Topping A70 Pro HP & Preamp Review

[fenallen]

If you put the output on 'HPA+PRE' you will get an 'Output Mode' Button option that allows you to select HPA, PRE or BOTH. So yes it does what you want. There is also an 'Output' that can change the channel if you are set up for IND individual.

Thank you for this info.

 

[Bleib]

A70 Pro version V2.08 firmware update - Topping audio

TOPPING, born in 2008, has evolved into a beloved global HIFI brand favored by users worldwide. We firmly believe that higher-quality music playback devices are essential for truly showcasing the allure of music. By investing extensively in professional technology and exceptional industrial...

www.toppingaudio.com

 

[marcom22]

A70 Pro version V2.08 firmware update - Topping audio

TOPPING, born in 2008, has evolved into a beloved global HIFI brand favored by users worldwide. We firmly believe that higher-quality music playback devices are essential for truly showcasing the allure of music. By investing extensively in professional technology and exceptional industrial...

www.toppingaudio.com

Whats new? Thanx-X

 

[Roland68]

Whats new? Thanx-X

Nobody knows...
The usual problem with Topping's communication:
Topping simply doesn't understand that the lack of transparency leads to a lack of trust among customers, resulting in significantly fewer device sales (and not only that).

Poor Topping, so much knowledge about the function of audio devices and so little understanding of how people work.

 

[Bleib]

They usually add something in the read me but I think someone was working too fast..
I would update anyway

 

[Pilifman]

I got a brand new replacement unit that had 2.05 from factory and i updated to 2.06 to see if i could fix a bug i have where i get a click sound about a second after changing volume when a song is playing, 2.06 did not fix it. My old unit that bricked did not have this issue but was on a older firmware. Does older firmware like 2.04 or 2.02 work better, or are they worth trying?

 

[Pilifman]

Try installing 2.02

A70 Pro version V2.02 firmware update-TOPPING

Do you still have the 2.02 files? If so i would really appreciate it if you could upload them here via google drive or mega? I am also looking for 2.04 files if anyone has them.

 

[Bleib]

Do you still have the 2.02 files? If so i would really appreciate it if you could upload them here via google drive or mega? I am also looking for 2.04 files if anyone has them.

Sadly no, I sold my unit and just use DX5 II

 

[Pilifman]

Sadly no, I sold my unit and just use DX5 II

I got a brand new replacement unit that had 2.05 from factory and i updated to 2.06 to see if i could fix a bug i have where i get a click sound about a second after changing volume when a song is playing, 2.06 did not fix it. My old unit that bricked did not have this issue but was on a older firmware. Does older firmware like 2.04 or 2.02 work better, or are they worth trying?

Here is a video showcasing the click sound. You can hear it clearly after i turn up the volume and put the phone closer to the earcup. https://drive.google.com/file/d/1DvxGWZ-loKDCi0DiXxqYrMU4fQWLrzZ2

 

[Roland68]

Here is a video showcasing the click sound. You can hear it clearly after i turn up the volume and put the phone closer to the earcup. https://drive.google.com/file/d/1DvxGWZ-loKDCi0DiXxqYrMU4fQWLrzZ2

Is the sound coming from the headphones or from the device itself?

 

[Pilifman]

Is the sound coming from the headphones or from the device itself?

It’s coming from the headphones but i get the same sound on other headphones and other cables too, but only with the A70 Pro 3 to 4 seconds after changing volume. When just listening to music and not changing volume then it sounds normal.

Have contacted Topping about it and sent the video, hopefully they help me with firmware or make a new firmware update asap.

 

[HiFiHelp]

How is the reliability of this amp for new units?

 

[Roland68]

It’s coming from the headphones but i get the same sound on other headphones and other cables too, but only with the A70 Pro 3 to 4 seconds after changing volume. When just listening to music and not changing volume then it sounds normal.

Have contacted Topping about it and sent the video, hopefully they help me with firmware or make a new firmware update asap.

To me, that sounds like a discharge crackling noise, so it could be a grounding issue. If that's the case, it's not directly related to the device itself, and a firmware update probably won't help much.

You could try measuring the resistance/continuity between one of the A70 Pro's RCA grounds and the power strip's wall socket ground using a multimeter.

 

[Mort]

How is the reliability of this amp for new units?

There were never reliability issues with this amp afaik. I've had two, neither ever had a glitch. Sold one off, still use the first daily.

 

[Roland68]

How is the reliability of this amp for new units?

In fact, I don't see any of the failure-prone components in the A70 Pro, for example, in the power supply/conditioning system, that led to failures in the A90D, among others. They also seem to have fixed the module issue.

Due to the very customer-unfriendly policy regarding warranty claims and repairs, I no longer recommend Topper devices over €300 to my friends and acquaintances, especially because of potential failures after the warranty period.

Above all, make sure you buy from a retailer who adheres to the warranty regulations applicable in your country.

 

[HiFiHelp]

I'm probably going to get SMSL H400, even though there are no sub 16 ohm measurements. I have this same issue on my SMSL SH-9 and the Topping L70 I recently tried.

 

[Roland68]

So the A70 Pro can power both single ended and balanced simultaneously, and lists output impedance for SE as 0.1 ohm and BAL as 0.2 ohm.

I know they're not just going to put those things in parallel and load down half of the balanced with whatever SE is plugged in...

So I'm wondering...

Looking at the L30 II, we can see that Topping uses 2x TPA6120A2 chips for the output stage. The chips are stereo. Advertised is 1400mA current and 0.1 ohm output impedance.
In the 6120A2 datasheet, 700mA is listed as maximum current.

This leads me to believe that in the A70 Pro, there are 4x TPA6120A2, two for SE, and two for BAL.

SE seem to tie the two channels together, while BAL uses one chip eg. Chip1's two channels do L+ and L-
This would make sense for the 0.2 ohm specified output impedance.. Or wait! It should be 0.4 ohms if two 0.2s are in parallel for SE to make 0.1.
But it's 0.2 ohms! So there must not be 4x TPA6120A2s in the A70 Pro, there must be SIX (6x).

I know the SE doesn't mess with BAL output at all because I've attached and removed low impedance loads from BAL while listening to SE, and there were no pops (yes, they're relay controlled, but that is switched from presence at the 4.4mm/XLR jack, and I attached and removed the load from the far end of the cable, with the cable already attached and enabled

So... Is this what it is? Are there 6x TPA6120A2 in the A70 Pro?
There's certainly room under that heatsink...
And the specs make me think so.

Unless output impedance doesn't double when you bridge an amplifier (assuming the chips are configured identically otherwise)...

We do also get to see quite the power output increase using the BAL side, which seems to coincide with a doubling of amplifier silicon and voltage together pretty well.


Thoughts?

Since the question regarding the output stage of the A70 Pro—specifically whether multiple TPA6120A2 chips are installed there as well—was never conclusively resolved, I decided to open one up and take a look myself. Given the significantly higher power output, this eventually struck me as unlikely.
Surprise: not a single TPA6120A2 in sight.

The output stage of the A70 Pro consists of eight standard SMD transistors—specifically two per channel (totaling four channels, as the design is balanced). It is, therefore, a discrete, balanced transistor amplifier.

As questions also arose regarding the capacitors used, I have included photos of those as well.

 

[totti1965]

There is also an 'Output' that can change the channel if you are set up for IND individual.

I have not read every comment here. But: Can you tell me if that means you are able to switch the right channel to the left channel and vice versa with this device?
Would be an interesting feature if you want to use the US$ 12 AKG EO-IG955 or the US$ 8 Samsung EO-IA500 IEM´s in the way that sharur suggests:

The Best IEMs in the World Are Just $8

....was the fancy title of a youtube video, that sharur just released yesterday ;) ok, here are some measurements I found: measured with B&K 5128 Head and Torso Simulator (HATS) measured with IEC 60318-4 (711) It seems to measure very very well after some corrections between the range...

www.audiosciencereview.com

The Best IEMs in the World Are Just $8

I was a bit slow: I have not seen, that sharur gave precise suggestions in the description of the video. He says: „The Samsung EO-IA500 and AKG EO-IG955 are the best sounding and measuring earphones money can buy, and only cost $8. This is the ultimate audio blackpill and will be hard to...

www.audiosciencereview.com

 

[Roland68]

I have not read every comment here. But: Can you tell me if that means you are able to switch the right channel to the left channel and vice versa with this device?
Would be an interesting feature if you want to use the US$ 12 AKG EO-IG955 or the US$ 8 Samsung EO-IA500 IEM´s in the way that sharur suggests:

The Best IEMs in the World Are Just $8

....was the fancy title of a youtube video, that sharur just released yesterday ;) ok, here are some measurements I found: measured with B&K 5128 Head and Torso Simulator (HATS) measured with IEC 60318-4 (711) It seems to measure very very well after some corrections between the range...

www.audiosciencereview.com

The Best IEMs in the World Are Just $8

I was a bit slow: I have not seen, that sharur gave precise suggestions in the description of the video. He says: „The Samsung EO-IA500 and AKG EO-IG955 are the best sounding and measuring earphones money can buy, and only cost $8. This is the ultimate audio blackpill and will be hard to...

www.audiosciencereview.com

I am not familiar with that feature on the A70 Pro—nor on other headphone amplifiers, for that matter. Even the large Phonitor HPA doesn't have it.

Wouldn't it be much simpler to make an adapter cable or solder on a new connector?

 

[Phony846]

I've had my A70 Pro for more than 2 years, and it's been flawless. About a month ago I updated the firmware to v2.08. For weeks it was just fine. However, now I'm experiencing a problem. Randomly after a few minutes of use the front headphone jack stops working then may (or may not) resume working. I can watch the FFT on the LCD it's still getting active audio signals (from my D70 Pro). During periods while the audio is cut out the front display display buttons are non-responsive, even while the FFT is active. After a minute or two audio resumes and the buttons once again work. I've done a cold power cycle several times, and it comes back. If I power off during the audio cut out then power back on it comes back. Any ideas?