Topping A90 Discrete Review (Headphone Amp & Preamp)

[Veri]

I returned my A90D - much happier with my SMSL SP400 (47k ohm input impedance, also with stepped resistor relay volume control, and the best THX amp modulates AAA-888)

No firmware issues.

Any more info, happier.. why?

 

[Music1969]

Any more info, happier.. why?

As mentioned above, no firmware issues to be solved, higher input impedance covers full gamut of DACs

A90D looks so sexy in person , i love the dot matrix volume display

But its a worry that a dumb analogue device needs firmware updates

 

[Veri]

A90D looks so sexy in person , i love the dot matrix volume display
But its a worry that a dumb analogue device needs firmware updates

I see. Thanks for explaining!

 

[staticV3]

It will clip because the input sensitivity is 3v?

It will clip because the maximum output voltage is reached.

Does that mean if I provide 3v in i will get the 17.3v out when the volume is maxed at high gain?

With 3V in, max volume, high gain you will get 3*10^(15.3/20)=17.46V out.
But since the A90D can only output 17.32V without clipping, you would get a slightly clipped output, though probably not audible yet

The highest voltage you can feed the A90D at max volume, high gain without output clipping is 17.32*10^(-15.3/20)=2.98V

Alternatively, you can feed the A90D 4V at high gain, and just keep the Amp's volume at -3dB. That'll give you 4*10^(12.3/20)=16.48V at the output.

There is no such thing possible as input clipping?

With high enough voltage, you can probably clip the A90D's input as well.
However, this voltage is neither specified by Topping, not tested by Amir.

Just as an example, here is a graph showing input voltage vs output THD+N for the Topping L70.
As you can see, the L70's input clips at 10.4V

Is it a simple formula to calculate Vrms-out for a given Vrms-in with a given gain factor in db?

Yes. Vin*10^(gain in dB/20)=Vout

 

[solid12345]

Apos was super slow in replacing my A90D that died with a -5 after a few months. Took numerous emails and slow response, but they are finally shipping me back a working A90D. Hopefully it lasts longer than a few months. Super disappointed in the A90D quality, as others have had -5 deaths too.

I just bought one and second time turning it on I have a -7, anyone know the meaning of this code? nothing is working for me and I dread doing an RMA…

 

[BossBunos]

It will clip because the maximum output voltage is reached.


With 3V in, max volume, high gain you will get 3*10^(15.3/20)=17.46V out.
But since the A90D can only output 17.32V without clipping, you would get a slightly clipped output, though probably not audible yet

The highest voltage you can feed the A90D at max volume, high gain without output clipping is 17.32*10^(-15.3/20)=2.98V

Alternatively, you can feed the A90D 4V at high gain, and just keep the Amp's volume at -3dB. That'll give you 4*10^(12.3/20)=16.48V at the output.


With high enough voltage, you can probably clip the A90D's input as well.
However, this voltage is neither specified by Topping, not tested by Amir.

Just as an example, here is a graph showing input voltage vs output THD+N for the Topping L70.
As you can see, the L70's input clips at 10.4V


Yes. Vin*10^(gain in dB/20)=Vout

Thanks for the explanation! Clarifies alot for me at least in layman's terms.
I think I get the point about max output and clipping (in relation to input).
But i still assume both are related? Input sensitivity and max output? Am i wrong to say that input sensitivity is derived from max output and gain factor? And in this case it's just a slight rounding 'error'?

 

[staticV3]

Am i wrong to say that input sensitivity is derived from max output and gain factor?

Input sensitivity is traditionally defined as the point at which the input clips.
Topping though spec input sensitivity as the voltage needed at the input to clip the output with the Amp at 100% volume.

 

[Urushi]

Would there be any reason to get this if I am using an HD800S?

 

[Music1969]

Would there be any reason to get this if I am using an HD800S?

Depends what you are currently using?

 

[WeBuild4Life]

Would there be any reason to get this if I am using an HD800S?

I bought the A90D along with the HD800s just as an "end game" system. Was super happy with it until the a90d broke so... I am enjoying the Jotunheim 2. If it measures worse, I can't hear it (Amir reviewed it favorably though!). It may somehow have less higher detail but I never A/B'd it so it doesn't matter. Has an insane amount of power.

 

[Urushi]

Depends what you are currently using?

I don't have the HD800S yet. Should be coming tomorrow. I bought the Topping L30II but I am not sure I am going to keep it because it sounds like they don't last. I am also not really sure if I should buy separates or an all in one

 

[Veri]

I don't have the HD800S yet. Should be coming tomorrow. I bought the Topping L30II but I am not sure I am going to keep it because it sounds like they don't last.

As far as I know... they last.

 

[nagster]

With high enough voltage, you can probably clip the A90D's input as well.
However, this voltage is neither specified by Topping, not tested by Amir.

Just as an example, here is a graph showing input voltage vs output THD+N for the Topping L70.
As you can see, the L70's input clips at 10.4V

Graph of measured THD+N ratio vs Generator Level .
I was measuring together with L70, but I skipped image editing..

 

[staticV3]

Graph of measured THD+N ratio vs Generator Level .
I was measuring together with L70, but I skipped image editing..
View attachment 281138
View attachment 281139

Awesome! Thank you very much!

 

[EdW]

I've not seen that feature on any Topping product, so I doubt it's an option. I've not found a link to the user manual, but there's probably one around somewhere.

I handle channel balance upstream of the DAC, but that may not be convenient for everyone.

Interested in what upstream of the DAC method you use to adjust channel balance

 

[maruko]

Now it is interesting to have a proper controlled listening test of A90 OP VS A90 Discrete to see if there is any audible difference.

I own the A90 (black) and I ordered the A90D (silver) on Amazon, just for fun.

First AB comparison was sighted, and I was 100% sure I heard clear differences.

I heard the same differences they claim in the various web reviews: A90D punchier, warmer, more textured midrange, more impactful bass.

I was so sure of it and so excited about the new sound that I was deciding to to keep the A90D and sell the A90, also for the pleasure of the remote control and the new volume knob.

But first, of course, I did a blind AB test with matched level volume (I used 1Khz tone). I missed 7 out of 10.

I was clearly influenced by the enthusiastic reviews of the A90D, and probably also about the silver colour and the nice white leds, that reminded me about some "hi-end" amplifier.

Furthermore, one of the reviewers claimed he did a blind AB test and guessed which was which (5 out of 6). So I was heavily influenced. I'm not sure if it was me not enough focused, since I had a friend behind me standing up having to do all the switching work, but these are my results.

Conclusion: i send it back to Amazon

 

[Veri]

I own the A90 (black) and I ordered the A90D (silver) on Amazon, just for fun.

First AB comparison was sighted, and I was 100% sure I heard clear differences.

I heard the same differences they claim in the various web reviews: A90D punchier, warmer, more textured midrange, more impactful bass.

I was so sure of it and so excited about the new sound that I was deciding to to keep the A90D and sell the A90, also for the pleasure of the remote control and the new volume knob.

... tale as old as time

 

[enricoclaudio]

... tale as old as time

I had a hard time even discerning between the A90D and HPA4… so I sold the A90D..

 

[long060189]

Thank you @amirm so much for the review, i 've just got one, enjoying.

 

[escalibur]

My unit seems to be hit with the -5 error code. After powering on -5 code appears for a few seconds then it gets replaced by the volume number.

Powering off, trying SE or BAL outputs doesn't matter -> no sound. The unit is already on the latest firmware. Last night it worked normally and ever since I haven't touched anything related to my A90D.

Any suggestions, or do I have to rely on it's warranty?