Topping A90
Jun 9, 2021 at 5:36 AM Post #1,261 of 1,359

raoultrifan

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My intention was to use the D90 as a fixed output level DAC, disabling its volume control, then use the A90 in preamp mode to control the volume level to the power amp via RCA. But that caused a hiss through the speakers. The hiss disappeared when I enabled volume control on the D90 and connected that directly to the power amp via RCA, limiting the A90 to headphones only.
Interesting. If I remember correctly, A90's line-level outputs are tied directly to headphones output through some resistors; this is a common practice for many manufacturers. I wonder if A90 has the same hiss when connected to sensitive IEMs.
 
Jun 9, 2021 at 5:50 AM Post #1,262 of 1,359

Baten

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Interesting. If I remember correctly, A90's line-level outputs are tied directly to headphones output through some resistors; this is a common practice for many manufacturers.
I think the 'flaw' is the RCA outputs, inputs, there is no total noise immunity in A90. I think A30 Pro even has better noise protection and has ground lift switch. With A90 if you have RCA noise issues you are f*cked.
 
Jun 9, 2021 at 6:21 AM Post #1,264 of 1,359

NickedWicked

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with e30, a90 and sundara I don't like the sound, too lean and fatiguing in the mid-highs, the a90 doesn't seem neutral to me
I can assure you the A90 is dead neutral, if it doesn’t line up with your preferences then you might want to check other (well-recorded) tracks or the tuning of the headphone is not to your liking in certain aspects.
 
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Jun 9, 2021 at 12:35 PM Post #1,265 of 1,359

TheMiddleSky

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with e30, a90 and sundara I don't like the sound, too lean and fatiguing in the mid-highs, the a90 doesn't seem neutral to me

Never heard e30, so can't say much about it.

Based on many amps I tried, I don't think A90 lean on bright/cold side though. It's kind of neutral with slight warm character.

Even though A90 produce excellent micro detail, I agree that this amp is not produce the most musical or high energy kind of sound, and may reveal some "dull" bite on mid to treble area. Of course impression come with my current set up Chord Qutest and ZMF Verite, ymmv.

Sundara itself, personally, a little bit harsh and there are some peaks at upper mid to treble area.
 
Jun 9, 2021 at 12:48 PM Post #1,266 of 1,359

Rantenti

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Never heard e30, so can't say much about it.

Based on many amps I tried, I don't think A90 lean on bright/cold side though. It's kind of neutral with slight warm character.

Even though A90 produce excellent micro detail, I agree that this amp is not produce the most musical or high energy kind of sound, and may reveal some "dull" bite on mid to treble area. Of course impression come with my current set up Chord Qutest and ZMF Verite, ymmv.

Sundara itself, personally, a little bit harsh and there are some peaks at upper mid to treble area.
Perhaps it is the dead neutrality of the A90 that makes it a bit "boring". If paired with a DAC with a rich and fast sound, the A90 can deliver the punch very well.

However, I've had two issues, one being the RCA noise which I avoided by switching to all XLR from DAC to A90 to speakers. The other is that the preamp of A90 seem to widen channel separation so that there is a "hole in the middle" with certain cables.

And yes, the Sundara sounds a bit harsh in the lower treble. I tried the Ananda and the Sundara in a shop and there is a sale on the Ananda. Couldn't listen to the Sundara after trying the Ananda! You can guess which one I bought...
 
Jun 9, 2021 at 12:54 PM Post #1,267 of 1,359

TheMiddleSky

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Perhaps it is the dead neutrality of the A90 that makes it a bit "boring". If paired with a DAC with a rich and fast sound, the A90 can deliver the punch very well.

However, I've had two issues, one being the RCA noise which I avoided by switching to all XLR from DAC to A90 to speakers. The other is that the preamp of A90 seem to widen channel separation so that there is a "hole in the middle" with certain cables.

And yes, the Sundara sounds a bit harsh in the lower treble. I tried the Ananda and the Sundara in a shop and there is a sale on the Ananda. Couldn't listen to the Sundara after trying the Ananda! You can guess which one I bought...
Currently no speaker around me here so not able to try the pre amp part. It's a bit abnormal though, to get hiss by using rca but not by xlr.

Yes, part of neutrality make it a little bit boring or in better word: more relax.
 
Jun 12, 2021 at 9:24 AM Post #1,270 of 1,359

raoultrifan

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I think the 'flaw' is the RCA outputs, inputs, there is no total noise immunity in A90. I think A30 Pro even has better noise protection and has ground lift switch. With A90 if you have RCA noise issues you are f*cked.
Did same test now to a friend: Roon > D90 > A90 (RCA) > Fezz Audio Titania > Piega Premium 3.2; no matter A90's gain used the noise was non-existent. Output volume to the amplifier was pretty high, definitelly >90 dB.

I guess your setup has a flaw, or perhaps your A90.

7F2D2D1E-7E4A-4EFF-B256-391FF853EB5A.jpeg
 
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Jun 12, 2021 at 10:13 AM Post #1,271 of 1,359

Rantenti

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Currently no speaker around me here so not able to try the pre amp part. It's a bit abnormal though, to get hiss by using rca but not by xlr.

Yes, part of neutrality make it a little bit boring or in better word: more relax.
Yes, hissing should be abnormal. My RCA noise issue was that of EMI interference/ ground loop/ computer GPU noise. Got me quite frustrated. Luckily, going balanced solved everything and good XLR cables are a bargain.
 
Jun 12, 2021 at 10:20 AM Post #1,272 of 1,359

Baten

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Did same test now to a friend: Roon > D90 > A90 (RCA) > Fezz Audio Titania > Piega Premium 3.2; no matter A90's gain used the noise was non-existent. Output volume to the amplifier was pretty high, definitelly >90 dB.

I guess your setup has a flaw, or perhaps your A90.

7F2D2D1E-7E4A-4EFF-B256-391FF853EB5A.jpeg
That's good to hear. But I've read other reports of RCA ground loop noise, even some freak occurrences of people getting ground loops over XLR inputs.

I've not read any such things about the A30 Pro, which has different PSU scheme and a ground loop switch.

if A90 works for you, you're golden, but I do think it's not optimally immune to noise.
 
Jun 21, 2021 at 3:04 PM Post #1,274 of 1,359

raoultrifan

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Both DACs (https://www.audiosciencereview.com/forum/index.php?threads/smsl-su-9-balanced-dac-review.16150/ vs. https://www.audiosciencereview.com/...ds/gustard-x16-balanced-mqa-dac-review.17419/) are measuring really good and both are on the same price range, so you should grab the one that you can find in a local store or an online store from your country/continent (from a warranty perspective only).

Of course, you can also find a Topping D90 (the non MQA version), second-hand, probably in the same price range too, so you can buy this one to have the entire combo from same manufacturer.

Not sure about the internal design of the first two DACs, but if there is no dedicated output buffer after the LPF, then the DAC may not be 100% compatible with the A90, due the very low input impedance of the A90 (40 Ohms on XLR inputs), as you really need good opamps installed in the output buffer to be able to drive the input stage of the A90.
 
Jun 21, 2021 at 10:10 PM Post #1,275 of 1,359

Kashen2020

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guys I have a question

I paired hifiman arya with A90/D90 and I find it to be harsh in many recordong and sibilant so a lot of people told me it is the amp and other people told me no it is the headphone so I bought sennhieser 6xx and a lot of people said it consider warm and highs turned off in it but I face the same problem with 6xx it is sibilant not forgiving in many vocal recordings iam really confused now I think it is really the amp dac thing.
 

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