Sabaj A30a announced

[Doodski]

The STA309A has DSP functionality, but of course something could also come in via the SRC Bridge CT7302SL.

I have replaced many dozens of DSP ICs that made similar noise. A can of freeze spray aimed at the offending IC might indicate more.

 

[voodooless]

The STA309A has DSP functionality, but of course something could also come in via the SRC Bridge CT7302SL.

This functionality cannot be used since it would change the signal to amplify, therefore working against the feedback loop of the Axign (which is also a big DSP machine).

 

[Roland68]

This functionality cannot be used since it would change the signal to amplify, therefore working against the feedback loop of the Axign (which is also a big DSP machine).

The Axign chip has no DSP functionality, just look at the data sheet.
The DSP functionality on the A30A is taken over by the STA309A, which you can also see in the menu of the A30a.
In front of the Axign AX5689 chip you can do whatever you want, as long as the AX5689 is fed with a suitable digital audio signal.

 

[voodooless]

The Axign chip has no DSP functionality, just look at the data sheet.

Of course, it does.

See the "sound processing". It has some limited possibilities for doing custom DSP sound processing inside of the chip. Nevermind that the rest is also digital signal processing, ergo "DSP"

The DSP functionality on the A30A is taken over by the STA309A, which you can also see in the menu of the A30a.

So, what does the menu say?

In front of the Axign AX5689 chip you can do whatever you want, as long as the AX5689 is fed with a suitable digital audio signal.

I think I'm confused here:

The STA is in front of the Axign and performs DSP functions. I assumed it would be the PWM power driver behind the Axign, which is another STA chip. I'm actually convinced that all of the audio processing could have been done on the Axign chip alone. It was just way more work to implement that.

 

[Roland68]

Of course, it does.
View attachment 361513
See the "sound processing". It has some limited possibilities for doing custom DSP sound processing inside of the chip. Nevermind that the rest is also digital signal processing, ergo "DSP"

This area is for internal processing/filtering/adjustment only. It has absolutely nothing to do with what we commonly refer to as "DSP" here.
If you look closely, the Axign AX5689 is of course an extremely specialized DSP chip with a PWM output, 8 ADCs, digital input and digital output.

So, what does the menu say?

The menu reproduces 1:1 the tables from the data sheet for all sound settings and sub. This is more than just a coincidence.

I think I'm confused here:

The STA is in front of the Axign and performs DSP functions. I assumed it would be the PWM power driver behind the Axign, which is another STA chip. I'm actually convinced that all of the audio processing could have been done on the Axign chip alone. It was just way more work to implement that.

Sorry to say it like that, but that is absolutely wrong.
You noticed it and changed something in your text.
However, it seems that Sabaj and SMSL also did not understand the concept of the Axign AX5689.
The Axign AX5689 is a closed system that only has 4 relevant transfer points. Digital input, digital output, PWM output and ADC input.
The use of a DSP in front of the AX5689 was specifically planned by Axign and thought through to the end. 2-4 of the ADCs can be used to feed in analog signals and output them digitally to the external DSP, so that externally supplied analog signals can be processed in exactly the same way as digital ones.
Axign did a really great job and if Sabaj and SMSL had understood the concept behind it, then there wouldn't be a mediocre PCM1804 implanted in the two devices.

And just as a note, how should the AX5689 know or notice that a DSP chip is working in front of it?
How was this chip supposed to recognize whether the digital audio data of the piece of music came directly from the studio or was changed with a DSP?

 

[Toku]

No, only speaker cables with banana plugs, no speaker switches or anything like that. I have now returned to my previous setup of Naim amp and SMSL DAC and everything works as it should.

I believe there is a problem with the A30a that I received from your report. Please return it and receive a new A30a.
In fact, I had the experience of returning the A30a I purchased due to an assembly problem during manufacturing, and the STA516BE in the power amplifier section overheating and shutting down.

 

[Nahkarankaisija]

I have recorded a short video about the constant noise with my Sabaj A30a, will send it to Hifi-Express while waiting for their response. Please use the Google Drive link to view the video, please lower your volume since the white noise is about 80 db so you dont blast your ears.

I also tried the reset procedure by @Roland68 with no effect, I think I will skip the firmware reflash so I don't mess anything up that Hifi-Express could use as an excuse against returning it, I do believe the problem goes deeper than simple software.

Volume Warning:

Sabaj A30a faulty.mp4

drive.google.com

 

[Toku]

I have recorded a short video about the constant noise with my Sabaj A30a, will send it to Hifi-Express while waiting for their response. Please use the Google Drive link to view the video, please lower your volume since the white noise is about 80 db so you dont blast your ears.

I also tried the reset procedure by @Roland68 with no effect, I think I will skip the firmware reflash so I don't mess anything up that Hifi-Express could use as an excuse against returning it, I do believe the problem goes deeper than simple software.

Volume Warning:

Sabaj A30a faulty.mp4

drive.google.com

I determine that the A30a you received has a serious problem. You should immediately request a return or exchange. Video footage is conclusive evidence.

 

[Roland68]

I have recorded a short video about the constant noise with my Sabaj A30a, will send it to Hifi-Express while waiting for their response. Please use the Google Drive link to view the video, please lower your volume since the white noise is about 80 db so you dont blast your ears.

I also tried the reset procedure by @Roland68 with no effect, I think I will skip the firmware reflash so I don't mess anything up that Hifi-Express could use as an excuse against returning it, I do believe the problem goes deeper than simple software.

Volume Warning:

Sabaj A30a faulty.mp4

drive.google.com

OK, that's really intense, I wasn't expecting that. I would also assume a hardware defect.
Let them send you a new one and don't worry too much.

 

[GiBo61]

I have recorded a short video about the constant noise with my Sabaj A30a, will send it to Hifi-Express while waiting for their response. Please use the Google Drive link to view the video, please lower your volume since the white noise is about 80 db so you dont blast your ears.

I also tried the reset procedure by @Roland68 with no effect, I think I will skip the firmware reflash so I don't mess anything up that Hifi-Express could use as an excuse against returning it, I do believe the problem goes deeper than simple software.

Volume Warning:

Sabaj A30a faulty.mp4

drive.google.com

Well, pretty impressive. I'm sure Hifi-Express will excange the defective amp with no further questions if they do not want to lose customers (likely more than 50% of them read the ASR forums...).

 

[GiBo61]

That's clearly abnormal.

Is there anything connected to the speaker terminals other than the cable from the speaker? A speaker switch cannot be connected.
Are the negative terminals connected to each other at some point in the speaker wiring?

I must say that I've always used my Sabaj A30a connected to the amp/speaker switch depicted below (SOLUPEAK P2). I initally used the switch to connect 2 amps to the same pair of speakers. After few months the almost 20 years old Rotel amp died (It already had problems before) so I started to use the switch to connect 2 pair of speakers to the Sabaj. IMPORTANT: when the two power amplifiers are connected to the switch, the ground is independent and is not shared (as stated by the manufacturer and confirmed by some users). R/L channel also have no shared ground, the ground and positive are switched separately（different from other products have a common ground). I'm no expert but I know that this feature is important also for other types of Class D amplifiers.

 

[Toku]

In recent PWM class D amplifiers, voltage is applied to the + and - speaker terminals depending on the circuit connection method. If you use a speaker switcher with the - terminal commonly connected to such an amplifier, the amplifier may malfunction or generate noise. Be sure to use a speaker switch that switches both + and -. Also, a similar problem will occur if the negative terminals of the speaker terminals of conventional analog amplifiers are connected in common.

 

[GiBo61]

Other adjustments under what input are the test results obtained: for example, BASS volume EQ BASS signal frequency

I just tested that everything is normal from 35 to 45 when the subwoofer volume gradually increased and did not decrease
I tested the adjustment when Bluetooth/coaxial /AUX input, EQ is OFF BASS volume is -15db bass signal frequency is 70 BASS signal frequency is 0

I tried to change different conditions but this state did not happen.

Thank you @peterwen for your contribution on this issue as a spokesperson (I guess) for Sabaj.
Did you make any instrumental measurements or did you simply evaluate the behavior of the subwoofer output by ear?

Tkx

 

[peterwen]

Received my Sabaj A30a yesterday and now I finally hooked it up and was immediately disappointed, loud white noise constantly even on 0 volume and on every input, tried usb, bluetooth and OPT, noise only stops when I press mute. Firmware 1.12, any tips what might be causing it?

Edit: I have tried another power cable and using an external DAC with RCA, no difference, the loud noise is constant even without any input cables connected, have messaged Hifi-Express for advice. The amp seems to work otherwise fine, powers on normally and all the menus work and so on.

SABAJ_A30a MCU_FW 221126(1).zip

drive.google.com

please try this new firmware and this can solve your problem

 

[Nahkarankaisija]

SABAJ_A30a MCU_FW 221126(1).zip

drive.google.com

please try this new firmware and this can solve your problem

I am trying to update the firmware but I can't get the amp to connect to PC during upgrade mode, I have done everything correctly but the update program keeps saying "disconnected". When the amp is on normal operation it is recognized by the PC as Sabaj USB DAC so everything should work correctly, I am using the latest 5.68 XMOS drivers.

Edit: Tried with 5.5 XMOS drivers, no help. Still stuck on "Disconnect". Handshake does nothing.

 

[Toku]

I am trying to update the firmware but I can't get the amp to connect to PC during upgrade mode, I have done everything correctly but the update program keeps saying "disconnected". When the amp is on normal operation it is recognized by the PC as Sabaj USB DAC so everything should work correctly, I am using the latest 5.68 XMOS drivers.

Edit: Tried with 5.5 XMOS drivers, no help. Still stuck on "Disconnect". Handshake does nothing.
View attachment 362003

The A30a MCU FW update procedure is a little difficult to understand, so please refer to what I explained previously.
However, the FW version is explained in SABAJ_A30a MCU_FW 220928.zip at that time.

Sabaj A30a announced

Thank you for providing the information about the difference in sound quality. But what I want to know is how the internal processing of the D30a works. The digital input of the AXIGN AX5689 chip supports 44.1~192kHz 32bit, but it is unknown what kind of signal is actually input. The resampling...

www.audiosciencereview.com

 

[Nahkarankaisija]

The A30a MCU FW update procedure is a little difficult to understand, so please refer to what I explained previously.
However, the FW version is explained in SABAJ_A30a MCU_FW 220928.zip at that time.

Sabaj A30a announced

Thank you for providing the information about the difference in sound quality. But what I want to know is how the internal processing of the D30a works. The digital input of the AXIGN AX5689 chip supports 44.1~192kHz 32bit, but it is unknown what kind of signal is actually input. The resampling...

www.audiosciencereview.com

I have tried your instructions to the letter with no success, when the amp is in upgrade mode Device manager does not recognize it's USB driver, maybe this could be the culprit? I am on Windows 11 but that should not matter.

 

[Toku]

There is an unknown device displayed on USB in Device Manager, but is the display the same even if I disconnect the A30a's USB cable?
Windows should be able to recognize the A30a without installing the driver XMOS_USBAudio_v5.68.0_2024-02-13_setup normally provided by Sabaj. Therefore, I suspect that the cause is either a problem with the PC system or a problem with the A30a's USB port.
Based on the noise in your video image, I suspect that the DSP-related IC chip on the A30a side is malfunctioning. Those chips also do USB communication.

Can the PC recognize other USB-connected devices?

 

[Nahkarankaisija]

There is an unknown device displayed on USB in Device Manager, but is the display the same even if I disconnect the A30a's USB cable?
Windows should be able to recognize the A30a without installing the driver XMOS_USBAudio_v5.68.0_2024-02-13_setup normally provided by Sabaj. Therefore, I suspect that the cause is either a problem with the PC system or a problem with the A30a's USB port.
Based on the noise in your video image, I suspect that the DSP-related IC chip on the A30a side is malfunctioning. Those chips also do USB communication.

Can the PC recognize other USB-connected devices?

Yes, all other USB devices are recognized normally, when I connect the amp without powering on I also get that error message. With the USB cable disconnected the error goes away.

Here is a picture with the amp powered on and connected via USB so you can see everything is working normally.

Edit: I have tried the supplied USB cable and another USB cable, both cables recognized in Windows but not in upgrade mode.

 

[Toku]

eh! Under normal operation, the A30a is normally recognized by the PC, but when I start the FW update tool and start the update operation, it is no longer recognized when I connect the A30a's USB cable to the PC, right?
eh! , why? 　I'm getting more and more confused. I'm seriously thinking about it now!