Sunday, February 26, 2017

Holo Spring Level 3 DAC - A mini review


I recently spent a few quality days with the Holo Spring Level 3 DAC, courtesy of Sound Affairs, Singapore distributor for Holo. There is plenty of chatter in various audio forums on the Holo Spring DAC, especially on the high level of performance it delivers for it's price.


The Holo Spring is a really nice looking DAC (I adore those copper side panels), and is solidly built. It probably has the largest display I've ever seen, and the dot matrix panel is fully legible even from my listening position. 

The Spring DAC is a R2R DAC design. What differentiates the Spring from the rest of it's competition is that fact that DSD is decoded using a R2R circuit too. This is achieved by having two separate R2R circuits - one for PCM and the other for DSD.

The front panel has four buttons. The first button puts the DAC in standby mode, while the rest of the buttons control the display intensity, oversampling mode and source. There are four oversampling modes, NOS (no over-sampling), OS (both PCM and DSD are oversampled in their native format), OS PCM (oversampled PCM - DSD is converted to PCM), and OS DSD (oversampled DSD - PCM is converted to DSD).

The rear panel has both single-ended and balanced analog outputs, while a total of 6 digital inputs are offered - USB (galvanically isolated), coaxial, BNC, AES, Toslink and I2S via HDMI (PS Audio standard).

In use, the Spring DAC runs quite warm. It was left powered on for the few days I had it in my system. 

Dimensions wise, the Spring DAC measures 430 mm x 300 mm x 55 mm, and weighs 8.5 kg. 

Sound Quality

I was not able to do detailed comparisons of the Spring DAC using various digital inputs or its oversampling modes due to the short evaluation period I had. However, I did find that NOS mode sounded the most pleasing to my ears, while the tone of the unit was similar via SPDIF and I2S. I had a slight preference for I2S (fed via a Singxer SU-1 USB / SPDIF bridge) and stuck to that.

To be continued ...

X Audio - Entreq event on 14 January 2017

Frankie Pang, representative of Entreq Asia was in town recently to meet up with Entreq users. Frankie spent an afternoon at X-Audio, the Singapore dealer for Entreq, mingling with both Entreq customers and prospective ones.

I have been using Entreq products for a while now, having owned and used the Minimus and Tellus grounding box (together with Eartha Silver grounding cables) for a few years now. I did a review on the Olympus Ground Box, Tellus and Eartha Silver grounding cables (click here for the Olympus Review, and here for the Tellus / Eartha review).

Frankie shared with me information on some new products, in particular the K2, Everest and Tellus 2.

The K2 and Everest are upgrades available to any Entreq grounding box user - you simply need to replace one or more of the binding posts with either the K2 or Everest. Frankie was confident that the use of either could significantly improve the performance of the ground box in question. He suggested that using one or two pieces should give the most significant gains.

Frankie explained that the K2 uses a basic alloy of metals, while the Everest utilises a more complex composition. According to Entreq, the addition of a K2 or Everest to the Minimus ground box (which has a single binding post), would allow it to outperform a Silver Minimum. 

Moving on to the Tellus II, this is a significant redesign of the original Tellus grounding box, and is in fact three grounding boxes in a single case - a Silver Minimus for the right and left binding posts, and a Silver Minimus and Atlantis Minimum for the centre binding post. Unlike the original Tellus, all three binding posts for the Tellus II are electrically isolated from one another.

I left the event with a K2 and Everest for experimentation. Stay tuned for the results !