Loud noise from the DS. Just noise.


#1

Today I turned the amp on and literally almost fell on the floor - the speakers exploded with noise! The DS is connected directly, no pre-amp in between, but when I tried to reduce the volume using the DS screen nothing happened - the digits ran down, but the cannonade remained deafening and shuttering. The quickest solution was to turn the power amp off and think.

Then I switched the DS attenuator on (it worked) and tried again - noise. I checked other DS inputs (the default is the Bridge) - noise. Power cycled the DS. After it booted up noise. Removed the Bridge - no noise! Aha, that must be the Bridge! Connected a laptop to the USB input - the DS plays OK. No noise from other inputs.

Power cycled again with the Bridge in - noise. Rebooted the Bridge from the command line - noise (just changed in the tone). Tried to play something through the Bridge - no changes, noise.

Removed the Bridge again. 10 seconds of silence, then noise from any input. The loudest is from the USB. On other inputs the noise can be quieter, or come like a wave, or begin in one speaker and move to another, etc. Installed 1.2.1 - noise, re-installed 1.2.3 - noise.

Checking the inside of the DS did not show anything obviously wrong, like loose cables, burns, hot spots, short circuits, etc.

Any ideas?

Just in case, the DS (the upgraded PWD II, which is in turn upgraded PWD I) was working fine for months.


#2

Alekz, this is very worrisome. Are you able to try the outputs that are currently not being used? I have nothing else to suggest, but I’m hoping someone can help identify the cause quickly.


#3

I tried only the Bridge (I2S) and USB. But it does not matter, because the noise is everywhere, regardless the input. So, I guess it is very close to the output ;)

@tedsmith : what do you think it might be?


#4

You might try reloading DS code again. Or go back to an older version of code then reload the latest.


#5

Yes, Dennis, I tried that already. Switched between 1.2.1 and 1.2.3 several times.


#6

Try a different sequence in switching on the devices (DS and Poweramp). I had the same problem. I have to power on the poweramp first and after that the DS (from standby).

JM


#7

forgot to say - i have no bridge installed !


#8

I read your first message yesterday and didn’t respond because I had no hypotheses at all. (And you know that I almost always have some hypothesis :) )

A night’s rest didn’t help either.

There’s a remote chance that if you send me a brief recording of the noise I might be able to guess what caused it, but if you have the inclination you might check the outlet and/or power supply voltages.

Anyway it doesn’t sound like a software problem to me. Certainly an email or call to Boulder is in order.


#9

Alekz, I think maybe Dennis was suggesting reloading the initial base code that came on that SD card with the DS upgrade kit. The one that takes several minutes to install.


#10
tony22 said Alekz, I think maybe Dennis was suggesting reloading the initial base code that came on that SD card with the DS upgrade kit. The one that takes several minutes to install.
I was just suggesting reloading the DS code and not the bootloader, which came with the upgrade kit.

Dennis


#11

Hm, I think I do not have the original code… I have 5407, 6115, 6518, 1.2.1 and 1.2.3. Can it be downloaded from somewhere?


#12

Just tried the power sequence suggestion. The DS was completely disconnected for 24 hours, when I turned it on, the USB input volume level was 104!!! (I left it at 2) Fortunately there was no noise on the USB input, but there was noise on the rest. The Bridge was not inserted.

Based on this experience, I wouldn’t turn the DS on after the amp if there is no pre-amp in between. It’s actually scary to use the direct connection now…


#13

If you use the latest OS and have the -20dB attenuator engaged, the volume goes to 105.


#14

The problem is - I left it at 2 before turning the DS off!!! And suddenly it jumped to 104 when I turned it on!!!


#15
Ted Smith said

if you send me a brief recording of the noise


Here it is: https://drive.google.com/file/d/0B953TpwRqSygOHItb2VZWVNVX1k/view?usp=sharing

If I switch inputs it may stay the same or fade “in waves”. There can be variations, like added “growl” when I was rebooting the Bridge.


#16

Boy that’s pretty white. I don’t hear or see anything that gives me an idea of what’s going on.

The fact that it changed based on which inputs are selected means that it’s probably not the analog hardware (it doesn’t know the difference.) The differences in the FPGA between USB, I2S and the bridge are quite minimal - they all have the same I2S to PCM receiver blocks and then they go into an input select and that’s it.

Perhaps since the volume is also changing capriciously there’s a problem with the display board/PIC/flash. Dennis can send you a SD card image to clear your flash and then you can install PP or 1.2.1. If the volume were being sent to the FPGA badly it could completely overload the SDM and cause white noise…

If it’s a hardware failure it’s best just to get it fixed before it hurts something else.


#17
Ted Smith said Boy that's pretty white. I don't hear or see anything that gives me an idea of what's going on.

The fact that it changed based on which inputs are selected means that it’s probably not the analog hardware (it doesn’t know the difference.) The differences in the FPGA between USB, I2S and the bridge are quite minimal - they all have the same I2S to PCM receiver blocks and then they go into an input select and that’s it.

Perhaps since the volume is also changing capriciously there’s a problem with the display board/PIC/flash. Dennis can send you a SD card image to clear your flash and then you can install PP or 1.2.1. If the volume were being sent to the FPGA badly it could completely overload the SDM and cause white noise…

If it’s a hardware failure it’s best just to get it fixed before it hurts something else.


The easiest way to to that is the DS kit upgrade, which clears the EEPROM. Email at dennis@psaudio.com and I will get it to you.

Dennis


#18

YES! YES! YEEEESSSSSSS!!! IT WORKS!!! Thanks all guys!!! :D

BTW, after the upgrade/reloading the volume meter showed “255”, “-” did nothing, but “+” set it to “2” (it was “1” before the total reset).


#19

Excellent news!

Happy listening.


#20

Ouch this is quite scary…

Any ideas what did happen and why?