The first version of AA SiG USB cable was developed just before NIAV 2024 last April. Since then, we have tweaked and improvised the cable based on customers, reviewers, and testers feedback we received. We also tested our cables in bespoke systems.
In 2024, we initially had SiG USB followed by SiG Ref. Later in 2024 we added the SiG XT. In 2025, we discontinue the SiG Ref so that the choice is limited to SiG USB and SiG XT, making it easy for customers to choose.
The 2025 changes we made to SiG USB and SiG XT include the following:
- Visible separate sleeves / insulators for data and power shields. Previously the shields for data and power are put together into one sleeve. Having each shield insulated and with a small distance from the other resulted in lower noise floor.
- The data shield is made more flexible to ease orienting the USB plugs.
There is a slight price increase (< 3%) for the SiG USB due to increased materials cost, but we like SiG USB Mk2 price-performance ratio better than the SiG Ref, hence the discontinuation of the SiG Ref. There is no price change for SiG XT Mk2.
It takes a while before reviews for SiG Mk2 appear as we are sending the latest Mk2 version to the reviewers.
The SiG Mk2 USB cables are ready for order. Please visit our Online Shop.
How We Voice Our USB Cables
We use our flagship AA Music Server (AAMS) comparing local files playback (ripped from CDs and SACDs) with Marantz SA-10 playing the same discs. The SA-10 has USB DAC input so we compare using CD/SACD transport versus AAMS as a digital transport using various USB cables. Most components including the SA-10 and AAMS are placed on HRS Nimbus footers.
With the latest Mk2 SiG USB cables, AAMS is able to better SA-10 transport when using both SiG USB and SiG XT. The SiG XT takes it to different level.
We also test our AA USB cables with Holo May KTE DAC in NOS mode. When playing CD using SA-10 coaxial output into Holo May coaxial input (PLL on), the differences with Holo May USB input is too much regardless of how expensive the digital coaxial cable used – Holo May’s USB DAC input always win by a big margin.
When using Oppo 205 as CD / SACD player, even the AA SG USB is able to better the transport.
For final validation, we test our cables in bespoke systems we don’t own.