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Topping A90 Discrete Review (Headphone Amp & Preamp)

Rate this Headphone Amp/Pre-amp

  • 1. Poor (headless panther)

    Votes: 9 3.1%
  • 2. Not terrible (postman panther)

    Votes: 9 3.1%
  • 3. Fine (happy panther)

    Votes: 50 17.3%
  • 4. Great (golfing panther)

    Votes: 221 76.5%

  • Total voters
    289

tritopia

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Joined
Apr 30, 2022
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Hows the noise floor in Single Ended and Balanced on sensitive stuff?

Volume levels (00-99) below 30 sound very low. When it gets smaller, it becomes a subtle sound and then becomes as silent as darkness. At first, I set the default volume to 10, but I was shocked to find out that it didn't work. Changed the default volume to 30.

Today, I am only listening to the sound with a preamplifier through XLR input/output.

I'm using two studio monitor headphones, both of which are connected via unbalanced 6.35 jacks.

The sound is... the sound of the topping. Accurate, transparent, and silent.

We don't have headphones that support balanced, so it's impossible to test it right now. please understand. ;)
 

carlcamper

Member
Joined
Aug 1, 2020
Messages
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87
Location
Cavite, Philippines
Volume levels (00-99) below 30 sound very low. When it gets smaller, it becomes a subtle sound and then becomes as silent as darkness. At first, I set the default volume to 10, but I was shocked to find out that it didn't work. Changed the default volume to 30.

Today, I am only listening to the sound with a preamplifier through XLR input/output.

I'm using two studio monitor headphones, both of which are connected via unbalanced 6.35 jacks.

The sound is... the sound of the topping. Accurate, transparent, and silent.

We don't have headphones that support balanced, so it's impossible to test it right now. please understand. ;)
Thanks. By noise floor I mean is there any hiss?
 

carlcamper

Member
Joined
Aug 1, 2020
Messages
92
Likes
87
Location
Cavite, Philippines
No noise is heard.

It doesn't degrade the DAC's Sinad level, and it doesn't impute any noise to the power amp.
Great to hear! Mine is due to arrive on July 4th, can't wait to test it on my sensitive IEMs
 

Haruko

Member
Joined
Sep 14, 2021
Messages
73
Likes
59
now I'm glad I didn't buy A90 right away and waited for this
 

tritopia

Member
Joined
Apr 30, 2022
Messages
41
Likes
47
I found one thing I didn't like.
The gap between the AC plug and the 12V trigger plug is narrow and interferes with each other.
Considering that the jacks on the 3.5 cables I use are slim, thicker ones will get in the way more.
Of course, there is no such interference with the bundled AC cable included with the A90D. It's a problem with the AC cable I'm using, but it would have been better if the terminal layout was slightly changed.

I removed the cap of the 3.5 terminal and am using it without any problem, and of course the function works very well.
Actually nothing is a problem. ^^

DSC08478.jpeg
 

enricoclaudio

Senior Member
Manufacturer
Joined
Jan 7, 2021
Messages
488
Likes
757
As proved by @amirm in several tests, there is no need to use fancy power cables as they do not improve SQ or anything. Good engineers know that and that's why the layout Topping used is correct ;)
 

enricoclaudio

Senior Member
Manufacturer
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Jan 7, 2021
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757

mocenigo

Addicted to Fun and Learning
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Dec 8, 2018
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So....why aren't Marantz delivering this level with their HDAM receivers and processors (or at least matching benchmark performance for that class of product)?

Incompetence?

Carelessness?

They just do not care.
 

pma

Major Contributor
Joined
Feb 23, 2019
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Prague
I appreciate that there a are no high order harmonics visible in the spectrum of the discrete A90 version, compared to the one with IC's. And also the cleaner noise bottom.

Topping A90 Discrete Measurements Headphone Amp Preamplifier Balanced.png Topping A90 Headphone Amplifier Unbalanced Audio Measurements.png
 

Haruko

Member
Joined
Sep 14, 2021
Messages
73
Likes
59
I appreciate that there a are no high order harmonics visible in the spectrum of the discrete A90 version, compared to the one with IC's. And also the cleaner noise bottom.

View attachment 215560 View attachment 215561
idk if it's time rounding difference but look at the grass at the bottom ... it looks much more flatter on A90 discrete
 

enricoclaudio

Senior Member
Manufacturer
Joined
Jan 7, 2021
Messages
488
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757
Volume levels (00-99) below 30 sound very low. When it gets smaller, it becomes a subtle sound and then becomes as silent as darkness. At first, I set the default volume to 10, but I was shocked to find out that it didn't work. Changed the default volume to 30.

Today, I am only listening to the sound with a preamplifier through XLR input/output.

I'm using two studio monitor headphones, both of which are connected via unbalanced 6.35 jacks.

The sound is... the sound of the topping. Accurate, transparent, and silent.

We don't have headphones that support balanced, so it's impossible to test it right now. please understand. ;)

That's because relay stepped volume controls behave logarithmically and not linear like pot volume controls. It took me sometime to get used to the stepped ladder volume control on my Parasound Halo P6 but the benefit of having perfect channel balance is worthy.
 

mocenigo

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That's because relay stepped volume controls behave logarithmically and not linear like pot volume controls. It took me sometime to get used to the stepped ladder volume control on my Parasound Halo P6 but the benefit of having perfect channel balance is worthy.
I think you have swapped linear and logarithmic.
 

Atanasi

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That's because relay stepped volume controls behave logarithmically and not linear like pot volume controls.
Stepped attenuators can be made with any steps. According to this thread, A90D maps the 0-99 scale to dB such that the highest steps are 0.5 dB apart, the middle ones are 1 dB and the lowest 2 dB.
 

mocenigo

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Stepped attenuators can be made with any steps. According to this thread, A90D maps the 0-99 scale to dB such that the highest steps are 0.5 dB apart, the middle ones are 1 dB and the lowest 2 dB.

This is true but this one is made as an R2R chain, IIUC, which is by definition linear. However, the controller skips (i.e. does not map) some steps at the intermediate and lower levels.
 

mrjayviper

Member
Joined
Jun 27, 2022
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2
recommended dac to pair with this amp? (I often see in aliexpress seller selling a combo of this amp + D90)

thanks in advance
 

Rottmannash

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This is true but this one is made as an R2R chain, IIUC, which is by definition linear. However, the controller skips (i.e. does not map) some steps at the intermediate and lower levels.
Is this why on the Schitt Frey+ the volume seems to jump exponentially the higher on the scale I go? Everything's chill until about 2 o'clock then each click is an enormous increase in volume. Or is it my imagination?
 
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