Geek Out IEM 100 USB DAC and Headphone Amplifier

Just received today, a Sunday, after ordering it the previous Friday (1 1/2 day delivery amazing). I'm not using this GO-100 dac/amp as a mobile soundcard but as a headphone amp/dac for home use via one of my laptops and a desktop, both Win 10. All of my headphones except my AKG 701/2's are easy to drive and this usb GO-100 amp/dac has really impressed with my 2 Audio-Technica models, the AD-700's and the more upmarket W-5000's. Using the .47ohm output has transformed the AD-700's into a real smooth dynamic performer and when streaming internet radio Chill/Downbeat stations, the GO 100's filter that reduces ringing through these cans really works and I find no need to eq. mid-upper bass/ mid frequencies. Very easy to listen to. I've got my Grado 125's playing thru the GO-100 as I write this little review and the GO-100 proves to be another smooth/dynamic amp here as well. I'm liking this amp/dac. I've read some reviews that considered this GO-100 a tad over dynamic, but all I'm finding is, again, a very smooth operator with really good dynamics and digging deep for musical info with excellent soundstaging.. This is a very good amp/dac for my listening habits and headphones...and the price is excellent for this performance. 5 stars all the way...price, performance, value....and a happy customer/listenerUpdate #1......Nearly a month has passed and I've been popping this wonderful dac/hp-amp in a bunch of systems and having it power some other headphones of mine. And, for me...thee most excellent match for this GO-100 is without a doubt my Sennheiser HD-595's! This a perfect music making combo that keeps me smiling and coming back for more, every time. These Senn's are very dynamic and can over emphasize the mids with lesser quality dac/amps in situ, but again, this GO-100 is just so smooooth AND dynamic, these Senn's are now my go to cans with the GO-100. I've got the original Fleetwood Mac (Green & Spencer, et al.) jamming on this combo amp/dac/cans while I write this update, and my oh my, this sounds like I'm there in the studio with 'em....a really great match up.....JMUpdate #2.....Now, the GO-100 is slotted into my new Acer Win 10 sff desktop and is sending a 32bit/192 internet streaming radio signal to my Croft pre and pwr amp and out to a pair of Triangle Stella speakers sitting on IsoAcoustics stands. All speaker and interconnects are DNM. Again...smooth, detailed, exciting, depth and width of sound stage...all excellent. I have other dac's but won't compare as this little GO-100 stands on it's own as one of my most musical and easy to listen to and very dynamic when called upon dac's....this with all genres. This relaxing Sunday a.m. it's Classical music.... wonderful thru this dac......saaa-weeet it is.

I have found this to be very useful and enjoyable way to listen to music from my computer while flying and in the office. I have used it with good headphones (PSB) and with some nice high-end desk-top speakers with good results in both cases. First time I switched from FLAC to DSD files, it freaked out a bit, but a flick of the buttons on the side and it was all good.

This device clearly improves the sound coming from the computer, as long as you use quality in-ear headphones. On the PLUS side, it is small, and weight next to nothing. On the MINUS side, it gets HOT (Class A Power Amplifiers) and decreases battery life. This unit has been designed specifically for in-ear headphones (I use them with the Ultimate Ears Reference Monitors) and the noise levels are vanishingly low, and the sound is spot-on.

Great for adding iem headphones to MacBook Pro...bypassing laptop DAC and providing amplification.