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

gasolin75

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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?
i leave mine at -30db not because of your post but because i thought it was the setting i wanna run it at in my ssytem with a behringer control 2 usb, i don't hear any noise
 
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ModDIY

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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?

I may have a lead, bought a USB isolator between DAC and PC.

I'm not an expert, I'm thinking of a ground loop.
 

Hiram67

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Hi everyone, I have recently given me a Sabaj A20a to listen to my music from the PC.
Currently my audio chain is PC -> DAC Topping E30 -> Sabaj A20a. As audio speakers I use two old Sony SS-CCP2, from an old all-in-one system. The dac and the amplifier are connected with an rca to XLR cable, I don't hear any noise in listening and I must say that listening is very pleasant. I listen mainly to blues, jazz and rock. I come to my request, the will is to upgrade the speakers and maybe add a subwoofer. The spending budget is not high at the moment and as speakers I would be in doubt between the kef q150 and the q acoustics 3030i, while as a subwoofer I would not know, as I do not understand if you need an active or passive sub with the A20a.
What my do you recommend? thank you
 

gasolin75

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No point in using xlr to rac

rca to rtca should give the same saound quality

Try the q acoustiocs 3030i, you won't be needing a subwoofer

On a low budget try the mission LX 2 or wharfedale diamond 12.1
 

Hiram67

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I thank you for the answer. My budget is in total max 600 euros and I was also looking at the used one. Unfortunately in the area where I live there are no HI-FI shops to listen to the speakers alone or with a subwoofer for a 2.1 system.
I thought q acoustic and kef sized speakers needed a subwoofer to help the bass.
But if you tell me that the Q Acoustics Q 3010i don't need a subwoofer, that's better so I can spend about half of my budget.
 

TjindarSingh

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The amp and dac a20a+a20d combo is awesome, way better than much I've tried that's way more expensive 10-30 times even in some regards.
 

ModDIY

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The amp and dac a20a+a20d combo is awesome, way better than much I've tried that's way more expensive 10-30 times even in some regards.
Cool.

I have the Sabaj A20a and love it. On the other hand, the RCA input (not your case with the DAC), there is a hissing problem with the high volume gain.

On my main channel I have a DAC with RCA and XLR outputs, the hiss can be heard with RCA, while on my second channel, the A20a plugged in with DAC and RCA outputs has absolutely NO hiss. I haven't found why.

If you have a balanced source, it's a great amplifier, with remote control and tone adjustment. In the end, I do not regret this purchase.
 

TjindarSingh

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Recently tested it against musical fidelity m6si a new one and the m6si didn’t have a chance against the Sabaj combo a20a and a20d. Didn’t expect that but the sabaj had much better control and a lot darker background than the m6si that cost way way more.
 

ModDIY

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Recently tested it against musical fidelity m6si a new one and the m6si didn’t have a chance against the Sabaj combo a20a and a20d. Didn’t expect that but the sabaj had much better control and a lot darker background than the m6si that cost way way more.
I'm not surprised.

The sound and transparency of the A20a (I don't have the dac) is really excellent.
 

TjindarSingh

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Bought a Yamaha a-s801 that have ok measurements according to audioholics and tested it against the Sabaj a20a the Yamaha don’t stand a chance in my system way to bloated in the bass /no control.

Is the class d amps better at controlling the bass ?

The a20a is really a bargain.

Somebody tried it against the smsl a0200 that also have the ma12070?
 

Toku

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Bought a Yamaha a-s801 that have ok measurements according to audioholics and tested it against the Sabaj a20a the Yamaha don’t stand a chance in my system way to bloated in the bass /no control.

Is the class d amps better at controlling the bass ?

The a20a is really a bargain.

Somebody tried it against the smsl a0200 that also have the ma12070?
I bought two A20a and AO200. I think the EQ and tone control of these amps are effective and work well. The AO200 SDB is especially useful when playing at low volume.
 

TjindarSingh

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I bought two A20a and AO200. I think the EQ and tone control of these amps are effective and work well. The AO200 SDB is especially useful when playing at low volume.
Okay that's s good feature.
As I understand the sabaj a20a has a bigger power supply and that should help when playing louder or better dynamics maybe.
 

TjindarSingh

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I bought two A20a and AO200. I think the EQ and tone control of these amps are effective and work well. The AO200 SDB is especially useful when playing at low volume.
Two A20A? In diifrent systems?
 

Roland68

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Bought a Yamaha a-s801 that have ok measurements according to audioholics and tested it against the Sabaj a20a the Yamaha don’t stand a chance in my system way to bloated in the bass /no control.

Is the class d amps better at controlling the bass ?

The a20a is really a bargain.

Somebody tried it against the smsl a0200 that also have the ma12070?
Both devices are built so similarly that the areas around the two MA12070 could also be superimposed. Since both devices also use the NJW1194 for volume control, there shouldn't be any major differences in this area either.
The A20a has a 350 watt switching power supply that is designed with active ventilation for 200 watts. The AO200 has a smaller switching power supply with 225 watts installed, with active ventilation 140 watts. That could be a small advantage for the A20a :cool:.
 

TjindarSingh

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Both devices are built so similarly that the areas around the two MA12070 could also be superimposed. Since both devices also use the NJW1194 for volume control, there shouldn't be any major differences in this area either.
The A20a has a 350 watt switching power supply that is designed with active ventilation for 200 watts. The AO200 has a smaller switching power supply with 225 watts installed, with active ventilation 140 watts. That could be a small advantage for the A20a :cool:

the power supply is a very important part so I clearly think its a advantage to the Sabaj A20A.
 

ModDIY

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the power supply is a very important part so I clearly think its a advantage to the Sabaj A20A.
As I wrote above, I have the A20a on my secondary chain, I don't regret this purchase, even if some people had a little hiss at the RCA input (not XLR), on my side it's silence even very loud volume and RCA inputs.

I like the JRC NJW1194 preamp, very practical and really a plus.
 

TjindarSingh

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Tested against a rotel ra-1592 it to didn't stand a chance sound wise. Way to blurry not as silent in between notes or how to say it.

Now I've tested a couple of amps way pricer than the a20a and none of them have sound as transparent an clean as the a20a+a20d.

Rotel ra-1592
Musical fidelity m6si the new one
Yamaha a-s801
All amps where also t sted with the sabaj a20d dac.

Amazing what you can get these days for not much money.
IMG_20220401_173435370_MP.jpg
 

TjindarSingh

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Newly rigged the kinki Studio ex-m1 and gustard p26+ Nord One SE NC500DM MKII Dual Mono Stereo.

Quick impression is that they gonna have trouble whit the sabaj combo.

I will use the sabaj a20d with all combinations.
 

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