Sabaj A30a announced

[KL....]

Back to the topic of subwoofer outputs on amplifiers.
In 95 - 98% of all cases, a subwoofer output is only an emergency solution. A digital DSP is much better, with much deeper options for intervening in the signal, e.g. via FIR filters, in order to then output the digital signal to amplifiers such as the A30a, regardless of whether it is for passive or active speakers or subs.

Yes, perhaps or perhaps not, there could/should be two SW outputs, 1/Analogue and 1/Digital, or other. Not possible with the a30a, is it?

 

[Roland68]

Yes, although 20 or 30Hz would be nice to separate music and movies. With full range speakers where for music set at 20 or 30Hz would be nice so that the sub only adds to the speakers and not takes over, where for movies (and some music) 30 or 40 or higher would be nice. All from the remote which is quite nice.

But it is fixed by this small AV DSP chip from ST which suggests that it is not possible....

What you want to achieve with the subwoofers cannot be achieved with a normal subwoofer output on an amplifier.
Subwoofers that can really complement speakers with a crossover frequency of 30 or 40 Hz are large and expensive. At this point it makes sense to control all speakers via DSP.

And the question again, what do you want with full range speakers? These are usually speakers that only have one chassis that covers the entire frequency range.

 

[Roland68]

Ah ok. Can analogue be connected directly to the Power/AX5689 chip for the a30a? If yes, is volume controlled by the AX5689 or the DSP chip behind it? Does the the DSP chip convert everything to DSD then delivers it to the AX5689 chip?

You cannot change or connect anything to the AX5689 chip in the A30a!!!

 

[ppataki]

Has anyone tried running 2 ohm speakers with the A30A?
I have some and plan to give it a try but first I wanted to check if anybody has relevant experience

 

[KL....]

What you want to achieve with the subwoofers cannot be achieved with a normal subwoofer output on an amplifier.
Subwoofers that can really complement speakers with a crossover frequency of 30 or 40 Hz are large and expensive. At this point it makes sense to control all speakers via DSP.

And the question again, what do you want with full range speakers? These are usually speakers that only have one chassis that covers the entire frequency range.

The speakers are a 2.5 way/one chassis/106db. The mid/woofer driver runs full range to about 2K, the Sub runs to 30-170 (usually set at about 140) to blend with the mid/woofer. If the a30a had a full range speaker and SW output then this would work and there would be no issue. Unfortunately when the a30a SW output is used then speaker output is high pass from the selected frequency (70-160). With the a30a, 20-170 would work for this speaker, and 30 or 40-170 might also work, but I do not think that 70-160 will be sufficient.

Wish List.... it would be nice if the a30a also had a full range speaker and SW output option (along with the Sub off option and speaker and SW output 70-160 options). Also, rather than 70-160, 30 or 40-170hz would be nice.

 

[KL....]

You cannot change or connect anything to the AX5689 chip in the A30a!!!

for the a30a, all analogue must be processed through the ADC/PCM1804, ok....

To ask.... it appears that the PCM4202 (I2S output) is compatible with the PCM1804.... is that correct? If yes, would it work and would it have higher performance?
You mentioned the E1DA Cosmos ADC.... is this one compatible with the PCM1804?

 

[Roland68]

for the a30a, all analogue must be processed through the ADC/PCM1804, ok....

To ask.... it appears that the PCM4202 (I2S output) is compatible with the PCM1804.... is that correct? If yes, would it work and would it have higher performance?
You mentioned the E1DA Cosmos ADC.... is this one compatible with the PCM1804?

Please don't be mad at me for telling you this so directly, but if you don't know enough to answer this question yourself, then you should stay away from such DIY modifications.
The circuitry and implementation is always more important than the chip, regardless of whether it is DAC, ADC, OPAmp, etc.
The measurement technology you need to achieve this is more in the 5-digit than 4-digit range.

The E1DA Cosmos ADC is an external ADC that requires modification to output SPDIF. This allows you to use a digital input with an analog device.
However, it is also the perfect device for the analog input of a FIR convolver on PC or MAC basis.

 

[Roland68]

The speakers are a 2.5 way/one chassis/106db. The mid/woofer driver runs full range to about 2K, the Sub runs to 30-170 (usually set at about 140) to blend with the mid/woofer. If the a30a had a full range speaker and SW output then this would work and there would be no issue. Unfortunately when the a30a SW output is used then speaker output is high pass from the selected frequency (70-160). With the a30a, 20-170 would work for this speaker, and 30 or 40-170 might also work, but I do not think that 70-160 will be sufficient.

Wish List.... it would be nice if the a30a also had a full range speaker and SW output option (along with the Sub off option and speaker and SW output 70-160 options). Also, rather than 70-160, 30 or 40-170hz would be nice.

This is the wrong thread for this discussion, because your questions about subwoofers have nothing to do with the A30a, but only with common questions about 2.1 systems.

With the A30a there are only 2 options in relation to the sub out!!!
1. Sub Off, then the entire frequency range goes to the speaker outputs, no output via the sub out!
2. Selectable crossover frequency between 70 Hz and 160 Hz, every 10 Hz, output of the upper frequency range to the speaker outputs, output of the lower frequency range to the sub out.
You have absolutely no option for further settings on the A30a. Regardless of whether you choose 70 Hz, 100 Hz or 160 Hz, the crossover frequency (high-pass/low-pass) is fixed for the speaker and sub and cannot be adjusted individually.
This is due to the fixed wiring in the ST chip and definitely cannot be changed with a firmware update.

This makes the A30a better than most 2.1 amplifiers.
Because these 2.1 amplifiers usually give the main speakers the entire frequency range, and either the full or just the lower frequency range via the sub out (this is exactly what wouldn't be necessary with an active sub, it seems that most amplifier manufacturers with 2.1 and sub out have no idea about the subject). But not relieving the main speakers of the lower frequency range is nonsense in my opinion. But in most cases it seems to work somehow.
That is exactly the reason for my statement that in 95 - 98% of all cases the subwoofer output is only an emergency solution, and above all a bad one. If you look into the topic in more detail, this should become clearer.
The amplifiers that solve the 2.1 issue better are AV amplifiers or 2.1 amplifiers specially developed with DSP, which are often in the 4-digit price range, e.g. Lyngdorf with RoomPerfect.

Everything has already been said about the A30a in connection with subwoofers in this thread, including what I have now written again.
Take another look at the subject of subwoofers and if you have further questions, look for the appropriate thread for it, or open a new one.

For more sensible (digital) solutions, just search for the keywords FIR filter, FIR convolver, MiniDSP, Acourate, active crossovers, etc.
This is one of the interesting threads on the subject.
Multi-Channel, Multi-Amplifier Audio System Using Software Crossover and Multichannel-DAC

 

[KL....]

Please don't be mad at me for telling you this so directly, but if you don't know enough to answer this question yourself, then you should stay away from such DIY modifications.
The circuitry and implementation is always more important than the chip, regardless of whether it is DAC, ADC, OPAmp, etc.
The measurement technology you need to achieve this is more in the 5-digit than 4-digit range.

The E1DA Cosmos ADC is an external ADC that requires modification to output SPDIF. This allows you to use a digital input with an analog device.
However, it is also the perfect device for the analog input of a FIR convolver on PC or MAC basis.

E1DA Cosmos ADC is an external ADC that requires modification to output SPDIF.... ok, FIR Convolver and outputs SPDIF. Do you know of any components with Analogue RCA and XLR input connection that you like and consider very high performing?

For the a30a, is the PCM4202 compatible with the PCM1804? If yes, would it work and would it have higher performance?

 

[Roland68]

E1DA Cosmos ADC is an external ADC that requires modification to output SPDIF.... ok, FIR Convolver and outputs SPDIF. Do you know of any components with Analogue RCA and XLR input connection that you like and consider very high performing?

What kind of devices are you talking about?

For the a30a, is the PCM4202 compatible with the PCM1804? If yes, would it work and would it have higher performance?

"The circuitry and implementation is always more important than the chip, regardless of whether it is DAC, ADC, OPAmp, etc."What was not understandable about my statement?
The data sheets are online, so you can check if it is possible.
I think it is nonsense to make such changes to the A30a. Time spent analyzing the entire circuit, adjusting the circuit, risk of damaging or destroying the A30a, no advantage over an external ADC.
Feel free to try it out and share your experience.

 

[KL....]

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.

I asked many questions because you indicated a mediocre PCM1804 implanted but perhaps and as you are indicating, 'it is more to do with the circuitry and implementation is always more important than the chip'. So, for the a30a, can the current circuitry and implementation, of the PCM1804, be easily improved? If yes, can you clarify/share?

''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.'.... I mistakenly thought that you were refering to the AX5689 (directly) but it would appear that you were refering to the DSP in front of the AX5689.... is that correct? If ok, do you mind clarifying and expanding on this? Such as, for the a30a, can the L/R Analogue signal be fed directly into the DSP in front of the AX5689, rather than going through the PCM1804?

I enjoy discussing aspects like these, but If you would prefer not to discuss, all ok, I will not ask any further....

 

[KL....]

Has anyone tried running 2 ohm speakers with the A30A?
I have some and plan to give it a try but first I wanted to check if anybody has relevant experience

Hi, perhaps ModDIY can help you with this....

I have the Focal Chora 826, 91db (with Sabaj A30a and Wiim Pro) and minimum impedance of 2.9ohms and no load problem, on the contrary the STA516BE output mosfets in pbtl mode (one per channel) is designed to support low impedance.

The musicality is perfect, very wide soundstage and excellent definition.

I configured in 2.1 and I muted the sub out at 70hz on the A30a. My sub doesn't have LFE, so I chose the highest cutoff frequency around 180hz, and the sub volume (not sub level on the A30a) at -3db, don't trust the value because it is a pot with printed indicator.

I tested at different powers and I did not feel a difference in level.

My Focal Chora 826 speakers have an impedance of 8ohm (2.9ohms at its lowest), 91db of efficiency and 250w maximum. I "tried" when listening to electronic music and a lot of bass to push the A30a to a very high level and it was already way too loud for my living room.

I'm going to do some more testing, but I didn't feel what you're describing.

On the other hand with some bad recordings, the tonal balance is not good, always occurs with studio recordings which I consider sloppy and made for radio or budget audio channels.

While on just about all good recordings, it stays balanced at all volumes.

 

[Roland68]

I asked many questions because you indicated a mediocre PCM1804 implanted but perhaps and as you are indicating, 'it is more to do with the circuitry and implementation is always more important than the chip'. So, for the a30a, can the current circuitry and implementation, of the PCM1804, be easily improved? If yes, can you clarify/share?

''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.'.... I mistakenly thought that you were refering to the AX5689 (directly) but it would appear that you were refering to the DSP in front of the AX5689.... is that correct? If ok, do you mind clarifying and expanding on this? Such as, for the a30a, can the L/R Analogue signal be fed directly into the DSP in front of the AX5689, rather than going through the PCM1804?

I enjoy discussing aspects like these, but If you would prefer not to discuss, all ok, I will not ask any further....

It's not about you asking questions, it's about you asking the same questions multiple times, ignoring the answers and then apparently expecting different answers.

Another point is that I don't like wasting my time on theories that can't lead to anything, or only to very stupid ideas.

Now let's be very clear and direct.
You can't change anything on the A30a in relation to the AX5689 chip.
1. You would need access to the A30a's software to control the AX5689.
2. You would have to connect everything that's missing to the AX5689 via an open-air cable, right in the middle of the power range and right next to the power supply. That would make for great antennas and would be a fiasco.
3. For all the changes that could make a difference, the AX5689 with the STA309A and the CT7302 is wired completely wrong. Changing that, apart from an exorbitant and completely wasted expenditure of time, would 99.9999999% lead to the destruction of the A30a.

And to make this quite clear, a new development with the AX5689 chip would be both simpler and significantly less time-consuming. And for someone who would be able to convert an A30a to the AX5689, the development would be a piece of cake.

And now for the very last time about the PCM1804 in the A30a, it is not a bad ADC, quite the opposite.
But there are measurements from the SMSL VMV A2 (presumably identical to the A30a) that suggest that the implementation of the PCM1804 was not very successful. And since you always ask about better ADCs that could be used/replaced in the A30a, you have missed an important point.
Implementation of the chip is almost always more important than the chip itself, in this case even crucial. The theoretically better chip could even deliver worse results. If you want to improve something, change the implementation of the PCM1804 or connect a better external ADC.

And here is another simple example of implementation.
A Topping D50 IIi and a Sabaj A10d 2022 have cheaper DAC chips installed, but are very high in the tests and measured values, even ahead of devices with much better and significantly more expensive DAC chips.
This is the result of a good implementation and also applies to ADC, or in general.

For me, these topics are now covered.

 

[Roland68]

''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.'.... I mistakenly thought that you were refering to the AX5689 (directly) but it would appear that you were refering to the DSP in front of the AX5689.... is that correct? If ok, do you mind clarifying and expanding on this?

Back to the specific point about AX5689 and DSP.
1. The AX5689 does not contain any DSP functionality.
2. The AX5689 has been equipped with, in my opinion, highly developed functionality for use with an internal or external DSP (chip, FIR convolver, DSP devices, etc.).
3. This means that the AX5689 enables completely digital integration (regardless of whether external or internal DSP), regardless of whether digital or analog sources are used.
4. Absolutely lossless (resolution) control of the volume.
5. Central volume control of several AX5689 chips or amplifiers is also possible.
6. This would make complex active systems (active speakers, active 2.1/2.2, AV systems) possible without additional DACs or ADCs.

Sabaj A30a and the built-in AX5689
1. None of the statements made above apply to the A30a and the built-in AX5689!
2. The AX5689's perfect integrated volume control is probably not even used (that would be very difficult to achieve with the STA309A and the subwoofer function). But I could be wrong.
3. The additional ICs PCM1804, STA309A and CT7302 built into the A30a would not be necessary at all. A simple DSP chip, in addition to the existing ARM processor, could have replaced all of them. This was probably the easiest way for SMSL and Sabaj to build an amplifier based on the AX5689 with the resources available.
4. Of course, you can put a DSP in front of a digital input on the A30a and connect the sources to the DSP.
5. But even so, the Sabaj A30a is an excellent amplifier, and not just for the price, it can keep up with much more expensive amplifiers. The same applies to the SMSL VMV A2, although it is much more expensive.

 

[ErkyPerky]

I'm about to pull the trigger and purchase this amp instead of the audiophonics da-s250nc. I can either buy it from Amazon or hifi express which is £70 cheaper than Amazon. Can I trust hifi express with a comment I have heard on this thread about not getting imbursed for the postage costs which they had to return two units that might have been defective. Also is it best to use PayPal ? Would it make a difference? If my unit became defective.

 

[Toku]

I'm about to pull the trigger and purchase this amp instead of the audiophonics da-s250nc. I can either buy it from Amazon or hifi express which is £70 cheaper than Amazon. Can I trust hifi express with a comment I have heard on this thread about not getting imbursed for the postage costs which they had to return two units that might have been defective. Also is it best to use PayPal ? Would it make a difference? If my unit became defective.

Even if there is product insurance for products purchased from overseas, it is customary for the buyer to pay the one-way shipping fee to the destination country, not just China. We should be aware of this before making a purchase. I have returned items about three times, and the one-way shipping fee was the buyer's responsibility.
I think PayPal is the safest way to pay.

 

[ErkyPerky]

Even if there is product insurance for products purchased from overseas, it is customary for the buyer to pay the one-way shipping fee to the destination country, not just China. We should be aware of this before making a purchase. I have returned items about three times, and the one-way shipping fee was the buyer's responsibility.
I think PayPal is the safest way to pay.

Shipping fee to the uk is free from hifi express.

 

[Toku]

Shipping fee to the uk is free from hifi express.

If there is a Hifi Express store in the UK there is no charge.

 

[ErkyPerky]

Obviously not, as probably coming direct from china, as on Amazon I can get next day delivery from a seller (hifi booster store which are selling smsl loxjie and sabaj products mainly) and dispatched from Amazon. So easy returns but at a higher cost. Shall I trust hifi express or compromise and pay more for Amazons extra fees for safety. Which do you think it's more trust worthy? To be honest I do not like returning things as I'm looking forward to this amplifier because I don't have one at the moment.

 

[Roland68]

Obviously not, as probably coming direct from china, as on Amazon I can get next day delivery from a seller (hifi booster store which are selling smsl loxjie and sabaj products mainly) and dispatched from Amazon. So easy returns but at a higher cost. Shall I trust hifi express or compromise and pay more for Amazons extra fees for safety. Which do you think it's more trust worthy? To be honest I do not like returning things as I'm looking forward to this amplifier because I don't have one at the moment.

I would rate HiFi-Express as trustworthy, among other things because it is probably the manufacturer's shop for SMSL, Sabaj and Loxjie. All items that are not offered in this shop were developed for other retailers/distributors or are sold out.
I also got my A30a from HiFi-Express and it was delivered from China to Germany surprisingly quickly.
For the UK you should choose shipping from the UK so that all taxes are included. Of course there is the possibility that it will still be shipped from China.
Important: In the next 2-3 weeks there will be the usual offers and discounts in many Chinese shops, probably also at HiFi-Express. Then the difference to Amazon will be even greater.

Amazon must always be seen as a service provider in such cases, because the free and uncomplicated return after 14-30 days, even for used devices, is very expensive for Amazon and the retailers and also has to be financed. So the return shipping costs to China correspond to what you pay at Amazon as a surcharge for this service.

Both Amazon and HiFi-Express offer cheaper customer returns, which may have visual defects.
I also bought my second A30a from a customer return.

For international orders, I would always recommend Paypal or another form of security.
But no matter what other people say, only you can ultimately decide where to order from.