Topping A70 Pro HP & Preamp Review

[staticV3]

@DouglasteR
The A70 Pro can output 4x more power at 50Ω than the DX7 Pro (6.6W vs 1.6W).

That translates to 50% more perceived volume (yes, only that much).

 

[DouglasteR]

Sounds really good (pun intended).

So, at 600ohms it should be at least 33% louder ?

 

[Ahmonge]

That translates to 50% more perceived volume (yes, only that much).

How does 6 dB more sound pressure translate into 50% more perceived volume? The dB scale for sound was not adopted because it is perceived more or less as linear by humans?

 

[staticV3]

How does 6 dB more sound pressure translate into 50% more perceived volume? The dB scale for sound was not adopted because it is perceived more or less as linear by humans?

Typically, a 10dB increase in volume is perceived as double the loudness.

Not sure what you mean by "the dB scale is perceived as linear by humans". dB is a logarithmic unit.

 

[staticV3]

So, at 600ohms it should be at least 33% louder ?

At 600Ω, the A70 Pro can output 3x more power (700mW vs 225mW).

That translates to about 40% higher perceived volume.

 

[DouglasteR]

At 600Ω, the A70 Pro can output 3x more power (1.37W vs 0.45W).

That translates to about 40% higher perceived volume.

Thank you so much.

Time to start saving (again)

 

[Ahmonge]

Not sure what you mean by "the dB scale is perceived as linear by humans". dB is a logarithmic unit.

As the human auditory system behaves like a logarithmic compressor, a logarithmic scale (in dB) is used to obtain a linear result from the human point of view.

A linear relation between loudness and decibels - Attention, Perception, & Psychophysics

A total of 37 uninitiated observers made repeated numerical magnitude judgments of the loudness of a sequence of octave band noises spaced at 1-dB intervals, from 0 to 5 dB above a standard of about 80 dB(A), which was called 10. The observers were not instructed to use numbers as ratios. When...

link.springer.com

 

[MJG]

I have just gotten one of these. I can only turn it up to about -7.0db with my HE-6 SE V2’s in high gain before it starts cutting into protect. DAC is feeding it 0.0db. Is going into protect at that level normal? It doesn’t seem *very* loud. It feels like it should be a little louder before hitting protect, anyway.

 

[MJG]

I guess this is going back to Amazon. It's a shame, I really like the VU and FFT modes. Any suggestions for driving HE-6 SE V2's? SMSL SP400?

 

[Roland68]

Is it normal to have a high pitched whine when the unit is in standby (power switch is on, but used remote to turn off power - so standby mode)? I assume it's SMPS related.. Sounds like coil whine, but I don't know if it should be there in standby mode. I tried different outlets in my power conditioner or direct into wall and no difference.

Note: It seems to only happen for a short time after I just put it into standby mode because this morning I checked and all I can hear is the tiniest high-pitched noise compared to just when the unit goes into standby and the whine is loud enough to hear from 6 feet away.

It shouldn't be, but unfortunately it sometimes happens with cheap switching power supplies.
I would always return a device like this.

 

[Ahmonge]

Is it normal to have a high pitched whine when the unit is in standby (power switch is on, but used remote to turn off power - so standby mode)? I assume it's SMPS related.. Sounds like coil whine, but I don't know if it should be there in standby mode. I tried different outlets in my power conditioner or direct into wall and no difference.

Note: It seems to only happen for a short time after I just put it into standby mode because this morning I checked and all I can hear is the tiniest high-pitched noise compared to just when the unit goes into standby and the whine is loud enough to hear from 6 feet away.

It happens to the A30 Pro as well when switching off from with the front switch and the back switch is left to ON, is PS related, very faint (in my unit) and disappears a) after several minutes or b) switching off the back switch or disconnecting the unit from AC by other means.

 

[formdissolve]

It happens to the A30 Pro as well when switching off from with the front switch and the back switch is left to ON, is PS related, very faint (in my unit) and disappears a) after several minutes or b) switching off the back switch or disconnecting the unit from AC by other means.

Thanks, I figured it was simply the SMPS inside. I am pretty sure if I sent it back and got a different one, that new unit would also have the SMPS whine.

 

[Roland68]

Thanks, I figured it was simply the SMPS inside. I am pretty sure if I sent it back and got a different one, that new unit would also have the SMPS whine.

That was not supposed to be like that. Small Meanwell switched-mode power supplies are installed in the device, where this type of thing does not normally occur.

 

[nagster]

Simple measurements and pictures of A70 Pro. Bought new on Amazon last week.
https://www.audiosciencereview.com/...g-a70-pro-hp-preamp-review.44636/post-1589231
https://www.audiosciencereview.com/...mark-hpa4-headphone-amp-pre.8141/post-1977315

 

[ObjectiveSubjectivist]

Simple measurements and pictures of A70 Pro. Bought new on Amazon last week.
https://www.audiosciencereview.com/...g-a70-pro-hp-preamp-review.44636/post-1589231
https://www.audiosciencereview.com/...mark-hpa4-headphone-amp-pre.8141/post-1977315

Extremely good numbers by Mola Mola

 

[JediMa]

I feel like a bad noob I must say but I haven't found out how to make it work with my powered Speakers. I plugged them by rca to the back ports on the A70, but no sound.

 

[formdissolve]

I feel like a bad noob I must say but I haven't found out how to make it work with my powered Speakers. I plugged them by rca to the back ports on the A70, but no sound.

Make sure the output mode is correct. Set it to PRE or HPA+PRE and make sure RCA cables are on the output

 

[JediMa]

Double checked, still no sound . Rca in Edifier speaker is in AUX in (tried also pc in and still no sound) and RCA in Topping are plugged in RCA Out and its set on HPA+PRE .. I dont know

 

[formdissolve]

Double checked, still no sound . Rca in Edifier speaker is in AUX in (tried also pc in and still no sound) and RCA in Topping are plugged in RCA Out and its set on HPA+PRE .. I dont know

Did you bress the A or B button when you are in PRE mode? That should tell you if the output is RCA/XLR or both. Other than that, don't know what else it could be.

 

[JediMa]

Did you bress the A or B button when you are in PRE mode? That should tell you if the output is RCA/XLR or both. Other than that, don't know what else it could be

Solved, it was the cable the was broken