• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Topping A90 Headphone Amplifier Review

Tks

Major Contributor
Joined
Apr 1, 2019
Messages
3,221
Likes
5,494
@Wegi76

Firstly, yeah, that does sound it would mess up your speaker.

The kid is a problem regardless of the idea of speakers biting the dust, you need to rectify this on your own by removing access to such things away from children. It wouldn't be his fault, and would obviously be yours (goes without saying), so even if you have to build a castle around it, it's something you need to simply do. The RME has a volume lock feature where you could limit output. To what volume level at what gain for your ideal aspiration and contextual use-case? I have no idea, you would need to measure that output at the A90's output yourself.

Also, if they're active speakers, why not digitally have them connected with a source? That will bypass the hit you take doing the AD conversion from the preamp to the active speaker which then also needs to do a DA conversion. On top of allowing your son to play with the volume knob of the A90 all day.

As far as practical advice with your son in the picture. Have the D90 maxxed out volume on lowest gain (unless the kid has access to gain as well somehow, then start with highest gain), and use volume control of the RME DAC while listening to some content. Take up the volume of the RME until you hit a limit that would be loud enough to where the kids' ears (or yours) would be a worry before the lesser worry of drivers frying (at least I hope drivers are a lesser cause of concern than you or your sons ears). Once that upper limit is found, just lock it in there, and forget about it until the kid grows up or something.

Sorry I couldn't be of more help. But it's tricky without measuring the output yourself and/or removing the child from equation.
 

Wegi76

Active Member
Joined
Apr 8, 2021
Messages
107
Likes
85
Thanks @Tks for your thoughts, really appreciate them.

Knobs and switches are simply irrisitible to him. I know, because he`s my son and I was no different as a child (probably still the case). Removing physical access to the gear won`t work, so I`ll have to be careful and check, if all settings are still like they should before starting playback.

Also, if they're active speakers, why not digitally have them connected with a source? That will bypass the hit you take doing the AD conversion from the preamp to the active speaker which then also needs to do a DA conversion. On top of allowing your son to play with the volume knob of the A90 all day.

My current setup is like this:
1) PC --> USB --> Active Speakers
2) PC --> USB --> RME ADI2DAC --> XLR --> A90
3) Chomecast TV Dongle --> HDMI Audio Extractor --> SPDIF --> RME ADI2 DAC --> XLR --> A90 --> XLR --> Speakers | Headphone Out

I connected things like this, because of the two separate sources which I both want to be able to listen to via the speakers OR via headphone. But thinking about it and your idea... Probably should have bought a SPDIF Splitter like this instead of the XLR cables to interconnect the A90 with the Speakers :rolleyes:

Alternative idea:
1) PC --> USB --> Active Speakers
2) PC --> USB --> RME ADI2DAC --> XLR --> A90
3a) Chomecast TV Dongle --> HDMI Audio Extractor --> SPDIF --> SPDIF Splitter --> SPDIF 1 --> RME ADI2 DAC --> XLR --> A90 for Headphones
3b) Chomecast TV Dongle --> HDMI Audio Extractor --> SPDIF --> SPDIF Spliiter --> SPDIF 2 --> for Active Speakers

--> Only digital connections to the speakers, no unnessary DA conversions and nothing could be destroyed easily.

Think I`ll try this out.

Cheers
Markus
 
  • Like
Reactions: Tks
Joined
May 3, 2021
Messages
9
Likes
4
@Wegi76

Firstly, yeah, that does sound it would mess up your speaker.

The kid is a problem regardless of the idea of speakers biting the dust, you need to rectify this on your own by removing access to such things away from children. It wouldn't be his fault, and would obviously be yours (goes without saying), so even if you have to build a castle around it, it's something you need to simply do. The RME has a volume lock feature where you could limit output. To what volume level at what gain for your ideal aspiration and contextual use-case? I have no idea, you would need to measure that output at the A90's output yourself.

Also, if they're active speakers, why not digitally have them connected with a source? That will bypass the hit you take doing the AD conversion from the preamp to the active speaker which then also needs to do a DA conversion. On top of allowing your son to play with the volume knob of the A90 all day.

As far as practical advice with your son in the picture. Have the D90 maxxed out volume on lowest gain (unless the kid has access to gain as well somehow, then start with highest gain), and use volume control of the RME DAC while listening to some content. Take up the volume of the RME until you hit a limit that would be loud enough to where the kids' ears (or yours) would be a worry before the lesser worry of drivers frying (at least I hope drivers are a lesser cause of concern than you or your sons ears). Once that upper limit is found, just lock it in there, and forget about it until the kid grows up or something.

Sorry I couldn't be of more help. But it's tricky without measuring the output yourself and/or removing the child from equation.

Why would the preamp being doing an AD conversion? Or the speakers?

Once the DAC does the DA conversion, the chain will remain analog. The A90 is an analog device. And the powered monitors are an analog device.

Using their stand alone DAC is likely to be much higher quality than the dac built into their powered monitors.
 

Tks

Major Contributor
Joined
Apr 1, 2019
Messages
3,221
Likes
5,494
Why would the preamp being doing an AD conversion? Or the speakers?

Once the DAC does the DA conversion, the chain will remain analog. The A90 is an analog device. And the powered monitors are an analog device.

Using their stand alone DAC is likely to be much higher quality than the dac built into their powered monitors.

The preamp wouldn't, the speakers would.

Now obviously you could have line level inputs that can bypass the AD and another DA conversion, but since I'm not sure if this is what OP has, or if he wants to sacrifice on-board functionality like the volume control (or whatever else may be going on). It also cuts down on the primary concern of his child messing with the A90's volume knob if he opts not to have the RME at anything other than a very high output.

So sure, I guess if his speakers support complete bypass if internal processing with the analog inputs - then what you say makes sense. Whether that's the case, I don't know.

Good point nonetheless.
 

Wegi76

Active Member
Joined
Apr 8, 2021
Messages
107
Likes
85
Hi there, my speakers would definitely perform an internal AD conversion when connecting them via one of the analogue inputs. So it would be a DA -> AD -> DA conversion... So Tks was right.

The speakers do have a DSP built in that works for all input (i.e. for room correction, HPF/LPF, EQing, etc...) If you´re interested...We`re talking about Nubert Nupro X4000 RCs

What I would really like to know: Am I reading the numbers wrong or would the A90 really spit out such high voltages? I have no voltmeter here to measure myself. If so, one must be very careful when connection anything that expects line levels, I guess. Will disconnect the XLR cables and wait for the S/PDIF Splitter to arrive.

Thanks guys!
 
Last edited:

Tks

Major Contributor
Joined
Apr 1, 2019
Messages
3,221
Likes
5,494
I've never seen those speakers, but man, they look amazing (props to them for the outstanding number of inputs, great functionality, and a bunch of features too).
 

Wegi76

Active Member
Joined
Apr 8, 2021
Messages
107
Likes
85
The Nubert brand is well known in Germany but probably not internationally. Besides all the tech stuff they sound fantastic and go down to 30hz. A shame that Amir probalby will never get a pair in, because they are are irrelevant in the US. But that`s enought OT in this threat, I think :)
 
Joined
May 3, 2021
Messages
9
Likes
4
Hi there, my speakers would definitely perform an internal AD conversion when connecting them via one of the analogue inputs. So it would be a DA -> AD -> DA conversion... So Tks was right.

The speakers do have a DSP built in that works for all input (i.e. for room correction, HPF/LPF, EQing, etc...) If you´re interested...We`re talking about Nubert Nupro X4000 RCs

What I would really like to know: Am I reading the numbers wrong or would the A90 really spit out such high voltages? I have no voltmeter here to measure myself. If so, one must be very careful when connection anything that expects line levels, I guess. Will disconnect the XLR cables and wait for the S/PDIF Splitter to arrive.

Thanks guys!

If that is the case, then why even connect them to the A90? You won't be gaining any sound quality, you would only be losing SQ.

Don't hook them up to your DAC or A90 at all. Just hook them up directly through USB. Going from D, to A, to D, back to A is going to degrade sound quality, and just be an invitation for problems, with zero benefit.

Just hook them up to USB and let the speakers do only one D to A.
 

Wegi76

Active Member
Joined
Apr 8, 2021
Messages
107
Likes
85
@TurdiesBirdies: Reason is, that I want to be able to listen to both sources (my Computer via USB and the Google dongle via S/PDIF) with headphones or alternatively via the loudspeakers without having to switch cables all the time. Since the ADI2 does not have a digital output and anlogue is already connected to the A90, the idea was to use it for this purpose. A simple pass through would have done the job also, since I absolutely do not need the volume control on the A90 (speakers already do it for me) Spending the few bucks for the XLR cables seemed to be a good idea to me in the first place, until the S/PDIF Splitter idea came up, which isn`t expensive either and should be the better solution (can`t damage anything / all digital, input switching within the speakers) :)
 
Last edited:
Joined
May 3, 2021
Messages
9
Likes
4
@TurdiesBirdies: Reason is, that I want to be able to listen to both sources (my Computer via USB and the Google Donge via S/PDIF) with headphones or alternatively via the loudspeakers without having to switch cables all the time. Since the ADI2 does not have a digital output and only analogue outputs which are already connected to the A90, the idea was to use it for this purpose. A simple pass through would have done the job also, since I absolutely do not need the volume control on the A90 (speakers already do it for me) Spending the few bucks for the XLR cables seemed to be a good idea to me, until the S/PDIF Splitter came into my mind, which isn`t expensive either and should be the better solution (can`t damage anything / all digital) :)

If your goal is sound quality, buy another USB cable. USB to speakers, USB to DAC to A90 to headphones. Then just change your sound output on Windows or Linux , whichever one you are using.

Since your speakers will convert any analog input back to digital, I would avoid their analog inputs all together.

I have a similar setup, except I have powered studio monitors, without any sort of digital stage in them.

So I run USB to X16 DAC, to A90, A90 preamp XLR to monitors, A90 RCA out to Sub, and A90 HP out to HP. And use the A90 to control the sound levels for all devices. Which gives me only one D to A conversion.

But in your setup it would double the D to A conversions. And possibly risk the input stage/ADC in your powered speakers. So it may not be ideal from a usability standpoint, but the best solution would be leaving the A90 and DAC out of your chain to the speakers.
 

Wegi76

Active Member
Joined
Apr 8, 2021
Messages
107
Likes
85
Maybe I did not explain it well, my english is not that great... So: Somputer is hooked up exactly like you said already, no problems what so ever here. My 2nd source (the Google TV dongle --> HDMI Audio Extraktor --> S/PDIF optical cable thing...) is a separate chain and does not run trough the PC... If I connect it directly to the speakers, I won`t be able to use headphones, if I connect it to the DAC, I won`t be able to use the speakers. Solution: S/PDIF Splitter behind the Audio extractor. One in --> 2 Out. One goes into the speakers Toslink input, one into the DACs Toslink input.

Using the A90s output switching feature was a stupid idea because the output level does not match the expected input level on the speaker side.

Thanks for your replies and greetings from germany :)
 

darth_elle

New Member
Joined
May 5, 2021
Messages
3
Likes
4
I was super excited to purchase an A90 to go alongside my EQ'ed HD800S. It's overkill for my current setup, but I wanted to purchase something that would drive whatever I buy in the future. However, [after purchasing today] it just occurred to me that I live in an old house and the bedroom is not wired with a ground line (US).

It's a very small rental house and the attic is inaccessible to run the ground line myself. I installed a GCFI outlet (without a ground line) in the office to safely plug up my workstation. However, this situation relies on my expensive power supply falling on the grenade in the case of some electrical malfunction (the A90 does not have that luxury). My bedroom outlet is not really accessible to do the install as it would take hours just taking things out of the room. I honestly don't want to go to that effort and risk scratching furniture or throwing out my back.

Any thoughts on safely plugging the A90 into the bedroom?
 
D

Deleted member 31750

Guest
That’s the only piece of equipment I had to return for a full refund. :(
 
D

Deleted member 31750

Guest
Kind of vague post. What do you refer to?
Had a grounding issue when using RCA. I will not mention the sound with XRL compared to other amplifiers I have because that can be subjective. My take from the measurements and what I’ve heard is that measurements does tell you if the design is free of faults but that as far as I would go.
 
Joined
May 3, 2021
Messages
9
Likes
4
Had a grounding issue when using RCA. I will not mention the sound with XRL compared to other amplifiers I have because that can be subjective. My take from the measurements and what I’ve heard is that measurements does tell you if the design is free of faults but that as far as I would go.
Another vague post.

Why are you even saying anything, if you aren't willing to actually say something?
 
D

Deleted member 31750

Guest
Another vague post.

Why are you even saying anything, if you aren't willing to actually say something?
You don’t have to be rude. The amplifier had a grounding issue when the usb and rca out was connected resulting to a buzzing noise. with the XLR out it didn’t have the same Issue. Regarding my impression on the amp I didn’t say anything because that’s my personal experience with the unit and is subjective. do you want to know my subjective experience with this unit?
 

AudioStudies

Addicted to Fun and Learning
Joined
May 3, 2020
Messages
718
Likes
398
Just got an A90. I had been leaning towards the A30 Pro, but choose the A90 for the preamp capability (instead of just pass through), and the fact that it doesn't look like swiss cheese on the top. Mine will be placed in plain view. Also matches my D90 as they sit side by side. Early impressions are that I think the A90 is fantastic. Drives my Sennheiser 650 clone very well, and also drives my Audeze Sine very well. Both those headphones I can drive on the low gain setting, even though I tried medium at a lower volume also. Sound is great, unit looks great, and yes -- works quite well as a preamp feeding powered monitors. Exterior depicts great build quality and the volume knob is fun to use. The only thing I wish they had done different -- is to have one more headphone output socket, so I wouldn't have to use an adaptor. Other than that, this is one helluva a great piece of gear. Great job, Topping.
 

Rantenti

Member
Joined
Mar 11, 2021
Messages
93
Likes
19
Thanks for your advice!

The ifi iDSD Signature does not have XLR outputs. I will receive a Gustard X26 Pro and some Mogami 2549 XLR cables soon, then I can start feeding the A90 balanced signals.

I had been using the iDSD Signature and recently received the Gustard X26 pro. I kept using RCA cables (stock cables / Mogami 2497) between the Gustard and A90, then XLR cables from A90 to the Neumann KH 80.

Buzzing noises could be softly heard on the Neumann, and it was very loud when I used IEMs plugged into the Topping A90.

1. I added an ifi iDefender to the USB cable, 90% of the noise is gone. This showed that there was a ground loop. Still some noise remained.

2. The remaining noise waxed and waned with GPU usage (eg. playing a video without sound), so there must be some EMI noise as well. Moving the A90 away from the computer and router lessened this noise. Moving the Gustard X26 Pro had no effect, perhaps due to shielding by the thick aluminum casing.

3. Occassionally, there was an extra 1kHz whine and intermittent buzz that the iDefender couldn't remove. I unplugged the router, it disappeared So the router (which was ungrounded), must be one of the culprits of noise too.

Today, I received my much needed second pair of XLR cables and now both my DAC-Amp and Amp-Neumann connections are Mogami 2549 XLR. All noises are gone, even without the iDefender.

There are a few interesting observations.

1. If I connect the DAC and the A90 with BOTH RCA and XLR cables in place, even if I flipped the switch to XLR input on the A90, all noises will be present.

2. The Wifi router related noise could not be replicated now, after I unplugged the router and all the LAN cables and replugged them in. I hope they don't come back.

3. The if iPurifier doesn't always reduce noise. In my previous configuration where the iDefender reduced 90% of the ground loop noise, adding an iPurifier to the USB gave me double the noise.

Finally, all my equipment are plugged by UK plugs (except the router) into two power strips (Belkin/ Schneider) going into one grounded wall mains socket.

Happy to share my experience and to learn from you all.
 
Last edited:

fendy323

Member
Joined
Jun 27, 2020
Messages
46
Likes
2
hello guys,
my setup is topping combo a90+d90,
sudenlly my headphone no sounds, but a90 and d90 power still on.
i already tried to change from usb source to bluetooth, but still no sound, what should i do?
 
Top Bottom