Apologies for immediately going above budget but I don't think you could get a better USB to SPDIF converter in your price range. That old AVA Hybrid DAC deserves the best.
The WaveIO is state-of-the-art board which was originally used in the well regarded
DDDac NOS DAChttps://luckit.biz/99 EUR - $112.92

Asynchronous USB interface:
Bit perfect audio streaming from the USB host (optimized for playback)
USB Audio Class 2.0 support with fall-back to USB Audio Class 1.0
Low latency (round trip as low as 3miliseconds)
16 to 32 Bit-transparent reproduction
44.1 to 384 kHz standard sample rates supported
Option for self- or USB bus-powered applications
USB and digital audio outputs:
Mechanically enhanced gold plated USB-B connector
Second multiplexed USB data input port available for off-board connection
Isolated I2S output using Giant Magneto Resistive (GMR) isolators from NVE
Non-isolated I2S port by means of 6GHz U.FL. mini BNC sockets
Two 75Ω isolated and non-isolated SPDIF outputs
All I2S and S/PDIF outputs can work in parallel
Hardware and layout:
4-layer gold-plated PCB with 1/2/2/1 oz copper thickness
Two 70µm copper layers are used for uninterrupted GND / GND & PWR rails
Careful layout to preserve signal’s integrity and keep the noise to minimum levels
Seven linear low-noise regulators bypassed by extensive decoupling networks
There are NO SMPS regulators present on this board
Three LP5900 LDOs (6.5µVrms) powers the oscillators & surrounding sensitive logic
High quality parts including OsCON SVP electrolytics & NP0/C0G caps
Two ultra-low phase noise japanese made oscillators (NDK – NZ2520SD type)
WaveIO is the first Asynchronous USB interface for Do-It-Yourself (DIY) market – and not only – adopting the NDKs famous NZ2520SD oscillators, starting back in 2012 year
We are offering the NZ2520SDA clock upgrade option for WaveIO
WaveIO in custom case with LED display, the builder used the J9 header
The J9 Header are for sample rate LEDs and additional signals:
L1 = 44.1 kHz
L2 = 48 kHz
L3 = 88.2 kHz
L4 = 96 kHz
L5 = 176.4 kHz
L6 = 192 kHz
L7 = Host Active
L8 = Audio Streaming.
Host Active is ON when the card is plugged into the USB port and is recognized.
