Block diagram of the SUPER-BNCD-INPT board
The Sefirot architecture includes the following boards, all available in this webstore:
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Super Balanced Input (SUPER-BNCD-INPT)
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Baxandall Volume Control (BAX-VOL-CTRL)
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Headphone Amplifier Stage (HEADPHONE-OPAMPLFR)
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Bandwidth Definition & Subbass Low-Pass Filter (BWLP-FLTR-MONO)
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Summing Amplifier Module ( SUMMING-AMP-L+R)
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LLLL-INDICATOR Log-Law LED Level System (LLLL-INDICATOR)
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Power Supply Module (PAMP-PSU)
The SUPER-BNCD-INPT board uses dedicated buffers for the hot and cold halves of the balanced signal. After buffering, two differential amplifiers operate in parallel, and their outputs are summed through low-value resistors. This architecture is implemented independently for each channel, as shown in the general diagram. The design is based on Douglas Self’s “Low-Noise Balanced Input” concept.
The following are the main features of the SUPER-BNCD-INPT board:
- Buffered balanced input that achieves low noise and THD, preserving pure Op-Amp analog quality sound.
- Sound quality built strictly on operational amplifiers – no integrated differential amplifiers, no balanced line receivers.
- Unbalanced outputs for each channel.
- Op-Amp Input Over-Voltage Protection
- THD+N:00001% at 1 kHz and 0.00009% at 10 kHz while driving a 600 Ω @ line level 1.23 Vrms (+4dbu).
- Output headroom: > +22 dBu
- Crosstalk: < -97 dBV @ 1kHz
- Bandwidth: 500 kHz
- Frequency response: -0.05 dB at 20 Hz and -0.13 dB at 20 kHz.
- High-quality double-sided plated-through-hole PCB (Lead-free HASL) with solder mask on both sides and full screen print.
- Input impedance: > 46 kΩ
- Current consumption: 80 mA Max. for both channels.
- PCB size: length=100mm, width=77 mm. It incorporates four M3 fixing holes.
- Common-Mode Rejection Ratio: Better than 80 dB at 120 Hz. Better than 77 dB at 1 kHz.
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.
