Topping A70 Pro HP & Preamp Review

[staticV3]

Yesterday I received the A70 Pro. Very nice and compact, though the finish is average at best. My first impressions are that it drives the Abyss 1266 fantastically well. BUT every time I turn it off from the amplifier and then turn it back on, it freezes, and the screen shows “DFU version v2.05.” If I switch it off from the back and then turn it on again, everything works correctly. Is this normal? I think it’s going back to Amazon.

Regards,

DFU mode is only for flashing the firmware.

According to Topping, the A70Pro should only go into DFU mode by flipping the power switch at the rear off, then back on while you press down the volume knob.

The Amp shouldn't go into DFU mode if you're not touching the volume knob during boot.

You could try updating the firmware, see if that helps: https://www.toppingaudio.com/download/a70-pro-version-v2-05-firmware-update

 

[jmdesignz2]

Yesterday I received the A70 Pro. Very nice and compact, though the finish is average at best. My first impressions are that it drives the Abyss 1266 fantastically well. BUT every time I turn it off from the amplifier and then turn it back on, it freezes, and the screen shows “DFU version v2.05.” If I switch it off from the back and then turn it on again, everything works correctly. Is this normal? I think it’s going back to Amazon.

Regards,

Are you using the remote to turn off?

 

[Earwax]

You have the latest Firmware according to Topping so that`s weird. Curious if the Ground loop switch is in Lifted position if that changes anything, worth a shot.

A70 Pro version V2.05 firmware update - TOPPING AUDIO

www.toppingaudio.com

Try Emailing them and post here what is the issue.

Scroll down to bottom of page.

About - TOPPING

www.toppingaudio.com

 

[Earwax]

Yesterday I received the A70 Pro. Very nice and compact, though the finish is average at best. My first impressions are that it drives the Abyss 1266 fantastically well. BUT every time I turn it off from the amplifier and then turn it back on, it freezes, and the screen shows “DFU version v2.05.” If I switch it off from the back and then turn it on again, everything works correctly. Is this normal? I think it’s going back to Amazon.

Regards,

Question how is it lined up in your system I was under the impression it turns off from the source when using Tigger connections...

 

[Earwax]

I've been curious about the A70pro ever since it was released. I'm looking for an excuse to buy one, but for some reason none of my TOPPING devices have broken so far...

I think the maximum allowed voltage for XLR input is 10.6V or less.　(Because it seems to have two 15V power supplies installed)
The RCA inputs may be similar, or 13.3V or higher(*) like the L70. (*AP Generator limitations)
If the RCA input impedance is 10kohm or more like A90D, I think the maximum allowable voltage is 10.6V or less.
In any case, it is sufficient for home use.
For professional use, the XLR input must be able to tolerate 12.3V (24dBu).

I`ve heard they need to double the switching power supply otherwise the low voltage would lose power when going through the chokes. So adding higher voltage negates this issue of losing dynamics.

Credit here. 10:30 mark

 

[Thighsofsteel]

Yesterday I received the A70 Pro. Very nice and compact, though the finish is average at best. My first impressions are that it drives the Abyss 1266 fantastically well. BUT every time I turn it off from the amplifier and then turn it back on, it freezes, and the screen shows “DFU version v2.05.” If I switch it off from the back and then turn it on again, everything works correctly. Is this normal? I think it’s going back to Amazon.

Regards,

I have had one for a few weeks now. It has been flawless.

 

[tonimccloud]

Question how is it lined up in your system I was under the impression it turns off from the source when using Tigger connections...

It's connected to my dac (Sony ta-zh1es) by RCA. I've connected a lot of amps and it's the first time that I have problems

 

[DrCWO]

BUT every time I turn it off from the amplifier and then turn it back on,

What exactly did you do?
It must be something that activates the DFU mode. This is necessary to load a new firmware and is not a failure of the Unit. The question is how did you provoke the activation of the DFU mode?

 

[tonimccloud]

What exactly did you do?
It must be something that activates the DFU mode. This is necessary to load a new firmware and is not a failure of the Unit. The question is how did you provoke the activation of the DFU mode?

It's quite easy: turn on the device with front button. After some hours of pleasant music turn off. And now if you try to turn on the device, the screen displays DFU and freezes, very strange indeed. At this moment you turn off with rear button and everything works fine.

Tomorrow I'll send It back to Amazon, I'll try with another brand (i like cayin iha8 and aune s17 pro evo, price is not the same though)

 

[Earwax]

Just received my A70 pro , due to inexperience the D50 III dac power was on I had 5 volt unplugged but usbc was still plugged into computer that was powered up so dac stayed on. Now after hooking up the A70 pro and B100's I was getting no sound I tried unplugging every connection again trying over nothing no sound, and the settings were perfect.

Turns out you need to have the Dac powered off before plugging in all your TRS/ XLR cables to all units in the chain.

After aunplugging the Dac usbc from the live computer and trying one last time it works flawlessly, the higher voltage output of the pre amps really puts a nice Topping on the purity of the music !!!

I'm thinking of downgrading to the L70 as I don't need a pro version EXT output or fancy screen but i do like the screen blackout option it labeled dim but it's blacked out vrry nice option for night movies .

My only vice is the unproven lower heat generation of the new amp modules the A70 pro stayed as cool as the D50 III Dac so I couldn't even feel if it had made any heat.

If that changes I'll edit thus post or add a reply stating findings.

I only had it playing for about 1 hour straight so far...

 

[olds1959special]

If you’re using the DAC as a preamp and it uses a digital volume control then it will make a huge difference if you’re a critical listener to use the Topping A70 Pro as a preamp

Digital volume control truncates in order to reduce volume

Digital volume control works by
multiplying the numerical values in a digital audio stream by a gain factor (less than 1) to reduce their amplitude, thereby lowering the volume. This process, known as attenuation, decreases the numerical data representing the audio signal, and while effective, it can lead to a loss of resolution by truncating the least significant bits.

This can decrease dynamics among other things

I'm using the A70 Pro as a pre-amp in my other system because using a digital volume would not be practical (too much gain in amps.) It works very well and I control the volume with the remote, which also works flawlessly. However, if you can use the higher end of the volume scale (60-99) of the DAC then I don't feel the quality loss is significant, and the fact that you are bypassing typical preamp analog circuitry and cables, means it can sound better. In my listening tests I have found that bit loss is not audible until in the lowest 15% of the volume range, and I'm not even sure about that (because to listen to it at that level I had to boost my pre-amp more and I was probably just hearing distortion!) It's nice that there's technically no quality loss at any volume with analog volume controls, but it doesn't necessarily mean it will be better in actual function and audible sound. My second system uses an Apogee Duet 3 interface as a source connected directly to a powered subwoofer and studio monitors using a digital volume control and it works fine, or at least to my ears. There is just no need for a pre-amp sometimes.

 

[DrCWO]

Digital volume control works by
multiplying the numerical values in a digital audio stream by a gain factor (less than 1) to reduce their amplitude, thereby lowering the volume. This process, known as attenuation, decreases the numerical data representing the audio signal, and while effective, it can lead to a loss of resolution by truncating the least significant bits.

At first sight correct, but please also take a look at my research regarding digital Roon volume control here:

The final truth about DSP Volume Control in Roon

In the net I found a lot of discussions regarding the quality of Roon DSP volume control. The discussions revolve around whether it is better to use the device volume, the DAC volume, or an analogue volume control. One of these threads for example here...

www.audiosciencereview.com

Also good DACs like the RME ADI-2/4 Pro use a mix of digital and analog volume control inside the unit. Please search fron "Auto Ref. Level" in the ADI-2/4 Pro Manual to see how the reference level is decreased in the analog domain by reducing output volume. This keeps the DAC chip above -24dB in a nearly lossless region.
Also starting at page 99 in this document you can find a lot of information about the advantages of digital volume if implemented correctly.

Best DrCWO

 

[jmdesignz2]

At first sight correct, but please also take a look at my research regarding digital Roon volume control here:

The final truth about DSP Volume Control in Roon

In the net I found a lot of discussions regarding the quality of Roon DSP volume control. The discussions revolve around whether it is better to use the device volume, the DAC volume, or an analogue volume control. One of these threads for example here...

www.audiosciencereview.com

Also good DACs like the RME ADI-2/4 Pro use a mix of digital and analog volume control inside the unit. Please search fron "Auto Ref. Level" in the ADI-2/4 Pro Manual to see how the reference level is decreased in the analog domain by reducing output volume. This hold keeps DAC chip above -24dB in a nearly lossless region.
Also starting at page 99 in this document you can find a lot of information about the advantages of digital volume if implemented correctly.

Best DrCWO

I haven’t seen measurements for those but it’s moot for me. I’m super happy with how the A70 Pro has transformed the sound of my system with its incredible high performance R2r volume control and insanely good SNR

In my case the digital volume control was definitely reducing transparency, dynamics etc

 

[Earwax]

I use an infrared thermometer laser temp gun after 30 minutes playing audio.

Top housing hottest area D50 III 30C, A70 pro 32C, B100 amps 34C L30 II 35C, The Harman Kardon AVR 140 43C... I have felt higher temps but today the room temps is only 21 C.

When using a large computer fan moving air across the top and bottom of the units the top of the housings hottest area reads: D50 III Dac 27 C, A70 Pro 29.5C, B100 Amp 31C.

Room temp 21C at 58 ish humidity. Vancouver Canada cooler October weather.

 

[Earwax]

I haven’t seen measurements for those but it’s moot for me. I’m super happy with how the A70 Pro has transformed the sound of my system with its incredible high performance R2r volume control and insanely good SNR

In my case the digital volume control was definitely reducing transparency, dynamics etc

Fully Agree, even with the audio in TV shows and movies have come alive so much more detail the purity appears 100% now even at lower volumes, also the situations where I need to crank up the volume has diminished greatly, When you crank it up the thunder fills the room very crisp and detailed thunder and lightening.

I`m thinking of down grading to the L70 as I don`t need a fancy screen or extension output and it`s $300 cheaper, but one vice is the A70 pro has the exact same T`ang-Ku-La module of my B100 amps...

 

[Earwax]

I stopped using it as a preamp as direct from dac sounded better.

Have you tried using dac only mode to the pre amp the D50 III I own is much louder in that mode it appears passing through the volume control mode is degrading the quality even at max volume...

Edited. .: Just to be crystal clear The audio is also noticeably louder in Dac only mode compared to pre amp mode full volume.

 

[jmdesignz2]

Have you tried using dac only mode to the pre amp the D50 III I own is much louder in that mode it appears passing through the volume control mode is degrading the quality even at max volume... ?

You must use the DAC at full scale, you should NOT use it in preamp mode if you are using the A70 as a preamp.

 

[formdissolve]

It's quite easy: turn on the device with front button. After some hours of pleasant music turn off. And now if you try to turn on the device, the screen displays DFU and freezes, very strange indeed. At this moment you turn off with rear button and everything works fine.

Tomorrow I'll send It back to Amazon, I'll try with another brand (i like cayin iha8 and aune s17 pro evo, price is not the same though)

This has happened to me before a handful of times as well in the year and half since I owned. The firmware is one version before the latest. I just shut it off with the remote to avoid that now.

 

[Earwax]

Mine arrived with the latest firmware no issues.

 

[HD800Fan]

Is there any teardown pictures of this unit?