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

I have a couple of queries regarding my 518.
I’m in the process of swapping out my 565 for a 568 to take advantage for upsampling to my DSP 24 bit 5500s and 5000C speakers.

Currently running my 500 transport into the 518 and out to the 565.
Will it be of any use with the 568? If so how is it best to set the in and out bit rate or would it simply be on bypass?

Thanks
Andy

Hello,

OK, if no one can answer my questions about the 518 into the 568, can anyone tell me what firmware the 568 should be running and where I can get any upgrades but it’s an old version?

It should arrive tomorrow and I would like to make any updates before installing.

Thanks for any help.
Andy

518 is still worth using with a 568 of any age, set it to 16C24 and set the 568’s input to 24bit.
If it’s a first generation 568, the latest firmware is 1.5, the 568.2 has several options, official, beta and and a hodgepodge…

ATB,

Steve

Andy - I am doing exactly what you are proposing in one of my set ups. I had a 565 and 24/96 5Ks and centre and i wanted to get their benefit so i got hold of a 568 V 1 which has 24/96 on front and centre. The rears are only 18 bit but that does not bother me because i am music only. If you want 24/96 all round you need the later versions of 568.

I inherited some other gear and then got a 518 to upsample some sources (CD and DAT) to 24bit . The 518 is a remarkable piece of kit but very complex - you need a PhD to read the manual! Its not so easy believe me, but it delivers.

Just this week I am rejigging again

All Sources to 562V3 to 518 to 568 to 5Ks

I can’t give you much concise instruction because I do a lot by trial and error ... but I usually get their in the end

I am planning some vinyl recording to DAT for fun and the 518 is handy for that ( my DAT is a Pioneer D07 which is another beast)

Stick with it it will be rewarding

Best regards Huw

Thanks for the replies. It’s nice to finally see the yellow lights come on in my 5500s. Quite impressed with Dolby Pro Logic II as well.
My DSP5000C 24 bit does not have any indication that it’s running in up sampling mode. Should it do?

Also another quick question. (Might be better posting this separately). Currently running a 500 transport but I do have my G98 DVD/CD which is not currently working. The 500 is starting to skip on some disks so is probably in need of a new laser. Which one would be best to get repaired? I listen to all sorts of music and still have some DVDs.

Cheers Andy

IIRC there is an extra "." illuminated on the display, but I'm not sure if 5000s / 5500s & 6000s upsample in the way that the later DSP models do.

Anyone have any insights regarding the best settings to use on 518 feeding into 568.2mm?

Currently running my new (used) 518 with the following settings: Type 1, Emphasis, Flat, +0dB, 24P24, optical in, coaxial out, NC (non-Meridian sources)

Based on manual it is my understanding that it is better to set input to 24 bit if digital source EVER provides 24-bit. Being that my Mac mini music server does sometimes provide 24-bit audio and my PS4 Pro can provide 24-bit DTS bitstream, it seems best to have it set to 24 bit input (to accept 16-24 bit inputs) and upscale everything to 24 bit (when needed) before outputting to 568.2mm set to 24 bit input. Or is this an incorrect understanding of the manual?

The different dither curves seem interesting but read on a different HH forum that people seemed to prefer “Flat” setting. What are people’s experiences with the different dither options? And with using “Gain’ setting instead of “Emphasis” setting? Emphasis seems to be the recommended setting for most media types.

Also, the last two settings in Config menu aren’t disused in manual: (1) DA Y/N (currently set to Y as presumably DA means “digital audio”?) and (2) DTSXX (currently set to DTSCD).

Have confirmed that current configuration does pass/enhance DTS bitstream @ 48khz.

Firmware is version 1.22 but might have a lead on an upgraded ROM chip (presuming it is worth the effort to upgrade to 1.25?).

Thank heaps!

Aside from the ability to add some gain, I really don't feel that the 518 will bring much to the table when connected to the 568.2mm. Louder is not better. The 568.2mm is a very capable DAC and processor.

If the 518 is set to 24P24, 16-bit (or any) input will not be enhanced to 24-bit, it will just pass straight through, other settings like Gain etc. will still have an effect.
It may be worth setting up separate sources (some call them phantom) for the different files and switch to suit.


Emphasis will change the frequency response, similar to a RIAA curve on vinyl, dolby NR on cassettes, in effect boosting the number of bits for high frequencies. But it should only be used with DACs that can de-emphasise (preferably in the analogue stage) and I don't think Meridian processors do.
Gain is useful for upping low output signals, optical out on a TV is a normally a good candidate, most are 8dB down.
Both emphasis and gain can cause clipping of the digital signal.

Info I had in my notes from years ago:
If you have a Meridian 518 Digital Processor, this will de-jitter a DTS signal for optimum sound quality.

However the resolution enhancement features of the 518 are not appropriate as DTS is a compressed digital stream, not standard digital audio. Hence your 518 should be switched to Bypass mode prior to listening to a DTS CD or LaserDisc.

There is an upgrade to the 518 software, Version 1.2, which allows it to detect a DTS stream. In this case, the 518 automatically selects Bypass when DTS is detected.

Version 1.2 adds four DTS modes to the 518 which can be assigned to sources in Config. The modes are:

· DTSMU – 518 mutes on receipt of DTS (used when 518 is a preamp).
· DTSCD – detects DTS with a normal strategy and selects Bypass.
· DTSLD – detects DTS with a rapid strategy and selects Bypass.
· DTSMA – mastering processor mode ignores DTS.

These can be selected according to Type as follows:

· Type 0 – all sources DTSMU
· Type 1 – all sources DTSCD except DVD and LD which are DTSLD
· Type 2 – all sources DTSMA

I thought 1.22 was the final version?

All the best,

Steve

Thanks for this insightful information. Just re-read this section of manual and it does indeed seem that I misinterpreted what it was saying. The vast majority of my digital audio collection is 16/44.1 CD rips in FLAC so will leave 518 set on 16P24.


Very insightful too. Will do some research to see if 568.2 de-emphasizes incoming digital audio. If not then I’ll switch to Gain mode. Read on an older thread that +6dB seems to be preferred over +5 or +8dB as, for some reason, +6bB is the most conducive to processing. Will experiment with this today, but being that my source is a computer perhaps no additional Gain is needed?


Thanks heaps for this info. Makes sense as when I select DTS source the display shows “DTS” instead of gain number. Thinking I’ll not run my DTS source through 518 as there doesn’t seem to be any advantage to doing so (eg, will just go directly into 568.2mm via Toslink).


You are indeed correct. I had misremembered and thought 1.25 was the latest. Very glad to know that this used unit already has the latest firmware version.


There seems to be mixed opinions about the 518 adding any benefit if placed before 568.2mm processor, which, apparently, applies Shape C noise shaping to all incoming digital sources anyhow (quote from older HH forum thread):


In light of this, perhaps if another noise shaping curve is applied by 518 then this could synergistically interact with the Shape C applied by the 568? Perhaps this is why 568 users tend to report the best sound when setting 518 to Flat because 568 is subsequently applying Shape C and, thus, if some noise shaping other than Flat is used by 518 it simply doesn’t jive?

In addition to the potential noise shaping synergy, it is my understanding that the 518 and 568.2mm employ twin PLL and FIFO de-jittering methods, respectively. If this is indeed the case then perhaps de-jittering digital sources with twin PLL (518) before subsequent FIFO de-jittering (568.2mm) also results in a synergy that yields even less jitter than would be achieved by the 568.2mm alone (i.e., “sounds better”)?

Will continue to experiment with different 518 setting (before 568.2mm) to see if any of them result in audible improvements. Current setup offers relatively easy switching of output from 3 way Toslink switcher between 518 and 568.2mm so will also experiment with listening to: (1) source > 518 > 568.2mm and (2) source > 568.2mm.

Thanks again for the insightful replies, very helpful indeed!

FYI, in the UK I use +12db gain on my 518 for the optical input from my pioneer TV using a 218 as a pre amp for my DSP5200 SE speakers…

You could set up a phantom source for the 24 bit files you have, so allocating another one of the 12 inputs to the physical input the computer is using

I'm pretty sure it doesn't, de-emphasis in the digital domain negates the benefits, the gains come in reducing the HF in the analogue stage of the DAC, which reduces any HF noise by the same amount.
I seem to recall that when I used a 518 with a 568, switching emphasis in would make the sound bright; this could seem like an improvement, but in reality it's the same as turning up the treble...

It's because +6dB is equivalent to moving up the whole PCM data by a whole bit, so in theory the maths is very simple, but the 518 has 72-bit processing, so 1dB increases will be transparent.
I'm still guilty of setting the volume on my G68 in 3dB steps; volume of 66 is okay, 65 isn't, so my start up volume is set to 66, not the default 65. I'm probably not the only one who does this!

From above "If you have a Meridian 518 Digital Processor, this will de-jitter a DTS signal for optimum sound quality", so may be worth it, especially over optical.

All the best,

Steve