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TOPIC: New DDRC88D SPDIF/BNC with BM

New DDRC88D SPDIF/BNC with BM 7 months 3 days ago #39300

  • Bronzeohr
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:(
Dear all,
I just have my DDRC88D for 2 days and really have doubts if the unit is defective.
No matter which source and no matter which output DAC (and I have a lot now) also different types...
There are more or less dropouts from simple sound "pops" to complete signal losses.
With crossover as well as with resettet configuration, with different computers...
The function of crossovers and routing and so on seems to be working.
But the unit never produces clear sound.
I never made this experience with the DDRC24 I own.
Can this be due to the BNC to cinch adapters? I have two types here and there is no other way because I am not in professional audio.
Is there anything to do or do I have to return the unit?

Regards, Lars
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New DDRC88D SPDIF/BNC with BM 7 months 1 day ago #39323

  • john.reekie
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:( That sounds like a support ticket -> support.minidsp.com
I am not miniDSP support.

"You must ask the right questions." - Dr. Alfred Lanning's hologram.
-> Have you read the User Manual??
-> Have you drawn and posted a diagram?
-> Have you posted a screenshot?
-> Have you posted your config file?
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New DDRC88D SPDIF/BNC with BM 6 months 4 weeks ago #39365

  • rts100x5
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The first thing Support is going to ask you to recheck is the gain structure in your DLCT ..... After having severe popping noises in my DDRC88 it came down to the unit overheating in my audio rack ..... but subsequent measurements yielded better results - making certain that signals were not being over driven in the Mic Gain / Channel Gain setup process....also keeping ambient noises to an absolute minimum
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New DDRC88D SPDIF/BNC with BM 5 months 3 weeks ago #39907

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Hi all,
if someone is interested in my findings here is my conclusion after approx 40hrs of testing and wiring. Now I´m tired.
I will get refund of my reseller because it doesn`t fit. The reseller says the unit is o.k. after checking it.
The limitations of the unit may be an issue for others too so maybe it`s helpful to read.

What I needed was just 1 digital input, so a DDRC88A was not the choice. Needed to buy masses of converter units for the rest.
Now I have a lot of converters to sell....

General function is nice and easy to use. Do not now why BNC because I could not find devices with BNC, only RCA- If anyone needs BNC to RCA adapters ->you`re welcome.
Support is willing to do It`best.

The unit can be used with native digital input devices. e.g Logitech Squeezebox Touch did well.

But

1) USB on the unit is a diva: no matter how short the cable is I only found one of 3 PC`s working with it and this was not stable.
Switchable Power plug was needed to reset the unit from time to time.

2) The unit doesn`t work with any of the "better" AD converters I could find on the market that have 96/24 or more. All of the converters worked fine directly connected to the Dac`s.
- Swissonic Converter AD 24/192
- QLS-HIFI QA01
- Oehlbach 6076 AD
- Creative 0404 USB (Dropouts)
The only one that worked on input 1&2 was an old 48khz interface, the Miranda ASD-771p which unfortunately required pro (high) input level so it was just for testing.

I didn`t understand why this is the behavior of the unit, maybe the converters do not deliver a constant "Masterclock" signal which is maybe needed.
My conclusion is that this unit is still a unit for professionals like the AES/EBU version because typical needs of home users can`t be met.
Hopefully there will be units that meet the requirements I would call "typical" for home enthusiasts.
SHD comes close but without 3way support ....

I went back to the DDRC-24 I still own.

Regards,
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New DDRC88D SPDIF/BNC with BM 5 months 3 weeks ago #39908

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I wonder if it's really AES3 unbalanced not SPDIF. en.wikipedia.org/wiki/S/PDIF#Hardware_specifications
I am not miniDSP support.

"You must ask the right questions." - Dr. Alfred Lanning's hologram.
-> Have you read the User Manual??
-> Have you drawn and posted a diagram?
-> Have you posted a screenshot?
-> Have you posted your config file?
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New DDRC88D SPDIF/BNC with BM 5 months 3 weeks ago #39909

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I checked with the support that it`s the SPDIF version PCB.
As described all other SPDIF equipment worked well. I could run the unit with some limitations. Just A/D is not possible with consumer converters. ->Too much trouble for a 1000€ unit in my opinion.
Nobody believes that, but the reseller (Audiophonics) as well as Minidsp never checked with such kind of (consumer) equipment I think.
The SPDIF version makes no sense for me because the only advantage to the AES Version is lost.

Regards
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New DDRC88D SPDIF/BNC with BM 5 months 1 week ago #40106

  • Wanderer
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Hello all,
after reading this thread I carefully tested two ADCs with DDRC-88D (w/ BNC connections) and found at least one possible solution to @Bronzeohr's problem.

The first converter I tried was Midiman Flying Calf A/D 20-bit. Everything worked without a hitch at both 44.1 and 48 kHz.

The second converter was M-Audio Flying Cow (24-bit). This time there was no sound, only random clicks in the speakers. Apparently, there was some kind of signal format or level incompatibility between the output of this ADC and the input circuitry of the DDRC . Or the ADC unit malfunctioned (less likely, because it still works fine when connected to a PC sound card and to miniDSP OpenDRC-DI).

As a last resort, I tried putting an Optical <-> Coaxial SPDIF converter between the Flying Cow and the DDRC. Some of these converters can act as signal repeaters (coax in -> coax out). I tested two such repeaters, and with one of them the sound was back; moreover, it worked even when ADC outputs were switched to AES mode. I am not sure if the SPDIF converter actually decoded data from the ADC and re-encoded them into a format compatible with DDRC inputs, or just changed the signal level.

The adapter that worked was one from an Australian store, they still sell it (link). This device can probably help @Bronzeohr and other DDRC-88D users with the same issue. I have no hardware to test its performance at 192 kHz, but can confirm that sampling rates of 44.1, 48, 88.2 and 96 kHz are all preserved on output.

Hopefully this post will be useful to future DDRC-88D owners as well.
Last Edit: 5 months 1 week ago by Wanderer.
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New DDRC88D SPDIF/BNC with BM 5 months 1 week ago #40143

  • devteam
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@Wanderer

Thanks much for this information. We're certainly going to investigate now to see if we can reproduce this issue. Time to source a couple of converters.. Just to confirm the "M-Audio Flying Cow" is the issue. Correct?

DevTeam
MiniDSP, building a DIY DSP community one board at a time.
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New DDRC88D SPDIF/BNC with BM 5 months 1 week ago #40147

  • Wanderer
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devteam wrote:
Just to confirm the "M-Audio Flying Cow" is the issue. Correct?

Correct. It is the revision with the "24 bit" label (older units were 20-bit).

Both ADCs I tested use Crystal CS8402A transmitter chip. I tried to check what chips were inside the opt-coax converters, but in both models the IC designations were erased... Damn those manufacturers.

HTH
Last Edit: 5 months 1 week ago by Wanderer.
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