AD DSP21489 with PCM1804 ADC and PCM1798 DAC 4x6, under $100

[mga2009]

Hi,

I was looking for a DSP in Aliexpress and stumbled upon this DSP.

It seems it is based on the newer AD chipsets, with 4 inputs and 6 outputs with some good quality ADC and DAC.

Also, the price is almost USD$100 which is quite cheap compared to MINIDSP products.

So, what do you think? I would like to know your opinion regarding capabilities and ease of use with this DSP. I assume I can use my USBi to configure it?

The vendor sent me the software that comes with the DSP and it seems it is Sigmastudio. I am still checking it.

I would use this for active XO.

Cheers

 

[ernperkins]

That certainly looks like a lot of HW for $100! If I read their listing correctly you can either use their GUI (miniDSP like) or use SigmaStudio to program directly via the USBi interface. Keep us posted!

 

[mga2009]

That certainly looks like a lot of HW for $100! If I read their listing correctly you can either use their GUI (miniDSP like) or use SigmaStudio to program directly via the USBi interface. Keep us posted!

Thanks for your reply. I checked some of the files they sent me and tried the software, which it seems quite complete. Also, it seems that it is possible to switch to "Sigma Studio Mode" and also go back to the "Factory Software".

I leave some pictures of the software.

I requested more information on the specs, like output and input sensitivity, SNR, balanced or single ended, etc.

The board comes with 2 ADC boards (4 channels) and 3 DAC boards (6 channels) but it have space for another DAC board for a total of 8 channel output.

 

[mga2009]

UPDATE:

I forgot to mention that I could NOT find any way to input FIR filters on the factory APP. With this kind of processing power it is really a shame. You probably need to switch to Sigma Studio to integrate them.

Also, there is no way for phase shift the signal.

 

[ernperkins]

I'm not sure what you mean by "phase shift the signal", but you typically use a delay to change the phase relationship between drivers (e.g. to account for acoustic offset differences between drivers).

 

[KaffiMann]

Perhaps mga2009 wants to phase flip the signal to reduce potential for "pumping" on the power amp.
Any more specs on that DSP than what it says in the link?
Looks like value for money.

 

[mga2009]

I'm not sure what you mean by "phase shift the signal", but you typically use a delay to change the phase relationship between drivers (e.g. to account for acoustic offset differences between drivers).

You are correct, but I thought sometimes DSP came with a more simple phase shift option, like the controls that generally comes with a powered subwoofer, to use when you dont have the proper measuring instruments.

In this case, only delay is available, and no possibility to implement FIR filters unless you switch to SIGMA STUDIO-compatible firmware. Also, the extra DAC board cost around USD$20 so you have a 4x8 last gen DSP for around USD$120, almost as twice as the ADAU1452 and trice as the ADAU1701.

 

[mga2009]

Perhaps mga2009 wants to phase flip the signal to reduce potential for "pumping" on the power amp.
Any more specs on that DSP than what it says in the link?
Looks like value for money.

I am asking for more detailed specs on the implementation of the DSP but they haven't responded. I am mostly interested in the input and output sensitivity, to see what kind of amp it can drive.

 

[KaffiMann]

A bit hard to see on the pictures, but wondering if it could be they're using MC33078 op amps.
More concerned about the input boards, PCM1804 is not "bad" but they might be the weakest link here. Would rather have digital in. Seeing as the design is modular, and they do mention SPDIF and I2S, perhaps it would be possible to use this for DI?
Lusya SPDIF coaxial fiber AK4113 receiver board I2S output for DAC board 32~192KHZ G10 007|Amplifier| | - AliExpress

 

[mga2009]

A bit hard to see on the pictures, but wondering if it could be they're using MC33078 op amps.
More concerned about the input boards, PCM1804 is not "bad" but they might be the weakest link here. Would rather have digital in. Seeing as the design is modular, and they do mention SPDIF and I2S, perhaps it would be possible to use this for DI?
Lusya SPDIF coaxial fiber AK4113 receiver board I2S output for DAC board 32~192KHZ G10 007|Amplifier| | - AliExpress

These are the schematics they sent me.

The thing is that my source is analog, in fact its the pre out of my receiver... from there y want to split the signal to go with active XO.

I think that if my source would be digital, specifically PC based, I would just process the audio with EqualizerAPO and rePhase.

 

[KaffiMann]

Yeah, for the inputs the 5532's are a good match for the PCM1804.
Was just looking at the output boards and trying to decipher the bits on there. Wondering if they're using the MC33078 on the outputs.

EqAPO + rePhase, been there done that. Works nice if delay is not a concern, input/output buffers + processing makes a bigger impact than I can live with. And I've tried stripping the delay down pretty good, it's not for me. DSP geared towards PA can be pretty good, just have to read the fine print before deciding.