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Topping A90 Discrete Review (Headphone Amp & Preamp)

Rate this Headphone Amp/Pre-amp

  • 1. Poor (headless panther)

    Votes: 12 3.5%
  • 2. Not terrible (postman panther)

    Votes: 12 3.5%
  • 3. Fine (happy panther)

    Votes: 58 16.8%
  • 4. Great (golfing panther)

    Votes: 263 76.2%

  • Total voters
    345

Phony846

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Sep 2, 2020
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San Diego
Only typec to typeA cable is supported.
I did some digging on this issue, and a USB standards expert says:

--
They've missed two 5.1kOhm resistors on CC pins. This is a spec violation, pretty common for manufacturers switching from micro USB ports.
--

So it appears the A90D violates USB-IF specs. Will Topping be fixing this issue in a HW rev?

Detailed thread:
(2) USB-C device ONLY works with a USB-C to USB-A cable - violates USB-IF specs? : UsbCHardware (reddit.com)
 
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enricoclaudio

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I don't get why people is making such a big deal for something you are going to perform maybe 2 or 3 times during the life of the amp? Topping already said you have to use a USB-C to USB-A Cable and that is all. We asked for Gain change using the volume dial and we got it. We asked to get the popping sound when unplugging the headphone from the unbalanced out fixed and we got it. I don't think getting the USB-IF up to specs is something that is going to improve performance which is what we really want. The A90D is not a DAC that has to be plugged into a computer 24/7.
 

Jimster480

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I don't get why people is making such a big deal for something you are going to perform maybe 2 or 3 times during the life of the amp? Topping already said you have to use a USB-C to USB-A Cable and that is all. We asked for Gain change using the volume dial and we got it. We asked to get the popping sound when unplugging the headphone from the unbalanced out fixed and we got it. I don't think getting the USB-IF up to specs is something that is going to improve performance which is what we really want. The A90D is not a DAC that has to be plugged into a computer 24/7.
I agree here. Although now that they know about the issue, they might be able to just fix it in the next HW revision since it will likely not cost much to fix it and this is their flagship product.
 

mrjayviper

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Jun 27, 2022
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how warm/hot does this get during normal operation? Thanks in advance!

(a thought came to mind suddenly. is the heat given out by the device directly proportional to volume?)
 

mrjayviper

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Jun 27, 2022
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any advantages of this amp vs the SP400? (similar price price in my country)

Thanks!
 

mrjayviper

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Looks like it has about 4db better SINAD into 50mv and better "best case" sinad as well. Not sure on the rest as I'm only going by the graph here.
after a certain number, those measurements are meaningless (coming from someone who does NOT know how to read graphs posted here. All I know is, high SINAD is good but only up to a point)
 

Jimster480

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after a certain number, those measurements are meaningless (coming from someone who does NOT know how to read graphs posted here. All I know is, high SINAD is good but only up to a point)
I would say it is relevant until around 105db. Past there it is near impossible to hear differences. 120db is sonic perfection..
So the 50mv result is solidly in audible territory IMHO.
 

mrjayviper

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I would say it is relevant until around 105db. Past there it is near impossible to hear differences. 120db is sonic perfection..
So the 50mv result is solidly in audible territory IMHO.
what's the graph for the 50mv result? thank you
 

Jimster480

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With an ambient temperature of 72 F, mine reaches a uniform 95 F at a volume of 67, low gain.
Now I am curious what my thx789 reaches. Or even the my EX5.
Do you have yours in a well ventilated area? And is it on the top of the DAC or another heat generating product?
 

PointyFox

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Oct 2, 2021
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25
Now I am curious what my thx789 reaches. Or even the my EX5.
Do you have yours in a well ventilated area? And is it on the top of the DAC or another heat generating product?

I have the Topping E50 sitting on it, which takes up about 2/3rds of the top.
The temperature is uniform all around the A90D and the E50 is only 89 F, so I don't think it's having much effect.
Otherwise the airflow around it is good.
 

Jimster480

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I have the Topping E50 sitting on it, which takes up about 2/3rds of the top.
The temperature is uniform all around the A90D and the E50 is only 89 F, so I don't think it's having much effect.
Otherwise the airflow around it is good.
Wow, that is pretty awesome!
 

enricoclaudio

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Just got my A90D delivered. It came with Firmware 2.3 already and after connecting it to my Mac Studio with a USB-C to USB-A cable, the firmware drive came up on my desktop immediately. Sound is as good as my A90. Can't really hear any difference with my Sennheiser 660s or with my Sundaras. I have it set it up in High gain and volume at 65 is plenty loud for me. This is really the perfect companion for my Matrix Audio X-SABRE 3 ;)

IMG_3174.jpeg
 

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Loomynarty

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Nov 27, 2021
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Canada
What's the input impedance? 2.5k again?
 

mrjayviper

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how many steps are there on the volume control?
 
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