d1-tube DAC


The d1-tube DAC is the version of the d1 DAC with a single ended tube output stage.
The d1-tube may be the only DAC using only tubes and Vishay Foil resistors in the conversion and analog section.
A DSD (DoP) option is available for the USB, spdif and AES-EBU inputs.

"I was completely shocked and actually spilled out the word wow without realising it." Dan, HIFIpig
"sensational natural sounding DAC.", Stefan Schickedanz, AUDIO
"Exceptional unit, both technically and musically. Amazing what you can still get out of the good old CD. A true experience, providing the rest of the system is on the same level." Jürgen Saile, HIFIstatement
"These d1-server + d1-dual or d1-tube set-ups attained a level for PCM and DSD which I’d not heard before.
After this review, the prize "Grand Frisson 2014" of Audiophile Magazine is obvious."
Thierry Nkaoua, Audiophile-Magazine and 6moons

The d2-tube was in demo at the Munich show 2013, see comments from journalists here: listening

Totaldac d1-tube front

-192KHz asynchronous Xmos USB, optical, RCA and AES-EBU digital inputs, selectable from a remote control.
-44.1KHz, 48KHz, 88.2KHz, 96KHz, 176.4KHz and 192KHz, 16 to 24 bit formats supported on all inputs except 96KHz max for optical input.
-as an option, DSD (DoP standard) supported on the USB, AES-EBU and spdif inputs.
-USB input compatible with Jplay in 24 bit "extreme hibernate" mode. The USB input have been simplified compared to the d1-dual USB input.
-embedded custom clock with anti-jitter FIFO memory.
-1.4Vrms max RCA output. The XLR connector carries only the un-balanced signal, so it is equivalent to the RCA output.
-volume control, adjusted by a remote control and an OLED display, works for all inputs, not only USB.
-phase polarity selected by remote control.
-non-oversampling DAC compensation filter activated or disactivated by remote control.
-display switched off by remote control or automatic.
-all unused inputs are completely disconnected (including the ground) to keep the optimum noise floor even when several sources are connected.
-R2R DAC technology using 0.01% VAR Bulk Metal® Foil resistors from Vishay Foil Resistors, 100 resistors per stereo channel.
-tube output stage using one ECC82/12AU7 double triode per channel. 420ohm output impedance.
-external power supply to minimize the noise on the embedded preamp.
-aluminium and PMMA enclosure with massive pure copper antivibration plate.
-power consumption 22W.
-DAC dimensions: height 110mm, width 360mm, depth 290mm.
-power supply dimensions: height 65mm, width 122mm, depth 180mm.
-weight: 6.5kg.

Available options:
-DSD (DoP) option.
-silver massive aluminium front panel.
-115V power option.
-BNC coaxial digital input instead of RCA.
-d2-tube and d3-tube, 69 bit 2 way or 3 way active crossover with RCA analog outputs including a digital preamp for the main volume control and also for the relative level between bass and treble. The crossover slope can be 6dB/oct, 12dB/oct or 18dB/oct. All parameters, crossover frequency, filter slope, relative volume, main volume, relative digital delay... can be controlled from the remote while listening to music. Only the last channel (high frequencies) uses a tube, the other channels use a transistor output stage.
With the d2-tube with DSD option the digital delays can't be used.
The d3-tube is not compatible with the DSD option (you can use a reclocker or d1-server as a DSD to PCM converter).
-USB cable with high performance filter for a noticable sound quality improvement, length on demand, 1m by default.
The list of embedded options is on the serial number sticker on the rear panel of the DAC.


Totaldac d1-single rear

Silver option:

Totaldac d1-tube silver

d2-tube inside, with subwoofer output:


1KHz -110dBFs sinewave spectrum, A ponderation applied to take into account the ear caracteristics:

FFT 1KHz -110dBFs d1-tube A pond

The measurement is done with USB as source, from a standard computer plugged on mains.
The noise floor is very low especially in the 200Hz-4KHz region where the ear is very sensitive. The hum noise typical of tube electronics is detected as only -137dB by the ear, very low.

1KHz -110dBFs sinewave spectrum, no A ponderation applied, with a 3.3Vrms reference voltage for an absolute comparison to the d1-single noise:

FFT 1KHz -110dBFs d1-tube ref 3.3Vrms

The noise floor in the sensitive frequencies for the ear is even lower than the d1-single noise, allowing a very low noise when driving directly a power amp without preamp.

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