In a Yamaha player, the output of the digital transmitter IC is connected to 4 parallel ( in-in-in-in out-out-out-out ) 74HC04 inverters via 1 k ohm. On the output there is a 220p cap to ground. This is coupled via 47 ohm and a cap to the output transformer.
That causes the irregular SPDIF square to look like an irregular sawtooth on the input of the inverters.
Any opinions on
- feeding inverters with a sawtooth signal ?
- using parallel inverters ?
- using inverters instead of NAND gates ?
Another Yamaha player with the same digital transmitter IC but 3 parallel 74HC00 Nand gates sounds very different on it's digital output.
That causes the irregular SPDIF square to look like an irregular sawtooth on the input of the inverters.
Any opinions on
- feeding inverters with a sawtooth signal ?
- using parallel inverters ?
- using inverters instead of NAND gates ?
Another Yamaha player with the same digital transmitter IC but 3 parallel 74HC00 Nand gates sounds very different on it's digital output.
You can try removing the 220p to ground. I'm not sure why it is there. It may have been put there to solve a EMI emissions requirment.
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