When used in the right-sized room with efficient speakers, the Olasonic Nano-UA1 player can deliver very high-performance sound. Its primary limitations are its small amplifier section and inability to play 24/192 tracks except when routed through its S/PDIF input. During my listening sessions, I used a variety of sources, including a Squeezebox Duet for streaming from Internet radio and my computer's music library, the Olasonic Nano-CD1 CD transport for CDs, and my MacBook Pro running iTunes, Amarra, Pure Music, and Audirvana for higher-definition digital music sources (with 24/192 files routed into an Empirical Audio Off-Ramp 5 to convert USB to S/PDIF).
As long as the device was operated within its comfort zone (with the volume level set below two o'clock), the sound from the Nano-UA1 was worthy of being called "high performance." Most of my listing via speakers was done through the Audience Clair Audient 1+1 speakers since they were the best match, sensitivity-wise. I was impressed by the Nano-UA1's ability to project a convincing three-dimensional soundstage with an excellent feeling of depth and well-localized spatial cues. While the spaces between instruments weren't quite as well defined as through the Cambridge Audio Minx Xi (review coming soon), the Nano-UA1 did match the Minx Xi in terms of inner detail and lack of extraneous low-level grain or electronic texture.
Using headphones with the Nano-UA1, I found that most, but not all, worked well. With the ultra-sensitive Westone ES5, the Nano-UA1 did generate some low-level hiss that could intrude on quiet passages. With the 600-ohm-impedance Beyer-Dynamic DT990 headphones, I would have liked more gain and the ability to play louder with the Nano-UA1. But some headphones, such as the new 32-ohm Oppo PM-1 open-ear headphones, had no background noise or hiss and could play loudly enough that I never felt that I needed more power.
• The Nano-UA1 is compact and very nicely finished.
• The sound quality is excellent.
• The built-in headphone amplifier will drive most headphones.
• The integrated amp offers trouble-free setup and operation.
• The amplifier is not very powerful.
• The USB connection is 1.0, so it supports up to only a 24/96 sample and bit rate.
• The Nano-UA1 lacks a dedicated subwoofer output.
Competition and Comparison
Although there are much less-expensive small integrated all-analog integrated amplifiers, such as the Trends 10.2, components with a similar feature set and miniature footprint are rare. For slightly more money, you can get the Cambridge Audio Minx Xi ($995), which includes more inputs, a bigger power amplifier, and streaming capabilities, but it is also a noticeably larger component. Like the Nano-UA1, the Minx is limited to 24/96 via USB due to its USB 1.0 implementation.
The new Sony HAP-S1 ($999) has most of the capabilities of the Minx Xi; but, instead of streaming from an external drive, the Sony has a built-in 500GB hard drive to hold your music, as well as an APP to transfer it from your computer's music library to the HAP-S1. The Sony also supports 24/192 and DSD music files and has an Internet radio tuner built in.
If you need a micro-sized integrated amplifier with a built-in DAC, the Olasonic Nano-UA1 could be the perfect choice. It sounds very good when used within its optimal operating parameters, but you will need a pair of power-efficient speakers, since the Nano-UA1 only has 13 watts of power into eight ohms. With an input for computer USB plus two digital inputs and one analog input, the Nano-UA1 can accommodate most sources. Its primary limitation is that it is a USB 1.0-compliant device that only supports up to 24/96 via USB. For higher-resolution music files at 24/192, the Nano-UA1 requires use of the S/PDIF digital input.
If desire truly miniaturized audio components, I suggest you take a look at Olasonic's NanoCompo line. These components offer fine sound in micro-sized packages.