp, when driving a 300-600 ohm headphone load? It seems to me that most audiophiles purchase tube amps for the even...

I just installed this firmware successfully on an American HA-1 unit, upgrading from some original release firmware I had (from the time the unit originally came out way back when). Everything seems to work fine. I hope that this firmware is fully compatible with US units.

  Finally, some sense here. The worst WORST *WORST* thing about my HA-1 is that damn analog volume control with its poor tracking and curious ability to spin in the wrong direction when adjusted with the remote.   I don't care about lost bits at low volumes, the DAC is 32-bit internally and...

Not just pie in the sky opinions, but measurements to back them up. This is how a review should be done!

I am sorry, but DXD is just stupid. Other than that your answer is the Oppo HA-1.

If this turns out to be static discharge related, I would strongly urge people to use a powered USB hub like the compatible one I provided a link to in my original post which should be good for at least 2kV of isolation (some industrial hubs offer 4kV - 15kV of isolation but cost hundreds of...

      I had a similar issue with my HA-1. The USB input stopped working when I powered it on one day. I tried other inputs like S/PDIF coax and that worked fine. I had to return it for repairs, because nothing I did could get that USB port working. Also, when connected the now broken USB...

  I agree, what he is saying isn't definitive, but I did give some weight to:   "...I'm being told the issue is not with the D18, but with poor quality supply bit streams - from three separate devices.     Draw your own conclusions."   and   "I've written to the seller and haven't...

  That is exactly my point. A product that is not properly supported by its manufacturer is no product I would ever buy, no matter how good. Nobody buys an awesome car that only lasts three months and the manufacturer refuses to repair. Why should this be true of audio gear?

It's not about the cause, it's about the lack of desire of Yulong to lift a finger to help (support) his customer and hardware in this case and to blame him instead.

With everyone and their grandma using USB outs from computer to DAC, I wonder how bad the USB jitter is. Have there been any articles that looked at USB jitter, or jitter present in Asynchronous USB implementations - the latest fad.

  This pos has sidebands 88 dB down, because the signal was at -70 dB. If the signal was at 0 dB, would the most noticeable sidebands be at -18 dB and the rest of them at -30 dB? If so, these would be clearly audible!   Update: Please disregard. I went and read the original article and the...

OK, short of running a fan over/under it, what do you guys do to keep you HA-1 running cooler?

What about this article which states that Jitter that is worse than 20 ps is audible?   http://www.madronadigital.com/Library/AudibilityofSmallDistortions.html

  Aside from amplifying the signal, they also add noise, crosstalk and inter-modulation distortion. On any good amplifier, these are measured and specified as part of the specs.   What separates an expensive transparent amplifier from a cheap one? Here are some items listed from most relevant...

  I think both sound about the same, I am wondering especially from a jitter perspective if S/PDIF is better than USB with a computer that has "noisy" USB ports. My S/PDIF out is pretty low jitter in comparison, but I would like to know how the HA-1 handles USB, post USB receipt by the USB...

  I also see mp3s play back as 44.1/32, so it's not just you. I think this is correct, but not sure why. If you load an mp3 file into Adobe Audition it also shows it as 32-bit, btw.

Does anyone know how Asynchronous USB data gets to the Sabre on the HA-1? Is it re-encoded into an S/PDIF signal, is it converted to an I2S signal or what other possibilities are there and which one of them is actually used?   I am still trying to figure out which is the better connection...

This is more of a question of whether the whole notion is BS or not.   To make a capacitor, a dielectric is needed. Where is the dielectric in the silver plated copper arrangement, since the barrier between them is conductive.

For this price I expect pure silver and lots of it (i.e., two wires per pin) not having to go through multiple degrading interconnects to get to headphones from the headphone amp.

I read somewhere that having a silver plated oxygen free copper cable increase's the cable's capacitance due to the silver/copper interface. Is there any truth to this and if so, how strong is the effect in relation to the normal small amount of capacitance found in cable pairs?

  I will try this test when I get home as well. But, with dither enabled in the downconversion to 10 bits, the noise floor should be at around -57 dBFS. So, how loud were you listening to be able to hear the noise floor clearly and how loud was the noise floor?

  Actually this covers 100% of humans. A superhuman with the ability to hear beyond 22 kHz has never been found.

  The rather extreme example you have provided requires 42.9 dB of dynamic range as you yourself correctly pointed out in a related post on a different thread. This can easily fit into 8 bits which would allow 48 dB of dynamic range (arguably even 7 bits (42 dB) would sound transparent)...

  Unless I am misunderstanding that post, the (out of the ordinary) example provided only needs 45 dB (-44.8 dBFS to 0 dBFS) of dynamic range. 10 bits would allow for 60 dB of dynamic range.