TOPPING A90 vs TOPPING A90 Discrete Comparison Chart

The upgrading of a classic is an exciting but potentially confusing event. Everyone loves quality of life improvements, but no one likes having to hack through a jungle of specs. We’ve created this comparison chart to help you quickly and easily judge the differences between the classic A90 and the upgraded A90 Discrete (AKA the A90D). For each category, we’ve highlighted the winner in Apos red.

	TOPPING A90 Headphone Amp	TOPPING A90D Headphone Amp
Price	$499	$599
Dimensions	8.7 x 6.2 x 1.7”	8.7 x 8.4 x 1.7”
Inputs	XLR RCA	XLR RCA
Outputs	Balanced XLR line out RCA 4-pin XLR headphone output 4.4mm balanced Single-ended 6.35mm	Balanced XLR line out RCA 4-pin XLR headphone output 4.4mm balanced Single-ended 6.35mm
Amplifier	Nested Feedback Composite Amplifier	Discrete Nested Feedback Composite Amplifier
THD+N	<0.00006%	<0.000055%
SNR	145dB	145dB
Gain Settings	3	2
Output Power	7600mWx2 @16Ω	9800mW x2 @16Ω
Output Impedance	<0.1Ω	<0.1Ω
R2R relay volume control	No	Yes
Output voltage	49Vpp@ balanced, 25Vpp@SE	49Vpp@ balanced, 25Vpp@SE
Ground loop noise terminator	No	Yes
Pre-amp functionality	Yes	Yes
12V trigger interface	No	Yes
Output volume memorization	No	Yes
Remote control	No	Yes
Front panel volume display	No	Yes

Takeaways

The A90D is an upgrade across the board. It’s more powerful, less distorted, and includes some great quality-of-life improvements. A front panel volume display and remote control allow you to control the A90D from the comfort of your couch. A ground loop noise terminator ensures clean output no matter how long your audio chain becomes. Output volume memorization allows you to dial in on the right level for you–and keep it there for next time. 

There is one place where the original A90 seems to outpace the A90D, and that’s its gain settings. It's worth explaining why that isn't actually the case. The A90 includes three gain settings (-9.5dB/ 0dB/ +9.5dB), while the A90D only includes two (0dB/ +9.5dB). At first blush, this might seem like a huge oversight by TOPPING, but in actuality it’s not–and it all has to do with the type of volume potentiometer used. The A90 uses a standard volume potentiometer. These often suffer from channel imbalance at low volumes, which makes listening to sensitive IEMs a challenge. To overcome this issue, TOPPING introduced a low gain setting on the A90, allowing the user some additional real estate on the volume knob for dialing in a suitable volume that doesn’t result in channel imbalance. The A90D, on the other hand, uses an R2R volume controller. These offer massive advantages over standard potentiometers, like outstanding THD+N, SNR, and extremely well-balanced channels. Thanks to the A90D’s R2R volume controller, a low gain setting on the A90D isn’t necessary.

That's it! We hope this helped and that you're as excited about the A90D as we are. Please reach out to our support team if you have any questions.