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Topping A90 Headphone Amplifier Review

ClicketEKlack

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There's quite some A90 bashing going on over at Head-Fi at the moment: https://www.head-fi.org/threads/topping-a90.927412/page-82
All started with someone reporting that his A90 died and took the headphones with it... it's still unclear why that happened, and there is still no official response from Topping. Anyone else experienced something similar with the A90?

It's the audiophile equivalent of anti-vaccine hysteria. One anecdotal incident causes widespread distrust. It's not enjoyable or informative reading.
 

AgentXXL

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I'm new here and am awaiting arrival of my Topping DX7 Pro and A90 mid-week. I saw the issue on Head-fi mentioned above re: A90 failure. There's one other user who also reported a failure, but it didn't damage their headphones. Based on the sheer number of users I'm seeing that love the A90, I tend to think these are not major concerns.

BTW - I chose the DX7 Pro (vs the D90) in the hope that it alone can adequately power my HD800, perhaps after some op-amp rolling. I ordered the A90 to pair with it as I've read a number of posts from HD800 owners stating that they pair very well with the A90. If by chance the DX7 Pro alone meets my needs, I'll just resell the A90 locally. I can use the money as it took me 3 years saving (disability income) to get to where I could afford a decent desktop setup.

Looking forward to at least giving the A90 a go.
 
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mrbungle

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I'm new here and am awaiting arrival of my Topping DX7 Pro and A90 mid-week. I saw the issue on Head-fi mentioned above re: A90 failure. There's one other user who also reported a failure, but it didn't damage their headphones. Based on the sheer number of users I'm seeing that love the A90, I tend to think these are not major concerns.

BTW - I chose the DX7 Pro (vs the D90) in the hope that it alone can adequately power my HD800, perhaps after some op-amp rolling. I ordered the A90 to pair with it as I've read a number of posts from HD800 owners stating that they pair very well with the A90. If by chance the DX7 Pro alone meets my needs, I'll just resell the A90 locally. I can use the money as it took me 3 years saving (disability income) to get to where I could afford a decent desktop setup.

Looking forward to at least giving the A90 a go.


As an owner of both: The Dx7 Pro can drive most headphones easily, especially with a balanced cable. It is my bedside setup for the Arya and it’s awesome. Plenty powerful, I usually have the volume at -31db. Sounds great. Bluetooth to the Apple TV is super reliable with zero lag.

And yeah, careful with the Topping bashing. Also a lot on Reddit right now. There is usually a Jotunheim 2 recommendation somewhere close, I guess just a lot of fan boi noise. Or in general anti-Chifi sentiments.
 

AgentXXL

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As an owner of both: The Dx7 Pro can drive most headphones easily, especially with a balanced cable. It is my bedside setup for the Arya and it’s awesome. Plenty powerful, I usually have the volume at -31db. Sounds great. Bluetooth to the Apple TV is super reliable with zero lag.

I forgot to mention that in addition to my health issues that forced me into retirement due to disability, 2 years ago I also developed tinnitus. It's the neurological variant and constant background music/movies/tv are the only thing that keeps me sane. Because of the tinnitus I tend to listen on the loud side, which is why I opted to add the A90 to my DX7 Pro order.

Glad to know the BT is solid... my Fiio Q5s seems to drift off and on, depending on the source material. I use an Nvidia Shield as my primary playback device but also own the Apple TV 4K. At least I have it as an option if the drift problem is actually the Shield. Thanks!
 

Veri

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I forgot to mention that in addition to my health issues that forced me into retirement due to disability, 2 years ago I also developed tinnitus. It's the neurological variant and constant background music/movies/tv are the only thing that keeps me sane. Because of the tinnitus I tend to listen on the loud side, which is why I opted to add the A90 to my DX7 Pro order.
I'm with mrbungle, you might not need the A90 at all.
 

Satyadhara

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Just noticed that my A90 makes a relatively quiet, but still clearly audible (from about 5cm distance), high buzzing sound (don't know how to describe it better), even when it's switched off at the front. When I turn off the main power switch at the back, the sound continues for another 30 seconds or so, then stops... any idea what that could be?
 

Veri

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Just noticed that my A90 makes a relatively quiet, but still clearly audible (from about 5cm distance), high buzzing sound (don't know how to describe it better), even when it's switched off at the front. When I turn off the main power switch at the back, the sound continues for another 30 seconds or so, then stops... any idea what that could be?
Seems like one of the power bricks inside is making that noise..
 

AgentXXL

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@mrbungle and @Veri - I received my DX7 Pro + A90 bundle yesterday, a day earlier than expected. I've spent the last day testing and becoming familiar with both devices. In my case I'm glad I opted to add the A90. While the DX7 Pro does a decent job on its own, I found it underwhelming for my SDR modded HD800 with Dekoni earpads. The HPA in the DX7 is more than ample for my Fiio FH7 and Shure SE846 IEMs, as well as my Hifiman HE560.

The HD800 itself is known to be a finicky can to pair with. The A90 handles it superbly, using Audirvana on my MacBook Pro with the Sonimus Soneq equalizer plugin. I don't need a full equalizer as I've never been bothered by the 6KHz peak that the HD800 has. I may still look at some op-amp rolling for the DX7, but for now I'm happy with the A90 for the HD800.

I had an 'ooops' moment when I couldn't get it to pair with any Bluetooth sources. Turns out I 'forgot' to install the Bluetooth antenna - it fell out of the box during unpacking, hit the floor and from there my cats made sure it was pushed far under the bed. Out of sight, out of mind. During troubleshooting I realized the antenna was missing so I went back to check the packaging and eventually found it under my bed.

Otherwise, my only other minor concern is that the DX7 Pro doesn't like my normal USB hub that's connected to the MacBook Pro. I actually have two hubs - a uGreen USB3 hub with integrated 1Gbps NIC that's velcro'ed to the MBP and connected all the time for the NIC. I then have a no-name brand USB3 hub connected that has worked well in the past with other USB DACs, but not the DX7. If I connect the DX7 directly to the MBP or to the uGreen hub, it works fine.

I'll want to keep on the lookout for a replacement hub that works as direct connecting or using the uGreen hub is a little kludgy when I'm using the MBP on my lap. Any recommended hubs from anyone? I know direct connection is preferred, but it's just a little inconvenient when using a laptop.


ToppingDX7Pro-A90-small1.jpg
 

AgentXXL

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A network music streamer may help direct USB connection or wirelessly via DNLA

Agreed. It was one of the items I had 'ordered' through the LH Labs/Indiegogo fiasco but like the rest of the $6300 US in product I'm owed, it's not very likely to ever get delivered. They had mentioned that work proceeded on the 'Geek Source' and they were even using it with the Roon OS. I'm not aware of anyone who contributed on Indiegogo actually receiving one though. Suspiciously, it looks like they used our contributions to develop the product and then sell a higher priced version on the parent Light Harmonic site. Sad, very sad.

I've thought about trying to use my old iPad Mini as a music server but haven't investigated the capability. I used to use it with a USB DAC so I could hopefully get it to work with the DX7 Pro. I just need to find which iOS software app will stream my FLAC/WAV/DSD content to the USB connected DAC without converting/transcoding it to a format that Apple supports.

In the interim, since I was able to get it working with the uGreen USB hub, I've done some re-wiring of my setup and now have a very convenient way of connecting to my MacBook Pro. In the long run I'd still like to get a streamer setup though. I'm not adverse to buying something else now that it's unlikely I'll ever receive the LH Labs items, but I need to rebuild my savings after grabbing the DX7 Pro and A90.

Oh, and the A90 has been performing extremely well with my HD800. Happiest I've been with them since purchasing them 6 years ago!
 

auronthas

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Agreed. It was one of the items I had 'ordered' through the LH Labs/Indiegogo fiasco but like the rest of the $6300 US in product I'm owed, it's not very likely to ever get delivered. They had mentioned that work proceeded on the 'Geek Source' and they were even using it with the Roon OS. I'm not aware of anyone who contributed on Indiegogo actually receiving one though. Suspiciously, it looks like they used our contributions to develop the product and then sell a higher priced version on the parent Light Harmonic site. Sad, very sad.

I've thought about trying to use my old iPad Mini as a music server but haven't investigated the capability. I used to use it with a USB DAC so I could hopefully get it to work with the DX7 Pro. I just need to find which iOS software app will stream my FLAC/WAV/DSD content to the USB connected DAC without converting/transcoding it to a format that Apple supports.

In the interim, since I was able to get it working with the uGreen USB hub, I've done some re-wiring of my setup and now have a very convenient way of connecting to my MacBook Pro. In the long run I'd still like to get a streamer setup though. I'm not adverse to buying something else now that it's unlikely I'll ever receive the LH Labs items, but I need to rebuild my savings after grabbing the DX7 Pro and A90.

Oh, and the A90 has been performing extremely well with my HD800. Happiest I've been with them since purchasing them 6 years ago!
Sorry to hear your bad experience Indiegogo.

You can get a cheaper solution like Raspberry Pi or fanless PC or Mac Mini as music streamer (I am using Auralic Aries Mini) connected to your music storage in external SSD. U can browse the music using bubbleUpnp apps via your ipad mini or phone. If music streamer is Roon supported, you can integrate them and control via Roon apps.
 

sev1

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Considering an A90 + Gustard X16 combination. So I'll be using the balanced in that case.

I have this combo and it’s fantastic. The low gain mode is great for IEMs. I’m only using the Dunu 17th Anniversary and it sounds amazing. Before I received my X16 I had my Motherboard sound card plugged into the SE input of the A90. There was a TON of noise coming from that card. With the X16 it’s dead silent. I also get to about 11-12 o clock on the volume knob.

The A90 is a perfect desktop amp. The switches work perfectly and the functions are sensible. No popping switching outputs either. Worth every penny.
 

AgentXXL

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Sorry to hear your bad experience Indiegogo.

You can get a cheaper solution like Raspberry Pi or fanless PC or Mac Mini as music streamer (I am using Auralic Aries Mini) connected to your music storage in external SSD. U can browse the music using bubbleUpnp apps via your ipad mini or phone. If music streamer is Roon supported, you can integrate them and control via Roon apps.
I've got a Raspberry Pi 3B that's sitting unused so I might look into using it for that purpose. My music is all accessible from my unRAID based NAS so rather than direct attach storage to the Pi, I'd rather just access it via SMB over the network. I suspect that's quite easy to do, but I honestly haven't looked at Pi for music other than toying around with a DAC hat (which I never did).

I'll take a look into apps for the iPad Mini as well.... also need a way to both power it and send USB to the DX7 Pro DAC at the same time so I'll need a dongle of some sort.
 

nimar

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Has anyone measured the SINAD vs Measured Level of the A90 balanced outputs in different gain modes in pre mode? From my finger in the air reading / by the specs sheet it looks almost identical to the pre90, but haven't been able to put my hands are actual measurements.

The equivalent of this from the pre90. I'm considering using an A90 mostly as a preamp, with bonus headphone amp and trying to work out Vrms vs Vpp etc etc to see if it makes sense with my power amps. Gut is it make sense, but as there are many ways to measure things its hard to make direct comparisons.

Topping Pre90 Measurements Preamplifier Balanced THD+N vs Level.png
 
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nimar

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Also do the input sensitivity numbers not suggest that in high gain it will be clipping with a usual 4Vrms balanced DAC output. Or do they mean something else entirely?

Screenshot 2021-03-23 at 3.16.22 PM.png


And am I correct in thinking with 120V power Vpp -> Vrms = (120/2)/sqrt(2) ? So 49Vpp = ~17Vrms ? Or is this totally off.

Screenshot 2021-03-23 at 3.19.14 PM.png


If I put these two things together (assuming the first is correct), does that mean with 4V coming out a DAC at medium gain, (4/8.8 = 45% of max), I can get 45% of the 17Vrms, so ~7.7Vrms coming out of the A90?
 
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Rantenti

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Definitely not. It functions as a preamp.

Great to know I can control my active speakers volume using the preamp knob.

But how do I know how much voltage the XLR output is pumping into my active speakers input at a certain position at a chosen gain (L/M/H)? My mains voltage is 220V.

My active speakers can only take eg. 24dBu at 94dB, I want to make sure I don't choose a gain setting or turn the knob too much to damage the speakers.

Thanks!
 
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