Meridian Unplugged - Powered by MrTechGuy.co.uk Forums Discussion Meridian - Systems S/PDIF to DB25 AES/EBU converter

Hi all, I am in the process of installing my new home theater which in the end will be based on some Atmos processor (Trinnov, Lyngdorf or similar) feeding my 271 which will feed my DSP's (8000's, 5200's, 3200's, 320.2's - in the end a 7.0.4 configuration with the 320's in the ceiling. All cabling etc. is in the walls, floor and ceiling, and all hardware except speakers is hidden in another room...
Until I have gotten to a decision on the Atmos controller I will have to use my G68ADV to feed my 271 for a more traditional surround config. Question then is:

Can I just make a SPDIF to DB25 AES/EBU (Tascam config) converter cable to feed the digital output of the G68 to the 271. Since the signal comes from the SPDIF there is only the hot/cold - but no Ground like on a traditional XLR connection.
Do I need to be concerned about differences in impedance - 75 ohm vs. 110 ohm?
Is the missing Ground on the SPDIF a concern?


I will also see if I can share some more info and pictures of the setup, the 320.2's rough boxes has been mounted and cables are almost ready - it will be great to have it finished

/lars

See my post in the Gallery and also see Robert Wistrela's threads in Meridian Streaming. Amazingly, Meridian did not design the 271 to work with their own processors. Perhaps you should try it, but Meridian told me they don't know whether it will work at all, but it might work, they say, if you throttle the output to 48kHz. Robert is trying it but he has not yet said how it is going. You could help us all by trying it! You would perhaps be best feeding your Speakerlink digital (it is balanced) into the Datasat/Storm RJ45 inputs on the 271 as one assumes those are also balanced digital inputs, but exactly what the interface is is not known to me.

In my post in the Gallery you can see what I have done. Until you get your new processor I think you may need to use your G68 analogue outputs into the 271. My solution definitely works (obviously it would as it is just a switch) but I wasn't trying to do what you are planning.

Thanks Nick, good input - will read through it! I am not keen on extra DA/AD, but maybe for a short period.
Do you know if there is risk of damage by making the SPDIF - DB25 wiring, or maybe your suggestion to go for the Datasat input?

My apologies, I didn't realise the G68 doesn't have SL outputs. There are some posts on Meridian Unplugged about converting SPDIF to SpeakerLink / AES using resistors, though I have never tried it. A better way involves the use of impedance transformers (have a look at the Rane website). However, it seems a lot of trouble for a temporary measure until you get your Trinnov. The ADCs in the 271 are of very high quality and I do not think you will be troubled by the sound quality if you simply use analogue in. Of course, if you are (like me) a perfectionist then intellectually you may feel uncomfortable knowing you are not doing things the best way even if you can't hear the difference. But perhaps you can overcome those reservations knowing that your plan is shortly to go fully digital with Storm, Trinnov etc. and use the time saved just relaxing and listening!

Regarding risk of damage as long as you don't connect directly to SL speakers but only via the 271 you should be OK. This warning is because some more recent M speakers have 12V power on the balanced SL signal inputs of the speaker (eg for powering an MS200 from the speaker) which could easily catch out the unwary.

Thanks, Nick - I have decided to go for the analog outputs for the interim period, then I will start evaluating controllers now...

Lars,

I would be very interested in your conclusions about immersive processors with digital output, especially if you are opening your mind to possibilities other than Trinnov. Despite finding my Marantz very good (outstandingly good actually with a great range of facilities) I continue to wonder whether I should go fully digital. Part of that is just the purist in me because the truth is I find that I can't conclude (with 7.1 material) which of the Marantz/271 or the 861 is better. I can detect what seem to be slight differences (the Marantz is a little brighter than the 861) but neither is better than the other for my taste, just slightly different (if I could be bothered, I expect a tweak of treble level would make them the same). I even find one or two of the more modern codecs on the Marantz very satisfying for music compared with Trifield (sorry for the heresy).

Nick

Nick, I will make sure to get back to you on this, for now I am delayed - have not even moved back to my house, concrete in new floors still drying up

As stated earlier I will start out using the analog out on my G68 and then my 818v3 for stereo... what I do next I am not sure.

Have been looking at both Lyngdorf and Trinnov, both looks like good solutions - but in both cases I invest in much more than I will ever use, I don't need the analog multichannel out, I don't need 16 or 32 channels (just 12)?, I don't need HDMI 2.1, I don't need the HDMI switching, I don't need all sorts of input and outputs...all of which adds to the cost...would be good to have a flexible, pure digital processor with limited connections and room correction, maybe something modular - why on earth does M not make this, really bad that the 271 cannot connect to M digital out...

Will keep you updated...
/lars

Lars,
Take your time and many thanks for letting me know. Sounds like there is still much to do if floors are only just being laid!
Nick

Regarding the SL to RJ45 inputs (Datasat), I gave it a whirl and no luck. I could see a data lock, but no sound. There is incompatibility there which I suspect is MHR related.

M told me that reducing the data rate to 48kHz might work. Did you try that? But your current experience is very useful to know. Thanks for posting it.