Block diagram of the BAX-VOL-CTRL board
The Sefirot architecture includes the following boards, all available in this webstore:
-
Super Balanced Input (SUPER-BNCD-INPT)
-
Baxandall Volume Control (BAX-VOL-CTRL)
-
Headphone Amplifier Stage (HEADPHONE-OPAMPLFR)
-
Bandwidth Definition & Subbass Low-Pass Filter (BWLP-FLTR-MONO)
-
Summing Amplifier Module ( SUMMING-AMP-L+R)
-
LLLL-INDICATOR Log-Law LED Level System (LLLL-INDICATOR)
-
Power Supply Module (PAMP-PSU)
The BAX-VOL-CTRL board can accommodate a passive Low Pass filter at the input to prevent radiofrequency signals from going deeper into the circuitry. Additionally, it offers a separate buffer for each audio input signal (Left and Right channels). Following the buffer, there is the Low-Noise Baxandall Active Volume stage, which comprises a section of amplification and two inverting amplifiers connected in parallel. This signal flow is applicable to each channel, as depicted in its block diagram. The design of this board draws inspiration from Douglas Self’s concept of implementing the Baxandall active volume with gain transferred to the first stage.
The following are the main operating characteristics of the BAX-VOL-CTRL board:
- Buffered inputs to achieve lowest noise and THD figures.
- Output gain between -inf to +10 dB.
- Balanced outputs for each channel.
- Independent power supply unit for each channel (optional).
- THD+N: @ Vin=1Vrms; Vo= 3 Vrms; 0.000032% at 1 kHz and 0.000096% at 10 kHz while driving a 600 Ω load.
- THD+N: @ Vin=1Vrms, Vo= 1.24 Vrms.; 0.000012% at 1 kHz and 0.000043% at 10 kHz while driving a 600 Ω load.
- Bandwidth: > 300 kHz.
- Frequency response: -0.26 dB at 20 Hz and -0.13 dB at 20 kHz.
- Crosstalk < -100 dB @ 1 kHz
- High-quality double-sided plated-through-hole PCB (Lead-free HASL) with solder mask on both sides and full screen print.
- Input impedance: > 46kΩ
- Current consumption: 130mA Max.
- PCB size: length=100mm, width=88 mm. It incorporates four M3 fixing holes.
A couple of interconnection diagrams to build a preamplifier using different boards designed by Olas Audio are displayed below.
Interconnection between different Olas Audio boards to build a preamplifier with two separate Low pass/Bandwidth Definition filters
Interconnection between different Olas Audio boards to build a preamplifier with one Summing Amplifier and a Low pass/Bandwidth Definition filter
The published price is for the PCB only. A bill of materials and assembly instructions will be provided upon purchase.
