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Three separate problems found in DA-FP boards!!! 6 years 5 months ago #25004

  • planetti
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Thank you, guys, for your investigation efforts.

It is not very satifying to hear that a solution of the radio noise is not apparent till now. :dry:

My experience with the three OpenDRC versions: wherein the analogue models suffer from the lately discussed tweeting "radio noise", an additional backround "working noise tone" from the miniSHARC section (which depends on the activation of the FIR section and/or and the number/amplitude of the 14 IIR parameters), and the AN additionally from a typical gentle analogue hiss/ white noise floor, the DA additionally from the polarity inversion. Any further ideas to technically reduce these noises apart from optimising the gain structure and the plastic screws?

A possible workaround for these problems seems to be choosing the DI version in combination with separate external DACs since the DI is free of these effects, or to use the AN or DA versions only for very low frequency tone applications wherein the noises are less noticeable. ;)
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Three separate problems found in DA-FP boards!!! 6 years 5 months ago #25014

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"or to use the AN or DA versions only for very low frequency tone applications wherein the noises are less noticeable. ;)"

Thats' what I did for my sub... B) But I realize that this a not a viable option if you want your filtering to extend further then 200 Hz.


Geoff, In addition to what Richard wrote: have a look at this:

www.neutrik.com/en/lighting/accessories/...e-adapters/na2m-j-tx

Neutrik offer various models for a transformer interface. I always use Neutrik for my interface adapters because they're reliable and rugged.

Just my 2 cents,

Xcel
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Three separate problems found in DA-FP boards!!! 6 years 5 months ago #25018

  • Richard
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Yes, those Neutrik adapters seem quite suitable, although that one's going from unbalanced jack input to male XLR output. Whereas Geoff wanted female XLR input to unbalanced RCA output. Fortunately Neutrik do offer those alternate versions, even with red or black colour coded sockets so you could buy a stereo pair to avoid confusion.
XLR in to unbalanced RCA out...
www.neutrik.com/en/lighting/accessories/...adapters/na2f-d0b-tx

XLR in to unbalanced jack out...
www.neutrik.com/en/lighting/accessories/...e-adapters/na2f-j-tx

Trouble is, you still can't switch the Neutrik's earth lift on or off - it's fixed by design. I prefer something that gives me the choice, for flexibility, and I just like the combination DI box style with XLR, jack and RCA for all inputs and outputs all in one product. Shame nobody makes that with an earth lift.
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Three separate problems found in DA-FP boards!!! 6 years 4 months ago #25738

  • Richard
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Any news recently on the polarity inversion fix via firmware update? Is that still in the works?
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Three separate problems found in DA-FP boards!!! 5 years 7 months ago #30506

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Any news recently on the polarity inversion fix via firmware update? Is that still in the works?


I've recently ordered a DA-FP board so would like to know this as well.
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Three separate problems found in DA-FP boards!!! 5 years 7 months ago #30512

  • Richard
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The replacement DA-FP boards they sent me still had the same output polarity inversion fault.
I've heard nothing more about them updating the firmware and it's been well over a year...
I think they'd likely say you can just change your polarity in the software plug-in, if absolute polarity bothers you!
I think given the whole purpose of FIR correction to correct amplitude / phase errors, getting loudspeakers and crossovers to measure sensibly, then having correct in-phase output definitely should be important to anyone who buys a product like this.
It seems like this unfortunate manufacturing hardware fault should be an easy thing to just fix with a firmware update.
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Three separate problems found in DA-FP boards!!! 5 years 7 months ago #30513

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That assumes there is a "correct in-phase output" in all cases. Program material varies and many polarity reversals take place in the recording chain long before the music arrives on your computer or CD Player or whatever. The result would probably be 50/50 one way or the other if you sampled all your music and noted which "way" sounds better.

FIR correction for amplitude and phase errors is completely irrelevant to this absolute polarity issue. The two aspects are unrelated.

Yes, a polarity reversal in this case is something that should have been addressed just for consistency purposes, but it's an extremely minor issue....IMO.

Dave.

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Three separate problems found in DA-FP boards!!! 5 years 7 months ago #30514

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The replacement DA-FP boards they sent me still had the same output polarity inversion fault.


How long ago was that?

Wondering if my recent order will come fro a different / corrected batch.

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Three separate problems found in DA-FP boards!!! 5 years 7 months ago #30568

  • Richard
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Hi watchnerd,

>"How long ago was that?"

Wel, let me see......
Tue 3 November 2015 - I ordered three OpenDRC-DA machines, plus three DIGI-FP boards (so I could choose either output options)

Mon 9 November 2015 - They were delivered from Hong Kong and arrived here in UK a week later.

Fri 20 November 2015 - After running many test signals, I gradually realised I had some faults, including common hardware polarity fault, and reported it in long detailed posts with some of my photos / screenshots which began this forum thread.. #22255

Approx a week later - DevTeam had acknowledged the polarity fault, and the other fault and agreed to ship me two new DA-FP boards. They also promised to issue a firmware update to fix the acknowledged DA-FP polarity fault.

Mon 14 Dec 2015 - Received two new replacement DA-FP boards delivered from Hong Kong. I tested them, etc. These work fine, except again, for the known common polarity fault, which means they are essentially identical behaviour to the one good non-faulty DA-FP board I already had kept from Nov. Now at least I own three matching, working DA-FP boards which all have the same inverted polarity output compared to digital input polarity, but I can just compensate for that by remembering to engage the "invert" button in the software plug-in. Therefore desired performance can be achieved.

NB. I actually posted earlier in this thread #22759 back in Dec 2015 to mention all that, and thank DevTeam for sending those new boards.

Today, Mon 13 Feb 2017 - Yes, myself and others would hope to see MiniDSP issue the promised firmware update to fix the polarity fault, but we're still waiting...

If you do buy some DA-FP boards, you could test them, using an asymmetrical waveform spike signal or something.
I'd be interested to know if they've now fixed polarity by redesigning the hardware wiring, but I doubt it, as the DA-FP is still in continuous production for both the OpenDRC and the newer Dirac series models. Anyway a firmware update would be much easier than hardware modifications, and they don't want to recall existing products sold either. The Dirac series use the same boards so, on paper, it affects them too, but their automatic correction algorithms would presumably include any polarity inversion as part of the measured error in the system, and thus correct for it in the FIR filter they generate.

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Three separate problems found in DA-FP boards!!! 5 years 7 months ago #30569

  • Richard
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That assumes there is a "correct in-phase output" in all cases. Program material varies and many polarity reversals take place in the recording chain long before the music arrives on your computer or CD Player or whatever. The result would probably be 50/50 one way or the other if you sampled all your music and noted which "way" sounds better.
Dave.


Read my earlier post carefully, where I explained my test methods, with a digitally generated spike waveform.
The DIGITAL INPUT WAVEFORM should be the same polarity as the ANALOG OUTPUT WAVEFORM and it isn't with the DA-FP board.
That is the fault!!!
DA-FP board inverts the polarity because pins 3 and 2 of the XLR plug are wired back to front.!
Correct wiring should be pin 1 = earth / pin 2 = hot / pin 3 = cold.
I don't care if you're reproducing pink noise, or hiss, or silence, or any music from Abba to ZZ Top... Doesn't matter if you can hear it or you can't hear it in your musical application, a basic wiring fault is a basic wiring fault, and wrong polarity is especially annoying in a "phase correction" FIR processor type device, always under the scrutiny of careful loudspeaker measurments and FFT analysers.

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Three separate problems found in DA-FP boards!!! 5 years 7 months ago #30570

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Richard,

I'm well aware of how to test it and what the correct polarity of an XLR jack is.

This is an absolute polarity issue only and is not related to FIR processing or any other type of processing. It would only be an issue (in a relative situation) if part of your music chain was transitioning on another path with an opposite polarity. It's unlikely your system configuration would be set up like that and the DA-FP board would most likely be your only source.

It's not unusual to find other commercial audio gear that has an internal polarity reversal. It's usually an oversight, but it's not the end of the world. As long as you are aware of it, it's a very simple matter to address.

Get a grip please.

Dave.

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Three separate problems found in DA-FP boards!!! 5 years 7 months ago #30620

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Dear All,

Mmmh, we're getting old I guess as we're forgetting things.. :-)
Somehow, we did miss to share that minidsp.bin file which is the firmware file to invert the polarity. Sorry about this.. :-(

See attached rename to minidsp.bin for the OpenDRC-2x2. Close the plugin first.
a) Go to your plugin folder: \Program Files (x86)\miniDSP\OpenDRC-2x2\add
b) rename existing minidsp.bin to minidsp_old.bin (for future if you guys keep toggling files)
c) Put the minidsp.bin in the attached zip.

File Attachment:

File Name: minidsp_Op..._inv.zip
File Size:12 KB

d) rename that file to minidsp.bin
e) Connect and restore to default.

Should do the trick. :-)

Keep us updated if any questions..

DevTeam
miniDSP, building a DSP community one board at a time.
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Three separate problems found in DA-FP boards!!! 5 years 7 months ago #30628

  • Richard
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Thanks DevTeam,

Is this new firmware only for use with OpenDRC machines that have DA-FP board installed (where polarity error exists)?

ie. Does that mean we need to switch back to the original firmware if using OpenDRC machine with DIGI-FP board installed? (ie. Because DIGI-FP board maintains consistent polarity input > output and doesn't have any fault.)

Or does the new firmware automatically detect which type of I/O board is connected to the OpenDRC machine it's installed into?

I don't own the AN-FP board, so I've never tested to know if that maintains its polarity or not.

Richard

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