Where are the Head-fi beta testers with their impressions??????
Waiting for our retail versions... (Most of us chose the silver cabinet, so we won't see them until some time in June.)
I'll chime in with an impressive story of OPPO's tenacity in finding and fixing problems....
Early on, with the first of two HA-1 beta prototypes, I was hearing a low-volume series of seven or eight pops, each series lasting about two to three seconds, but occurring randomly every minute or two. Trying to isolate it, I discovered that I could hear the pops in my headphones, no matter which source input was selected and with nothing plugged into the HA-1 except the power cord (and the headphones, of course). And it made no difference where the volume control was set, but the more efficient the headphones, the louder the pops. It really made testing the HA-1 difficult.
I eventually figured out that it was WiFi noise getting into HA-1 from my el cheapo Acer Aspire One netbook.
Have a look at how closely it was sitting to the front panel of the HA-1 prototype - this photo was taken in mid-December of last year:
PM-1 and HA-1 prototypes, HD800, LCD-2 rev.1, HD600, DACmini CX, TBI MG3, Def.Tech.SM45s
HD650, Resonessence Concero, Beresford Bushmaster MkII, and Schiit Vali were later added during beta testing.
As you can see in the photo, my netbook was just a few inches from the HA-1's front panel. In addition to the intermittent sets of pops, whenever I was in the middle of downloading any large files to my netbook, I could hear a very faint sizzling sound in the headphones - again, even with no cables attached except for power and headphones, and adjusting the volume control made no difference.
As I moved the netbook away from the HA-1, the noise problems faded proportionately. Other HA-1 beta testers weren't having problems with noise - it would have been easy for OPPO to consider my situation a "fluke," doing nothing about it. Instead, they asked me a bunch of questions, leading eventually to my telling them the make and model of the WiFi radio in my netbook, as well as the driver revision I was using for it. It took them a couple of weeks, but they actually reproduced my problem -AND- came up with a solution!
Here's what was happening...
In the early photos of HA-1 prototypes, you can see that the Bluetooth antenna was positioned at bottom-center on the rear panel:
Source: http://www.computeraudiophile.com/f6-dac-digital-analog-conversion/oppo-ha-1-a-18033/
It turns out that even when Bluetooth wasn't selected as a source, the antenna was receiving signals from my Acer's WiFi radio, energizing the shielded cable that was routed through the chassis in close proximity to some portion of the HA-1's audio path.
OPPO killed two birds with one stone...
Beta testers had been complaining about having to access the rear of the unit to adjust the two-position Gain screw (with a flat-blade screwdriver) every time we wanted to switch to headphones that required the other Gain setting (Normal vs. High). So OPPO got rid of the Gain screw (that originally resided above the antenna), making the Gain setting a front-panel controlled software function, then moved the Bluetooth antenna up to where the Gain screw had been located, while also re-routing the antenna's cable to keep it away from the audio section. Joy!
Compare the prototype's rear panel to the version that's shipping:
Source: http://www.oppodigital.com/headphone-amplifier-ha-1/headphone-amplifier-HA-1-Images.aspx
A "Trigger In" has also been added where the Bluetooth antenna previously resided.
Best of all - my WiFi noise is completely gone! I can set my Acer netbook on top of the HA-1, right next to it - in front, behind, or to either side - and I hear absolutely no WiFi noise. All gone!
I must have had one of the noisiest laptops in the beta group, but OPPO tenaciously pursued a fix for my problem, and in doing so, made the product more bulletproof for everyone. And that's just the tip of the iceberg, really. Lots of enhancements were recommended by beta testers - several of them implemented, some not, especially via firmware.
OPPO's practice of releasing their products
after lots of end-user testing and multiple firmware upgrades, is in stark contrast to my experience with many other audio manufacturers (DAPs come to mind, especially). I can assure you, the wait for OPPO to release the HA-1 will have been more than worthwhile for those who have been gnashing and grinding their teeth in anticipation. This thing is ready for use!
Mike