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Dual Merus MA12070 Amplifier Sabaj A20 fully balanced : pictures inside )

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Thanks...so maybe i should looking for alternatives of the little dac that i have. Could you link some of your choices?
Come on, there is such a wide range of pure DACs available. Should not be too hard to make a choice.
Every MQA free DAC sale is even more appreciated than someone buying gear with that carcinogenic origami bogus implemented.

Maybe waiting for Ivan's E1DA "Cosmos DAC" is the best choice if you're not in a hurry. It might become the hottest pick of 2022.

Otherwise, go to https://www.audiosciencereview.com/forum/index.php?pages/Audio_Equipment_Reviews click on "Goto Rankings" click on "Type" and in that drop-down menu mark "DAC (Dedicated)" exclusively. In a descending order you will find the best measuring DACs. Then choose within the price range you're willing to pay, e/g the Schiit Modius.

It heavily depends on the speakers used whether you will hear any difference at all. E/g 20 years old Wharfedale Diamonds won't reproduce any differences between DACs.
 

Nozza

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I got one of these this week.

I've not experienced any noise problems on the RCA inputs mentioned in this thread. Just lots of good, clean power. Reading the comments I was mentally selecting a balanced DAC to replace my current one but I needn't have worried.

It sounds noticeably different to the amp it replaced which was Cambridge Audio one built in 2009. I think that was quite a warm, soft sound so this is brighter and clearer sounding.

I'm using an SMSL M100 MkII DAC via RCA cables. The only noise I can detect is if I turn it to max (0dB) with no input, and put my ear right to the speaker and then I can hear a very faint noise. I.e. it is essentially silent without input. It has plenty of power. I can't go much over -30dD in my small room without distressing my ears so loads of headroom.

I can't get too excited by amps but does exactly what I wanted: plenty of power, quality clean sound, small footprint, low cost. £145 from Hifi Express and unexpectedly delivered by Amazon.

If Amir ever tests one, will be interesting to see how it measures.
 

ModDIY

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I got one of these this week.

I've not experienced any noise problems on the RCA inputs mentioned in this thread. Just lots of good, clean power. Reading the comments I was mentally selecting a balanced DAC to replace my current one but I needn't have worried.

It sounds noticeably different to the amp it replaced which was Cambridge Audio one built in 2009. I think that was quite a warm, soft sound so this is brighter and clearer sounding.

I'm using an SMSL M100 MkII DAC via RCA cables. The only noise I can detect is if I turn it to max (0dB) with no input, and put my ear right to the speaker and then I can hear a very faint noise. I.e. it is essentially silent without input. It has plenty of power. I can't go much over -30dD in my small room without distressing my ears so loads of headroom.

I can't get too excited by amps but does exactly what I wanted: plenty of power, quality clean sound, small footprint, low cost. £145 from Hifi Express and unexpectedly delivered by Amazon.

If Amir ever tests one, will be interesting to see how it measures.

Can you describe the size of the room and which speaker sensitivy?
 

ModDIY

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Mine is plugged into my system from my office, with DAC and RCA output and I have no noise. On the other hand in my main room I have a hiss with the RCA input and so I tried it with balanced inputs and it's silent.

As I have written on several occasions, I really like the A20a.

My room in my office is 3.5x3.5m and bookshelf speakers are 87db. It does not lack power.
 

lockheed

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Does anyone know what is the max Amperage value for the 15V output on the back of A20a?
 

Toku

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Does anyone know what is the max Amperage value for the 15V output on the back of A20a?
The 15V power output is prepared for the DAC A20d, so I think it's about Max 1A. Unfortunately, there was no description anywhere.
 

lockheed

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The 15V power output is prepared for the DAC A20d, so I think it's about Max 1A. Unfortunately, there was no description anywhere.
I am hesitant to assume it is only as much as the DAC puts out. I think it would be more difficult to limit it to just 1A, than to let it go at least several Amps more as a bolt-on to such a large power supply.
 

Toku

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I am hesitant to assume it is only as much as the DAC puts out. I think it would be more difficult to limit it to just 1A, than to let it go at least several Amps more as a bolt-on to such a large power supply.
No, it is easy for such a power supply unit to get a sub-output of 15V.
 

lockheed

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I got Sabaj A20a and it paired beautifully with Topping D30 (which draws 3W 15V when on), powering it from its own internal PSU with included cable. Sound was clear and background was silent.
However, I just got DX3 Pro+ (draws 6W 15V when on), and it causes the Sabaj PSU to coil-whine when DAC is in standby, and makes it even louder when DAC is turned on. I think it is the Sabaj, but it's hard to tell with such a short cable in between the devices.
This does not happen when the DAC is powered with its own factory PSU.
This is a bummer, because makes equipment placement much harder if DAC can't be powered form the Amp.

Is there anything that can be done to remove the coil whine?

EDIT:
Actually, if I am powering the DAC from external PSU, then Sabaj A20a (bought a week agon on Amazon.de) clicks like crazy while playing bass-intensive music (Toto - Odenkoza).
So it is either coil whine or crazy clicking.
Feck...
 
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Toku

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I got Sabaj A20a and it paired beautifully with Topping D30 (which draws 3W 15V when on), powering it from its own internal PSU with included cable. Sound was clear and background was silent.
However, I just got DX3 Pro+ (draws 6W 15V when on), and it causes the Sabaj PSU to coil-whine when DAC is in standby, and makes it even louder when DAC is turned on. I think it is the Sabaj, but it's hard to tell with such a short cable in between the devices.
This does not happen when the DAC is powered with its own factory PSU.
This is a bummer, because makes equipment placement much harder if DAC can't be powered form the Amp.

Is there anything that can be done to remove the coil whine?

EDIT:
Actually, if I am powering the DAC from external PSU, then Sabaj A20a (bought a week agon on Amazon.de) clicks like crazy while playing bass-intensive music (Toto - Odenkoza).
So it is either coil whine or crazy clicking.
Feck...
Topping's DX3 Pro + is a model with a built-in headphone amplifier in the DAC and consumes a lot of power in the headphone amplifier.
The A20a's DC15V output is not intended for use with such large current loads.

Your A20a seems to make a clicking sound from the internal power supply, is it an early model?
The A20a currently on the market has been improved so that there is no click sound.
 

lockheed

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Topping's DX3 Pro + is a model with a built-in headphone amplifier in the DAC and consumes a lot of power in the headphone amplifier.
The A20a's DC15V output is not intended for use with such large current loads.

Your A20a seems to make a clicking sound from the internal power supply, is it an early model?
The A20a currently on the market has been improved so that there is no click sound.
So the coil whine is because of excessive (3W) power draw from Sabaj 5V output?
I wish there was a way to disable the headphone amp on DX3 Pro+, as I will never use it.

The A20a I bought was from Amazon.de and was purchased 3 weeks ago - so it should be the new edition, but of course there are no serial numbers to verify it. Seller said it was the new version, but since its relay clicks like crazy, I think the seller must be mistaken and it is some old stock. I ordered the second one from the same seller in hope it was from a different batch - it should arrive on Monday.
 

Moosi

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Serial numbers are printed on the PCB.
If your A20a starts clicking with the base-line of a track, there is a problem with the relay. Coupling the A20a with a DAC from the 15V out does better it by raising the limit at which the amp starts clicking to a higher volume level. This will give you some room, but will most likely not totally rid you of it. It might still occur on very high volume. I had the same problem. I did not want to wait for a new amp from China. So I bought a Meanwell RPS-400-24 and installed it instead. Yep, sounds better. No clicking, no whining, no burst [email protected] possibly creating interference in the audio band anymore. Idle power consumption goes up from 2W->6W.
All in this thread
 

lockheed

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Serial numbers are printed on the PCB.
Do you know what means what in a serial number? What designates the newer, fixed version?

If your A20a starts clicking with the base-line of a track, there is a problem with the relay. Coupling the A20a with a DAC from the 15V out does better it by raising the limit at which the amp starts clicking to a higher volume level. This will give you some room, but will most likely not totally rid you of it. It might still occur on very high volume. I had the same problem. I did not want to wait for a new amp from China. So I bought a Meanwell RPS-400-24 and installed it instead. Yep, sounds better. No clicking, no whining, no burst [email protected] possibly creating interference in the audio band anymore. Idle power consumption goes up from 2W->6W.
All in this thread
Paying an extra 100euro for a PSU to fix a brand you 180euro AMP just to make it right is not my idea of a good deal :/
 

Toku

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Do you know what means what in a serial number? What designates the newer, fixed version?


Paying an extra 100euro for a PSU to fix a brand you 180euro AMP just to make it right is not my idea of a good deal :/
Since it is the symptom that occurred at the beginning of the release, I think it is better to return it if it can be returned.
 

lockheed

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I got another A20a from the same seller (amazon.de). This time it is the updated version.

The differences:
- no relay clicking
- higher power draw. It consumes 2W more power (idle: 3W vs 1W, music: 6W vs 4W).
- a sticker with a serial number underneath
- the previous A20 had an extra hole on the back panel (right side to the 15V DC output) which was masked with some black sticker. This newer version doesn't have such hole.
- and one more thing:

My audio chain is like so: PC -> DAC -> A20A -> Speakers. With the old A20a, speakers are near dead-silent when not playing a sound. But with the new one, there is a constant electronic noise that is audiable and quite annoying at 2 meters from the speakers even at -20db at the amp (it becomes inaudible around -30db).
The noise goes away when I unplug the PC, but that defeats the purpose. The A20a is the only variable here - even the cables are the same.
I tried turning the internal voltage regulator to the max, as suggested earlier in this thread, but that did not change anything.

Any idea what can cause that difference in noise or how to get rid of it?
 
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