Topping D70S fried my speakers...

[Snoopy]

I have run my DAC as pre-amp with no problem, so long as you follow best practice. That is, ensure you turn pre amp to zero when turning off. No surprises when turning on next time!

The problem is with DAC volume controls glitching. That could happen while you listen to music

 

[rentaclaus]

I've seen a lot of otherwise really great chinese products where one detail goes south.

e.g a torch light which can be assembled the wrong way so the on/off switch doesn't work (could be avoided by making the case symmetrical so it doesn't matter in which way it is assembled) , a beautiful an good working hairdryer which sucks long hair (a better filter at the air duct would prevent this)

If the default volume in pre-amp mode would set to zero, such things would not happen.

 

[Roland68]

I've seen a lot of otherwise really great chinese products where one detail goes south.

e.g a torch light which can be assembled the wrong way so the on/off switch doesn't work (could be avoided by making the case symmetrical so it doesn't matter in which way it is assembled) , a beautiful an good working hairdryer which sucks long hair (a better filter at the air duct would prevent this)

If the default volume in pre-amp mode would set to zero, such things would not happen.

I have run my DAC as pre-amp with no problem, so long as you follow best practice. That is, ensure you turn pre amp to zero when turning off. No surprises when turning on next time!

It really has nothing to do with Chinese products at all, but exclusively with the integrated DSP function for volume reduction in the DAC chips.

And it doesn't matter if you set the default volume to the lowest volume in preamp mode.
When the DAC is switched on, these registers in the DAC chip must first be written in order to reduce the volume. If an error occurs, the DAC chip remains at 0dB = full volume.
If an error occurs, these registers can be cleared or the entire DAC can be reset to normal DAC mode.
Several users have also reported on this.

Please also read https://www.audiosciencereview.com/...ing-d70s-fried-my-speakers.38706/post-1501351 and https://www.audiosciencereview.com/...ing-d70s-fried-my-speakers.38706/post-1501058.

 

[rentaclaus]

Thanks for the clarification, so using a "volume attentuator" (e.g. a preamplifier) seems the only way to be on the safe side.

 

[MCH]

Thanks for the clarification, so using a "volume attentuator" (e.g. a preamplifier) seems the only way to be on the safe side.

That depends on your system and situation.
I personally have a fixed attenuation in an input card that does dirac that can only be defeated by plugging and unplugging cables, a master digital volume control in a SBC and another fixed attenuation in the output dac, all digital.
Are the chances that all three attenuators fail simultaneously higher than a toddler (often around in my place) goes and turns an analog knob to the max without anyone noticing? I don't think so...
I don't think there is an universal answer, each case is different.

 

[Mnyb]

For active speakers you can set the volume control to something reasonable ie full tillt on the DAC is as high as you ever want to listen

 

[Roland68]

Thanks for the clarification, so using a "volume attentuator" (e.g. a preamplifier) seems the only way to be on the safe side.

Yes, you have to make sure somehow that the maximum volume cannot destroy anything.
This can be a simple attenuator/voltage divider, or a preamplifier. Then there is nothing wrong with continuing to use this function.

 

[sarumbear]

It really has nothing to do with Chinese products at all, but exclusively with the integrated DSP function for volume reduction in the DAC chips.

And it doesn't matter if you set the default volume to the lowest volume in preamp mode.
When the DAC is switched on, these registers in the DAC chip must first be written in order to reduce the volume. If an error occurs, the DAC chip remains at 0dB = full volume.
If an error occurs, these registers can be cleared or the entire DAC can be reset to normal DAC mode.
Several users have also reported on this.

Please also read https://www.audiosciencereview.com/...ing-d70s-fried-my-speakers.38706/post-1501351 and https://www.audiosciencereview.com/...ing-d70s-fried-my-speakers.38706/post-1501058.

The integrated DSP function is a facility. How you use it is the matter here. You say "if an error occurs," why does it occur, why there isn't a routine to avoid that to happen or if it happens to avoid the volume to go to max? It is standard in software driven devices to cater for errors. Topping haven't done that. At worst you should have a very short pop but that should be all. This is why I placed a passive volume control in between my Topping and power amp. Because I do not trust a small Chinese company to be able to write capable software to protect what is happening.

 

[Audioquest]

Call me an old analogue man in a digital world, but I'll never eliminate a preamp with a manual gain control from my system. I just like an old school knob to know where I'm at, plus to my ears, a good trransparent preamp adds heft to the scale and makes my big speakers perform better. If I were to go anything with a digital gain control straight into manpower amp, I'd turn that unit on first and check the gain, which is recommended practice anyway, before turning the power amp on. Amp ON last, amp OFF first is SOP.

 

[computer-audiophile]

There has to be some kind of real limiter in the chain so that the power amp doesn't burn out the speakers. That's the case with my analogue DIY tube amp systems anyway, but I also have these level controls in my digital systems with active speakers, which I mostly listen with. Anything else would be negligent, even though I have not yet experienced the problems described.

 

[Roland68]

The integrated DSP function is a facility. How you use it is the matter here. You say "if an error occurs," why does it occur, why there isn't a routine to avoid that to happen or if it happens to avoid the volume to go to max? It is standard in software driven devices to cater for errors. Topping haven't done that. At worst you should have a very short pop but that should be all. This is why I placed a passive volume control in between my Topping and power amp. Because I do not trust a small Chinese company to be able to write capable software to protect what is happening.

I try to make that clear all the time.
You can't catch it with programming or any other firmware. This is not possible in the constellation we are talking about in this thread.
If an error occurs, the part of the software that is supposed to prevent the registers of the DAC chip from being reset and thus being at 0dB is also disabled.

The problem is and remains that the starting point in the DAC chip is always 0dB. That's hardwired and a fact.

One possibility would be an intervention after the DAC chip, e.g. a switch-off that must be actively enabled by the user, or an adjustable maximum volume (better both).

The manufacturers should leave this function out of their devices (I mean exclusively the volume reduction in the DAC chip) or inform the buyer in detail and explicitly about the dangers of this function.

If I were the manufacturer and put a device with this function on the market, the owner would have to report to the website with a code generated by the device, register with an e-mail address and serial number and activate the function in the device with a code (received after confirmation of the waiver statement).
After that, I wouldn't care if the owner grilled their speakers or the amp.

 

[sejarzo]

My solution to this problem is the use of a Schiit Heresy as an analog volume control between my DAC and power amp. For balanced systems the Schiit Magneus does the same. They are simply decent alps controls buffered by the output stage. Cheap and no mess, no fuss.

I would also have done that in the past, except the volume pots in both my original Magni 3 and Heresy were way too noisy to be acceptable. Never had that problem with my JDS Atom. I would gladly have paid $75 more for either Schiit product if they'd simply used an Alps Blue Velvet pot instead. Never had a problem with a Blue Velvet in any component or the little passive preamp I built myself years ago.

 

[Trell]

The manufacturers should leave this function out of their devices (I mean exclusively the volume reduction in the DAC chip) or inform the buyer in detail and explicitly about the dangers of this function.

If I were the manufacturer and put a device with this function on the market, the owner would have to report to the website with a code generated by the device, register with an e-mail address and serial number and activate the function in the device with a code (received after confirmation of the waiver statement).
After that, I wouldn't care if the owner grilled their speakers or the amp.

This sounds a bit excessive, to be honest.

 

[Deleted member 58722]

It really has nothing to do with Chinese products at all, but exclusively with the integrated DSP function for volume reduction in the DAC chips.

And it doesn't matter if you set the default volume to the lowest volume in preamp mode.
When the DAC is switched on, these registers in the DAC chip must first be written in order to reduce the volume. If an error occurs, the DAC chip remains at 0dB = full volume.
If an error occurs, these registers can be cleared or the entire DAC can be reset to normal DAC mode.
Several users have also reported on this.

Please also read https://www.audiosciencereview.com/...ing-d70s-fried-my-speakers.38706/post-1501351 and https://www.audiosciencereview.com/...ing-d70s-fried-my-speakers.38706/post-1501058.

My DAC has analogue volume control.

 

[Deleted member 58722]

The problem is with DAC volume controls glitching. That could happen while you listen to music

My DAC has analogue output control. It's never glitched.

 

[amarsicola]

I try to make that clear all the time.
You can't catch it with programming or any other firmware. This is not possible in the constellation we are talking about in this thread.
If an error occurs, the part of the software that is supposed to prevent the registers of the DAC chip from being reset and thus being at 0dB is also disabled.

The problem is and remains that the starting point in the DAC chip is always 0dB. That's hardwired and a fact.

One possibility would be an intervention after the DAC chip, e.g. a switch-off that must be actively enabled by the user, or an adjustable maximum volume (better both).

The manufacturers should leave this function out of their devices (I mean exclusively the volume reduction in the DAC chip) or inform the buyer in detail and explicitly about the dangers of this function.

If I were the manufacturer and put a device with this function on the market, the owner would have to report to the website with a code generated by the device, register with an e-mail address and serial number and activate the function in the device with a code (received after confirmation of the waiver statement).
After that, I wouldn't care if the owner grilled their speakers or the amp.

When you buy a car that claims to have air conditioning, you do not expect a bug by which it spits out only cold air in the winter, and you get sick. And you don't want a process to activate air conditioning since it can be dangerous.
Your way of thinking does not make sense to me. You are paying for a product that is supposed to have some features and you expect them to work flawlessly from day one. What's wrong?

 

[BR52]

The problem with the "preamp mode" DAC glitches is an implementation problem because of not well done (bad) engineering. With real preamps, shit can happen as well, a broken output stage can fry with a lot of DC speakers for example.
The discussion is moving more or less in the direction of two ideologies.

 

[Moderate Dionysianism]

My DAC has analogue volume control.

Good for you, but @Roland68 is talking about a very specific solution implemented in the product that reportedly failed. Take time to read his earlier posts here, highly informative.

When you buy a car that claims to have air conditioning, you do not expect it to have a bug by which it spits out only cold air in the winter, and you get sick.

A faulty drive-by-wire system would be a better analogy imho. And these do fail, don't they? Hence redundancy in airplane controls for example. And roughly the same dilemma: whether you want to trust a vital control entirely to software, which will never be 100% error-free.

I had a scare like this (no gear damaged tho) with a DragonFly Red fed from a smartphone. Since then, I avoid 100% digitally controlled volume with high power sources.

 

[Snoopy]

My DAC has analogue output control. It's never glitched.

This topic is about the Topping D70 that is digital

 

[JeffGB]

I would also have done that in the past, except the volume pots in both my original Magni 3 and Heresy were way too noisy to be acceptable. Never had that problem with my JDS Atom. I would gladly have paid $75 more for either Schiit product if they'd simply used an Alps Blue Velvet pot instead. Never had a problem with a Blue Velvet in any component or the little passive preamp I built myself years ago.

I also had quite a bit of noise with my Heresy volume pot but I opened it up and sprayed cleaner into it and twisted it back a forth a bit. It's been perfect ever since. I wasn't sure if there was really an opening that would allow the cleaner to enter the pot, but apparently there was.