Topping A90 Discrete Review (Headphone Amp & Preamp)

[John B]

I just got my unit back from service with a significant channel mismatch. I had the channel failure everybody is having with same error codes until it completely bricked. Freq response and output are way off now. Anybody have an experience with this happening? Did you have to send it back again? Service has been OK so far. Will share if that changes.

 

[John B]

Update, topping took care of my issue and was reasonably responsive even though I had to chase them now and again.

 

[Predatowned]

I'm buying a pair of used krk rokit 7" powered studio monitors from my buddy soon and I'm checking how my existing a90D would fair driving via XLR lineout vs connecting directly to my d30 pro DAC with XLR lineout? I'm a noob and I'm not sure what I'm looking at when comparing tech specs between devices

 

[fametrano]

I'm buying a pair of used krk rokit 7" powered studio monitors from my buddy soon and I'm checking how my existing a90D would fair driving via XLR lineout vs connecting directly to my d30 pro DAC with XLR lineout? I'm a noob and I'm not sure what I'm looking at when comparing tech specs between devices

I would go d30 -> a90D -> rokit (see my signature for a similar setup)

 

[fametrano]

I've swapped my old A90 with a new A90D and I'm happy about it.

My only issue: I used to provide power to the mains to turn both D90SE and A90 on; instead, the A90D when powered goes into standby and I have to use the front power button. I know that the A90D has a 12V trigger that can be used as 12V trigger IN, but the D90SE does not have a 12V trigger OUT.

Is there any setting I could use to solve this issue?
Is there a cheap power sensing device that can sense when a power comes on and sends a 12V trigger to the A90D?
I am aware of the audiophonics 12v trigger, but that is trigger IN, while I'm looking for a trigger out for the D90SE.

 

[wwenze]

I've swapped my old A90 with a new A90D and I'm happy about it.

My only issue: I used to provide power to the mains to turn both D90SE and A90 on; instead, when powered the A90D goes into standby and I have to use the front power button. I know that the A90D has a 12V trigger that can be used as 12V trigger IN, but the D90SE does not have a 12V trigger OUT.

Is there any setting I could use to solve this issue?
Is there a cheap power sensing device that can sense when a power comes on and sends a 12V trigger to the A90D?

Any 12V power supply can work as a trigger

For me I'd just take the power supply of an unused router and replace the head with 3.5mm

 

[bequietjk]

After all these years has the A90D been deemed to be more problematic than is worth buying at this time? Perhaps I'm overlooking something... I'm just looking for a hpa south of $500 south with perfect channel matching for audio recording/mixing/mastering. Yes, an audio interface would suffice but we love gear, why wouldn't we have an external hpa connected to your audio interface? Need something 99.9% reliable set-it-and-forget-it.

 

[ivanfraser]

Having swapped out all rcas in favour of xlr - I've installed the ext90 - I have eliminated all trace of noise in my system.
A question for those who know. Is 99 level output equivalent to passthrough?
I have the kit set to output from DAC via xlrs to the xlr input on the A90D; and from the A90D via xlr output to the xlr input on my amp.
It seems good so far and levels seem equivalent to player direct to xlr.
Is this a neutral path from player to amp, when preamp output is set at 99?
Would there be benefit to lowering that?
Would there be any benefit to using high gain on that chain?
Thanks in advance.

 

[staticV3]

A question for those who know. Is 99 level output equivalent to passthrough?

Low gain + Volume 87 is effectively pass-through, as Amir's measurement shows:

Is this a neutral path from player to amp, when preamp output is set at 99?

If by neutral you mean transparent, then yes.

Would there be benefit to lowering that?
Would there be any benefit to using high gain on that chain?

Depends on the Amplifier.

 

[ivanfraser]

Low gain + Volume 87 is effectively pass-through, as Amir's measurement shows:
View attachment 402955


If by neutral you mean transparent, then yes.


Depends on the Amplifier.

Thank you for that. The aim is to have equivalent to passthrough with 4v xlr input, and you've given the exact answer I was seeking.
Only 1 thing is a little unclear to me: if 99 is neutral/transparent signal, does this mean that between 87 and 99 there is some amplification? (or is this merely the result of the increased output voltage of 4, over the more usual 2?)
I'm used to old school preamp which is basically a pot that only reduces amplification from full 0db to -db.
I had assumed the same with the A90. That 'full' volume equalled a 0bd passthrough.
And if that is neutral/transparent, it wouldn't affect signal.

Otherwise, the 99 setting would theoretically be risking clipping, depending, as you say, on amp.
Mine's an Audiolab 9000A.
UB9000 via xlr to A90D, and an Audiolab 8300CD as dac to a second XLR on the A90D, which outputs 4.2V via balanced xlr.

I did think I could detect some clipping at 99 just now on a cd which is mastered very loud (Bruce Dickinson's Tattooed Millionaire), and so changed to 87, which appears fine.
That's via the 4v dac.

However, the UB9000 Br player outputs 2v balanced via xlr.
Do you know what is the ideal output level for that as basic 0db transparent passthrough?
I suspect the 99 will be ok then?

The volume level at that setting appears to be equal to that when direct from player to amp via xlr.

Thank you once again for a super quick and super useful reply!

 

[staticV3]

if 99 is neutral/transparent signal, does this mean that between 87 and 99 there is some amplification?

You misunderstood.

I meant transparent as in high fidelity. Gain is a separate, unrelated matter.

Keep in mind that 87 volume in Low gain ≠ 87 volume in High gain.

If you want to make sure that you've set your A90 to Unity gain, then all that you need is a basic multimeter.

 

[ivanfraser]

You misunderstood.

I meant transparent as in high fidelity. Gain is a separate, unrelated matter.

Keep in mind that 87 volume in Low gain ≠ 87 volume in High gain.

If you want to make sure that you've set your A90 to Unity gain, then all that you need is a basic multimeter.

Your answer re 87 at low gain seems ideal. I don't use high gain generally.

To my ears, low 87 seems pure hi fidelity to me via amp/speakers.

I had only just realised the voltage difference between my 2 xlr inputs - the one at 4 and one at 2. There will be an ideal setting for the 2v - presumably different from the 4v one?

Thanks again.

 

[mackman]

I'm confused. What would be the advantage of using a pre-amp between a dac and a power amp if you're setting it to unity gain?

 

[ivanfraser]

I'm confused. What would be the advantage of using a pre-amp between a dac and a power amp if you're setting it to unity gain?

It's my headphone amp. So all my kit needs to run through the dac via spdif, (and my BR player) to the A90D.
Therefore, the output to the main (integrated/power) amp comes from the A90D as a preamp.
But it only needs a static signal to use with the amp's xlr input.

I have 2 choices: use the xlr out to the xlr in on the integrated amp; or, use the A90D as a pure pre-amp direct to the main amp via the power amp setting.
If I use the xlr in on the integrated amp, I need a same in/same out via the A90D - as though in pass-through mode. Hence setting the output level on the A90D to a static level.

I chose xlr-only route because I have noise issues in various wiring configs (only with rca and coax combos, as well as some power line level issues, not just ground loop issues), so have eliminated rca and coax connections in favour of optical and xlr and figured the best power line arrangement. Now I have zero noise at max volume in any of my outputs/inputs.

Next step is to see if using the A90D as a preamp with the power amp is better than the former. I have only the rca from pre to power option, and hope this does not introduce any noise.

If it doesn't then I will be using the A90D as a preamp proper.

 

[simplywyn]

Mine came with FW 2.4 out of the box, so I probably got one of the later batches of 2022. Looking at the trends in this thread, it seems that only the first few of batches have this particular issue and newer 2023 batches seem fine. I do have an optimistic hunch that this is something they fixed in later batches, but on the extremely pessimistic side, it may be a time-related trigger that later batches might eventually encounter. I do honestly hope it is the former.

I use my A90D almost daily since my purchase, and I enjoyed it very much... That's why this is quite devastating to me personally.

My Topping A90D just went kaput, what can I do? I bought around the same time in April 2023, and now it's giving me a -5 error and doesn't turn on.

 

[johny_2000]

My Topping A90D just went kaput, what can I do? I bought around the same time in April 2023, and now it's giving me a -5 error and doesn't turn on.

-5

1. Abnormal headphone amplifier DC 2. Unit may be defective

1. Try to turn down the volume level, and reboot A90D after it cools down (in 1 minute). 2. Disconnect all the inputs and outputs, and reboot A90D after it cools down. If that still not works, unit is considered defective.

 

[simplywyn]

Doesn't seem like it's working now, just constantly shows -5...

 

[johny_2000]

Doesn't seem like it's working now, just constantly shows -5...

If that still not works, unit is considered defective.

 

[simplywyn]

So never buy topping amps? Seems like all their amps are unreliable (I've owned ton of their amps and they've all broken in a year)

 

[johny_2000]

So never buy topping amps? Seems like all their amps are unreliable (I've owned ton of their amps and they've all broken in a year)

It appears that their discrete amplifiers (potted nfca transistor modules) are less reliable than integrated circuit amplifiers.