An FPGA-based digital-to-analog converter engineered from first principles. No off-the-shelf chips. No compromises. No shortcuts.
Concept — Brushed Aluminium
Concept — Obsidian Edition
Concept — Nero Portoro Edition
Enclosure design concepts. Final form factor in development.
The BELLA DAC 1 runs a custom signal processing pipeline entirely inside a Xilinx Artix-7 FPGA. The audio signal passes through a 229,376-tap polyphase FIR reconstruction filter before reaching a discrete pulse array output stage. No delta-sigma modulator chip. No generic DSP. Every multiply, every accumulate, every output pulse is defined in our own RTL.
INPUT PCM / DSD via USB Audio Class 2.0, S/PDIF Up to 24-bit, 16 kHz to 768 kHz FILTER GOAT — Generalized Optimal Aperture Taper Custom polyphase sinc reconstruction FIR 112 DSP tiles × 8 taps × 256 phases 229,376 coefficients, 25×32-bit native multiply Custom coefficient generation (MATLAB) SHAPING 20th-order sigma-delta noise shaper Custom topology, multi-stage modulation OUTPUT 2×25 element multi-bit resistor array Differential, inherently linear Multi-rate: 256×, 128×, 64×, 32×, 16× Analog reconstruction via passive filtering CONNECT XLR balanced output (L/R) RCA unbalanced output (L/R) 6.35mm headphone output 4.4mm balanced headphone output PLATFORM Xilinx Artix-7 XC7A200T FPGA Custom multi-layer PCB OLED display, rotary encoder, IR remote
Commercial DAC chips (ESS, AKM, Burr-Brown) impose fixed architectures and known limitations. The BELLA DAC 1 implements the entire digital-to-analog conversion in programmable logic. Every parameter is tunable. Every trade-off is ours to make.
The custom sinc reconstruction FIR filter runs 229,376 taps across 256 polyphase stages. This is not a marketing number. It is the actual number of multiply-accumulate operations performed on every sample. The result: near-perfect impulse response with no pre-ringing artifacts.
The output stage uses a 2×25 element differential multi-bit resistor array. Inherently linear. No DNL errors from component matching. Balanced and unbalanced outputs, plus headphone amplification via 6.35mm and 4.4mm balanced.
The FPGA bitstream is field-updatable. Filter profiles, noise shaper topology, output stage configuration, and oversampling rates can be modified after purchase. The hardware grows with the firmware.
“If it doesn’t exist, build it yourself.”— Pretty Good DACs founding principle
We are currently finalizing the hardware design and preparing for initial production. For inquiries about the BELLA DAC 1, manufacturing partnerships, or distribution, get in touch.
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