Topping A90 Headphone Amplifier Review

[JohnYang1997]

sorry for the trivial question, using two headphones at the same time can create problems with the A90?

No. As long as you don't use two Aeon with balanced out and playing at very high volume.

 

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Space and cost and no.

ic, I used to think those solutions like Muse chips can use a single IC to do that so saving space and no need for hand matching would save cost

 

[JohnYang1997]

ic, I used to think those solutions like Muse chips can use a single IC to do that so saving space and no need for hand matching would save cost

That's not relay based tho. IC was previously used in A50. It degrades performance by a large margin.

 

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That's not relay based tho. IC was previously used in A50. It degrades performance by a large margin.

Never thought of that, I used to think chips like muses 72320 could provide better performance than a normal pot

 

[JohnYang1997]

Never thought of that, I used to think chips like muses 72320 could provide better performance than a normal pot

Now you know.

 

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Now you know.

yea, lucky I am still happy with my old auralic with a mod to very expensive but good quality DACT stepped attenuator, but tbh, I really think you should offer an paid option for the DACT, I know that cost 50% of the A90, but if you offer that also I believe some money no object audiophile will bite the bullet, as buying kind of an endgame amp with everything as needed would tempt customers, just like how Hifi speakers sells better when they mark up the price, insane but it works

 

[JohnYang1997]

yea, lucky I am still happy with my old auralic with a mod to very expensive but good quality DACT stepped attenuator, but tbh, I really think you should offer an paid option for the DACT, I know that cost 50% of the A90, but if you offer that also I believe some money no object audiophile will bite the bullet, as buying kind of an endgame amp with everything as needed would tempt customers, just like how Hifi speakers sells better when they mark up the price, insane but it works

Dact only has 24 steps. Way too little. Also it's bulky also don't meet the specification of our requirement. We want 1-2.5kohm pots to minimize noise. DACT only has 10k. There's a preamp coming out using relay based volume control. No issue to connect that to a90 if one wants.

 

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Dact only has 24 steps. Way too little. Also it's bulky also don't meet the specification of our requirement. We want 1-2.5kohm pots to minimize noise. DACT only has 10k. There's a preamp coming out using relay based volume control. No issue to connect that to a90 if one wants.

Thanks John for the advise, the preamp is attractive in one sense but 2 box solution might not be optimal for some, 24 steps from my personal use is actually quite ok for use, I admit that when tracks varies the volume kind of either too little or too loud at times, but with current great streaming like Tidal and great dacs I actually prefer using ~10% digital volume control with the DACT, the imaging improvement by the perfect channel matching is out-weighting the imperceptible dynamic range change from digital volume control on dac side.

 

[JohnYang1997]

Thanks John for the advise, the preamp is attractive in one sense but 2 box solution might not be optimal for some, 24 steps from my personal use is actually quite ok for use, I admit that when tracks varies the volume kind of either too little or too loud at times, but with current great streaming like Tidal and great dacs I actually prefer using ~10% digital volume control with the DACT, the imaging improvement by the perfect channel matching is out-weighting the imperceptible dynamic range change from digital volume control on dac side.

Even the stock volume control on A90 is equal or better in real world use than DACT in almost every way. Stock pot has no clicks, allows precise volume control, balanced to pretty much the lowest volume. I just don't like DACT (or any stepped volume pot for that matter) especially for the insanely ridiculous price. I'll think about it at all if it's 48 steps, 2kohm and only 20 dollars or less.

 

[Tks]

Even the stock volume control on A90 is equal or better in real world use than DACT in almost every way. Stock pot has no clicks, allows precise volume control, balanced to pretty much the lowest volume. I just don't like DACT (or any stepped volume pot for that matter) especially for the insanely ridiculous price. I'll think about it at all if it's 48 steps, 2kohm and only 20 dollars or less.

My biggest problem with pots on things like headphone amps is they all eventually go scratchy. I'm currently suffering this on a year old 789 and I want to chuck it out the window just for this single reason.

 

[Doodski]

My biggest problem with pots on things like headphone amps is they all eventually go scratchy. I'm currently suffering this on a year old 789 and I want to chuck it out the window just for this single reason.

That was pretty fast for it to go scratchy. Perhaps it's time to order in a can of cleaner/lub. Don't use Nutrol because it dries up and gets really stiff.

 

[JohnYang1997]

My biggest problem with pots on things like headphone amps is they all eventually go scratchy. I'm currently suffering this on a year old 789 and I want to chuck it out the window just for this single reason.

789's pot was known for it. It rarely happens in other models.

 

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789's pot was known for it. It rarely happens in other models.

My biggest problem with pots on things like headphone amps is they all eventually go scratchy. I'm currently suffering this on a year old 789 and I want to chuck it out the window just for this single reason.

same kind of issue to me, my old taurus Mk II ALPS blue and the Burson soloist SL before not really go scratchy, but as I mainly just use one headphone (HE-500) so the volume was mostly stuck in one position, after around 2 years it have a very obvious dent in the usual location and if I rotate pass that it have a little noise passing that notch, eventually I used some contact cleaner into it and that damages the ALPS, so finally I opted for the DACT. maybe due to hot and humid weather here or something, contacts in stepped attenuators normally don't have problems for me but pots always get kind of stuck if not rotate frequent enough. which is pretty annoying at times

 

[gwarlek]

@JohnYang1997 Sorry for tagging, but you seem to be related to the company in some capacity as I gathered from other threads and I couldn't find this question elsewhere: do XLR and RCA on this unit output the signal simultaneously?

 

[JohnYang1997]

@JohnYang1997 Sorry for tagging, but you seem to be related to the company in some capacity as I gathered from other threads and I couldn't find this question elsewhere: do XLR and RCA on this unit output the signal simultaneously?

yes

 

[pplum]

@JohnYang1997 Sorry for tagging, just got two a90 and both found a slight noise in the power supply part, guess its from the switch mode power supply a90 used. Noise is very common for switch mode AC-DC modulator and you can find tons of complains of phone charger's annoying sound, slight but still hearable while in a quiet environment. So, could you please think of replacing switch mode power supply to a traditional transformer + linear dc-dc power supply? The high frequency noise of A90 while its working is really irritating while you notice that.

 

[JohnYang1997]

@JohnYang1997 Sorry for tagging, just got two a90 and both found a slight noise in the power supply part, guess its from the switch mode power supply a90 used. Noise is very common for switch mode AC-DC modulator and you can find tons of complains of phone charger's annoying sound, slight but still hearable while in a quiet environment. So, could you please think of replacing switch mode power supply to a traditional transformer + linear dc-dc power supply? The high frequency noise of A90 while its working is really irritating while you notice that.

Better smps possibly. Linear no. We noticed the 10k noise in the development. L30 uses linear supply. So if that's what you need, get that.

 

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Better smps possibly. Linear no. We noticed the 10k noise in the development. L30 uses linear supply. So if that's what you need, get that.

May I ask that why insist on using SMPS when you noticed the 10k hiss??

 

[JohnYang1997]

May I ask that why insist on using SMPS when you noticed the 10k hiss??

Better solution? Try packing that amount of power in the small box. Try 40W transformer, what's the size of it. Not even considering the heat.
Also considering that the noise is really faint. I have two A90 on the desk and I can't hear anything even in the night. I can only hear it when I put my ear up against the power supply section.

 

[pplum]

Better smps possibly. Linear no. We noticed the 10k noise in the development. L30 uses linear supply. So if that's what you need, get that.

Thx for reply, but I guess the smps noise is unavoidable since I found it in every charger of my device! Maybe ignore that is a betere solution...