Sabaj A30a announced

[Toku]

I do not use the USB input. Can you better explain what you mean when you say "noise mixes into the SW output when using USB input"?

It is a symptom that noise is mixed in the subwoofer output when the input of the A30a is switched to USB.
The noise sounds like white noise or digital noise, and it feels quite loud.
When the USB cable is pulled out, the noise level changes greatly, but it does not disappear.
I inserted a USB isolator into the USB cable, but there was no change. No noise at all with OPT and COAX input.
The SW output signal is created by the A30a's DSP, converted to DA, and output to analog.
So I think there is some problem in the firmware of the DSP processing during USB input.
I've reported this to Sabaj, but they don't seem very keen on improving it.

 

[ModDIY]

It is a symptom that noise is mixed in the subwoofer output when the input of the A30a is switched to USB.
The noise sounds like white noise or digital noise, and it feels quite loud.
When the USB cable is pulled out, the noise level changes greatly, but it does not disappear.
I inserted a USB isolator into the USB cable, but there was no change. No noise at all with OPT and COAX input.
The SW output signal is created by the A30a's DSP, converted to DA, and output to analog.
So I think there is some problem in the firmware of the DSP processing during USB input.
I've reported this to Sabaj, but they don't seem very keen on improving it.

Me too, I don't use USB, before yes, now I use Wiim Pro as a source with the optical input, and of course the sub output of the A30a.

I thought the "white" noise or other issue had been fixed.

I am very disappointed to hear this.

I own 2 Sabaj amps, the A20a 2019 and the A30a, I am very happy with their sound, and have recently recommended other Sabaj models to friends.

For me it's over with Sabaj, I will not be able to recommend or buy their products. Finally Sabaj are very disappointing and they lack respect for their customers.

 

[Toku]

Me too, I don't use USB, before yes, now I use Wiim Pro as a source with the optical input, and of course the sub output of the A30a.

I thought the "white" noise or other issue had been fixed.

I am very disappointed to hear this.

I own 2 Sabaj amps, the A20a 2019 and the A30a, I am very happy with their sound, and have recently recommended other Sabaj models to friends.

For me it's over with Sabaj, I will not be able to recommend or buy their products. Finally Sabaj are very disappointing and they lack respect for their customers.

Reading your message reassured me that the noise on the SW output is not just my A30a. Sabaj's customer service was very good in the beginning but not so good these days. Still, if you compare it with SMSL, the correspondence is good.
I think the A30a is a very good product, but there are still some details that need to be improved. I think Sabaj should try to improve their product more. I think that will lead to the future development of the company.

 

[ModDIY]

Toku I think I expressed myself badly, I used USB with other devices, ie external DACs with PC and or PI4.

But I never used USB with the A30a. As I explained, with the toslink input, there is no noise on the SUB output.

 

[titilandus]

In my opinion, Sabaj A30a sounds best with a usb input.

 

[EmilW]

Hi everyone,
Its been 42 very insightful and interesting pages to read. I pulled the trigger after the first 10 pages, and so 32 pages later, now I have had my Sabaj a30a for about a week. It came with the 1.12 firmware from hi-fi Express with a transit time of about 2 weeks. I have been out of the hi-fi game for a few years, coming from Elac FS247BE with an old Pioneer lx75 (everything now sold) and now creating a small table top style studio listening home office environment running a pair of Wharfedale Evo 4.1 with the Sabaj and looking to add a subwoofer.

I was out looking at subwoofers yesterday, and wanted to test if the issues reported here was a deal breaker for me - and it for sure does not work well with a sub as reported by many of you. The subwoofer signal does not scale correctly with the speaker volume, the frequency cut don’t go low enough to blend the sub proper, and the lack of providing full range to the speakers while running a subwoofer signal, is really annoying.

For the sound quality, i still have a lot of testing to do, and the comparison i ended up making yesterday at the local hi-fi dealer, was not fair by any stretch. Compared to the Cayin 170i, on the Martin Logan floor standers (none electrostatics closer to the center), with the AMT tweeters, sounded harsh, lean and fatiging in comparison to the Cayin (again, sorry to compare 450 to 7000 usd amps, but all i had) - hence why i need to test more. But it was one of those moments, where i really felt like the difference was not just 2-5%, but it completely changed the listening experience. Maybe the combination had a lot to do with it, i don’t know. What do you guys think? Is the amp sensitive to different speaker designs in how it performs?
Have you compared it to High end tube amplifiers like the Cayin and found similar differences? I run Flat Sound profile with no tone control added. Comparison test done with both coax and line in from highend streamer using Tidal connect.

If we don’t get a firmware that handles the subwoofer issues mentioned by many, i might need to sell or send my unit back. Any news from anyone in direct contact with Sabaj?

Again, thank you everyone for an interesting read and journey so far.

 

[voodooless]

If you compare a not very linear amp with a linear one and find the linear amp is harsh, then blame the speakers, not the amp. The Cayin only has a 54 SINAD The only thing high-end about it, is the marketing.

 

[GiBo61]

I guess that those who like the sound tube amps will never like class D amplifiers, no matter how much they cost. I'll just add that in my Sabaj A30a setup I can't tell that the subwoofer output volume is not linear with that of the main speakers.

 

[EmilW]

I have never owned anything with tubes, and it came as a surprice to me in this setting actually. It felt more right in a way. Not like the speaker had flaws it fixed, but i can’t say that it isen’t the case.

54 SINAD i’m not sure what means, but i guess you suggest distortion is an issue with the amplifier i mentioned? I’m sorry if this is yet another hand on the head moment for you.

The linearity of the subwoofer output was a big issue when i tested here. Higher relative to speaker at low volume, lower relative to speaker output at higher volumes.
I tried to connect and drive the electrostates with the Sabaj also, but it did not work for some reason. Maybe the semi active nature of those speaker with the active bass is similar to issues of using FDA with highinput on subwoofers?

Thanks for your answers.

 

[robbbie]

Regarding sub-out volume issue - I've recently purchased UMIK-1 mic and have made a few basic measurements - including sub volume. I'm a total newbie to acoustic measurements so take it all with a grain of salt but still - it looks like confirmation of what many here reported.

Normally my sub is placed in a corner of my room and is connected with wireless transmitter but to remove one variable i moved the sub inbetween the main speakers and connected it to sabaj with rca cable.

To measure volume i used pink noise - octave 125Hz - which should not be affected strongly by room modes.

The results are as follows:

Additional observation - if I keep sabaj volume at level at whitch I performed level matching and then only use volume control in PC then the subwoofer output is just right down to the quietest levels. It can be a workaround for this issue but for me it's a bit of annoyance.

If there won't be any update addressing this issue I will probably sell a30a (to someone using 2.0 configuration).

 

[voodooless]

That almost looks like loudness compensation.

 

[EmilW]

Regarding sub-out volume issue - I've recently purchased UMIK-1 mic and have made a few basic measurements - including sub volume. I'm a total newbie to acoustic measurements so take it all with a grain of salt but still - it looks like confirmation of what many here reported.

Normally my sub is placed in a corner of my room and is connected with wireless transmitter but to remove one variable i moved the sub inbetween the main speakers and connected it to sabaj with rca cable.

View attachment 276847

To measure volume i used pink noise - octave 125Hz - which should not be affected strongly by room modes.

The results are as follows:View attachment 276845

Additional observation - if I keep sabaj volume at level at whitch I performed level matching and then only use volume control in PC then the subwoofer output is just right down to the quietest levels. It can be a workaround for this issue but for me it's a bit of annoyance.

If there won't be any update addressing this issue I will probably sell a30a (to someone using 2.0 configuration).

Amazing work! Thank you so much. If the y axis scale is right and somewhat relative representative, then it looks like a several dB difference, and as we know, every +-3dB is equal to double or half the output.
Again, Thank you so much for your time, im so om board with you, if they don’t fix this in a firmware, i need to sell, as my initial plan is to use it with book shelves speakers and a sub. It would be a shame to sell due to a subwoofer output not working as intended.

 

[Leo2079]

Hi, I bought the Sabaj A30a on March 27. The first connection with my speakers was great, but I could hear some fizz noise from my speaker. After a few days, I changed the left speaker cable from 3 ft to 10 ft to better arrange everything. After turning the system on, I heard unbearable white noise from the left speaker. I could still play music, but the noise was louder than the music I played. Immediately I thought the left channel output was broken, but everything became fine after I switched the new 10ft cable back to the old 3 ft cable. At that point, I thought it must be the cable issue, so I replaced the 10 ft cable three times. That did not fix anything. Thinking I couldn't be so unlucky and get three broken cables, I bought another cheap amp and finally realized that it was A30a's problem. The fizzing noise was gone no matter how long the cable I used. I wonder if this is because my A30a unit is malfunctioning or because my speaker is too sensitive and the cable I use is too long. I was frustrated because I could handle the fizz sound with a 3 ft cable, but I need to use the 10ft one. I am using the monitor audio studio and have upgraded A30a to the newest firmware.

 

[hiisukun]

I've been testing a Sabaj A30a, and while the sound is good it doesn't present a hardware volume control over its USB interface. This means I can't use it for some multi-room scenarios (such as with Moode or Volumio). Just posting in case someone else is curious, has a solution, or noticed different performance. This is with the firmware "A30a MCU_FW_220928".

Here is a comparison output of `lsusb` for the A30a (no volume), vs the Aiyima T9 Pro (which has USB hardware volume control):

# SABAJ A30a
hiisukun@audio-lounge:~ $ lsusb | grep -i SABAJ
Bus 001 Device 015: ID 152a:85df Thesycon Systemsoftware & Consulting GmbH SABAJ USB AUDIO
hiisukun@audio-lounge:~ $ lsusb -v -d 152a:85df | grep -i volume
Couldnt open device, some information will be missing
hiisukun@audio-lounge:~ $

# Aiyima T9 Pro
hiisukun@audio-study:~ $ lsusb | grep -i audio
Bus 001 Device 003: ID 262a:9123 SAVITECH Corp. USB HIFI Audio
hiisukun@audio-study:~ $ lsusb -v -d 262a:9123 | grep -i volume
Couldnt open device, some information will be missing
          Volume Control (read/write)
          Volume Control (read/write)
hiisukun@audio-study:~ $

 

[peterwen]

Hi, I bought the Sabaj A30a on March 27. The first connection with my speakers was great, but I could hear some fizz noise from my speaker. After a few days, I changed the left speaker cable from 3 ft to 10 ft to better arrange everything. After turning the system on, I heard unbearable white noise from the left speaker. I could still play music, but the noise was louder than the music I played. Immediately I thought the left channel output was broken, but everything became fine after I switched the new 10ft cable back to the old 3 ft cable. At that point, I thought it must be the cable issue, so I replaced the 10 ft cable three times. That did not fix anything. Thinking I couldn't be so unlucky and get three broken cables, I bought another cheap amp and finally realized that it was A30a's problem. The fizzing noise was gone no matter how long the cable I used. I wonder if this is because my A30a unit is malfunctioning or because my speaker is too sensitive and the cable I use is too long. I was frustrated because I could handle the fizz sound with a 3 ft cable, but I need to use the 10ft one. I am using the monitor audio studio and have upgraded A30a to the newest firmware.

This noise may be caused by the grounding problem. You can replace a30a power cord to try.

 

[EmilW]

This noise may be caused by the grounding problem. You can replace a30a power cord to try.

Hi Peter,

Do you plan to release a firmware update to fix the issues reported ?

The following points needs to be fixed:

1. Subwoofer volume and speaker volume is not proportional
2. No options for full range speaker frequency respons when using a subwoofer
3. No option to go lower than 70hz for subwoofer cutout (should go all the way to 30hz)

If above issues are fixed, the usability of the amp will be improved massively for A LOT of people.

Please

 

[Gret_as]

Hi Peter,

Do you plan to release a firmware update to fix the issues reported ?

The following points needs to be fixed:

1. Subwoofer volume and speaker volume is not proportional
2. No options for full range speaker frequency respons when using a subwoofer
3. No option to go lower than 70hz for subwoofer cutout (should go all the way to 30hz)

If above issues are fixed, the usability of the amp will be improved massively for A LOT of people.

Please

And resolving moment with going to defense with mute sound after volume 65.

 

[hiisukun]

Hi Peter,

Do you plan to release a firmware update to fix the issues reported ?

The following points needs to be fixed:

1. Subwoofer volume and speaker volume is not proportional
2. No options for full range speaker frequency respons when using a subwoofer
3. No option to go lower than 70hz for subwoofer cutout (should go all the way to 30hz)

If above issues are fixed, the usability of the amp will be improved massively for A LOT of people.

Please

And presenting a hardware volume control over its USB interface! This should be an easy one, as the XMOS chip already supports it.

Here is a full descriptor, by way of example:

...
     AudioControl Interface Descriptor:
       bLength                18
       bDescriptorType        36
       bDescriptorSubtype      6 (FEATURE_UNIT)
       bUnitID                10
       bSourceID               3
       bmaControls(0)     0x00000003
         Mute Control (read/write)
       bmaControls(1)     0x0000000c
         Volume Control (read/write)
       bmaControls(2)     0x0000000c
         Volume Control (read/write)
       iFeature                0

 

[ModDIY]

And presenting a hardware volume control over its USB interface! This should be an easy one, as the XMOS chip already supports it.

Here is a full descriptor, by way of example:

...
     AudioControl Interface Descriptor:
       bLength                18
       bDescriptorType        36
       bDescriptorSubtype      6 (FEATURE_UNIT)
       bUnitID                10
       bSourceID               3
       bmaControls(0)     0x00000003
         Mute Control (read/write)
       bmaControls(1)     0x0000000c
         Volume Control (read/write)
       bmaControls(2)     0x0000000c
         Volume Control (read/write)
       iFeature                0

We want it with the DSP.

 

[Tonton_ZEeD]

After reading about the SW volume output being non-linear, i made tempoary fix to my audio set-up.

Before this fix, i was listening to my A30A volume control set betwin 20 et 35 but I changed the a30a sub vol constantly, i seat in front of a desk, my speackers are at an armlength of my head, the SW is under the desk near my feet.

The "fix":

1st point: i use the coax input of the a30a.
Signal chain is: PC-usb->topping D10s-coax->A30a
2nd point:
I set the volume on the A30A to 40, sub vol to 0db, that seems to be the balance point according to robbbie's measurements.
3rd point:
I use my pc as a pre-amp for volume control with windows 10 master volume control. Not bit perfect but realible.
4th point:
i set my SW volume pot to my preference.

With a Flirc and an old TV remote, i can control the volume from anywhere in the room.

Thank to Robbbie for his measurements and all of you for being kind. ASR community is great !

Sorry for my bad english.