The craziest DAC ever #9038AP with distortions analyzer onboard.

[IVX]

It was last year, I've got an idea to add to a DAC THD analyzer working on the same principle as APx555(analog notch filter +DSP and some "photoshop" to turn notched FFT plot to a normal view). The very first proto I made was on a mono PCB, and had unsolvable current loops problem(probably 6 and more layers would help). The second one I made the same like AP analyzers does 30 years i.e. mother PCB and small modules, daughter PCBs on it. That approach instantly eliminates current loops issues, in the result, inexpensive single ES9038Q2M shows SNR/Dynamic range -126/126db(A-weighted, actually, so far I've got -125.6db but I hope to tweak it up), and distortions level -130-135db + cleanest noise floor like a baby's tear!
Now a little about the analyzer. A normal analog notch filter for 1kHz should contain highly precise resistors and capacitors and at least two potentiometers to adjust F and Q as during production and calibration during exploitation as well. I moved a bit more parameters from analog to the digital domain to avoid such adjustment at all, and it works, hence, I can offer soon $100/pcs range PCB assembly 150x50mm with:
USB-C1 input 32/384 DSD256
USB-C2 for the power only
ES9038Q2M single or dual configuration(one or two DAC daughter PCBs use), ES9038Pro version also possible
XLRs balanced output 4VRMS
3.5mm jack unbalanced output 3.4VRMS, 300mA current, ready for >500mW@16ohm headphones, 330mW@32ohm
just in case 3.5mm jack has optical SPDIF in as well
Bluetooth Low Energy interface to control the analyzer, DSP, and ES9038Q2M registers by iOS/Android app. The app will allow you to see 20 harmonics(1kHz..20kHz) and adjust 2nd and 3rd harmonics levels and see that online at any particular load. If you like, you may minimize distortions for your few favorites cans and save it as presets. Or you can maximize 2nd harmonic up to .3% if you believe it makes tube-sound and so on. In other words, you have your own "AP analyzer" to see distortions up to -130db level, you don't need to visit that site anymore to see the mismatch of specs vs measurements
Also, I keeping the ability to use DSP for the audio as well. I had no such plans but our discord-channel guys asked me to use that option even if DSP has only 24/96 resolution. Almost for free about 100 parametric EQ, compressor itc.

A couple of plots with 1kHz and 12kHz FTT XLR output.

Video shows the DSP analyzer in action(0db corresponds -100db), THD measurement on the fly, and quite good matched with AP analyzer result. Noise floor first, next, no-load distortions, and 32ohm load in the end of the video.

 

[Veri]

Looks very clean :O

 

[rubendub]

Amazing!!

 

[IVX]

Looks very clean :O

and this is a single ES9038Q2M

 

[gvl]

How about a self-calibrating DAC?

 

[BDWoody]

Very cool...
Appreciate your innovative approach.

 

[Max]

Nice project ! I follower this thread

 

[IVX]

gvl, a self-calibration is possible too but to me, the manual approach looks more sexy so far.

 

[Tks]

 

[maxxevv]

While you are at it, was wondering if its possible to make DACs "modular" ?

In that you can add channels to them as needed by "stacking" them and controlling them via a master USB controller.

It has possible applications of multi channel home theater use.

Similarly, it can be the basis of active speaker crossovers that can be adjusted via software.
Like say a 2 way speaker with a 2 channel module each , that are then connected via a "master"module that splits and controls the channels.
A 4 way speaker using 2 x 2 channel modules.

Its just a wild idea but its not something that I have come across on the market. though

 

[IVX]

maxxevv, it is possible too but not really optimal for the audio performances and the main PCB size has to be redundantly long(about feet or more) for 16pcs XLRs when in stereo version only 2 XLRs used. BTW, I made the PCB 150x50mm only to move BLE interface as far as possible from the DACs, without this 100x50mm could be enough.

 

[maxxevv]

Oh, I meant modules that stack either like PCI cards or as boxes that connect up to a "master module".
So the box won't be ridiculously big if you use it as cards nor as add-on box modules.

In any case, its a wild idea. There might not be a viable market size for it anyway.

 

[Max]

Oh, I meant modules that stack either like PCI cards or as boxes that connect up to a "master module".
So the box won't be ridiculously big if you use it as cards nor as add-on box modules.
.

I think it's not the stack of pcb itself but the XLR connectors in the rear panel that take a lot of space.

 

[maxxevv]

I think it's not the stack of pcb itself but the XLR connectors in the rear panel that take a lot of space.

There is the option of mini-XLR.

 

[ZeDestructor]

There is the option of mini-XLR.

Or DB-25/VHDCI/8P8C to XLR breakouts.

A third alternative would be to just have 16 XLR outs per 1U chassis and stack those. For many of us running multichannel setups, racking up gear (storage, HTPC, networking, amplifiers, networking, automation, etc) is the norm and a big 42-45U rack isn't all that expensive if you can find one being decommissioned from an office closeout/downsize or such.

 

[dudiflug]

It was last year, I've got an idea to add to a DAC THD analyzer working on the same principle as APx555(analog notch filter +DSP and some "photoshop" to turn notched FFT plot to a normal view). The very first proto I made was on a mono PCB, and had unsolvable current loops problem(probably 6 and more layers would help). The second one I made the same like AP analyzers does 30 years i.e. mother PCB and small modules, daughter PCBs on it. That approach instantly eliminates current loops issues, in the result, inexpensive single ES9038Q2M shows SNR/Dynamic range -126/126db(A), and distortions level -130-135db + cleanest noise floor like a baby's tear!
Now a little about the analyzer. A normal analog notch filter for 1kHz should contain highly precise resistors and capacitors and at least two potentiometers to adjust F and Q as during production and calibration during exploitation as well. I moved a bit more parameters from analog to the digital domain to avoid such adjustment at all, and it works, hence, I can offer soon $100/pcs range PCB assembly 150x50mm with:
USB-C1 input 32/384 DSD256
USB-C2 for the power only
ES9038Q2M single or dual configuration(one or two DAC daughter PCBs use), ES9038Pro version also possible
XLRs balanced output 4VRMS
3.5mm jack unbalanced output 3.4VRMS, 300mA current, ready for >500mW@16ohm headphones, 330mW@32ohm
just in case 3.5mm jack has optical SPDIF in as well
Bluetooth Low Energy interface to control the analyzer, DSP, and ES9038Q2M registers by iOS/Android app. The app will allow you to see 20 harmonics(1kHz..20kHz) and adjust 2nd and 3rd harmonics levels and see that online at any particular load. If you like, you may minimize distortions for your few favorites cans and save it as presets. Or you can maximize 2nd harmonic up to .3% if you believe it makes tube-sound and so on. In other words, you have your own "AP analyzer" to see distortions up to -130db level, you don't need to visit that site anymore to see the mismatch of specs vs measurements
Also, I keeping the ability to use DSP for the audio as well. I had no such plans but our discord-channel guys asked me to use that option even if DSP has only 24/96 resolution. Almost for free about 100 parametric EQ, compressor itc.

A couple of plots with 1kHz and 12kHz FTT XLR output.
View attachment 67144
View attachment 67145
Video shows the DSP analyzer in action(0db corresponds -100db), THD measurement on the fly, and quite good matched with AP analyzer result. Noise floor first, next, no-load distortions, and 32ohm load in the end of the video.

View attachment 67146

Hi Ivan
When are you going to lunch the DAC and speaker amplifier? I've been waiting a long time ...

 

[IVX]

dudiflug, you know this is all my laziness, DACs so easy to design and produce versus high power-density amps, that I just can't give up. Anyway, when I have time I'll back to HiFiTOY but as I see, most people waiting for my DACs.

 

[dudiflug]

dudiflug, you know this is all my laziness, DACs so easy to design and produce versus high power-density amps, that I just can't give up.

Have an estimated date to launch?

 

[IVX]

no.

 

[somebodyelse]

Or DB-25/VHDCI/8P8C to XLR breakouts.

A third alternative would be to just have 16 XLR outs per 1U chassis and stack those. For many of us running multichannel setups, racking up gear (storage, HTPC, networking, amplifiers, networking, automation, etc) is the norm and a big 42-45U rack isn't all that expensive if you can find one being decommissioned from an office closeout/downsize or such.

Or master clock in/out to keep multiple boards in sync despite having separate USB connections - just stack up as many as you need for your channel count.