Cambridge 851N question

Maybe premature since still Beta but I have been running Roon on my 851N and I’m confused by the signal path. I have 96 kHz MQA until a sample rate conversion is applied at the end - with only 48khz output to the preamp. I don’t have any SRC applied by me. Whats going on?

I think the 96 is showing the original sampling rate of the file, but the MQA file is 48 before decoding and rendering. Im no expert though.

Roon is showing you that the 851N is up-sampling to 384kHz.

I have the 851n output to a Rotes ra1580 preamp - which shows that only 48 is being received

Connected how?

Im using optical

Ra, RC or rap 1580?

RC 1590 pre-amp

The 851N isn’t presently capable of fully decoding and MQA file.
Line one tells you two things: the actual file and the target file if properly decoded.
Line two is confirmation that Roon detects the MQA file.
Line three confirms transmission from your core to the 851N.
Line four shows the 851N upsamples everything it sees to the maximum it handles. Possibly because that is the way it has been configured?
Line five shows the upsample signal is available at the analogue and digital outputs.

In short your system is just treating the file as it would any other. If you want to restore some of the resolution MQA has to offer I would set Roon to perform the first unfold. You do that in Roon’s advanced setup for the 851N.

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The up-sampling is a DAC feature. As you don’t use the DAC it seems not to be relevant for your use case. It looks like the digital input signal gets just passed trough to the digital outputs of the 851N. There is usually no conversion done (unless for compatibility reasons?) much as Roon handles it on default settings. I guess that the 851N does not signal the output in use (it most-likely doesn’t know that himself) as the outputs often work in parallel and the user is free to uses which ever output he wants.

So while the up-sampling seems to be true for the analog outputs (prior to the D/A conversion) it seems to be not true for the use of the digital outputs. A signaling of the output in use is not happening (and maybe impossible). The signal path in Roon seems to be wrong here, showing that the up-sampling is taking place before the “Output” through “Analog/Digital Outputs”. Have you clicked on the blue star behind the “Sample Rate Conversion” entry (this might reveal additional information)?

As all this is discussing internals of the 851N, have you contacted Cambridge Audio also?

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