Topping A90 Headphone Amplifier Review

[rupert3k]

Considering upgrading for use with LCD2C, currently running L30.
Worthwhile or folly?

 

[kurosawa]

Can the Topping A90 output 10V into 64ohm from the balanced xlr headphone output?

 

[Poganin]

Has anyone here heard of or experienced intermittently shifting balance in the A90?
I got a second-hand A90 and I don't mind that the thing still plays music with the volume pot turned all the way down, but the balance in this thing is all over the place, constantly shifting to the right slowly and then going back to the middle, only to shift left. At first I thought that maybe it was because the device was cold after the delivery, but after several hours it is still doing it.
Any idea what's causing this and can I fix it by myself or is it a manufacturing issue and I should just RMA the thing?

 

[Giangi71]

Has anyone here heard of or experienced intermittently shifting balance in the A90?
I got a second-hand A90 and I don't mind that the thing still plays music with the volume pot turned all the way down, but the balance in this thing is all over the place, constantly shifting to the right slowly and then going back to the middle, only to shift left. At first I thought that maybe it was because the device was cold after the delivery, but after several hours it is still doing it.
Any idea what's causing this and can I fix it by myself or is it a manufacturing issue and I should just RMA the thing?

RMA, sure

 

[Poganin]

Alright, after some more testing it looks like the issue is not in the A90 but in my AFO because switching the cable between left and right cup kept the balance shifted to the right, and connecting the AFO to my Shanling M6 DAP displays the same behaviour.

 

[Bruzur]

Is there any downside to utilizing low gain to drive the HD 800 S?

I've done some testing, and my previous sources were not nearly as efficient, because "low gain" (on the A90) makes the HD 800 S seem like an unbelievably "easy-to-drive" headphone.

I asked about a potential "downside," namely because I've read that "loss of resolution" can occur if not powered appropriately. My desktop setup is the A90 + D70s, and on low gain, approaching noon is pretty darn loud (depending on the genre).

 

[hmscott]

Is there any downside to utilizing low gain to drive the HD 800 S?

I've done some testing, and my previous sources were not nearly as efficient, because "low gain" (on the A90) makes the HD 800 S seem like an unbelievably "easy-to-drive" headphone.

I asked about a potential "downside," namely because I've read that "loss of resolution" can occur if not powered appropriately. My desktop setup is the A90 + D70s, and on low gain, approaching noon is pretty darn loud (depending on the genre).

For my own use I use the variable output of the D90 to allow me to utilize the M and H gain positions. I can set the D90 to Pre mode (hold down SEL button as you power up to get options), then reduce D90 MQA output to -9dB and -15db to use M and L gain settings.

I don't notice a degradation in the resolution of the audio, nor an increase in noise, by using the D90 in Pre mode.

 

[ninetylol]

Is there any downside to utilizing low gain to drive the HD 800 S?

I've done some testing, and my previous sources were not nearly as efficient, because "low gain" (on the A90) makes the HD 800 S seem like an unbelievably "easy-to-drive" headphone.

I asked about a potential "downside," namely because I've read that "loss of resolution" can occur if not powered appropriately. My desktop setup is the A90 + D70s, and on low gain, approaching noon is pretty darn loud (depending on the genre).

Low and Medium gain both have lowest distortion possible. If you reduce dac volume you lose dynamic range though.

Tldr just use low gain if its loud enough.

PS: my Harmonicdyne Zeus are already pretty loud at low gain 9 a clock, thats when you can actually turn down dac a bit so you dont run into channel Balance issues at the start of the potentiometer.

 

[ALex_hha]

Will I get any advantages of A90 + D90/MQA combo vs A90 + other non topping DAC (Matrix Audio Mini-i Pro 3) ?

 

[Giangi71]

Will I get any advantages of A90 + D90/MQA combo vs A90 + other non topping DAC (Matrix Audio Mini-i Pro 3) ?

The Roon streamer function. Mini-I Pro 3 is also a headset amp, D90 no

 

[Bruzur]

Low and Medium gain both have lowest distortion possible. If you reduce dac volume you lose dynamic range though.

Tldr just use low gain if its loud enough.

PS: my Harmonicdyne Zeus are already pretty loud at low gain 9 a clock, thats when you can actually turn down dac a bit so you dont run into channel Balance issues at the start of the potentiometer.

I've kept my D70s in (pure) "DAC mode" since I've paired it with the A90.
It has been a really enjoyable listening experience thus far. I think this pairing is exceptional for the price.

 

[Rantenti]

I seem to have EMI issues when using the Topping A90.

My audio chain is:
Computer USB --> ifi iDSD Signature RCA out --> Topping A90 --> Neumann KH80 active speakers OR headphones/ IEM

After the addition of the A90, I clearly hear background buzz over all outputs (both RCA and XLR to speakers, both balanced and SE headphone out) which gets stronger when my computer's GPU is working harder (like playing videos or loading apps).

One interesting point is this phenomen remains the same when the iDSD Signature DAC is turned OFF, and only the A90 is turned ON.

Before I had the A90, the ifi iDSD Signature feeds my IEMs/ headphones/ speakers directly and the background was nearly silent, though I can detect more "hiss" when playing videos (with the video player volume at zero and the headphone out of the iDSD turned all the way up), but nothing as loud as when using the A90.

Any suggestions will be appreciated! Thanks.

 

[ALex_hha]

The Roon streamer function.

probably I was not quite clear. I just want to clarify - if I use any none Topping DAC with A90 will I get some "penalty" compared to A90 + D90

Mini-I Pro 3 is also a headset amp, D90 no

A90 already has headset amp. Is there any sense/advantages in 2 headset amp in such combo ?

 

[ninetylol]

I seem to have EMI issues when using the Topping A90.

My audio chain is:
Computer USB --> ifi iDSD Signature RCA out --> Topping A90 --> Neumann KH80 active speakers OR headphones/ IEM

After the addition of the A90, I clearly hear background buzz over all outputs (both RCA and XLR to speakers, both balanced and SE headphone out) which gets stronger when my computer's GPU is working harder (like playing videos or loading apps).

One interesting point is this phenomen remains the same when the iDSD Signature DAC is turned OFF, and only the A90 is turned ON.

Before I had the A90, the ifi iDSD Signature feeds my IEMs/ headphones/ speakers directly and the background was nearly silent, though I can detect more "hiss" when playing videos (with the video player volume at zero and the headphone out of the iDSD turned all the way up), but nothing as loud as when using the A90.

Any suggestions will be appreciated! Thanks.

ground loop through pc usb. use xlr and issue will be gone.

 

[DuncanDirkDick]

probably I was not quite clear. I just want to clarify - if I use any none Topping DAC with A90 will I get some "penalty" compared to A90 + D90


A90 already has headset amp. Is there any sense/advantages in 2 headset amp in such combo ?

You mean if there's a synergy between A90/D90? No, besides that they'll fit nicely on top of each other. There's no penalty either.

 

[Rantenti]

ground loop through pc usb. use xlr and issue will be gone.

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.

 

[pma]

I do not understand why so many audio manufacturers (and designers) remain blind to obvious ground loop issues and design their low-power components (DACs, preamps) as class I components with signal ground connected to mains protective earth. Are they such ignorants or what? And unfortunately even the reviewers do not emphasize this issue enough and make their tests in unnatural clinical laboratory conditions, like AP with its floating or balanced I/O. What do you think, @amirm ?

 

[Poganin]

In my case I eliminated USB ground loop hum and interference by changing the power strips my devices are connected to, so in my case the PC, monitor, router, and external hard drive are connected to power strip A, while the DAC and amps are connected to another power strip. No interference.

 

[Atanasi]

design their low-power components (DACs, preamps) as class I components with signal ground connected to mains protective earth

I assumed this design allows better SINAD. I think all the best performing DACs and amps are class I.

 

[ALex_hha]

You mean if there's a synergy between A90/D90?

exactly. Maybe some additional features which are not available in A90/non Topping DAC