Sabaj A30a announced

[Roland68]

Hello, this is my first post on this forum. Some days ago I buyed a second-hand A30a from Germany and I would share my experience. My English is poor, so please be patient...
Sonically speaking, my expectations on this little jewel are certainly satisfied: detail, naturalness, transients speed, bass control, low listening fatigue are its qualities. I prefer it to my actual dac Smsl D6s + self-assembled pair of Icepower 300as1 mono power amps.
However, there is one big drawback: the Sabaj would seem incompatible with my favorite speakers, a pair of Braun Ls120 which I upgraded replacing all the electrolythic caps with jantzen poly caps. Connecting this '90th german speakers to the A30a, It happens what the forum member Nahkarankaisija complained a few pages back: loud white noise constantly even on 0 volume and on every input (and the tweeter fuses burn). BUT in my case this happens only when connected to the Ls120's: with all of mine other speakers (Kef Ls50, Kef CS3, Grundig box 550) the Sabaj works fine! On the other hand,the Ls120's play loud and clear with all of my other power amps!
I just tried the firmware update and the reset procedure suggested by Roland68 (thanks).
I point out that the tweeters' polarity (as in the original crossover scheme) is inverted, but I think it doesn't matter. But it's also true that (sometimes, not every time) if I remove the Ls120 tweeter fuses, the A30a starts to play again.
After so many attempts I'm going crazy... any idea? Thank You.

Did you also change the coils?

 

[voodooless]

From a quick glance I would say that possibly C4 may be the issue, it may short the amp at higher frequencies. Would be good to model the crossover to see what it exactly does.

Yeah, just checked out the impedance, at 100 kHz the impedance is 2 Ohm, at 1 Mhz the impedance is almost zero:

Never mind the frequency response, I just used some random chassis to test this.

So, at the switching frequency of the amp, basically, the speaker shorts the amp! No wonder it causes issues. You may just want to remove C4 first to see if that fixes the issue. If so, probably another configuration can be found to get the same effect.

 

[Antbom]

Did you also change the coils?

No i didn't, in order to
mantain the original resistance values

 

[Antbom]

Yeah, just checked out the impedance, at 100 kHz the impedance is 2 Ohm, at 1 Mhz the impedance is almost zero:
View attachment 424595
Never mind the frequency response, I just used some random chassis to test this.

So, at the switching frequency of the amp, basically, the speaker shorts the amp! No wonder it causes issues. You may just want to remove C4 first to see if that fixes the issue. If so, probably another configuration can be found to get the same effect.

Please do you know what is the purpose of this cap C4? Could a simple (let's say) 50khz R-C low-pass filter help to solve the problem?

 

[GiBo61]

Hello, this is my first post on this forum. Some days ago I buyed a second-hand A30a from Germany and I would share my experience. My English is poor, so please be patient...
Sonically speaking, my expectations on this little jewel are certainly satisfied: detail, naturalness, transients speed, bass control, low listening fatigue are its qualities. I prefer it to my actual dac Smsl D6s + self-assembled pair of Icepower 300as1 mono power amps.
However, there is one big drawback: the Sabaj would seem incompatible with my favorite speakers, a pair of Braun Ls120 which I upgraded replacing all the electrolythic caps with jantzen poly caps. Connecting this '90th german speakers to the A30a, It happens what the forum member Nahkarankaisija complained a few pages back: loud white noise constantly even on 0 volume and on every input (and the tweeter fuses burn). BUT in my case this happens only when connected to the Ls120's: with all of mine other speakers (Kef Ls50, Kef CS3, Grundig box 550) the Sabaj works fine! On the other hand,the Ls120's play loud and clear with all of my other power amps!
I just tried the firmware update and the reset procedure suggested by Roland68 (thanks).
I point out that the tweeters' polarity (as in the original crossover scheme) is inverted, but I think it doesn't matter. But it's also true that (sometimes, not every time) if I remove the Ls120 tweeter fuses, the A30a starts to play again.
After so many attempts I'm going crazy... any idea? Thank You.

Apparently something similar happens with the Marantz M1 full-digital amplifier, also based on the Axign's post filter feedback loop technology.

 

[voodooless]

Please do you know what is the purpose of this cap C4? Could a simple (let's say) 50khz R-C low-pass filter help to solve the problem?

It's designed to tilt down the tweeter response a bit. Without it, it should sound a bit brighter. The amp has tone controls, so you could try simply turning down the highs a bit to compensate. Or just not toe the speakers in.

 

[Antbom]

It's designed to tilt down the tweeter response a bit. Without it, it should sound a bit brighter. The amp has tone controls, so you could try simply turning down the highs a bit to compensate. Or just not toe the speakers in.

Thank You, I'll try.

 

[syzygy]

Someone should point this out to Nahkarankaisija - I think Voodooless has identified the root cause of that white noise problem with the 2 or 3 units he'd tested?
This is very useful to know the interaction between a (or at least this) Class D amp and a pure capacitive load that some speaker crossovers can present...

​

 

[voodooless]

Someone should point this out to Nahkarankaisija

That’s easy: @Nahkarankaisija, see several posts up for a probable root cause for your noise issues.

- I think Voodooless has identified the root cause of that white noise problem with the 2 or 3 units he'd tested?

I didn’t test anything, just simulated the crossover that caused the problem and found the likely cause of the issue.

 

[syzygy]

That’s easy: @Nahkarankaisija, see several posts up for a probable root cause for your noise issues.

I didn’t test anything, just simulated the crossover that caused the problem and found the likely cause of the issue.

(I meant the 2 or 3 A30a amps that I thought I remembered Nahkarankaisija had tried & returned? - I could be wrong, I haven't reviewed)

 

[Antbom]

Thank You, I'll try.

It's designed to tilt down the tweeter response a bit. Without it, it should sound a bit brighter. The amp has tone controls, so you could try simply turning down the highs a bit to compensate. Or just not toe the speakers in.

Ok, I removed the 1uF cap in parallel with the tweeter and the problem is solved!
I turned down the tweeter -2db and the results is similar to the original (female voices are a bit too much... airy).
I wonder if mantaining the parallel cap (maybe slightly increasing its value) followed by a resistor (4-8 ohm?) might be a better solution.

 

[ErkyPerky]

Is the latest firmware V1.12, just to confirm? As this is showing in the reset menu.

Also I want to add a wiim streamer, so the options are the pro or pro plus. Is the pro plus overkill or is the pro sufficient just to use as a transport connected via digital coaxial to the A30a?

 

[Roland68]

Is the latest firmware V1.12, just to confirm? As this is showing in the reset menu.

Also I want to add a wiim streamer, so the options are the pro or pro plus. Is the pro plus overkill or is the pro sufficient just to use as a transport connected via digital coaxial to the A30a?

Wiim Pro and Pro Plus are the same devices, except for the DAC and ADC. The DAC is irrelevant for the A30a, the better ADC can be interesting if you want to connect one or two devices with an analog output in your setup.
There is no difference for the digital output in relation to the A30a.
There are two things you should also consider: the resale value is a little better for the Pro Plus and if you want to buy a remote control for the Pro, the price difference will also be a little smaller.

1.2 is the current firmware version.

With a new device, I would reset it once and then go through all the menus and configure it.
Be sure to check the subwoofer setting (SUB CUTOFF) and set it to SUB OFF if you don't have a subwoofer connected.

Which Mission speakers do you have?

 

[ErkyPerky]

So basically the pro would be enough for me as I don't need a remote nor would I use the dac inside the pro plus. Should I connect it via RCA or coaxial to the A30a?

I haven't reset the amplifier, but I should do that actually. Also I'm guessing I need to update the firmware

The mission speakers I have are the QX-4 MKII.

 

[GiBo61]

So basically the pro would be enough for me as I don't need a remote nor would I use the dac inside the pro plus. Should I connect it via RCA or coaxial to the A30a?

I haven't reset the amplifier, but I should do that actually. Also I'm guessing I need to update the firmware

The mission speakers I have are the QX-4 MKII.

Honestly, for a few dollars more I would definetly opt for the Wiim Pro Plus, it has a much better DAC than the Pro. It is true that the DAC is not needed when you connect the streamer to the Sabaj A30 using either the coaxial or optical cable (not the RCA!) but in the future, if you decide to use it with a "traditional" amplifier, the good performance of the Pro Plus' internal DAC may come in handy. In addition, as mentioned before, also the Analog-to-Digital Conversion is of better quality in the Pro Plus. If you plan to use a subwoofer with your Mission speakers I recommend you to consider the Wiim Ultra streamer which has a very flexible and complete bass management. It is true that the Sabaj A30a allows you to manage the connection with an external Active subwoofer but the low pass filter cannot be set below 70 Hz, an important limitation if you have floorstanding speakers like your Mission. In my setup I currently have a Sabaj A30a and a Wiim Ultra streamer and I'm extremely satisfied with them (I also have a Wiim Pro Plus that is now connected to a "conventional" class A/B amplifier).

 

[Roland68]

So basically the pro would be enough for me as I don't need a remote nor would I use the dac inside the pro plus. Should I connect it via RCA or coaxial to the A30a?

I haven't reset the amplifier, but I should do that actually. Also I'm guessing I need to update the firmware

The mission speakers I have are the QX-4 MKII.

I already wrote that V1.12 is the current firmware, which is also on the Sabaj website. Since these have been around for a long time, your device probably came with them. But you can flash the firmware again.
You should stay away from other firmwares, as they were for specific problems and nobody knows what was changed in them. According to my information, this did not solve the respective problems.

 

[ErkyPerky]

Honestly, for a few dollars more I would definetly opt for the Wiim Pro Plus, it has a much better DAC than the Pro. It is true that the DAC is not needed when you connect the streamer to the Sabaj A30 using either the coaxial or optical cable (not the RCA!) but in the future, if you decide to use it with a "traditional" amplifier, the good performance of the Pro Plus' internal DAC may come in handy. In addition, as mentioned before, also the Analog-to-Digital Conversion is of better quality in the Pro Plus. If you plan to use a subwoofer with your Mission speakers I recommend you to consider the Wiim Ultra streamer which has a very flexible and complete bass management. It is true that the Sabaj A30a allows you to manage the connection with an external Active subwoofer but the low pass filter cannot be set below 70 Hz, an important limitation if you have floorstanding speakers like your Mission. In my setup I currently have a Sabaj A30a and a Wiim Ultra streamer and I'm extremely satisfied with them (I also have a Wiim Pro Plus that is now connected to a "conventional" class A/B amplifier).

Yes I might just go for the pro plus. Also I'm still learning with all this frequency crossover high pass low pass etc etc. So basically if the A30a's limit is 70hz does that mean my main speakers woofers won't produce anything lower than 70hz? Sorry bit of a noob here.

 

[Maciekw]

Honestly, for a few dollars more I would definetly opt for the Wiim Pro Plus, it has a much better DAC than the Pro. It is true that the DAC is not needed when you connect the streamer to the Sabaj A30 using either the coaxial or optical cable (not the RCA!) but in the future, if you decide to use it with a "traditional" amplifier, the good performance of the Pro Plus' internal DAC may come in handy. In addition, as mentioned before, also the Analog-to-Digital Conversion is of better quality in the Pro Plus. If you plan to use a subwoofer with your Mission speakers I recommend you to consider the Wiim Ultra streamer which has a very flexible and complete bass management. It is true that the Sabaj A30a allows you to manage the connection with an external Active subwoofer but the low pass filter cannot be set below 70 Hz, an important limitation if you have floorstanding speakers like your Mission. In my setup I currently have a Sabaj A30a and a Wiim Ultra streamer and I'm extremely satisfied with them (I also have a Wiim Pro Plus that is now connected to a "conventional" class A/B amplifier).

I have a slightly different opinion on this issue. Once I had to decide on something myself. And it is not worth overpaying since I will be inputting the signal to Sabaj exclusively via Coax SPDiF. The analog input has Sabaj poor compared to the performance of digital inputs. So why pay for an additional and unnecessary better DAC, when the transport is the same in Wiim Pro and Wiim pro plus.

As for using the Wiim with another amplifier, since you've decided on the Sabaj, you're unlikely to swap it for another amplifier in two or three months. And in a dozen months or in a few years, there may already be other options to consider. Because by then, the Wiim Pro Plus may already be a relic. Anyway, buying a good DAC better than the internal DAC from Wiim is not a big expense.

As for the Wiim ultra and the possible use of a subwoofer, it is better to connect the subwoofer to Saba and is set to a fixed gain on this amplifier. You will adjust the gain in the Wiim Pro.

Well, but this is just my opinion.

 

[GiBo61]

Yes I might just go for the pro plus. Also I'm still learning with all this frequency crossover high pass low pass etc etc. So basically if the A30a's limit is 70hz does that mean my main speakers woofers won't produce anything lower than 70hz? Sorry bit of a noob here.

Exactly, your main speakers' woofers won't produce anything lower than 70 Hz.
It's perfectly fine for bookshelf speakers (I set a cutoff of either 70 or 80 Hz for my Elac Vela BS 403), it may be too high for floorstanding ones (for my Elac Carina FS 247.4 the ideal cutoff is around 45 Hz, in this case I can only get it through the Wiim Ultra, not directely from the Sabaj A30a).

 

[suur13]

Exactly, your main speakers' woofers won't produce anything lower than 70 Hz.

"Anything" is maybe too strong word here. 70Hz is "cut-off" point, which is actually only -3db from nominal. It rolls of from there (either 12db octave or 24db octave). For example I have Naim Unitiqute, which has similar built-in high-pass filter at 100Hz ! And there is still noticeable signal at 60...70Hz then. So I would only assume your towers would produce output at ~50Hz with 70Hz crossover. Rolloff.