DS Jr Loud Humming Noise from Speakers


#1

Hi All

My current system consist of a PWD MkII (Bridge II) connected to an Integrated Valve amp (KT88 power side and 6SL7 & 6SN7 on the preamp side) instead of using the preamp on the amplifier, I am using the PWD as a preamp. The sources are:

  1. Turntable to NWPC via HDMI to PWD.
  2. NAS on home network to PWD via CAT5 network cable.
The above system works perfectly and i really like this setup especially the PWD and NWPC. Top Notch Equipment.

About 2 months ago I decided to upgrade to the DSJr. I decided to download Huron and update the DSJr. I then went through the normal sequence of turning on the DSJr followed by the amp(acting as power amp) and there is a loud hum coming from both channel of the speakers. I thought this will go away after the burn in period. After about 3 weeks (approximately 50 hours) the hum is still there. I am using a PS Audio DecTet by the way. I have tried everything including removing all source such as NWPC, CD Player, USB(Computer) from the equation and the hum still exist. I have tried changing interconnect, power cables and even running a dedicated power line just for the HiFi system.

I even tested the DSJr with my other power amp and it still produce the humming effect on my speakers (Monitor Audio 89dB), i have also tested it with a B&W CM10 and it still the same.

I have also tried the attenuator low setting and the hum is still there but much lower and it affects the music listening experience. I then revert back to the old Torreys and i can hear a significant improvement. The hum have been reduce but still audible from my listening position about 3 meters away from the speakers. All in all i have tried 4 different combinations of amplifier and all of them produce the humming effect. The only amp the does not produce the hum is a BHK Stereo amp. By the way i have tried the cheater plug option too. The only way i can get rid of the hum is to basically use the pre amp on my integrated valve amp.

I got a few question in regards to the above issues.

  1. Is this a compatibility issue (between the DSJr and my Valve Amp)?
  2. If i was to ditch the DSJr and change to the DS Sr. will the hum go away?
Further to that i have turn off all appliances in the house, including fridges, AC, TV and even the solar panel inverter but the hum is still there. All my cables are quality product such as Furutech (single ended, pwer cables), Audioquest (single ended), Kimber (Speakers) and Curious (USB).

Really appreciate if anyone can suggest any recommendations to eliminate the hum. Thank you.


#2

Sorry you’re having a hum issue. It’s not inherent in the design so we should be able to figure this out.

Maybe I missed it, but how are you connecting? Single ended or balanced?

Is it a low hum or is it a higher pitched buzz?


#3

Welcome, song!

You have tried those things I would have suggested. There should not be a hum, but I do not have a guess what is causing given your testing. Perhaps others here will have suggestions.


#4

Hi @song

You mentioned using a cheater plug and that it didn’t help. Did you use a cheater plug on both the DSJ and the amp at the same time?

Feel free to reach out to service@psaudio.com and we’ll be able to help you out.

-jamesh


#5

Good catch, jamesh.


#6
Paul McGowan said

Sorry you’re having a hum issue. It’s not inherent in the design so we should be able to figure this out.

Maybe I missed it, but how are you connecting? Single ended or balanced?

Is it a low hum or is it a higher pitched buzz?


Hi Paul

Thanks for the prompt response, the DSJr is connected to the valve amp using single ended furutech interconnect. I have tried using a balance interconnect on the DsJr and a single ended adapter on the valve amp side as my amp does not have balance input and it still hum. It is a low hum and is audible from my listening position about 3 meters away. Thank you.


#7
jamesh said

Hi @song

You mentioned using a cheater plug and that it didn’t help. Did you use a cheater plug on both the DSJ and the amp at the same time?

Feel free to reach out to service@psaudio.com and we’ll be able to help you out.

-jamesh


Dear Jamesh

Yes, used a cheater plug on both devices. Also tried using cheater plug for the Dectet. Thanks


#8

If it’s a low hum as opposed to a buzz it’s likely 50Hz rather than 100Hz. This is important because it means that it’s likely not a ground loop, but something else instead. I don’t suppose the DSJ is sitting atop another piece of equipment that might induce transformer hum? You mentioned an opportunity to also try a DirectStream Senior - is that still a possibility? Just to see?


#9
Paul McGowan said

If it’s a low hum as opposed to a buzz it’s likely 50Hz rather than 100Hz. This is important because it means that it’s likely not a ground loop, but something else instead. I don’t suppose the DSJ is sitting atop another piece of equipment that might induce transformer hum? You mentioned an opportunity to also try a DirectStream Senior - is that still a possibility? Just to see?


Dear Paul

The DSJr is not sitting directly on any other equipment. I have tried isolating both equipment by sitting them on a piece of wood (25mm thick) seperately and placing them on the floor(carpeted) and it is still the same. I will speak to my local supplier if they have a spare DSD Sr that i can loan to test it. out. Thanks for the reply and have a good weekend.


#10

Hi @song ! ; Read my replies in bottom of this thread for a possible solution ;

http://www.psaudio.com/forum/directstream-all-about-it/dsjr-single-ended-ground-loop-problem/


#11

Hi Guys all good now. I have upgraded to the DSD Snr. No more humming noise. Thanks for all your help.