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!)

 

[Music1969]

How is A90D QA/QC now?
Have they fixed all early issues?

 

[dartinbout]

How is A90D QA/QC now?
Have they fixed all early issues?

I have been using the A90D plus the EXT continously since 10\22, without issues.

 

[ivanfraser]

How is A90D QA/QC now?
Have they fixed all early issues?

Zero issues here, on latest firmware. I use it almost daily for several hours. I have the EXT with 2 bal inputs (stereo DAC and UB9000), and a bal pre out, using as preamp at static unity level for XLR on the integrated amp. I use the balanced TRS out to Sennheisers. No glitches. I've had it for a year or so.

(To get unity on the DAC at 4v output, I have 87 in output, and change to 99 with the BR player's analogue which is at 2v output - alternative setup would be to use the preamp mode direct to power - but I chose the XLR route and don't have an xlr in on my power amp).

Probably unrelated as I had some ground loop issues and DC distortion for a while (most noticeable on high vol high gain) I used the rcas in preamp mode on the A90 also with a harshness - but very unlikely to be an issue with the A90D. Now all is balanced, I haven't tried the rcas to see if there's an issue.

Very happy with my choice of this amp.

 

[Bernd]

For all headphone intents and sound related purpose, this is my endgame amp as long as it lasts. I have been enjoying it for 1 year and I cannot see that there is anything seriously better coming down the pipeline anytime soon for those who like a sharp, detailed and analytical amp.
For those who like a warm, analogue and encompassing sound look elsewhere

 

[mediocrebutarrogant]

Ok, so my trusty old A90 D seems to be in a bit a of a pickle. In this season, we have a lot of static, and when I touch appliances, they spark. Not with the A90 D but I digress. My lovely Aryas and Sundaras when connected to the Amp, give a low humm , and sometimes crackle I tried lifting the ground switch, I moved the stack to a different surface, nothing seems to work. While music plays , the crackling is buried, it does sound ok, but I am used to totally black background , tight performance from my chain. This is bothering me to no end. So any of you know how to fix this? What amp I should I get if this is not fixable? A90D has served really well. 2 years its worked flawlessly. A70 Pro maybe? Prefer to fix A90D if you gents know what I can do ? Or is it new amp day? Opinions on hifiman prelude? A70 pro seems to have iffy reliability..

 

[solderdude]

Did you not notice it before or did this suddenly develop ?
Always present/repeatable ?
Do you also hear it when the amp is not connected to other devices ?
Using grounded mains cables/wall sockets/ext. cords ?
Is it present on both channels or just one channel ?

 

[metasharp]

Maybe try to update the firmware.
And try to unplug all for 1min then plug again.

 

[Snoopy]

So after problems with one topping unit that look like QC or build quality issues your first thought is replacing it with another topping unit that is already known to have QC issues ?

I would look at a reliable manufacturer.. RME ? Lake People ? Teac? Sure you spend a bit more but I’m done with throwing money at SMSL, Topping, Fosi etc.

 

[mediocrebutarrogant]

Did you not notice it before or did this suddenly develop ?
Always present/repeatable ?
Do you also hear it when the amp is not connected to other devices ?
Using grounded mains cables/wall sockets/ext. cords ?

this developed suddenly, and its always there when music is not playing. I also got the noobsound dac switcher , I am using fully balanced connections from E50 dac and `denafrips enyo, both giving crackle

 

[mediocrebutarrogant]

So after problems with one topping unit that look like QC or build quality issues your first thought is replacing it with another topping unit that is already known to have QC issues ?

I would look at a reliable manufacturer.. RME ? Lake People ? Teac? Sure you spend a bit more but I’m done with throwing money at SMSL, Topping, Fosi etc.

well A90D makes my equipment sing, I would buy another one of these easy

 

[solderdude]

On both channels or just one channel ?