Topping A90 Discrete Review (Headphone Amp & Preamp)

[julyjol]

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.

Contact the seller if you have a warranty, sending it to China on your own is not feasible.

 

[Lupin]

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)

I own two Topping amps and both are running great since launch a couple of years ago.

 

[bequietjk]

What's the 1/4" power for 300ohms in this sucker? I was seriously considering the L70 but I'm looking for an amp to get at least 200mw into 300ohms on low gain.

 

[staticV3]

What's the 1/4" power for 300ohms in this sucker? I was seriously considering the L70 but I'm looking for an amp to get at least 200mw into 300ohms on low gain.

Source: https://www.toppingaudio.com/product-item/a90-discrete

But to achieve 250mW @300Ω @1/4" output in Low (unity) gain, you'll have to find a DAC that's capable of ~9Vrms Line output.

 

[bequietjk]

View attachment 408787
Source: https://www.toppingaudio.com/product-item/a90-discrete

But to achieve 250mW @300Ω @1/4" output in Low (unity) gain, you'll have to find a DAC that's capable of ~9Vrms Line output.

After posting that comment I realized those are quite absurd numbers and are not very realistic hahaha. I think i've been on the PC too long looking at amp numbers and need to just freakin' buy one.

 

[trog69]

I just hooked up my new Drop version of the a90d and the output on high gain is extremely low. at almost twice the power of my Midgard amp, I know something's wrong. There was some talk about various settings for volume that I don't know how to bring up to adjust. Any help would be very appreciated.

 

[staticV3]

I just hooked up my new Drop version of the a90d and the output on high gain is extremely low. at almost twice the power of my Midgard amp, I know something's wrong. There was some talk about various settings for volume that I don't know how to bring up to adjust. Any help would be very appreciated.

Key settings are Gain, Safe Volume, Volume Curve, and currently set volume.

These will get you up to speed:

A90 Discrete user manual - TOPPING AUDIO

www.toppingaudio.com

Also, common misconception:

Gain dictates volume, power dictates headroom.

With low input voltage, a 20dB Amp with 1W will play louder than a 10dB Amp with 10W.

The A90D has 9.5dB gain with Single-ended output and 15.5dB gain with Balanced output.

In contrast, the Midgard has 14dB gain regardless of which output you use.

That means that if you went from the Midgard to the A90D's single-ended output, then the maximum output volume will go down by 4.5dB, in other words about 75% of the Midgard.

 

[trog69]

Key settings are Gain, Safe Volume, Volume Curve, and currently set volume.

These will get you up to speed:

A90 Discrete user manual - TOPPING AUDIO

www.toppingaudio.com

View attachment 410432

Also, common misconception:

Key settings are Gain, Safe Volume, Volume Curve, and currently set volume.

These will get you up to speed:

A90 Discrete user manual - TOPPING AUDIO

www.toppingaudio.com

View attachment 410432

Also, common misconception:

Gain dictates volume, power dictates headroom.

With low input voltage, a 20dB Amp with 1W will play louder than a 10dB Amp with 10W.

The A90D has 9.5dB gain with Single-ended output and 15.5dB gain with Balanced output.

In contrast, the Midgard has 14dB gain regardless of which output you use.

That means that if you went from the Midgard to the A90D's single-ended output, then the maximum output volume will go down by 4.5dB, in other words about 75% of the Midgard.

Key settings are Gain, Safe Volume, Volume Curve, and currently set volume.

These will get you up to speed:

A90 Discrete user manual - TOPPING AUDIO

www.toppingaudio.com

View attachment 410432

Also, common misconception:

Gain dictates volume, power dictates headroom.

With low input voltage, a 20dB Amp with 1W will play louder than a 10dB Amp with 10W.

The A90D has 9.5dB gain with Single-ended output and 15.5dB gain with Balanced output.

In contrast, the Midgard has 14dB gain regardless of which output you use.

That means that if you went from the Midgard to the A90D's single-ended output, then the maximum output volume will go down by 4.5dB, in other words about 75% of the Midgard.

Gain dictates volume, power dictates headroom.

With low input voltage, a 20dB Amp with 1W will play louder than a 10dB Amp with 10W.

The A90D has 9.5dB gain with Single-ended output and 15.5dB gain with Balanced output.

In contrast, the Midgard has 14dB gain regardless of which output you use.

That means that if you went from the Midgard to the A90D's single-ended output, then the maximum output volume will go down by 4.5dB, in other words about 75% of the Midgard.

Thank you for the link. I did try the SE output briefly but I got no sound, or it was so low as to be inaudible. Hopefully that's in line with the much lower gain via SE and issues with the Safe Volume settings. At least for now I know it was the problem was between the keyboard and the chair.

EDIT: Also, I am using almost all balanced HPs, and I'll likely try out using this amp as a balanced out to my NAD 208 balanced power amp for speakers.

 

[trog69]

And as always, thank you Amir for the review. The discrete circuit was originally a fun project in early 2020. And it made to a final product(after a lot of pain of course).

Sorry for resurrecting this, but I've had the a90d for a couple of months and it changed my entire system for the better. Now, I just got my grubby paws on the D70 OCTO DAC today. I'll be hooking it up tomorrow as a x-mas gift to myself. (I had to have the VU meter!)