Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems 518 into 568

Thanks for the suggestion. Clever workaround.


OK, thanks for the insight. Based on this and DTS de-jittering it seems best to run 518 in Gain mode (within Type 1) when feeding a 568.2 Processor.


Good to know! Will experiment with increasing gain. 568.2 generally runs in the 60-75 range depending on source material. Would it be ideal to use 518 to reduce gain so that 568.2 runs closer to 87 (unity)? Is this reduction in gain by 518 any different than just reducing the output volume from computer source (only digital source with volume control)?


To clarify, when DTS sources trigger Bypass (via DTSCD setting) in Type 1 this still applies twin PLL de-jittering to signal? On page 20 of 518 manual it states: “Bypass transmits all 24 bits on the input to the output without any processing”. So it seems the question is: is DTSCD mode (DTS displayed on front panel) the same as Bypass mode (wherein all front panel controls are disabled)? If so, then it seems that the 518 does not de-jitter DTS signals as these are automatically bypassed.


Based on this helpful feedback it seems best to run 518 as Type 1 in Gain mode with 16P24 enhancement (manually switching to 24P24 for 24-bit audio files) for 2 channel digital audio sources and continue to pass DTS signal through for potential de-jittering.

Next up is experimentation with the various dither curves. After ideal settings are found will then remove 518 from chain to assess how the same digital sources sound when connected directly to 568.2 via 3in1out Toslink switcher (i.e., 568.2 de-jittering and Shape C dithering only as opposed to 518 de-jittering and dithering before 568.2 de-jittering and dithering).

Thanks heaps!

I’d also like to clarify one thing from a previous post in an older 518 thread: do the front panel buttons on the 518 actually apply setting changes?

For example, does switching from Emphasis to Gain via front panel actually apply this change to the signal? This would make the most sense but a previous post (circa 2008) has left me feeling confused about this. Or perhaps I misunderstood the meaning of the post.

Switched mine to Gain mode tonight and can’t hear any audible difference when switching from Flat to Shape A. Haven’t listened closely to High Pass or Shapes B-E yet.

Rearranged my setup and now have a different DAC connected to 518 via AES/EBU using XLR-to-RCA interconnect. Looking forward to A/B comparisons of this DAC (PS Audio Digital Link III; 24/48 input up-scaled to 24/96) versus 568.2mm (also up-scales 24/48 from 518 to 24/96).

Thanks heaps!

Best practice for gain is to maximise the channel use and only attenuate when needed, so keep the levels high to maximise S/N and attenuate at the end.
I beleive the processors use a hybrid analogue / digital attenuation; once you drop the level a few dB, analogue attenuation is applied and the digital signal is put back up to 0dB, keeping the the benefit of all the bits.

The twin PLL de-jittering is always applied, the processing is gain / dither etc.

See above.

Yes; you may need to double check some of the settings in the set-up to make sure they are enabled correctly (been a few years since I've set up a 518!)

To be honest, even with critical listening I couldn't hear the differences between the dither settings; maybe the 568 afterwards negates the differences and if the 518 was used straight into a DAC they may be more noticeable...

The 568 will go 24/44.1 to 24/88.2, it doesn't look like the PS Audio does 88.2 or 176.4, so it may not sound as good as the 568, but it may well do a good job of non integer upsampling.

All the best,

Steve

I used a 518 with the 566 DAC, and I couldn't discern a difference between the dither patterns. And I never got my head around the advice in the 518 manual to apply preemphasis to the signal.

Does anyone know if it is possible to configure the 518 to respond to FN+Source commands from remote?

If so, can this be done without 518 being connect to downstream processor (e.g., 568.2mm) via Comms Link cable?

Manual clearly states ability to configure to respond to FN+Volume by selling “Vol. S” but nothing about configuring to respond to FN+Source (i.e., secondary source).

Thought I read somewhere that this might be achievable by setting SA to a value other than 1?

I ask as my 568.2 is nearby and trying to find a way for 518 to not respond when Source keys are pressed to change 568.2 inputs but still have ability to remote control 518 input selection (i.e., remote control source selection independently for both units). They might be far apart enough that command intended for 568.2 won’t trigger 518 to change to that source too. Alternatively, can get a remote controlled Toslink switch for 2-3 Toslink sources but thinking it could be better to convert one or two of my Toslink source(s) to coaxial before 518 (have converters) than introduce any signal degradation due to Toslink switching (maybe a moot point but not much info about how Toslink switch works online).

Also, has anyone encountered clipping when DTS signal is de-jittered by 518 at unity gain? Have noticed some glitches/pops when streaming DTS movies via PS4 Pro when signal is de-jittered by 518 before 568.2 as well as when PS4 Pro is connected directly to 568.2 via Toslink. Perhaps -5dB gain (or more) imposed by 518 will resolve this issue (presuming it is due to clipping). Happens the most during loud and complex passages, which does suggest clipping.

Thanks heaps!

Please disregard the questions in the previous posting. Figured out how to turn off inputs on 502, 518, and 568.2 so now I can use one remote to interact with only the desired unit. Problem solved!

Thanks anyhow for the (undoubtedly) insightful information

Been playing around with 518 gain control and wanted to inquire with HH community if there is a rule of thumb regarding the best way to set the gain/volume relationship on 518/568.2, respectively?

For example, is it better to have 518 set to 0dB gain and 568.2 set to -25dB volume or better to have 518 set to -20dB gain and 568.2 set to -5dB volume?

Think I read somewhere that it is ideal to have 568.2 running close to 0dB volume to maximize DAC/processing? Or is this a moot point in that there is no actual difference between these two gain/volume relationships (e.g., 518 low and 568.2 high or 518 high and 568.2 low)?

Thanks heaps!

The expertise here is amazing. For a bear with as little brain as I have, this whole site is a bit of a lifesaver. Thank you, all.