[Green Golden Retriver]

Is thier a remote to control the volume that I can buy and use with the a90 not connected to the d90. I sit quite far away and connected to my dap that can’t control volumeeee ><

 

[makatech]

I am probably buying a used A90. First I plan on using my Zen Dac as a dac (not sure for how long though). Connecting the Zen Dac to computer using USB and through a power supply with balanced 4.4mm cable for my HD 6XX.

Question: Reading it's rather common with hiss/noise connecting external active speakers or dac through RCA connections on the A90? I am guessing this is a grounding issue because of the built in power supply?

I don't want to invest in an expensive balanced 4.4mm -> dual 3 pin XLR for my Zen Dac. Hopefully I am lucky and not getting any noise.

 

[Green Golden Retriver]

I am probably buying a used A90. First I plan on using my Zen Dac as a dac (not sure for how long though). Connecting the Zen Dac to computer using USB and through a power supply with balanced 4.4mm cable for my HD 6XX.

Question: Reading it's rather common with hiss/noise connecting external active speakers or dac through RCA connections on the A90? I am guessing this is a grounding issue because of the built in power supply?

I don't want to invest in an expensive balanced 4.4mm -> dual 3 pin XLR for my Zen Dac. Hopefully I am lucky and not getting any noise.

I got a used one too as the retail price in Thailand is 330 usd above price in the states!

 

[makatech]

I got a used one too as the retail price in Thailand is 330 usd above price in the states!

Cool, connecting your dac through rca or balanced xlr?

 

[TheRealDz]

Ok. I have a few hundred hours on mine now.

I am nearing the end of my return window, so I unplugged my A90 and switched my Drop Cavalli Liquid Carbon X back into my system. I missed the Cavalli's richness, and wondered if the A90 was worth the extra $300 or so difference.

I really didn't want to spend the extra money - especially if I had regrets about missing the Cavalli. But those thoughts didn't last very long, and now I've plugged the A90 back in permanently.

Now that the A90 is fully burned in, I find that it isn't lacking in richness when the recording brings it. Nor is it harsh - it matches well with my chord hugo after all. And most of all, its clarity and effortlessness was starkly apparent in direct comparison to the Cavalli. The Cavalli, while pleasant, sounded cloudy, thick, and lacked the A90's detail and spaciousness.

I was perfectly satisfied with my Cavalli previously, and had only snagged the A90 on a whim. But the A90 is truly a big step up...

 

[Green Golden Retriver]

Ok. I have a few hundred hours on mine now.

I am nearing the end of my return window, so I unplugged my A90 and switched my Drop Cavalli Liquid Carbon X back into my system. I missed the Cavalli's richness, and wondered if the A90 was worth the extra $300 or so difference.

I really didn't want to spend the extra money - especially if I had regrets about missing the Cavalli. But those thoughts didn't last very long, and now I've plugged the A90 back in permanently.

Now that the A90 is fully burned in, I find that it isn't lacking in richness when the recording brings it. Nor is it harsh - it matches well with my chord hugo after all. And most of all, its clarity and effortlessness was starkly apparent in direct comparison to the Cavalli. The Cavalli, while pleasant, sounded cloudy, thick, and lacked the A90's detail and spaciousness.

I was perfectly satisfied with my Cavalli previously, and had only snagged the A90 on a whim. But the A90 is truly a big step up...

Nice. How much of a improvement did the chord Hugo do to the a90?

 

[hmscott]

I am probably buying a used A90. First I plan on using my Zen Dac as a dac (not sure for how long though). Connecting the Zen Dac to computer using USB and through a power supply with balanced 4.4mm cable for my HD 6XX.

Question: Reading it's rather common with hiss/noise connecting external active speakers or dac through RCA connections on the A90? I am guessing this is a grounding issue because of the built in power supply?

I don't want to invest in an expensive balanced 4.4mm -> dual 3 pin XLR for my Zen Dac. Hopefully I am lucky and not getting any noise.

The RCA "noise" is indeed ground loop noise - and ground noise brought in from USB cable through your DAC, in my case I was able to solve the noise issues with cables designed to reject noise - the shield is used as a "faraday cage" wired to ground at the source end but left to float on the A90 end - and the cable wires are twisted pair - 2 pair - with shielding on top of that to prevent EMI noise. Then the USB cable has 2 ferrite cores - one on each end - and after replacing my "high end" cables with those better shielded (and cheaper!) cables I only have noise on RCA at the extreme end of A90 amplification - H Gain @ 75% volume, which I'll never see in normal use.

You want to keep the cables short, and it can be tough to find the 1ft cables, but keep looking on Amazon and they will restock.

I used "Worlds Best Cables" built with Mogami 2534 4-wire XLR and RCA 1ft cables, but WBC builds other wire brands that may do the same or better - or worse - so check specs for other wire before buying.

I was told Mogami 2549 2-wire sounds better - while the Mogami 2534 has better noise rejection, and I bought them too, but I haven't tried the 2549 cables yet. I'm giving the 2534 wire more than the recommended 175 hour burn in before switching to 2549 for A-B testing.

Here's my original posts with links:
https://www.head-fi.org/threads/topping-a90.927412/post-15789465

Here's the current 1ft listings + USB, they are currently in stock - note I set my A90 / D90 MQA side by side and these cables reach fine.

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/Foot-Directional-High-Definition-Interconnect-Connectors/dp/B01ALHTVMO

I also run the XLR cables with 2534 between the D90 MQA and A90 for A/B comparison between the XLR and RCA - and I found the RCA route is almost 1dB less volume than the XLR position on the A90 with both RCA and XLR runs using WBC 2534 wires. XLR sounds better to me, but that 1dB difference comes in handy sometimes with sensitive IEM's - I run he D90 in PRE mode @ -15.0 with those same IEM's. Remember you need to order 2 XLR cables, but the RCA's come packed as a pair.

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. (order 2!)
https://www.amazon.com/Foot-Balanced-Microphone-NC3MXX-B-NC3FXX-B/dp/B00WU1BP10

To reduce noise induced onto the power wires of the USB which transfers through the DAC ground either get a cable built / tested with the appropriate ferrite cores - or look for "real" ferrite cores to clip on to your favorite USB cable, this Tripp Lite cable was designed with the spurious nose rejection in mind, and is cheap to boot - and sounds good too as compared to my original "audiophile" USB cable:

Tripp Lite USB 2.0 Hi-Speed A/B Cable with Ferrite Chokes (M/M) 3-ft. (U023-003)
https://www.amazon.com/Tripp-Lite-Hi-Speed-Ferrite-U023-006/dp/B008VOPCGY

If you find cables that work for you please share them here on Head-fi

 

[Arniesb]

The RCA "noise" is indeed ground loop noise - and ground noise brought in from USB cable through your DAC, in my case I was able to solve the noise issues with cables designed to reject noise - the shield is used as a "faraday cage" wired to ground at the source end but left to float on the A90 end - and the cable wires are twisted pair - 2 pair - with shielding on top of that to prevent EMI noise. Then the USB cable has 2 ferrite cores - one on each end - and after replacing my "high end" cables with those better shielded (and cheaper!) cables I only have noise on RCA at the extreme end of A90 amplification - H Gain @ 75% volume, which I'll never see in normal use.

Keep them short, it can be tough to find the 1ft cables, but keep looking on Amazon and they will restock. I used "Worlds Best Cables" Mogami 2534 4-wire built XLR and RCA 1ft cables, but WBC builds other wire brands that may do the same or better - or worse - so check specs for other wire before buying. I was told 2549 2-wire sounds better, and I bought them too, but haven't tried them yet, I'm giving the 2534 wire more than the recommended 175 hour burn in before switching / A-B testing.

Here's my original posts with links:
https://www.head-fi.org/threads/topping-a90.927412/post-15789465

Here's the current 1ft listings + USB, they are currently in stock - note I set my A90 / D90 MQA side by side and these cables reach fine.

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/Foot-Directional-High-Definition-Interconnect-Connectors/dp/B01ALHTVMO

I also run the XLR cables with 2534 between the D90 MQA and A90 for A/B comparison between the XLR and RCA - and I found the RCA route is almost 1dB less volume than the XLR position on the A90 with both RCA and XLR runs using WBC 2534 wires. XLR sounds better to me, but that 1dB difference comes in handy sometimes with sensitive IEM's - I run he D90 in PRE mode @ -15.0 with those same IEM's. Remember you need to order 2 XLR cables, but the RCA's come packed as a pair.

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. (order 2!)
https://www.amazon.com/Foot-Balanced-Microphone-NC3MXX-B-NC3FXX-B/dp/B00WU1BP10

To reduce noise induced onto the power wires of the USB which transfers through the DAC ground either get a cable built / tested with the appropriate ferrite cores - or look for "real" ferrite cores to clip on to your favorite USB cable, this Tripp Lite cable was designed with the spurious nose rejection in mind, and is cheap to boot - and sounds good too as compared to my original "audiophile" USB cable:

Tripp Lite USB 2.0 Hi-Speed A/B Cable with Ferrite Chokes (M/M) 3-ft. (U023-003)
https://www.amazon.com/Tripp-Lite-Hi-Speed-Ferrite-U023-006/dp/B008VOPCGY

If you find cables that work for you please share them here on Head-fi

What usb have to do with A90 having the problems with rca inputs only? Even designer said that if you have this problem you should use A90 little brother.
With xlr inputs there shouldn't be any problem.

 

[hmscott]

What usb have to do with A90 having the problems with rca inputs only? Even designer said that if you have this problem you should use A90 little brother.
With xlr inputs there shouldn't be any problem.

A90 picks up noise via shared grounds. Ground pin's on power - A90 / D90 MQA in my case, and USB ground noise coming in from PC to D90 MQA to A90 via USB power, those combined to make the A90 RCA interconnects unusable. I had to use XLR only between the D90 MQA and A90 initially until I researched better RCA cables.

When I had the old RCA cables and USB cable connected to the D90 MQA / A90 and I removed the USB cable - disconnected from the D90 MQA end - a good portion of the "noise" coming through my headphones connected to the A90 stopped.

Here's the designer John's response to my ASR posting that I had solved the noise problem with these cables:
https://www.audiosciencereview.com/...d90-balanced-usb-dac-review.10519/post-475851
and my response:
https://www.audiosciencereview.com/...d90-balanced-usb-dac-review.10519/post-475864

I was going to return the A90 if I couldn't solve the noise problem one way or the other, but I am very happy I was able to swap out all the cables for noise rejecting cables so I could keep the A90 / D90 MQA - they sound sweet together, and just keep getting better over time.

I'm still considering different shielded AC power cables as well, I posted about that here:
https://www.head-fi.org/threads/topping-a90.927412/post-15796154

I am also using AC powerline noise filtering power strips to help reduce the induced noise coming through AC:

Rocketfish™ - 8-Outlet/2-USB Surge Protector Strip - Black
https://www.bestbuy.com/site/rocket...protector-strip-black/4689072.p?skuId=4689072

Model RF-HTS2815 has the highest EMI/RFI rejection of any in that price class, I looked for quite a while:
https://www.rocketfishproducts.com/pdp/RF-HTS2815/4689072

"47dB EMI/RFI noise filter: Protects against electromagnetic interference and radio frequency interference on power lines that can interfere with equipment performance..."

I also have another Power filter strip to put into service with better filtering specs, but the new RCA / XLR / USB cables reduced the A90 RCA noise so much I still haven't plugged it in:
" EMI/RFI Filtering 50 dB: 150 KHz ~ 1 MHz, 40 dB: 1 MHz ~ 30 MHz"

APC C25B AV C Type 10 Outlet Power Saving Power Filter, 120V,Black
https://www.amazon.com/gp/product/B00NTJ2QRY
https://www.apc.com/shop/us/en/prod...-Outlet-Power-Saving-Power-Filter-120V/P-C25B
https://download.schneider-electric.com/files?p_File_Name=MMIS-8GXJMP_R5_EN.pdf&p_Doc_Ref=SPD_MMIS-8GXJMP_EN&p_enDocType=User guide

I used to have higher performance filters, isolation transformers, and they are still available but they now priced way too high. I've had high performance devices that require filtering before, but it's been many years since I've needed to solve this problem. It was a nice trip solving it this time too.

Why would I want to downgrade to the A50s / D50s from the A90 / D90 MQA?


You'll come across some noise / hum issues over time, it's good to learn how to solve them so that you don't have to "throw in the towel" and get something other than what you want to use.

 

[Arniesb]

Well if i would buy this i just use Xlr inputs.

 

[Green Golden Retriver]

I sit quite far away from my amp . Is thier any way I can control the volume from far away. Is thier a remote I can buy - -“

 

[MatW]

I sit quite far away from my amp . Is thier any way I can control the volume from far away. Is thier a remote I can buy - -“

Only through the DAC, in pre-amp mode.

 

[Skullar]

How much is used a90 going for these days?
Lookikng to add it to smsl 500 for XLR hp out and 4.4m for iems as i only use pentagon jacks on my iems.

 

[hmscott]

I sit quite far away from my amp . Is thier any way I can control the volume from far away. Is thier a remote I can buy - -“

Not directly on the A90, but I use the D90 MQA remote control with the D90 MQA set in PRE mode - works nicely when I'm not directly next to the A90 / D90 MQA stack.

@JohnYang1997 (on ASR) said the P90 - Preamp version - will have a stepped attenuated power driven (remote controllable) volume control. But, AFAIK no retrofit for the current A90 is planned.

Maybe the next generation A90 Mark II will have a nice powered volume control too.

 

[hmscott]

How much is used a90 going for these days?
Lookikng to add it to smsl 500 for XLR hp out and 4.4m for iems as i only use pentagon jacks on my iems.

The A90's I've seen selling used are trying to get as close to $499 back... you won't save much and IDK if the sellers warranty is transferable - Hifigo said they would transfer warranty from me to the new owner (when I was thinking of selling my FiiO M15 early on), so probably buying new would be not much more than used overall.

This one went for $430:
https://www.head-fi.org/threads/topping-a90-sold.942627/
$455
https://www.head-fi.org/threads/sold-wts-topping-a90.939828/
$450
https://www.head-fi.org/threads/sold-fs-topping-a90-amp-black.937580/
$425:
https://www.head-fi.org/threads/sold-topping-a90.940213/

There is also this one that was pressed to sell, for $400, so if you find a desperate person you might save enough to make it worthwhile, if the warranty transfers:
https://www.head-fi.org/threads/like-new-topping-a90-sold.942881/