I went to the Bristol Hifi Show on Friday, mostly focusing on headphones. This is not a collection of reviews but a few notes about the more interesting higher end headphones on the market.
Measurements and experiments carried out on a more spacious AK4490 test board
- Better understanding on improving AK4490 performance
- Encouraging results regarding Wee DAC performance goals
- Massive boost of 10-15 dB in THD+N at low frequencies
- THD+N at 1 kHz measured beyond -110 dB on test board
- Does not mean Wee DAC will achieve these though
- Modifications will increase BOM cost so need to consider the benefits and find a good compromise
I bought a second hand M-DAC a while ago to have a well-known commercial reference in terms of measurements and sound. After teardown it is time for measurements. The first part focused on the base performance and this second part dives into the digital filters and their impact on measurements.
Summary of initial Wee DAC tests:
- Estimated performance:
- SNR and Dynamic Range: around 120 dBA
- THD+N: at least -105 dB @ 1 kHz, 0 dBFS
- This performance is not achievable on the first/current PCB revision; re-spin required
- More performance studies on AK4490 will be carried out before PCB re-spin
Care must be taken when using ungrounded devices, such as laptop, on measurement bench
- There may be tens of volts difference between mains earth and ground of the ungrounded device
- It is not dangerous to you but to sensitive electronics it can be
- Easy solutions exist but sometimes problems may be tricky to identify
Currently on test bench is a new stackable modular DAC design, Wee DAC (maybe should have called it Tower DAC!), consisting of several modules:
- W-Input – S/PDIF input board with one coaxial and one Toslink input, and I2S output
- W-DAC – High performance 768 kHz 32-bit DAC with I2S input and single-ended analog output
- W-Output XLR – Balanced output module
- Several base board options, such as W-Breakout for signal breakout and W-PSU for individual power supplies
I bought a second hand M-DAC a while ago to have a well-known commercial reference in terms of measurements and sound. After teardown it is time for measurements. This first part consists of basic performance measurements.
Small sealed subwoofer stands for desktop monitor speakers
- Tang Band W6-1139SIF 6.5″ woofer
- Sealed cabinet with around 10 litre volume
- Form factor to fit behind computer monitors; white paint and black fabric finish to fit desktop environment
- Linkwitz Transform and digital room correction on miniDSP
- Woofer size and cabinet size limit performance but gives solid boost for small speakers
I bought a second hand M-DAC to have a well-known commercial reference in terms of measurements and sound. Obviously I needed to open it and see what’s inside. This is not a detailed reverse-engineering report but a glance inside with plenty of photos. Measurements are coming later.
I have a few assembled and tested Addon BalOut boards available, with or without XLR connectors.