Topping A90 Headphone Amplifier Review

[GeorgeWalk]

The extender requires the preamp pre90 as output. Existing a90 can interface with pre90 but not the extender.

Are you talking about two devices: pre90 and extender in addition to the A90? Also, I did a quick google search can't find either of those devices, can you send links?

 

[JohnYang1997]

Are you talking about two devices: pre90 and extender in addition to the A90? Also, I did a quick google search can't find either of those devices, can you send links?

A90
Pre90
Extender to Pre90
The latter two have not been released yet.

 

[DavidH]

I've not had my A90 for long, but it's obvious straight out of the box that it's an amp that sounds great, not just one that measures well. No surprise there, of course but it's especially good for the asking price. Design and build quality are very impressive.

Four subjective first impressions from me:
1) Great features, front switches and balanced in/outs (so far I've only used SE output). Runs only warm.
2) Very clean, neutral, dynamic sound, as measurements would suggest. Well controlled bass.
3) Pairs really well with my HD800. Perhaps not quite as smooth & open sounding as HD800+Trilogy 931, but impressively close.
4) Good sound with DT880 600Ω. Usually enough volume using high gain, though I am at >75% volume for some classical. The A90+DT880 sound is possibly a little flat compared with amps that can provide more power. I might try to provide the A90 with a 3V input to see if that helps it pair better with the DT880s.

I am exceptionally happy with the A90. It will displace others in my collection. It's a stunningly good amp for nearly all of my headphones.

If I didn't love the sound of the 880s when driven with 600mW potential, I now probably wouldn't need any other headphone amp. So for most people, this could be an 'end game' amp. I am now likely to order the D90 to pair with the A90, so I'll get remote volume control.

This headphone amp will embarrass many far more expensive amps.

(I used: QobuzHD/FLAC->Roon->USB->Chord Qutest @ 2V/SMSL Sanskrit 10th Mk2->A90 SE->54yr-old ears. Classical, Indie & Hard rock music.)

 

[JohnYang1997]

I've not had my A90 for long, but it's obvious straight out of the box that it's an amp that sounds great, not just one that measures well. No surprise there, of course but it's especially good for the asking price. Design and build quality are very impressive.

Three subjective first impressions from me:
1) Great features, front switches and balanced in/outs (so far I've only used SE output). Runs only warm.
2) Very clean, neutral, dynamic sound, as measurements would suggest. Well controlled bass.
3) Pairs really well with my HD800. Perhaps not quite as smooth & open sounding as HD800+Trilogy 931, but impressively close.
4) Also good sound with DT880 600Ω. Usually enough volume using high gain, though I am at >75% volume for some classical. The A90+DT880 sound is possibly a little flat compared with amps that can provide more power. I might try to provide the A90 with a 3V input to see if that helps it pair better with the DT880s.

I am exceptionally happy with the A90. It will displace others in my collection. It's a stunningly good amp for nearly all of my headphones.

If I didn't love the sound of the 880s when driven with 600mW potential, I now probably wouldn't need any other headphone amp. So for most people, this could be an 'end game' amp. I am now likely to order the D90 to pair with the A90, so I'll get remote volume control.

This headphone amp will embarrass many far more expensive amps.

(I used: QobuzHD/FLAC->Roon->USB->Chord Qutest @ 2V/SMSL Sanskrit 10th Mk2->A90 SE->54yr-old ears. Classical, Indie & Hard rock music.)

Can relate on the dt880 600ohm. Just got mine today due to Zeo's review. I had mine in 2017 and was my favorite but sold it for something else. Still sounds great, a bit bright and sibilant sometimes but is controlled to an acceptable level.

 

[DavidH]

Can relate on the dt880 600ohm. Just got mine today due to Zeo's review. I had mine in 2017 and was my favorite but sold it for something else. Still sounds great, a bit bright and sibilant sometimes but is controlled to an acceptable level.

True. I find DT880 600 are great for certain music though.
I'm not a fan of Zeos but I think he's right that DT880+Emotiva A-10 is a really good match. Still, your A90 is superb for everything else I've tried. Big respect, sir.

 

[Ddd]

Beautiful 9090 stack!

Raised some height for both unit's feet for better heat dissipation!

 

[Ntrax]

Legend.

 

[Ben Tuinstra]

You can simply turn the volume on A90 all the way up and use pre90 to do the volume control.

Hi I was thinking in the same direction as Bumelant. It would be great to have the pre90 as center device off a system with headphones and speakers where both have their own volume control, the speakers through the pre amp and the headphone through the a90. But, therefor a line out is needed on the pre90. But reading here seams to hint in an other direction. I' m not sure how to accomplish this. Happy owner of d90 and a90

 

[dixter]

True. I find DT880 600 are great for certain music though.
I'm not a fan of Zeos but I think he's right that DT880+Emotiva A-10 is a really good match. Still, your A90 is superb for everything else I've tried. Big respect, sir.

I can say I really like the DT880 600 with a tube amp.... just fantastic...

 

[Ddd]

Update:
Got my replacement A90 in today. First one had a weird feel of the wipers in the pot. A minor issue but Apos replaced the amp absolutely no questions asked. Shockingly good service. Popped it open to confirm topping did indeed use thermal paste on the heatsink this time, applied well too. I tossed on some pads in it's place as that's what I've got on hand. Requires a 10inch key wrench to open so, beware there. Really nice build quality... Here are some PCB shots for the curious.
View attachment 68288
View attachment 68289
View attachment 68290

Hello

May I know what is the experience you had with the volume wiper port issue? Is it loose?

 

[Veri]

Hello

May I know what is the experience you had with the volume wiper port issue? Is it loose?

I asked him and he replied "The wipers in pot were (too) tight, there was a few mm of soft movement followed by tightness from the wiper assembly movement during volume adjustment." so basically the pot not functioning as it should. Not loose, though.

My A90 arrives monday it was friday but got delayed. of course.

 

[JohnYang1997]

I asked him and he replied "The wipers in pot were (too) tight, there was a few mm of soft movement followed by tightness from the wiper assembly movement during volume adjustment." so basically the pot not functioning as it should. Not loose, though.

My A90 arrives monday it was friday but got delayed. of course.

This can happen. It's due to external fource being applied to the pot. However this is not an issue in normal use.

 

[Ddd]

This can happen. It's due to external fource being applied to the pot. However this is not an issue in normal use.

I see, because my unit is as what Veri mentioned, that the volume pot have few mm of loose turning movement before it grips the potentiometer and tighten a bit like a clutch in and volume changes..

During the loose movement, there's no volume changes until the potentiometer gets the grip

Is this normal?

 

[JohnYang1997]

I see, because my unit is as what Veri mentioned, that the volume pot have few mm of turning loose movement before it grips the potentiometer and tighten a bit and volume changes..

During the loose movement, there's no volume changes until the potentiometer gets the grip

Is this normal?

EDIT: In short, it's normal. So no worries.
This behavior can varies from units. But I consider this normal as you can adjust volume just as usual.
It's not normal if you get severe imbalance at low volume position. That case it's faulty.

 

[GeorgeWalk]

EDIT: In short, it's normal. So no worries.
This behavior can varies from units. But I consider this normal as you can adjust volume just as usual.
It's not normal if you get severe imbalance at low volume position. That case it's faulty.

I got my A90 on Saturday and I have been listening too it a lot. I haven't had any issues with the volume pot. Mine moves smooth as silk and is responsive all across its range. I haven't noticed any channel imbalance.

 

[Veri]

I got my A90 on Saturday and I have been listening too it a lot. I haven't had any issues with the volume pot. Mine moves smooth as silk and is responsive all across its range. I haven't noticed any channel imbalance.

Awesome

 

[Rigel]

I see, because my unit is as what Veri mentioned, that the volume pot have few mm of loose turning movement before it grips the potentiometer and tighten a bit like a clutch in and volume changes..

During the loose movement, there's no volume changes until the potentiometer gets the grip

Is this normal?

Hi Ddd. I think I know what you mean. It's a slight slack, but if it's like in my case, I don't see it as a problem beyond that.

I don't see it affecting the volume setting which is good and I also appreciate it balanced on the two channels. It has a better feel than that of the SP200 for example, the movement is much smoother and transmits more quality and as a curiosity, the knob of the potentiometer is made of solid aluminum, like the buttons of the D90.

The quality of internal and external finishes like the D90, are good and with nothing to reproach at a glance. Welding, machining etc. And its sound, which is important, just as very good.
Neither of them disappointed me. Thanks again to the forum and its reviews.
If you want, I can put photos if someone wants to see something in particular.

BTW, although I initially placed the order with Audiophonics, they gave me a very long lead time. Finally I ordered it directly from Shenzenaudio and it arrived in a few days. I live in Spain.

 

[dixter]

Just in case some of you may use the A90 amp and move it from time to time and require the shipping box.... the internal foam is not cut out correctly for the three switches... and you need to take care when putting the A90 back into the shipping box and taking it out of the box or you will damage the three switches..... this is the same shipping box they use for the D90 and it does not have switches like the A90... if you plan on using the shipping box quite a bit it might be better to cut out the section of the foam to keep the switches safe....

 

[DavidH]

Good call. I noticed that too. I modified the foam in my box immediately.

 

[Pillars]

This can happen. It's due to external fource being applied to the pot. However this is not an issue in normal use.

The pot in question had not experienced any external force. I had planned to open the unit for photos however after feeling the pot I contacted Apos for a replacement same day. I believe this was a one off, my second unit was flawless.