Topping A90 Headphone Amplifier Review

[Svperstar]

So I usually just use my RME ADI-2 headphone out in low power mode, but sometimes I will use my SMSL SP200 which is connected over XLR. On the SP200 the "balanced" XLR headphone out and single ended out give the exact same power since it isn't a "real" balanced amp. I only use single ended cables. I have not recabled everything even tho I have a balanced DAC.

Anyway I thought of getting an A90/A90 Discrete just for fun but I would be running RME ADI-2 XLR balanced -> A90 -> single ended output, unless I want to buy balanced cables for all my headphones........which I don't lol.

Topping was nice enough to provide a handy chart and it looks like running XLR balanced Input on the Amp then single ended output is lower performance then just going all single ended(it won't embed but here is the link):

https://m.media-amazon.com/images/I/71vDu065E-L._AC_SL1100_.jpg

 

[Veri]

That is purely theoretical though. On really short shielded cable runs then sure, but if there is some signal pollution XLR has excellent noise rejection, can be very useful with DACs.
Furthermore balanced headphone output can yield larger output power should you need it but honestly I've never owned headphones that could not be powered running a single ended cable..

 

[renaudrenaud]

Do you think this A90 is able to power a speaker with a 100dB/1W @8Ohms?

 

[Blorg]

Do you think this A90 is able to power a speaker with a 100dB/1W @8Ohms?

It's not a speaker amp. Do you mean, wiring the speakers into a headphone jack? You'd get sound out of it, should be able to use the balanced headphone out for the most power. Spec is 7.6W at 16Ω. I don't think this would make any sense though.

 

[renaudrenaud]

It's not a speaker amp. Do you mean, wiring the speakers into a headphone jack? You'd get sound out of it, should be able to use the balanced headphone out for the most power. Spec is 7.6W at 16Ω. I don't think this would make any sense though.

At the moment a 1W amp is ok for the spaker, I was wondering if the A90 was able to do the job...

 

[MyCuriosity]

Bought this amplifier and returned it thanks to Amazon’s great return policy. I was surprised that such a great measuring amplifier had constant noise when connected to the rca input. During that period I’ve looked around and here to find that this is actually a faulty design with ground loop issues. A fail for me on this design.

 

[enricoclaudio]

Bought this amplifier and returned it thanks to Amazon’s great return policy. I was surprised that such a great measuring amplifier had constant noise when connected to the rca input. During that period I’ve looked around and here to find that this is actually a faulty design with ground loop issues. A fail for me on this design.

That’s why in all new Topping amps, including the A90D, they put a Ground Loop Switch.

 

[MyCuriosity]

That’s why in all new Topping amps, including the A90D, they put a Ground Loop Switch.

View attachment 284943

Great and I was thinking to go with the D90 but it doesn’t have switches. I like simple things. Still the A90 is a fail

 

[GeorgeWalk]

Great and I was thinking to go with the D90 but it doesn’t have switches. I like simple things. Still the A90 is a fail

Ground loops are a system problem, not necessarily a single unit problem. You most likely still have a ground loop in your system, it just that other equipment masks or mutes it better. There are easy ways to track down and isolate ground loop problems.

BTW, what are you going to replace it with?

 

[MyCuriosity]

Ground loops are a system problem, not necessarily a single unit problem. You most likely still have a ground loop in your system, it just that other equipment masks or mutes it better. There are easy ways to track down and isolate ground loop problems.

BTW, what are you going to replace it with?

I get your point but still, it is a poor implementation since I don't have any issue with other equipment. I don't know which one yet but I most likely will go for the Schiit Jotunheim 2

 

[MyCuriosity]

My D30 Pro into A90 RCA is dead quiet even with A90 in high gain, 100% volume. D30 Pro in DAC mode.

What was your source into A90?

Did you try RCA to XLR cables?

The source was a cord quetest and an RME ADI-2 DAC fs. No issues on the XLR part. anyway, happy I returned it and will stay away from their equipment.

 

[MyCuriosity]

That’s why in all new Topping amps, including the A90D, they put a Ground Loop Switch.

Lifting the ground is not an option for me. I'd rather stick with well engineered devices.

 

[LancerFIN]

Sure.

Just to make sure. Do you recommend the Topping A90 for Hifiman HE-6's? Or is these some other amplifier you'd recommend for the HE-6's?

Asking here as not to grave dig the HE-6 thread.

 

[MRC01]

From what Amir has published here about the A90 and HE-6:
HE-6: 50 ohms, 94 dB SPL @ 1.25 V
A90: max 4.8 W into 50 ohm, which is 15.5 V and 0.3098 A
15.5 V is 21.86 dB louder than 1.25 V, so it drives the HE-6 to 94 + 21.86 = 115.86 dB SPL
That should be loud enough to set your hair on fire.

The A90 Discrete is not quite as powerful, maxing out at 3.7 W into 50 Ohms. That would "only" drive the HE-6 to 114.7 dB SPL. Enough to deafen you but not set your hair on fire. But the A90D has a stepped volume control with perfect channel balance at all settings, so if you are inclined in this general direction, the A90D may be the way to go.

PS generally speaking, it's unusual for the discrete version to be less powerful than the op-amp version. But it does sometimes happen.

 

[Blorg]

Just to make sure. Do you recommend the Topping A90 for Hifiman HE-6's? Or is these some other amplifier you'd recommend for the HE-6's?

Asking here as not to grave dig the HE-6 thread.

I use it with the HE6SEV2, Amir measured the HE6SE as even harder to drive than the HE6. It's way more than enough, I'm nowhere near running out of power, even using Oratory1990's EQ with negative pre-amp. Oodles of power. I got it specifically for this headphone, it's a great pairing IMO.

 

[Blorg]

PS generally speaking, it's unusual for the discrete version to be less powerful than the op-amp version. But it does sometimes happen.

By the spec, A90D is the slightly more powerful one, particularly into lower impedances (spec is 9.8W vs 7.6W max at 16 ohms). Wolf's measurements also seem to confirm the spec, although there isn't a direct comparison at 50/64, he has a 50 number for the A90 (4.3W, a bit lower than Amir) and 68 chart for the A90D.

Either should be more than enough for it though.

Measurement of Topping A90 Headphone Amp - L7Audiolab

台式设备 这是一篇早就发布在ASR上的测量。为什么我一直拖到现在才发布在自己网站上？因为我当时拿到的是工程样机。直到我从朋友处拿到一个零售版并对比基础数据没有变化之后，我才决定把测量放在这边。

www.l7audiolab.com

Measurement of Topping A90Discrete Pre/Headphone Amp（Pre Retail) - L7Audiolab

台式设备 拓品的旗舰耳放上一次更新是两年多前的2020，这两年全世界都在魔幻，在我看来世界变化之大不亚于上世纪的1989-1991。……这两年里面……拓品的核心架构研发在干什么呢？在做全分立……这就是今天我们见到的 Topping A90Discrete 了……

www.l7audiolab.com

 

[LancerFIN]

I have owned Audio-gd Master 11 since 2015. It has served me well but as we now know that Audio-gd gear isn't that great...
If the Master 11 would sell for 1000 euros that would be enough for Topping A90 + D90. Especially if both are bought used.
A90's and A90D's seem to be well available on the used market. D90's less no.

I need the DAC to also work as preamplifier with a remote for my speaker setup. D90 seems to be capable of that. Need to research well all the different versions.

edit:
A90 Discrete can be used as preamplifier and comes with a remote. So it is a better choice over the A90.

 

[MRC01]

... I need the DAC to also work as preamplifier with a remote for my speaker setup. D90 seems to be capable of that. Need to research well all the different versions. ...

If your system is balanced make sure the A90's unusually low 2 kOhm input impedance won't be a problem. From what I read, it's 10 kOhm for unbalanced, which most people use, and that won't be a problem.
More on this earlier in this thread.

 

[ChrisCables]

but as we now know that Audio-gd gear isn't that great...

based on what?

 

[LancerFIN]

based on what?

Raw measurement data from few Audio-gd product reviews on this site. Not a review of Master 11 specifically.

I don't have access to other gear to compare. I do not really know how well signal chain gear measurements translate in to audio quality.

I am a firm believer of science. Headphone measurements, speaker measurements and acoustics. I don't believe in distortion enhancing sound.

So good measurements should translate into good sound. How much it matters in the real world remains to be seen.