TDA1541A, no-compromise.
Now, it is S5b.
Originally released in 2021, as another step on the design principles and standards set with the Audial S series of D/A converters, the S5 easily established itself as a reference in TDA1541A design, by associating the supreme audio performance with ultimate connectivity.
The current version, S5b, moves even further, confirming Audial’s leading position in the TDA1541A world, and adding the remote control capability and one more input.
The S5b is thus by far the best-equipped TDA1541A DAC ever, with USB, S/PDIF, optical, and I2S LVDS and A-link direct inputs, and optional transformer coupled output. And, two S5/S5b units can even operate as a four-channel USB DAC.
or € 2,500 with output transformers
Under the hood
Performance and connectivity
The S5b mates so many things that usually don’t come together in the audiophile world. No compromise performance and ultimate connectivity. Non-oversampling D/A conversion and high-resolution capability. Advanced topology and fancy parts. Firm soundstage and natural ambiance. Resolution and definition, and natural tone and colors.
Versatility
In addition to the USB, coaxial S/PDIF, and optical S/PDIF (Toslink) input, the S5b also includes two PCM (I2S) direct connections, using the interface with HDMI connectors.
The one is our A-link, which may also turn two S5b units into a four-channel USB DAC. The A-link specifications are available as open source (please check out the documents below). The S5b also includes a more widespread LVDS I2S input.
Toroidal output transformers
In 2018, we worked with designer Menno van der Veen and transformers manufacturer Trafco and came up with high-performance, unique devices, designed exactly for our needs. They were first employed in the S4 DAC, and we continue using them in the S5/S5b.
The low external field of toroidal transformers ensures unbeatable resistance to environmental noise, so they clean out the artifacts caused by the system grounding issues, not picking up the noise on their own at that.
A-link (PCM / I2S direct) specifications
Windows USB drivers download requires login with the customer account.
Harmonic distortion, capacitor coupled output, 1 kHz, -6 dBFS dithered sinewave, THD = 0.0022%
Harmonic distortion, capacitor coupled output, 1 kHz, -60 dBFS dithered sinewave, THD = 0.886%
Intermodulation distortion, capacitor coupled output, CCIR IMD = 0.0015%
Square wave 1 kHz, capacitor coupled output
Square wave 10 kHz, capacitor coupled output
Square wave 10 kHz, transformer coupled output
S/PDIF input jitter suppression effectiveness, while locking on data (red curve) or pre-amble (back curve), with middle-class S/PDIF source (J-test signal)
August 2024, starting with serial #A01-3324:
(1) Under certain circumstances, mostly while using direct inputs (I2S LVDS or A-link), or (more rarely) by the input change, one or both channels might drop, due to excessive output DC offset. The unit could be (re)set back to regular operation by the power cycling / reboot. This issue affects previously shipped S5b units with output transformers. Now it is prevented by the change in the output DC offset nullifying circuit. The fix will also be available to the previous customers, at authorized repair service centers, at no cost.
(2) The USB stage firmware is updated to version 3.80 (2-channel) / 3.81 (4-channel). Previously shipped units, when used with Windows, might have a problem starting the playback at 44.1/88.2/176.4/352.8 kHz Fs, and instead, in order to work, the playback might need to start first by using the other string of Fs (48/96/192/384 kHz). This firmware update solves this. The update files are also available to the previous S5 and S5b users (as well as to the AYA 5 and USB I/F Mk3 board users), in the “Files” area, accessible with the customer accounts.
July 2024, starting with serial #A01-2824:
(1) Samsung remote control codes for input selection are removed, so these commands do not interfere with A20 amplifiers made in 2021/2022 (or with some Samsung devices).
April 2024, starting with serial #A01-1224 (S5b release):
(1) Remote control capability is added. Consequently, because the input selector is now driven by the rotary encoder instead of the mechanical switch, the front plate has been redesigned so it includes input indication LEDs.
(2) LVDS I2S direct input is added.
(3) The output stage power supply regulators are further improved. The output DC offset nullifying circuit is also improved.
September 2022, starting with serial #A01-3422:
(1) The output stage power supply regulators are improved.
(2) Polystyrene I/V resistors’ bypass capacitors are replaced with PPS.
(3) Following the A-link specifications from November 2021, both A-link connectors’ pins 19 are not connected to the ground anymore but are left floating.
(4) The other minor parts changes and practical improvements (with input switch etc.).
June 2021 (applies to all units shipped after 1st June 2021):
(1) Elna Silmic II (RFS) is used instead of Rubycon ZA for the output stage local supply bypassing.
Recommended reading:
Multichannel or 2-channel USB stage?
A-link (PCM / I2S direct) specifications (community)
Another story about TDA1541A: 384 kHz
Connecting the S5 transformer coupled RCA output to the A21 balanced input
Transformer coupling pros and cons
CS8416 performance (S/PDIF pre-amble vs data lock), Wayback Machine archived DIYHiFi.org topic
Mark Cargill and Elite Audio UK unboxed the S5 DAC and liked it very much. Later, they awarded the S5 the best DAC up to £6000.