It’s been a while since I bought my QLS QA-550. Although I haven’t played much with it, but in overall, I like the quality of the player. Now, the new version has come, the QA-660.

One thing to be noted, this new player is much-much more expensive than its predecessor (well, you can find the retail price yourself). But spec wise, you will find a lot of improvement to. The major improvement is the support of multiple file format, like FLAC, APE, WavPack, and for sure, MP3. I don’t have to mention WAV, right? And the bit depth/sample rate also up to 24/192. This makes it a simple high resolution audio player. The screen also got updated with a massive 2.8″ AMOLED (you will know the reason why if you ever use QA-550). More gorgeous and expensive remote control also provided.

Enough for the introduction, let the pictures tell us more.

The front panel looks neat with black finish, and you can see some basic navigation buttons.

We have a complete output options, from Coaxial RCA, BNC, XLR AES/EBU, Optical, and IIS via RJ-45 type connector.

The USB is not for Flash Disk. So far, it’s reserved for future development.

The remote control and USB SD Card Reader. The remote looks expensive with a good grip (alhough not too heavy), while the SD Card Reader also performs very well in copying large files.

The basic structure inside the QLS QA-660. I would see and expect some performance upgrade by upgrading some components there.

The main transformer has three secondaries, 2x 17VAC and 1x 12VAC.

We can see Vishay capacitor to smooth out the DC signal there.

The output stage of the QLS QA-660. Some transformer also could have benefit from upgrading.

We have two master clock for 44.1 and 48 kHz. QLS claims 1PPM low jitter clock are used there.

One of them is 24.5760 MHz.

The other one is 22.5792 MHz.

The regulator is LT1086. Not just one, we can see few of regulators around, and all are LT1086 from Linear Technology. One of my favorite. Edit: There are 317, 337, 7805, and 7808 lying around. Sorry to miss this.

Most of the capacitors are Matsushita. Not a high grade capacitor, but I believe they could serve the purpose very well. This also could benefit for some upgrade.

Spec wise, this is quite promising. But then I have to find an adequate DAC to match this transport. At least, 24/192 must be supported as some of my collection now started to shift to 24/96 or 192 kHz.  Thinking of Buffalo from Twisted Pear, but it seems Mr. Russ White is ‘on holiday forever’ so most of the time I always see ‘out-of-stock’ for his Buffalo kit and no emails ever replied (sorry!). Whether they make it too few, or the demand is too high. Only God knows 😉 The other option is to go if complete DAC, like Lavry or Lynx. Will see whatever meet the performance and the value.


Also one of the reader asks for detail shoot of the I2S chip. So here you go, Greg!