We accept high-resolution WAV or AIFF files – the most optimal resolution and format for us is if you provide one continuous WAV file per side at 96 kHz / 24-bit (we support audio from 44.1kHz / 16-bit up to 192 kHz / 32-bit).
You can send us audio files peaking near 0 dBFS, but not too close to 0 dBFS. Leave some small headroom there, maybe 0.1-0.5dB.
We have enough additional headroom for D/A conversion in our vinyl mastering software sending audio signals to our cutting lathes through PrismSound Orfeus converters.
Please note it is better not to use hard-limiters (brickwall, peak limiters) to a great extent. We have to reduce the cutting levels if there are a lot of limited sections in the supplied audio.