Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems Help: External DAC's and Digital Bypass

Hi,

Has anyone here used an external DAC such as the Benchmark DAC, Lavry DA 10 or any other DAC to bypass Meridian's internal DAC's, specifically 568.2?

I have a Lavry DA10 D-A converter, which was not used in my hi-fi system prior to the purchase of the 568.2MM, I was wondering if I could integrate the DA10 with the Meridian?

From what I've read is that unless you enable the speakers for DSP, the l/R main digital outs are disabled, as well as encrypted?

I noticed the 568.2MM has a digital bypass and was wondering what is the exact function of this? I have scoured the forums but couldn't really get a definitive answer.

Is the purpose of the bypass to bypass internal DAC's? If from w hat I have read about the someone using an 861 and used the bypass into 568, can this be used to feed to output of the bypass in the Lavry DA-10, whic hare then fed into amplifiers? What channels are actually passed through the Digital Bypass and where is this configured? Or have I got the definition of the bypass completely wrong and serves a different purpose?

What I am hoping to achieve is to bypass the 568's front L/R main dacs and instead pass the signal into the Lavry.

The Lavry DA10 has XLR and SPDIF and optical and coax digital input and balanced analogue outputs. I have cables to convert from XLR to RCA and the Lavry is able to internally convert the blanaced XLR into unbalanced.

I'm also thinking that if the Lavry DA10 is not a workable solution that I will instead use it with the computer for video/audio editing

I'm still new here but would appreciate your help on this matter.

Thanks for you help on advance.:)

Cheers
Mark.

Hi Mark,

I think (but haven't checked), that the bypass outputs are for things like 'tape', headphone amps with DACs or for feeding your main output to another room in your house. They carry your main source, pretty much unaltered.

I think that you can enable the DSP speaker option, and as long as you don't select MHR, it should be standard SPDIF.

The problem you have in both cases is a lack of volume control, though. To maintain SNR, modern Meridian kit doesn't output the volume reduced values over the digital outputs. If you were to plug in DSPs, they would handle volume (in a hybrid analogue/digital fashion). They would receive full scale values over digital.

The only item I can think of that you can plug straight into a DAC is a 518. I believe that there are undocumented (or at least rarely used) modes of the 562 that support it too.

I did use an external DAC for a while (not as good as yours, mind) with a 518, but I found that when I switched to Meridian, the built in DACs were phenomenal. That was a 568.2 as well (although I'm now on a G68).

I guess if you were very keen on using it, you could plug bypass (or the front DSP outputs for multi channel) into it, then send the output to a pre-amp and switch that in for pure stereo. If you were really brave, you could plug a Meridian pre-amp in after the DAC and set it to follow the main system volume. That would 'fully integrate' your DAC. The downside is that you have a longer analogue chain, which may offset any potential gains in your DAC. You may also have volume tracking problems if there are any slight differences in the 1/2db steps with the 568.2 and 501.

I would have grave concerns about your DAC introducing latency or phase effects which might kill the psycho-acoustic cleverness in many of the Meridian DSP modes. Not due to any design faults in the DAC necessarily. It would have been designed for stereo systems. So any latency (such as that produced by a FIFO buffer if it's a really good design) would not matter in stereo, but could cause lots of integration problems in multi-channel.

In summary; if you desperately want to do it, yes you can. Probably.

Cheers,

Mark.

So a search for posts by GARYG

Mark

Manually 'type' the 568.2 to 7.1 AAA and the L/R digital outputs will be active and volume controlled. You may experience 'clicking' on the Lavry when the DSP mode changes during the trailers on a DVD in which case try setting the 'level' for the L/R channels below zero, eg. -3 (Ronomy is the best person to give you advice on that).

Regards
Gary

Keep in mind that there are some issues with this that get complicated.

Like how do you plan to control volume, the digital levels are fixed at all the digital ouputs. In the DSP speakers they apply a hybrid digital/analog volume control, controlled by the COMMs.

There is a trick some 861 owners did where it will apply a digital volume on the DSP outputs but it gets tricky to setup. But some believe doing digital volume reduces the quality of the signal.

Also in some cases you'll be limited to 24/48 and with digital attenuation it may be 18-22 bits.

George

On the 568.2, when manually 'typing' to 7.1 AAA from the front panel the level of the digital outputs are variable, just like the analogue outputs.


Regards
Gary

I mentioned that. Wasn't sure if it worked on 568 or not. But someone else had tried that on an 861 and had one heck of time keeping it working. You can't use MConfig or it will snap back. Not using MConfig cripples things in my opinion.

And again using digital attenuation isn't a great idea. You'll be compromising so many things to get it to work then the ever so minor difference in the DAC will be hard to attain.

I've tried manually setting the 568 to 7.1 AAA, in my case 2.0 A as my system is still in pieces and only using main L/R for the moment.

The problem is that soon as I manually type set to 2.0 A, the DVD source switches to multichannel from D2 and therefore get no signal. Also, the speakers are switched to Analogue from Large DSP.

When I connect my DAC to the main L/R digital output, the Lavry will only decipher the output sugnal when the speakers are set to Large/Small DSP. The DAC will not work when the speakers are set to Analogue or 96.24 DSP modes.

Is there a workaround for this?

Another thing, when I play a CD or DVD, the Lavry detect the source at the constant 44.1khz. When I check the Meridian DVD is present in Msconfig, the Lavry picks up signals from 88Khz down to 44.1 depending on whether CD or DVD is in use. Even though I do not have a Meridian DVD, does enabling or disabling the Meridian DVD check box, changes things, processing wise?

Any suggestions would me much appreciated.

Thanks and cheers
Pasadena.

Mark

As per George's post, you can't use a computer (MConfig) to configure the 568.2 and have volume controlled digital output. If you want to use your external DAC the only configuration available to you is from the front panel and you must use the AAA typing. It's been a few years since I went through the options so I can't remember what settings work but for me 7.1AAA and 5.1AAA worked fine with DVD, maybe 2.0 doesn't work. Your options are limited, but if you have a good enough external DAC it's still worth doing. Earlier this week I sold my external DAC and have gone back to using the 568.2 internal DACs on the L/R channels and am still coming to terms with the drop in quality.

Regards
Gary

Hi Gary,

Thanks for the feedback.

I manually set the front panel of the 568.2 to 2.0 A and even tried the other settings, 7.1 AAA and got the same result. As I've only just received my 568 so I'm still learning how to use the front panel controls.

The only way I could get the Meridian to work again was to use the msconfig from the PC. No sooner I used the front panel controls, the overides settings would not work for me.

I'll have to peruse through these forums and other hi-fi forums about all this and work on it again and see if I've missed anything.

As you said, being such a good DAC, it's worth the pain and hassle of trying to get it going as even you know what the advantages and quality it brings to the front channels. It would be a shame if I couldn't use the DAC but even so, the internal DAC's of the 568.2 are still exceptional. Ate least it's WAAAAAY better than what I had before so I can't complain to start of with.

Get back soon with some more updates.

Cheers
Mark.

Hi Guys,

I've said this before about the 568.2. The power supply is linear and it has no line filtering. That's good! If it is powered by the same AC lines with a component that has a switching power supply the analog outputs tend to sound hard and more like digital on the 568.2. That's bad! The 568.2 has a small transformer with taps that run to each board. Small regulators supply DC to the circuits. The 568.2 with a power regenerator like from PS audio is magical with the 568.2. The 568.2 needs to be on it's own power source to sound its best. I'm getting incredible smooth sound with a deep and large soundfield. The walls and speakers disappear. Without clean power I cringe. It is that much of a difference. I've owned Wadia DAC's in the past and I don't miss it.

Ron

Mark

When you set the 'type' from the front panel you are effectively resetting the system so if you've set 'AAA' the digital outputs should be active. From memory I think the default setting is to enable upsampling so change the H/S out flag to 'N' and try setting the DA 10 to wide. So if you just set the 'type' to 'AAA' and set the H/S flag to 'N' and not do anything else you should have active digital outputs.


Ron

Are you using a Squeezebox?

Regards
Gary