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Topping A70 Pro HP & Preamp Review
- Thread starter amirm
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Yes, only use high gain if low gain is not enough.
honn
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Am I right that the A70 Pro is the best measured headphone amplifier in this forum in most metrics such as distortion and power availability, and as such a better amplifier than the $3,500 Benchmark HPA4? Or is there something more in HPA4 performance-wise that surpasses A70 Pro here? So $500 amplifier beats the 7x more product, or am I missing anything here? Thanks!
Antagron
Member
That is kind of what I’m digging for too. Seems like it should be a no brainer (I bought one so I definitely agreed with that sentiment) but you will always hear people saying xyz is just better. Hard to pin it down. Could be placebo, cost justification, nice distortion, or something magical. I don’t know since I have never side by side compared any of these other amps.
Hmm... That would imply another level is set too high somewhere else (no digital track released to the public as music should be able to cause that)
If you can't find where to fix it, the best thing to do is go to google search online tone generator, pick the first or second one (it's orange) - change the volume from 50 to 100%, press play, then adjust the volume until you see OVR. Back it down by 0.5dB from that point, and you'll get the best quality sound (ie. everything you paid for) from the DAC
Yes, it is. The $3,500 Benchmark, if released by Topping (part for part), would probably sell for $1,500.
Some of the price difference between the two will be seen in ultimate lifespan, the rest, overbuilding.
I think if you buy the A70 Pro and use it for 6-8 hours a day, you'll get 7-10 years out of it. The Benchmark you might be able to leave on 24/7 for 12-15 years, maybe even 20.
One way sound might differ between the two is with more reactive loads - the Benchmark and A70 Pro have different feedback designs. Most often they will sound the same, and when there is a small difference, there's no way to predict which will sound better. The Benchmark might be a little more likely to be the better sounding option in those few cases. Since 99% of the time there should be no difference (most headphones are pretty non-reactive (they don't have ported enclosures or crossovers), the likelihood the Benchmark would do better is like a tenth of a percent. Basically not worth mentioning, but you're wondering if there's _anything_
So if there was something, I'd say it was that.
I'd get the Topping (and I did lol). If you're in a place that Amazon sells it, you get to try it risk free, too, so it's not much to worry about
It shows OVR at +2.5 dBFS for the line-out (manual v3.3 section 15.2 p.32). At 0 dB volume, that could be because part of the signal is boosted somewhere in the DSP such as by using EQ, Bass/Treble and/or Loudness. Single tones may not reveal the issue then.Hmm... That would imply another level is set too high somewhere else (no digital track released to the public as music should be able to cause that)
If you can't find where to fix it, the best thing to do is go to google search online tone generator, pick the first or second one (it's orange) - change the volume from 50 to 100%, press play, then adjust the volume until you see OVR. Back it down by 0.5dB from that point, and you'll get the best quality sound (ie. everything you paid for) from the DAC
There is no benefit to a higher volume setting on the DAC other than less noise being amplified by the A70 Pro for the same output. At -13 dB DAC volume with the A70 Pro in low gain at 0 dB volume, maximum SPL for a sine is 94 - 20*log10(1.25) + 10*log10(0.6) + 19-13 + 6 = 101.84 dB SPL. The DAC's SNR is 121 dB so its noise is at least 108 dB below the signal at -13 dB volume and thus at most at -6 dB SPL. Inaudible except for very extreme circumstances.
Hello, not sure if already covered by some posts here, in that case I apologize. Is it possible to exclude the outputs from the volume control? I mean using the volume control for HPA only and routing the input signal unamplified to the outputs? From the manual I guess it is not possible.
Thanks
Thanks
Your post doesn't make sense.
If you have DSP on your PC which increases the digital audio level past 0dB, Windows will compress it back down to 0dB, lowering sound quality in the process, so you have to be careful to NOT exceed 0dB with your EQ and DSP settings. If the DSP is in your DAC, the DAC will also clip itself at 0dB - it won't be sending anything out higher than 0dB to the A70 Pro (the DAC will probably output absolute maximum either 4 or 5v RMS - it'll say +2.5dBfs, but it won't be sending a signal out that hot. Even if it did, if it was clean, so what? The A70 Pro's input can handle up to 10.6V RMS)
Your math looks good for pop music, but what about a movie? When people are talking, levels are down at -60dB, possibly lower... The DAC has a SNR of 121dB (and I assume DNR) of 121dB... Why would you immediately and effectively permanently disable it into something with 108dB dynamic range, when 121dB was bought and paid for? It's right there! You don't have to throw it away! It also reduces the maximum level by 13dB, which he might need with such insensitive cans - literally you almost took away the "High" gain setting with your -13dB....
There is literally no reason to turn the volume on the DAC down - none! The only reason it should be touched is if it is being used as a digital preamp. You leave it at 0dB and adjust other things accordingly
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Read the manual for the DAC in question. It has a DSP and internal headroom.
108 dB SNR from the DAC is no problem in low gain because the noise will be inaudible using the headphones discussed. In high gain, noise the DAC's noise in amplified a further 14 dB leading to it being at around 8 dB SPL at full volume with the headphones discussed. This may indeed be audible. With the DAC's output of 19 dBu, the A70 Pro clips at 20*log10(54) - 10*log10(8) - 10*log10(0.6) - 20 - 19 = -11.16 dB in high gain balanced. This leaves 2 dB on the table with the DAC's volume at -13 dB.
One reason to turn the volume down on a DAC is to avoid intersample over distortion. Around 3 dB is usually enough, though. If the DAC has enough internal headroom, this is of course not required.
Antagron
Member
Well, it’s all for naught because my A70 popped the old HP DC Abnormal error and is officially toast. Now I’m trying to see about a warranty claim. Hopefully they really do have a 2 year warranty. The amp has been operating since November 2023 until this week.
Bleib
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Have you tried what is said in the Topping FAQ?
"HP DC abnormal
Amplifier circuit outputs abnormal DC voltage.
After changing the song or turning down the volume, Unplug and re-plug the power cable and reboot the unit.
Disconnect other devices and reboot. If the problem still persists, your unit may be defective. Please contact the store where you purchased it."
Hello everyone,
After reading and following this topic for a while, without an account, I'd decided to purchase the topping a70 pro + d70 pro sabre stack, along with a hifiman arya stealth. I've tried nearly everything, started a topic on another forum, and am unable to get sound out of the dac as the playback device. Everything else seems to work, device is recognized, drivers are installed, firmware is up to date, etc.: https://forums.whathifi.com/threads...rking-through-my-dac-need-some-advice.135190/
Would anyone happen to know what more troubleshooting I could do to get sound to work everywhere? I had only been able to achieve sound through Foobar2000, playing a downloaded .mp3 file through ASIO4ALL. No sound outside of Foobar2000.
I don't know if this topic is the right place, and I apologize if it isn't. I'm (very) new in the audio/hifi world. Any help is very much appreciated, my messages are open!
After reading and following this topic for a while, without an account, I'd decided to purchase the topping a70 pro + d70 pro sabre stack, along with a hifiman arya stealth. I've tried nearly everything, started a topic on another forum, and am unable to get sound out of the dac as the playback device. Everything else seems to work, device is recognized, drivers are installed, firmware is up to date, etc.: https://forums.whathifi.com/threads...rking-through-my-dac-need-some-advice.135190/
Would anyone happen to know what more troubleshooting I could do to get sound to work everywhere? I had only been able to achieve sound through Foobar2000, playing a downloaded .mp3 file through ASIO4ALL. No sound outside of Foobar2000.
I don't know if this topic is the right place, and I apologize if it isn't. I'm (very) new in the audio/hifi world. Any help is very much appreciated, my messages are open!
staticV3
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It sounds like a PC configuration issue.
Do you have another computer or phone that you could try as source device? Just plug-and-play, without installing drivers.
Edit:
Actually, shouldn't this be in the D70 Pro thread?
Not through USB at the moment, I could try a laptop later today though.
I'll put this in the D70 Pro thread, thanks for the heads-up!
Antagron
Member
Yes, did all that. As soon as the unit boots, it shows my spectral analyzer screen for about 1s and then drops to the error message. No further interaction with the unit is possible. It does go into firmware update mode without issue. I updated after the error happened successfully but it didn’t help.
For me TOPPING is dead ........ no more items from them. My A70 still works but I fear it
Yeah, it's a shame but the company's history of failures and unreliability and lack of consumer transparency or any apparent systemic efforts to fix these things while still plowing ahead with new product release after new product release has really damaged it's reputation in my eyes and will make it hard for me to buy another Topping piece unless and until things are changed. I have an OG D90 and yes, an A70, which still works, but I only use it as a preamp not a headphone amp (I'm only very, very rarely a headphone listener); and it's worked flawlessly and wonderfully as a preamp, but I dread connecting any headphones to it.
I use it 75% as preamp and 25% as headphone amp ........ but I love it as preamp, less as headphone amp. I have 2 kind of headphone:
- BeyerDynamic DT770 80ohm
- Hifiman Sundara
with Beyer no problem but with Sundara I have dropping audio around -20db. Finally the power is not like as described from Amir, my ears are not exploded with Sundara in HIGH GAIN (I arrived at -8 Db).
Antagron
Member
It does make me think twice about buying any more Topping devices. I think this is a great unit in terms of design and sound but reliability trumps all of this. Things that grenade themselves for no apparent reason make you feel like the sword of Damocles is hanging over your head. The “when not if” class of design issues. People say the HE6se will eventually get its magnets stuck. The 789 potentiometer will eventually fail. The list goes on.
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