• ctrlm
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Topic: Ref Level & Volume to Musical Fidelity Integrated Amp

Hi,
go easy on me - I am a new owner & totally confused as to what sort of settings I should have set on my RME ADI-2 DAC FS to my Musical Fidelity M6 500i Integrated Amp using the XLR balanced outs. My speakers are B&W 803 D2. Up until now I have only used DACs without a preamp.

The Musical Fidelity published specs are sparse and their literature is mostly marketing BS at best. This is all they divulge:

Amplifier
Power output: 500 Watts per channel into 8 Ohms (27dBW)
THD(+ noise): <0.01% typical, 20Hz to 20 kHz
Signal to Noise Ratio: >100dB ‘A’-weighted
Frequency Response: +0, –0.1dB, 10Hz to 20 kHz
Inputs
4x Line Level RCA / Phono
1x Line Level XLR Balanced

I have emailed MF twice about getting some sort of max or recommended input voltage and they have just ignored me. After a lot of searching on the internet, the only other sort of additional info came from a HiFi World UK review and some of their own supposed testing, I have quoted some of that below:

"....input sensitivity has been raised to a very high 68mV..." ?

Power 450 watts

CD/tuner/aux (all RCA inputs)
Frequency response: 15Hz-46kHz
Separation: 106dB
Noise: -80dB
Distortion: 0.006%
Sensitivity: 85mV
Damping factor: 73

Any guidance on theoretically best settings for my setup would be appreciated smile

2 Reply by KaiS (edited by KaiS 2020-12-21 15:25:07)

  • KaiS
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Re: Ref Level & Volume to Musical Fidelity Integrated Amp

Look here.
If you do use other sources directly connected to the MF amp, like e.g. a FM-Tuner, Vinyl- or CD-Player, usecase 1. might be your choice:
https://forum.rme-audio.de/viewtopic.ph … 21#p161721

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  • ctrlm
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Re: Ref Level & Volume to Musical Fidelity Integrated Amp

KaiS wrote:

Look here.
If you do use other sources directly connected to the MF amp, like e.g. a FM-Tuner, Vinyl- or CD-Player, usecase 1. might be your choice:
https://forum.rme-audio.de/viewtopic.ph … 21#p161721

Thanks so much for that. A ref level of +7 dBu at 0 volume seems to mimic the volume levels that I am used to with previous DACs that had no preamp function.

Out of interest I tried using RCA to the integrated amp's Home Theatre bypass input using the RME auto reference level, eliminating the MF preamp and using the RME for volume control.

The auto reference level set itself to -5 dBu and -27 dB was what I perceived as a comfortable volume level. This sounded pretty good and my initial impression was that it was better than going through my amp's preamp.....but there could be some psychoacousitics at play here wink I would also assume that at -5 dBu & -27 dB that the SNR would not be optimum?

4 Reply by KaiS (edited by KaiS 2020-12-22 02:20:05)

  • KaiS
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Re: Ref Level & Volume to Musical Fidelity Integrated Amp

ctrlm wrote:

Out of interest I tried using RCA to the integrated amp's Home Theatre bypass input using the RME auto reference level, eliminating the MF preamp and using the RME for volume control.

The auto reference level set itself to -5 dBu and -27 dB was what I perceived as a comfortable volume level. This sounded pretty good and my initial impression was that it was better than going through my amp's preamp.....but there could be some psychoacousitics at play here wink I would also assume that at -5 dBu & -27 dB that the SNR would not be optimum?

With Auto Reference Level "ON" -27 dBr is well acceptable.
It's 9 dB below DAC's fullscale.
Auto Reference Level has 18 dB analog switching range that improves S/N ratio.

dBr means relative to maximum possible level including Auto Reference Level's 18 dB switching range.
If you switch OFF Auto Reference Level, volume is shown without the r, relative to DAC's fullscale.

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  • ctrlm
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Re: Ref Level & Volume to Musical Fidelity Integrated Amp

Thanks again for the advice!

My HT bypass unfortunately is exclusively used by my AVR.

I have also experimented with lower reference levels to the MF in fixed mode and there doesn't seem to be any additional noise with having to use more volume on the amp, +1 dBu & 0 volume sounds fine. As it is rated @500w per channel, I doubt that it is anywhere near working too hard. The volume control on it is a rotary encoder that doesn't have any hard ending so it's difficult to say where half volume might be.

  • ctrlm
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Re: Ref Level & Volume to Musical Fidelity Integrated Amp

Interestingly, I got a reply from MF:

“The 500 will take maximum of 8Vrms on the line inputs. However to match any other inputs (if any) I'd recommend setting dac output to 0dBfs = 2.2Vrms...”

I don't use any other inputs apart from the HT bypass for my AVR.

  • KaiS
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Re: Ref Level & Volume to Musical Fidelity Integrated Amp

ADI-2 DAC's DAC-chip works with the same quality no matter what reference level you choose.

Choose the reference level that works most convienient for you.

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