S.M.S.L SD-793II Optical Coaxial DAC Digital to Analog Converter Built-in Headphone Amplifier Black

Works as advertised. I tried it with various sources and everything sounds great--no noticeable problems or issues. My unit is crystal clear without any background noise even with the volume maxed out. It ran cool for hours without any heat build up. Build quality is simple but solid. Packing and instructions are also minimalist and plain. This is not meant to be fancy, which is fine by me as I just want something that works with no frills. 1/4" TRS jack is a plus.The only caveats are the front LED lights are a bit nonsensical in operation (they both toggle for input selection as well as an active link--you have to see it to understand that it is a bit non-intuitive) and hard to see at off-angle; and the coax and optical connectors are a bit close together, so that if you have a large sized plug they may not fit side by side.The sound quality is neutral, just the way I like it, though some might want more warmth or fullness to their sound. I think this is a great deal for the price.

The first one I got from amazon seller smsl died in about two hours of use. No problems returning it for a full refund including shipping. I ordered a second one from Shenzhen amazon seller and it has been working great for weeks.I use this with my Samsung tv for night listening to avoid waking up the house. I originally tried the Roku remote with headphone jack but got frequent dropouts probably due to the wifi transmission. I tried Bluetooth headphones but didn’t like recharging often. Both these wireless solutions had passable but not great sound quality and were weak in low frequencies.This DAC has sound quality that just sounds effortless and pure through my koss porta pro headphones. And it has plenty of signal to drive these high efficiency headphones louder than I would ever need.What was disconcerting was the differences between the two units I got from the different sellers/lots. The LEDs were different brightness and patterns, and whereas the smsl unit had non locking buttons the Shenzhen unit had locking buttons that mechanically had in and out positions. This tells me that they have very loose specs around parts and just use whatever is cheapest and or available.But this strategy works: I got a unit for very cheap price that has sound quality in the same class as my old Denon $2000 receiver with burr brown DACs. It was worth the hassle of dealing with a defective unit.It is definitely worth taking the time to run a toslink cable around the baseboards from tv to the couch to avoid the hassles of wireless. And this works just fine with a 25 foot Toslink and 25 foot headphone extension.One annoyance is that there is a mechanical relay inside which clicks every time the audio signal comes or goes. This means you hear the clicking every time a tv program starts, and it clicks when pressing pause or switching sources. The signal doesn’t have any clicks (once I made sure I wasn’t feeding it 5.1 formats; set your source to pcm) but the sound comes from the box itself. Not an issue once used to it but it seems strange to use a mechanical relay in this day and age. I don’t remember the relay clicks from the first unit so again this may be a part difference. Or maybe I didn’t have a chance to notice it on the first unit before it died.Unlike other reviews I found the toslink connector to be perfectly tight with the bluerigger cable sold on amazon.Enjoy!

I bought it in Feb of 2016....long story short. It works very well but....it just broke on me. Literally just right now, it stopped working.Changed wires, uninstalled/re-installed software for sound card...no sound.This item was well taken car of and in a area where there was a lot of ventilation.Not sure what happened.Overall, the item did it's job,to amp up my headphones.-HD 558-Beyer-dynamic 990 250 ProsIt powered the HD558 great, since they are around 50ohn.Beyer's...ehh. It did power them but..... not loud enough.Overall, it's a good item, just be warned, it might break on you, it might now. So far, this is the first product I buy from SMSL. I will give them one more change, i'll buy a different headphone amp. If it breaks again, then so long and goodluck to you SMSL.I suggest get warranty, just in case.

I originally purchased a USB amp for my PC but found that it had some hissing and distortion which drove me crazy. So I opted for this instead given the optical input, which is crystal clear. I am pairing this with a pair of Audio-Technica ATH-M50x headphones. These headphones don't technically require an amp, but using one delivers subtle yet noticeable improvement in audio quality. Set up was a breeze - just plug in the optical cable and the ac adapter. Then, enable the audio in your computer's sound options, and you're done. My only complaint is that I wish there was a bass boost option, which some of these amps have. Also, no optical cable included. Well worth the purchase, I would definitely recommend this to anyone looking for a good affordable amp.Two Month Update: Changing from 5 stars to 1 star. started to get loud crackling and hissing sounds that were at first infrequent but then became constant over time. the sound even occurred when there was NO audio source plugged in, meaning the device itself is bad, or possibly the power connector was causing voltage problems. in any event, it's totally unusable. i need to purchase a different DAC but it definitely won't be this brand.