Topping D70S fried my speakers...

[strea]

I had this happen today with Topping E70. My monitors are fine, but pretty ridiculous, the unit randomly shot from -30db to 0db and LOCKED at 0db. I was unable to move the volume whatsoever via the knob, LOCKED at 0db. I eventually figured out to lower my Windows volume.. quite depressing and scary for the future. Leaving my Windows volume at 50% for the next few days to see if it happens again.

 

[marcom22]

I had this happen today with Topping E70. My monitors are fine, but pretty ridiculous, the unit randomly shot from -30db to 0db and LOCKED at 0db. I was unable to move the volume whatsoever via the knob, LOCKED at 0db. I eventually figured out to lower my Windows volume.. quite depressing and scary for the future. Leaving my Windows volume at 50% for the next few days to see if it happens again.

It's gone in DAC mode

 

[strea]

It's gone in DAC mode

Which shouldnt be possible. To set to DAC mode requires setup menu, and to access setup menu you need to turn off the unit with physical switch on back of unit, then push front knob in while switching unit back on then navigate to that setting, switch on, etc.

 

[Roland68]

I'm always stunned when I read this.
Anyone who uses a DAC as a volume control should find out how this control, or rather volume reduction, works.
As long as the volume reduction is implemented via the DSP function of the DAC chip, the default volume is always 0dB, whether the owner likes it or not.
In any kind of error or malfunction, 0dB is the starting point, whether due to voltage fluctuation, touch surge, software or firmware error, etc.
The starting point of the DAC chip is then always 0dB.

As long as the DAC manufacturers only use this internal function of the DAC chips and do not install any further measures after the DAC chip in the analog part, it is the owner's responsibility to ensure the protection of his loudspeakers and power amplifiers.

 

[Deleted member 48726]

I'm always stunned when I read this.
Anyone who uses a DAC as a volume control should find out how this control, or rather volume reduction, works.
As long as the volume reduction is implemented via the DSP function of the DAC chip, the default volume is always 0dB, whether the owner likes it or not.
In any kind of error or malfunction, 0dB is the starting point, whether due to voltage fluctuation, touch surge, software or firmware error, etc.
The starting point of the DAC chip is then always 0dB.

As long as the DAC manufacturers only use this internal function of the DAC chips and do not install any further measures after the DAC chip in the analog part, it is the owner's responsibility to ensure the protection of his loudspeakers and power amplifiers.

Can't really blame the user on this though. How would the average user know this or even know how to look it up?
It should be the manufacturers duty to either inform about the risk or better, implement a secondary volume control.

 

[strea]

Can't really blame the user on this though. How would the average user know this or even know how to look it up?
It should be the manufacturers duty to either inform about the risk or better, implement a secondary volume control.

Was going to say this myself. It's great that you have a wealth of experience @Roland68 , but I spent weeks researching products and went with a highly reviewed one from this website. I tried my best. They should simply create the product properly with no faults and charge whatever it costs for proper implementation. Faulty products are a danger to the speakers as well as the users.

 

[Snoopy]

@Roland68 but you will see frequently people here recommending using DACs as volume control for their 250 watt monoblocks.

Seems crazy to me as well. But software could always glitch out.

 

[amarsicola]

@Roland68 but you will see frequently people here recommending using DACs as volume control for their 250 watt monoblocks.

Seems crazy to me as well. But software could always glitch out.

I ended up by setting the maximum input voltage of my power amplifier from 4V to 10V. It is the "bypass mode" of the Audiophonics Purifi.
In this way I am loosing a lot of power, but still the volume can get very loud, much more than enough for normal listening.
Not ideal but now I am safe.
I should have done this from the beginning. Also, the dac delivers best sinad at high voltages and the bypass mode of the amp is slightly better as well.

 

[Sokel]

It should be the manufacturers duty to either inform about the risk or better, implement a secondary volume control.

Yes,but then the measurements would not show that good.
It would still be WAY inaudible but would not get the "SOTA" label.
There's no free lunch.

 

[Roland68]

Let's be honest, if someone has informed themselves in detail about DACs and the integrated volume reduction, then hasn't he stumbled across the many warnings in this and all other forums on the subject?

Or have you ignored those warnings and listened to the people who say it works great for them and they have no problems?
I use the term "integrated volume reduction" deliberately. At least when you switch off the DAC, the registers are cleared and the volume is at 0dB. Do you understand the problem?

I'll just say it very simply, directly and harshly. Each user is primarily responsible for the operation of their system, and the emphasis is clearly on responsibility.
The only exception: you have paid a dealer or a specialist to put something together or recommend something for you. It doesn't matter whether the payment was made directly or through the purchase of the system.

If you choose your own devices, you must familiarize yourself with all aspects of operation, including the (possible) problems, and that is your job.

 

[restorer-john]

If you plug a device which has the potential to output enough signal to drive your amplifier to full power or beyond into a power amp directly, you run this risk.

When you put the control of that output signal in the hands of a micro, running firmware, written by goodness knows who and subject to lockups/resets/power cycle defaults you have the recipe for disaster. I've warned of this for many, many years.

It's not rocket science. Use a proper volume pot and never have this problem. Ever.

 

[strea]

If you plug a device which has the potential to output enough signal to drive your amplifier to full power or beyond into a power amp directly, you run this risk.

When you put the control of that output signal in the hands of a micro, running firmware, written by goodness knows who and subject to lockups/resets/power cycle defaults you have the recipe for disaster. I've warned of this for many, many years.

It's not rocket science. Use a proper volume pot and never have this problem. Ever.

Can you provide me with a "proper volume pot", I've asked a couple times now and haven't received any product names or links.

 

[sarumbear]

If you plug a device which has the potential to output enough signal to drive your amplifier to full power or beyond into a power amp directly, you run this risk.

When you put the control of that output signal in the hands of a micro, running firmware, written by goodness knows who and subject to lockups/resets/power cycle defaults you have the recipe for disaster. I've warned of this for many, many years.

It's not rocket science. Use a proper volume pot and never have this problem. Ever.

How do the AVR manufacturers manage it? They sell a lot of units with digital volume control.

 

[restorer-john]

How do the AVR manufacturers manage it? They sell a lot of units with digital volume control.

Better hardware, better software, better designers, less glitches.

Leave an AVR unplugged long enough and it will forget everything too.

 

[restorer-john]

Can you provide me with a "proper volume pot", I've asked a couple times now and haven't received any product names or links.

See @sarumbear link above. That is a motorized Alps (more likely a Chinese copy) blue with driver PCB and a ratty looking remote. There's tons on Ebay and Ali.

They last forever, track really well, have a smooth, solid feel and are the defacto standard for high quality volume pots used by all leading manufacturers in their upper range gear.

Build one (either a remote unit or a purely manual unit) into a box, with inputs and outputs and stick it inline. If you are using balanced XLRs, you'll need to find a 4 gang version.

 

[strea]

See @sarumbear link above. That is a motorized Alps (more likely a Chinese copy) blue with driver PCB and a ratty looking remote. There's tons on Ebay and Ali.

They last forever, track really well, have a smooth, solid feel and are the defacto standard for high quality volume pots used by all leading manufacturers in their upper range gear.

Build one (either a remote unit or a purely manual unit) into a box, with inputs and outputs and stick it inline. If you are using balanced XLRs, you'll need to find a 4 gang version.

I'm utilizing balanced XLR's. Interesting that you need to "build one" or buy some shady copy.. is there no simple quality option to buy from a typical manufacturer?

Guess I'll just have to spend on an ADI-2-DAC or Benchmark or something

 

[sarumbear]

Better hardware, better software, better designers, less glitches.

Leave an AVR unplugged long enough and it will forget everything too.

I have not unplugged my Trinnov since I bought it!

 

[sarumbear]

I'm utilizing balanced XLR's. Interesting that you need to "build one" or buy some shady copy.. is there no simple quality option to buy from a typical manufacturer?

Guess I'll just have to spend on an ADI-2-DAC or Benchmark or something

You are not building, just assembling it. I used a local electronics repair man to assemble mine. FYI, they are not shady. As @restorer-john said, they are used in many upmarket products. China is the supplier to the world and AliBaba is their shop front.

 

[Roland68]

How do the AVR manufacturers manage it? They sell a lot of units with digital volume control.

You are completely confusing several things here.
No normal AVR uses the volume reduction of the DAC chips.

In the AVR you have a digital control of an analog volume control in the small signal range after the DAC chip. Without specific control, no signal is output, or only at the lowest level. This is also the basic setting when switched off or when it is reset by an error.

 

[sarumbear]

You are completely confusing several things here.
No normal AVR uses the volume reduction of the DAC chips.

In the AVR you have a digital control of an analog volume control in the small signal range after the DAC chip. Without specific control, no signal is output, or only at the lowest level. This is also the basic setting when switched off or when it is reset by an error.

Shouldn’t a glitch effect those volume control devices as well? After all they are controlled digitally by a processor that runs a software (firmware).