Topping A70 Pro HP & Preamp Review

[marcom22]

Ideally songs should not have DC but failing that: DC should be blocked at the DAC - before 0Hz gets amplified...

What DAC do you use?

SMSL SU-9 ...... I configured a HighPassFilter 20 Hz, Q=1, 24db\octave on my Jriver. Nothing changed, same problem.

 

[CJG]

Just hooked up my A70 to my RME, and wow does this thing sound phenomenal!

 

[marcom22]

Just hooked up my A70 to my RME, and wow does this thing sound phenomenal!View attachment 356558

Also mine sounds phenomenal BUT you dont have my headphones ;-)

 

[Veri]

Also mine sounds phenomenal BUT you dont have my headphones ;-)

I sure hope he would not, it would mean he'd be a thief!

 

[marcom22]

I sure hope he would not, it would mean he'd be a thief!

I'm italian sorry for my poor english

 

[Imaraptor]

DC is the 0Hz.
It's not about cheap or expensive,is more about choices and how one implements the filter ,some are way too sensitive.
In most of the songs you will maybe see some content at 0Hz but it's low on level,usually under -65db and it's mostly the combination of DC and level that may trigger a sensitive filter.

I would prefer a well made filter or even one not so good than none.
DC can cause mayhem down the chain.

BUT,DC is not only about songs,a broken DAC for example can output DC which eventually or suddenly can cause problems.
The sensible thing to do is get a DMM (even a cheap one) put it in the DC scale and test the outputs of the devices,that's what I do out of the box,without even plugging them for the first time.
Why?
Because DC will be amplified down the road and can damage speakers,headphones,etc.

Okay, thanks for the insight!
I figured I was getting into another esoteric hobby, but I was trying not to dive in headfirst, but here we are and I'm ready! I just didn't really know where to begin.
DMM is a digital multimeter, correct? Could you recommend one (preferably sub $200, unless if that's not feasible or if they get much better at a slightly more expensive price? And maybe a YouTube channel or website where I could read up and understand more of where to begin to understand how to use it and what to look for? Lastly, if you wouldn't mind, could you give me the name of the software that you're using to analyze the waveforms of the songs that I listed? I'd like to use it so see if my other music that was causing this in the past is similar. I imagine it will be as I tend to listen to/study a lot of smaller and horribly mixed artists/music.

Also, do you think that purchasing the D70 Pro or Matrix Mini I-4, or SMSL D400 could rectify this issue through their implementation of high pass filters on a hardware level, or am I confusing the capabilities of the RME ADI-2 FS DAC to filter out DC with my potential current issue? No pun intended.

 

[Sokel]

You can get a more than decent DMM for half that money ,check Extech or Amprobe for their lower models,is more than enough for the job and safe.
Or get a fluke for about the money you say and be done with it forever,it's endgame for amateurs like us and it's useful everywhere.

Not a particular YT channel,there's a gazillion of them to tell how to measure depending what you want to measure.For DC you just put it in the DC scale and you should see no more than a few mV or zero ideally.

The software is Audacity,you load the song,right click on the down left window to split the stereo track,double click on the waveform to choose the whole song and then go Analyze > Plot spectrum and you're done.

About the different DACs,you must seek user experience about them to be sure.

 

[Imaraptor]

You can get a more than decent DMM for half that money ,check Extech or Amprobe for their lower models,is more than enough for the job and safe.
Or get a fluke for about the money you say and be done with it forever,it's endgame for amateurs like us and it's useful everywhere.

Not a particular YT channel,there's a gazillion of them to tell how to measure depending what you want to measure.For DC you just put it in the DC scale and you should see no more than a few mV or zero ideally.

The software is Audacity,you load the song,right click on the down left window to split the stereo track,double click on the waveform to choose the whole song and then go Analyze > Plot spectrum and you're done.

About the different DACs,you must seek user experience about them to be sure.

Thanks for all of your help man! I truly appreciate it!
How can I make my high pass "less sensitive"? I don't think that's the correct term but I'm cut out more low frequency to prevent the amp from cutting out as often because I ran into a couple more instances while trying to listen with my gf last. Ideally it would be through the Q value right to prevent from cutting out too much audible data from the music, but the Q value seems to be acting as a peak filter as well when I change it and view it as a graph (attached). Will lower the Q value do what I want without amplifying the 20Hz range?
EDIT: Would a Highpass butterworth filter be a better tool in this scenario? I feel as if it sounds the best and the graph moves how I would prefer it to.
I also downloaded audacity and have been viewing some of my music and this is an invaluable tool! topping support wasn't even 1% as helpful as yourself. I feel like they could have atleast pointed me in a direction. Thanks tremendously! If you have a cash app, please message me!

 

[Sokel]

Thanks for all of your help man! I truly appreciate it!
How can I make my high pass "less sensitive"? I don't think that's the correct term but I'm cut out more low frequency to prevent the amp from cutting out as often because I ran into a couple more instances while trying to listen with my gf last. Ideally it would be through the Q value right to prevent from cutting out too much audible data from the music, but the Q value seems to be acting as a peak filter as well when I change it and view it as a graph (attached). Will lower the Q value do what I want without amplifying the 20Hz range?
EDIT: Would a Highpass butterworth filter be a better tool in this scenario? I feel as if it sounds the best and the graph moves how I would prefer it to.
I also downloaded audacity and have been viewing some of my music and this is an invaluable tool! topping support wasn't even 1% as helpful as yourself. I feel like they could have atleast pointed me in a direction. Thanks tremendously! If you have a cash app, please message me!

Yes,a Butterworth with a steep slope is closer to a classic subsonic filter,play with that at about 15-18Hz and see how it goes.
No cash needed,glad I could help!

 

[Aud99]

Bought mine a month ago from Amazon Canada.

It was doing great - until, today, the display showed the “HP DC Abnormal” error.

Tried to contact their customer support using the address on their website, and then received this other error “Your message wasn't delivered to [email protected] because the address couldn't be found, or is unable to receive mail.”

Well, I am still 4 days in Amazon’s return window, so I will just ship it back and find another amp from a different company.

I hope my headphones are still OK, as they were plugged in when it happened.

 

[Human Bass]

Bought mine a month ago from Amazon Canada.

It was doing great - until, today, the display showed the “HP DC Abnormal” error.

Tried to contact their customer support using the address on their website, and then received this other error “Your message wasn't delivered to [email protected] because the address couldn't be found, or is unable to receive mail.”

Well, I am still 4 days in Amazon’s return window, so I will just ship it back and find another amp from a different company.

I hope my headphones are still OK, as they were plugged in when it happened.

The A70 is a massive disappointment. The worst "best" amp in the market. Topping should actually recall all units not yet sold.

Glad it died inside the return window

 

[Music1969]

the display showed the “HP DC Abnormal” error.

Ah this matches the suspicious initially raised by @staticV3 about DC issue in the music itself

What DAC are you using? This is what should ideally be filtering for DC in my opinion... well it shouldn't be in the music at all but you know what I mean.

I've not had an issue with my Topping A70Pro but as prevention now I add high pass filter at 1Hz in my headphones EQ file.

Frequency response not affected above 20Hz

Filter 1: ON HP Fc 1.0 Hz

 

[Kaligogrrrrr]

Ah this matches the suspicious initially raised by @staticV3 about DC issue in the music itself

What DAC are you using? This is what should ideally be filtering for DC in my opinion... well it shouldn't be in the music at all but you know what I mean.

I've not had an issue with my Topping A70Pro but as prevention now I add high pass filter at 1Hz in my headphones EQ file.

Frequency response not affected above 20Hz

Filter 1: ON HP Fc 1.0 Hz

Sorry what is DC and why is it an issue? I just ordered a Topping L30II, to go with my E30 - and now getting concerned.

Topping were pretty much ruling a couple of years back when I was last into this hobby, coming back I seem to get the vibe there are some QC/reliability issues with some Topping lines. (This may just be that a huge portion of Topping users also use this forum so a small percentage of cases seem more prominent - not to mention often people only speak up when there is a problem or concern)

 

[Bleib]

Sorry what is DC and why is it an issue? I just ordered a Topping L30II, to go with my E30 - and now getting concerned.

Topping were pretty much ruling a couple of years back when I was last into this hobby, coming back I seem to get the vibe there are some QC/reliability issues with some Topping lines.

This have not been reported with the gear you have ordered

 

[delamelon]

I only use my A70 Pro as a preamp.
Is this a problem exclusive to the use of headsets?

 

[Music1969]

Sorry what is DC and why is it an issue?

It is in the music. in previous few pages the guy that had issue mentioned the song

Song was analysed and you can see DC in it (as I mentioned above)

So that was cause of the amp DC error.

DC in music bad.

 

[Aud99]

Ah this matches the suspicious initially raised by @staticV3 about DC issue in the music itself

What DAC are you using? This is what should ideally be filtering for DC in my opinion... well it shouldn't be in the music at all but you know what I mean.

I've not had an issue with my Topping A70Pro but as prevention now I add high pass filter at 1Hz in my headphones EQ file.

Frequency response not affected above 20Hz

Filter 1: ON HP Fc 1.0 Hz

The source was Tidal streaming, using the DAC of an Eversolo DMP-A6 Master Edition.

 

[Music1969]

The source was Tidal streaming, using the DAC of an Eversolo DMP-A6 Master Edition.

Yes same source we discussed a couple pages back

its more to do with the actual music track, not which streaming service

DC in the track itself...

 

[Roland68]

Ah this matches the suspicious initially raised by @staticV3 about DC issue in the music itself

What DAC are you using? This is what should ideally be filtering for DC in my opinion... well it shouldn't be in the music at all but you know what I mean.

I've not had an issue with my Topping A70Pro but as prevention now I add high pass filter at 1Hz in my headphones EQ file.

Frequency response not affected above 20Hz

Filter 1: ON HP Fc 1.0 Hz

It's not a problem with DC, DACs or music.
It's just because of these stupid modules filled with potting compound. The problem with the A70 Pro and A90D is probably that direct current components from the power supply get into the small signal processing. You can't compensate for this externally, even with filters.

Does Topping actually realize how many customers they have already lost and how many devices they are not selling because of these stupid modules?
For me alone it's an A70 Pro, two LA90Ds and a PA5. In my circle of friends there are at least another 50 devices that were not purchased from Topping.

Addendum:
A topping DX9 is also on the list of devices I didn't buy. Since there was no clear information as to whether the device will be delivered with open modules or potting mass, I left my money with SMSL for a D400EX DAC worth €1100.

 

[Imaraptor]

Bought mine a month ago from Amazon Canada.

It was doing great - until, today, the display showed the “HP DC Abnormal” error.

Tried to contact their customer support using the address on their website, and then received this other error “Your message wasn't delivered to [email protected] because the address couldn't be found, or is unable to receive mail.”

Well, I am still 4 days in Amazon’s return window, so I will just ship it back and find another amp from a different company.

I hope my headphones are still OK, as they were plugged in when it happened.

Sorry that happened to you man!
They are a little hard to get a hold of, but you do have the support email slightly incorrect.
I have [email protected], whereas, you have an additional "s" after "service".
Hopefully that helps a little and I'm hoping your headphones are fine, but they should be. My understanding is that this DC protection is in place to protect the headphones.