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DAC failure?

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DAC failure?

Postby RichardT » Fri Jul 31, 2020 9:18 am

I have a Mytek Brooklyn DAC / headphone amp. Last night I was listening to it via phones and the sound was very strange - I would say echoey and phasey. I have checked out what it could be, and it doesn’t appear to be the phones, and it doesn’t appear to be me (I was quite concerned about that).

Before I go to the hassle of sending it to Mytek in Poland and being without it for a few weeks, can anybody let me know if this is a feasible failure mode for a DAC / headphone amp?

Many thanks

R
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Re: DAC failure?

Postby blinddrew » Fri Jul 31, 2020 9:51 am

So you've checked with a different set of headphones, and you've checked with a different you ( ;) ) - have you checked the source? Can you route your DAW output to a different device to check? Do your speakers run the through the Mytek? Is it just DAW stuff or is it all computer sounds?
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Re: DAC failure?

Postby Hugh Robjohns » Fri Jul 31, 2020 9:57 am

RichardT wrote:I have a Mytek Brooklyn DAC / headphone amp. Last night I was listening to it via phones and the sound was very strange - I would say echoey and phasey.

That description could easily fit the experience of listening to the 'stereo difference' signal (L-R) which is a monitoring option on the Mytek Brooklyn DAC if I remember correctly.

( I have reviewed the DAC+ and Liberty converters: )
https://www.soundonsound.com/reviews/mytek-brooklyn-dac
https://www.soundonsound.com/reviews/mytek-liberty-dac

So, I would start by doing a power cycle, counting to at least 30 between turning off and on again, just to make sure it hasn't got confused following a mains glitch or somethign.

Next, go through all the menu options and make sure they are all set to sensible things.

Then I would check the analogue line outputs (both balanced and unbalanced) to see if they exhibit the same problem as the headphone outputs -- thereby checking whether it's just a headphone amp problem, or something related to the core of the DAC system itself.

Next, I would try the analogue inputs to check the front-end and analogue signal paths, bypassing the D-A converter section completely.

I'd also try different digital input sources and connections to check the digital receiver circuitry.

And finally, I'd try different sample rates to see if the DAC is working normally...

That lot ought to give you a much clearer idea of what section of the unit is not working correctly...

But my money is on a mis-set menu option...

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Re: DAC failure?

Postby RichardT » Fri Jul 31, 2020 10:22 am

Thanks Hugh and Drew,

yes, it's time for some systematic checking. Thanks for the guidance.

My first thought last night was that the DAC was in mastering mode and set to mid/sides or L-R, so I checked that and all seemed to be well.
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Re: DAC failure?

Postby RichardT » Fri Jul 31, 2020 3:56 pm

Results so far

- running exactly the same setup (computer, DAW / iTunes, usb port, usb cable, and phones) through a different DAC sounds OK

- resetting the unit to factory defaults, re-flashing the latest firmware and turning off for >30 seconds made no difference

- the same problem occurs through the balanced (XLR) outputs.

- running audio into the line inputs sounds OK.

- Running Mac diagnostics on the computer shows up no hardware problems.

- The same problem occurs whichever USD output I use on the computer

So the main output circuitry is working OK.

Unfortunately I don't have another digital source to try - at least, not without buying a thunderbolt / USB adaptor for my iPad.

Do you think what I have done effectively rules out a computer fault? Is it possible that a) both USB outputs on the computer would have the same problem at the same time and b) another DAC would work fine with these problematic USB outputs while the Brooklyn does not?

If there's any doubt about it, I will investigate the computer option further before I send the unit back to Mytek.

Many thanks

R
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Re: DAC failure?

Postby Hugh Robjohns » Fri Jul 31, 2020 5:13 pm

RichardT wrote: resetting the unit to factory defaults, re-flashing the latest firmware and turning off for >30 seconds made no difference

Oh dear! That's a shame.

- running audio into the line inputs sounds OK.

Good... so the headphone amp and analogue paths (and your headphones) are all working correctly.

I'm not clear on whether the analogue inputs are converted to digital for processing or not... I assume not

It's looking like either a problem with the digital receiver section, or the digital processing, or the DAC itself.

Unfortunately I don't have another digital source to try - at least, not without buying a thunderbolt / USB adaptor for my iPad.

Your computer may have an SPDIF output, as might your TV or video etc (optical, probably) etc. I'm sure you can find a digital source somewhere...

Do you think what I have done effectively rules out a computer fault?

Yes, It's not likely to be a computer problem if a different DAC works correctly.

It does sound very much like a problem with the Mytek.

Testing with a different digital source might reveal whether it's a problem with the input selection/handling, or the DAC/processing software, but either way it's going to need some specialist attention.
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Re: DAC failure?

Postby RichardT » Fri Jul 31, 2020 5:20 pm

Thanks Hugh.
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