miniDSP 2x4 HD (DDRC-24) V2 simple measurement and teardown pictures

[wbenjin]

Since Amirm has reviewed miniDSP 2x4HD, there is new V2 version with different DAC/ADC chip (probably due to AKM fire), seems no one has published the measurement data and pictures of internal components, so I make some simple measurements and teardown. I am new to audio measurement field, so feel free to correct me if I was wrong.

First are teardown pictures:

PCB clearly shows 2x4 HD-V2:

Analog Devices "SHARC" ADSP-21489:

XMOS XU216

New codec chip - TI (former Burr-Brown Audio) PCM3168A:

TI LM2941CS LDO:

nichicon capacitor at each input/output:

And measurement data (Using E1DA cosmos ADC grade A, REW V5.30, output level set to -1dB yield best results):

1KHz RTA:

We got 102 SINAD which is better than previous version.

J-test:

Looks clean.

Multitone:

Also not bad, if REW compute correctly it has 19 bits of ENOB.

I only measured USB in/RCA OUT 1, according to the results, I think DDRC-24 is a very good value DAC/DSP, you got Dirac Live full range ($200), UMIK-1 microphone ($80), DSP hardware and most importantly, DAC performance better than majority of low to mid-end amplifier. Although my measurements are simple, in my opinion, DDRC-24 (V2 version) is worth recommended.

 

[AaronJ]

Thanks for taking a look at this! Any evaluation of the ADC?

 

[wbenjin]

Thanks for taking a look at this! Any evaluation of the ADC?

I have no proper way to measure ADC performance, so I left it for someone to done

 

[Sokel]

It would be nice to repeat the tests but with filters engaged as shown in this thread but for the analog performance:

DSP Measurements and Rising Noise Floor

In several threads related to DSP platforms I've seen requests for measurements with filters engaged. I thought it unlikely that implementing filters in a DSP would have measurable effect on noise / distortion other than the obvious change in the fundamental, however @Sokel recently mentioned...

www.audiosciencereview.com

 

[TurtlePaul]

Impressive that the THD+N on the MiniDSP is able to perform 8 dB better than the DAC chip’s (PCM3168A) spec sheet value (102 dB vs. 94 dB). Good implementation by MiniDSP.

Can you run a 90 khz bandwidth test to see if it have the same out of band noise as the AKM implementation?

 

[koustuvk17]

Thanks for the measurements! Is it possible to measure the resampling performance, the original was pretty rough in this regard.

 

[peniku8]

Multitone:
View attachment 338547
Also not bad, if REW compute correctly it has 19 bits of ENOB.

It does not. REW's ENOB takes the ADC's 0dBFSpk as reference, which means this metric is only applicable to ADC measurements.
Your actual measured ENOB for the miniDsp would be around 17,7 bits, if you didn't check the "minimize cest factor" option.

 

[wbenjin]

It does not. REW's ENOB takes the ADC's 0dBFSpk as reference, which means this metric is only applicable to ADC measurements.
Your actual measured ENOB for the miniDsp would be around 17,7 bits, if you didn't check the "minimize cest factor" option.

Thanks for your correction, I will edit the post.

 

[ViperDom]

Thanks for the info wbenjin.

Do we know when the V2 become available?

Is there any way to verify when ordering direct or 3rd-party that you will receive a V2 and not new old stock of the V1?

 

[wbenjin]

Thanks for the info wbenjin.

Do we know when the V2 become available?

Is there any way to verify when ordering direct or 3rd-party that you will receive a V2 and not new old stock of the V1?

I bought my unit on July 2022, so I think if you order directly from miniDSP you will get V2 version.