Topping A70 Pro HP & Preamp Review

[Blashyrkh]

preordered
I hope I will be able to compare it to the L70 before the return period expires

 

[HYQID]

What is that "new 3-stage feedback circuit"? Does the amount of feedback increase as the output power increases (something I kind-of see in AP plots.... 3 instances when the graph creeps up, and then drops), thus the low THD+noise even at extremely high output levels (for a headphone amp)?

Or.... do they use multiple nested negative feedbacks in their design??

View attachment 285269

I think it means TOPPING doesn't want people knowing the circuit.Because three-stage structure is very common in amps,and feedback is a neccessary thing in every amp.

 

[Tony Roma]

Maybe the Raal SR1a.

Thats why ill be getting this amp

 

[oozlum]

Someone asked how warm it gets. After all my testing it had gotten a bit warm but nothing seriously worrisome.

Another asked for preamp measurements. That was the first part of the review!

I know. What I meant that meassurements data are the same although you write “RCA input this time did cost us a bit as it normally does” (see attached picture):

 

[Nango]

Still prefer the Adi RME Dac-2 as AiO.

 

[solderdude]

(something I kind-of see in AP plots.... 3 instances when the graph creeps up, and then drops)

That is the 'range switching' in the AP.
That won't be happening in the amp.
Probably a combination of local and overall feedback in 3 following stages (so more overall gain, more BW, more feedback, less distortion) where, most likely, the input stage opamp has different properties than the next to stages.
I am certain JohnYang won't spill the beans.

 

[AdamG]

high-end chi-fi products.

Hi shuppatsu,

Since you are new here, firstly allow us to Welcome you Aboard!

I know you don't mean this in a derogatory manner but let's avoid the term Chi-fi as it can have negative connotations for such companies. I hope you understand. Thank you for keeping an open mind and willingness to work with us on this.

 

[shuppatsu]

Hi shuppatsu,

Since you are new here, firstly allow us to Welcome you Aboard!

I know you don't mean this in a derogatory manner but let's avoid the term Chi-fi as it can have negative connotations for such companies. I hope you understand. Thank you for keeping an open mind and willingness to work with us on this.

Yeah, another user already mentioned this. It was not meant in a derogatory manner and I am in fact a Topping fanboi, but it seems like a reasonable guideline to follow if in fact people are bothered by it.

 

[gvl]

Good news about more sane input impedance and the overall performance. I just can’t get excited about DAC/HP amp reviews anymore since I got my RME DAC.

 

[Extreme_Boky]

I think it means TOPPING doesn't want people knowing the circuit.Because three-stage structure is very common in amps,and feedback is a neccessary thing in every amp.

You are a funny guy...

It is not input, VAS and output, i.e. it is not a 3-gain structure. It is a 3 stage feedback structure. Feedback, got it?

Feedback is not required in every amp. The amount of feedback used shows how good the design actually is. The best-sounding amps are those with very little or no feedback.

What topping did here, is they just cranked the feedback to the nth degree... until they were ready to approach Amir, so that the AP plot could look amazing.

 

[shuppatsu]

I know you don't mean this in a derogatory manner but let's avoid the term Chi-fi as it can have negative connotations for such companies. I hope you understand. Thank you for keeping an open mind and willingness to work with us on this.

Excuse me but what else is it supposed to be .... Hi-Fi ?? Hifi is to me way more than just beating the benchmark by again 0,25dB, not to mention using 4 or 5 different fonts in the front, as they use to do.

Case in point, I suppose...

 

[AdamG]

Case in point, I suppose...

Exactly

 

[raif71]

You are a funny guy...

It is not input, VAS and output, i.e. it is not a 3-gain structure. It is a 3 stage feedback structure. Feedback, got it?

Feedback is not required in every amp. The amount of feedback used shows how good the design actually is. The best-sounding amps are those with very little or no feedback.

What topping did here, is they just cranked the feedback to the nth degree... until they were ready to approach Amir, so that the AP plot could look amazing.

At the end of the day, it will all be about how it sounds. I remember demoing the A90d and did not like it how it sounded. I plan to demo this amp too

 

[Ziroz]

I mean how many inputs does it have?

With their ext90 it could be expand up to 2 sets of RCA and 4 sets of XLR.

 

[Blashyrkh]

demoing the A90d and did not like it how it sounded.

Why?

 

[anmpr1]

Let's see Benchmark give us this performance for $500.

Let's see Topping open a manufacturing facility in NY (or any other 'business friendly low tax' state LOL), hire someone to man the phones and the other relevant staff, including accountants, HR, janitors, etc. (and pay their salaries, Social Security, possibly a 401K benefit, medical insurance, and so forth), deal with OSHA, offer a five year warranty, a 30 day money back trial, and include all of the features of the DAC 3 HGC.

As good as the Chinese product is, you can't just say, "why can't ________ (fill in the blank with a US company) offer something as good for the same dollars as a (pick your Asian) foreign company. That makes absolutely no sense.

And as far as 'performance', other than on the 'scope, how are you going to actually hear these miniscule distortion numbers? What will they mean to person in his living room?

Please don't think I'm anti-Topping, or anti-Chinese. Nothing could be farther from the truth. Just asking for a little perspective.

 

[Music1969]

Why?

Maybe due to low inputs impedance, mismatch with DAC

A70Pro should be much more flexible

I'll wait till Black Friday - not just for sale but for issues to be fixed

 

[raif71]

Why?

Sounds kinda veiled. Increasing the volume did not produce the joy I had when increasing volume of ifi zen can, schiit asgard 3 or smsl sp400 which is kinda disappointing considering the price.

 

[amirm]

I updated the RCA input dashboard:

 

[Jochen]

Here's the Max Power vs Load for Topping's most powerful headphone Amps:
View attachment 285144

I rechecked everything for this graph, and noticed that I made a mistake on the last iteration here.
As you can see the A90 and A90D are actually quite similar. I'm sorry for potentially misleading some folk.
I'll try my best to be more careful going forward.

It is a nice graph, visualizes well the measurements. It is also interesting to see that both D90s are more powerful below 10 Ohm. But how meaningful is this when apparently all amps go into protection below 12 Ohm?