[ra990]

Those are excellent cables. I used a 6" RCA from WBC (i believe it was the gotham cable, not mogami) and had no problems with noise when I used the Qutest over RCA with the A90.

 

[RuiNguyen]

Sorry for the late response. Short answer is No. As a preamp the A90 is not near as good as its Headphone portion. It can add gain via the volume knob to the preamp however. But it is not a very good preamp. Probably why Topping is making a separate P90 preamp. I had the A90 preamp connected to the Dragon IHA-1...sound quality was only average compared to other sources via A90. Hope that helps.

P.S. I did have high hopes for the A90 as a preamp, that was my initial plan. Ended up buying a Schiit Freya S instead for my headphone station. My first Schiit product ever. Very impressed with it as a preamp. Just dont sit too close to it. The volume resistors are noisy and will be heard through open back HP if seated within a few feet of the unit. Otherwise excellent preamp for the cost.

Thank you. I think I would buy Freya S or Saga+

 

[KPzypher]

With a little research I was able to mitigate the noise problem by finding RCA / XLR cables made with wire designed for really good noise rejection and EMI / RFI protection in a build that uses a Faraday cage design for the wiring. I was about to send back the A90 / D90 MQA, but the new cables got rid of so much of the noise - and the A90 / D90 MQA sound so much better now that the noise floor has been dropped so far - that I decided to keep them.

I have both RCA and XLR cables between the A90 and D90 MQA and am switching back and forth between the interconnects with that switch on the A90, I have spent hours listening on the RCA connection and it sounds great

Here are the details I posted on ASR:


Good news, the Mogami 2534 based World's Best Cables (WBC) got rid of the RCA noise. The WBC Mogami 2534 RCA cable pair also got rid of most of the USB noise.

I also got a Tripp-lite shielded cable with Ferrite Chokes, and it does reduce the small amount of GPU load noise by a noticeable amount, but just swapping in the RCA Mogami 2534 wired cable was the biggest change. A WBC Mogami 2534 XLR pair round out the cable changes.

Now I can only hear a smidge of GPU noise at 100% GPU usage, but it's so low I can't hear it while playing media - I can enable / disable the GPU load and not hear any difference in the audio. No more USB crackling either.

I can turn up the A90 volume to 100% on H Gain switched to XLR and no noise. On H Gain switched to RCA the "low level hum" without hash noise starts in at 2 oclock. So far I have no headphones that need that much drive. The highest I drive my headphones is 12 oclock on H Gain.

For now that's all good enough, and it was worth the cost and effort.

I also bought a Mogami 2549 based RCA cable pair, I'll try that out later. I'll probably pick up a WBC 2549 based XLR pair too and pair them all up together. Comments say they sound better than the 2534 heavy shielded cable, but I went with the heavy shield product first to make sure I gave the new cabling the best chance.

The cables aren't "cheap", but they aren't expensive either. If you have RCA noise problems or USB noise problems I'd recommend them as a last ditch solution before giving up on the A90 / D90.

Spoiler: New cables:

1 Foot – Quad Balanced Microphone Cable Custom Made by WORLDS BEST CABLES – Using Mogami 2534 Wire and Neutrik NC3MXX-B Male & NC3FXX-B Female XLR Plugs. *sold as a single cable, buy 2x*
https://www.amazon.com/gp/product/B00WU1BP10

1 Foot – Directional Quad High-Definition Audio Interconnect Cable Pair Custom Made by WORLDS BEST CABLES – Using Mogami 2534 Wire and Amphenol ACPR Die-Cast, Gold Plated RCA Connectors
https://www.amazon.com/gp/product/B01ALHTVMO

1 Foot – Directional High-Definition Audio Interconnect Cable Pair Custom Made by WORLDS BEST CABLES – Using Mogami 2549 Wire and Amphenol ACPR Die-Cast, Gold Plated RCA Connectors
https://www.amazon.com/gp/product/B01ALFR02Y/

Mogami 2534 wire:



Mogami 2549 wire:



WBC RCA Faraday cage wiring design:


Tripp Lite USB 2.0 Hi-Speed A/B Cable with Ferrite Chokes (M/M) 3-ft. (U023-003)
https://www.amazon.com/gp/product/B008VOPCGY

https://www.audiosciencereview.com/...d90-balanced-usb-dac-review.10519/post-475832

I can answer questions here

I'm glad you found a workaround, but you shouldn't have to take all those steps just to get it to work properly. It should work properly out of the box, balanced or SE. I'm keeping mine, but it is true that the SE side is bit of a mess.

 

[elricofchaos72]

Hi All, I just came across this video about distortion on RCA connection , since I am planning to use it with Hugo 2 via RCA only I need to know if anyone else facing same issue of distortion on RCA.

That ground loop issue was resolved months ago production run wise. Sajunky seems to have serious personal issues with Topping and their marketing in which he makes outlandish claims against them. Check his South Africa feeds to see how others view his opinion.
The only way I have introduced distortion via the Mojo was to increase the gain from the Mojo while it was turned on in Preamp mode. A90 is just a victim of overhype that should not be held against it. For $500 it is an over performer in its weight class. Is it better than a Hugo TT2? Of course not. But it was never meant to be. Apos gives a 30day free return. Try it for yourself. Use clean power. Etc.

 

[elricofchaos72]

I'm glad you found a workaround, but you shouldn't have to take all those steps just to get it to work properly. It should work properly out of the box, balanced or SE. I'm keeping mine, but it is true that the SE side is bit of a mess.

A simple Audioquest RCA cable was enough on my end. XLR was Benchmark Media. No hum whatsoever switching back and forth. Using IEMs to Abyss to Audeze and 800 S....no noise!

 

[bahamot]

I'm glad you found a workaround, but you shouldn't have to take all those steps just to get it to work properly. It should work properly out of the box, balanced or SE. I'm keeping mine, but it is true that the SE side is bit of a mess.

To be fair, I have no issue with A90's RCA. I am just using Klotz cable.

 

[NickT23]

I'm comparing the 789 and A90 on an SMSL M200 and Topping E30 dac. Really hard for me to put into words since I'm not really good at describing sound like some of the others on this thread. The biggest difference to me is that since the A90 is a little warmer than the 789. And the 789 maybe due to the less warm nature seems to be better at lower end detail. It also feels like the higher are slightly brighter. Since Im using it on a HD-6XX I don't have the best opinion on soundstage. I feel like some songs sound better on the A90 and others on the 789. Sorry for confusing you even more. I have to decide if Im going to keep the 789 by tomorrow since that is the last date for a full refund return. Also there is a possibility I might sell the A90 on here. I have the volume wobble others have talked about but otherwise in excellent condition.

Hello ! Is your THX 789 the nicer looking ones or the hideous ones ?

 

[jincuteguy]

That ground loop issue was resolved months ago production run wise. Sajunky seems to have serious personal issues with Topping and their marketing in which he makes outlandish claims against them. Check his South Africa feeds to see how others view his opinion.
The only way I have introduced distortion via the Mojo was to increase the gain from the Mojo while it was turned on in Preamp mode. A90 is just a victim of overhype that should not be held against it. For $500 it is an over performer in its weight class. Is it better than a Hugo TT2? Of course not. But it was never meant to be. Apos gives a 30day free return. Try it for yourself. Use clean power. Etc.

How do I get clean power for my A90?
Also, I got some XLR cables from HeartAudioCAble and Monoprice. The Monoprice cables are 16awg guage and cheaper. I jus tdon't get why the ones from HartAudioCable are more expensive, they're like $40 for a pair of 6" XLRs. The Monoprice cables are only $5.50 each so $11 for a pair of 1.5ft.

 

[Sean_MR]

I'm comparing the 789 and A90 on an SMSL M200 and Topping E30 dac. Really hard for me to put into words since I'm not really good at describing sound like some of the others on this thread. The biggest difference to me is that since the A90 is a little warmer than the 789. And the 789 maybe due to the less warm nature seems to be better at lower end detail. It also feels like the higher are slightly brighter. Since Im using it on a HD-6XX I don't have the best opinion on soundstage. I feel like some songs sound better on the A90 and others on the 789. Sorry for confusing you even more. I have to decide if Im going to keep the 789 by tomorrow since that is the last date for a full refund return. Also there is a possibility I might sell the A90 on here. I have the volume wobble others have talked about but otherwise in excellent condition.

Thanks for the info! So in terms of pure technical prowess then, would you say the 789 has a slight edge? Does the A90 “trade” some of the detail retrieval for the warmth? I’m trying to see if it’s a pure upgrade, or more of a sidegrade.

Also, what’s the volume wobble problem? Is that fairly common?

 

[Gene4797]

I’m using cheap xlr cables, from d90 to a90 and never have any noise problems, plus all my system very close from each to other, but I’m using just comp.TIDAL

 

[hmscott]

Those are excellent cables. I used a 6" RCA from WBC (i believe it was the gotham cable, not mogami) and had no problems with noise when I used the Qutest over RCA with the A90.

That's great!, I am actually planning on finding alternative wire to Mogami that offer better noise rejection - made by WBC or otherwise, fortunately WBC builds many cables with alternative wire and termination:

Mogami, Canare, Lava, van Damme, Gotham, Beldan terminated with Neutrik, Neutrik-Rean, Amphenold, Eminence, and KLEI
https://www.amazon.com/stores/WORLD...LES/page/D5DC000C-B9F2-4E19-9143-22DE290EE84B

I don't see all of them advertised on Amazon, so I may need to make a build request for specific wire to be used directly from WBC.

Fortunately the A90 is very sensitive to noise - like many preamps - so there is a noise floor to deal with and perhaps I can find a way to measure the noise foor other than listening for it - but that's what really matters in the end - how the music free from noise sounds to you.

There are other characteristics that differ between the wire brands / types that can affect matching the connection between the DAC and the AMP, and eventually the powered speakers or AMP / Speakers. But for me noise reduction was the most important characteristic.

I'm glad you found a workaround, but you shouldn't have to take all those steps just to get it to work properly. It should work properly out of the box, balanced or SE. I'm keeping mine, but it is true that the SE side is bit of a mess.

Yup, I usually don't have to worry about reducing noise into the device to this level of attention, but overall I am happy in that it made me research the noise rejection properties of the wires my cables were using and the ferrite core efficacy of my new USB cable - and as I add more ferrite cores / wraps.

The A90 is so sensitive to noise inputs I can use it as an instrument to judge the efficacy of my cables at noise rejection.

A nice side-effect of reducing the noise floor is that the resulting noise reduction contributed to the filling out of the soundstage and widening of the sound stage - which may also be due to the wire capacitance and inductance characteristics - which I will be listening for in the other wire versions of WBC cables with different brands of wires down the road.

I'm much happier with the A90 / D90 MQA sound characteristics after re-cabling with the WBC Mogami 2534 wire, and it took the A90's oversensitivity to noise to get me here.

 

[jincuteguy]

So the power cable that comes with the A90 is a bit short. If I want to get a longer power cable, any recommendations? I'm scared to get one on amazon and then it would burn my A90

 

[CANiSLAYu]

Just get one that’s UL rated. I got these for my D90/A90 stack and they do the job.

 

[jincuteguy]

Just get one that’s UL rated. I got these for my D90/A90 stack and they do the job.

What do you mean UL rated? what's UL? I always thought the stock power cable has s omething special in it that you have to built to some kind of specifications?

 

[CANiSLAYu]

Underwriting Laboratories. Google it.