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October 17, 2021, 12:33:27 PM

Author Topic: Noise with Computers, USB DACs, and Powerline Ethernet Kits  (Read 11218 times)

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Offline Paul Joppa

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Re: Noise with Computers, USB DACs, and Powerline Ethernet Kits
« Reply #105 on: March 29, 2021, 06:39:57 PM »
That works for noise control, but is not as safe as it should be. The chassis plate and transformer cores should be bonded to the safety ground with no interruptions; the ground lift should occur between the signal ground and chassis; i.e. at terminal 28.

That's a pretty inconvenient location, unfortunately - a great many wires go to that terminal. It will be tricky!
Paul Joppa

Offline sl-15

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Re: Noise with Computers, USB DACs, and Powerline Ethernet Kits
« Reply #106 on: March 30, 2021, 05:44:00 AM »
Thank you Paul, indeed terminal 28 would be tricky. PB said on the first page of this thread:

I don't see issues doing this with any of our products.  I do also plan to test whether a UF4007 can throw a 20A breaker and survive, as this could also be a suitable part to use.

If you are saying that this mod is not the safest for the Foreplay then I would consider reversing it, it's nice without the noise but I rather would go the safe route.
Could you or PB confirm the safety of this mod? Thanks, Best, Stefan
stefan hampel
ortofon sl-15 with step-up, modded technics sl-1200mkII, seduction c4s, eros phono, extended foreplayIII, crack, pioneer spec4/mc225, sonus faber electa

Offline Paul Birkeland

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Re: Noise with Computers, USB DACs, and Powerline Ethernet Kits
« Reply #107 on: March 30, 2021, 05:54:17 AM »
This is a workaround for older kits.  For new kits, we separate the audio ground and the chassis plate with the antiphase diode arrangement plus some other parts, and this is the safest choice.  For our older kits that are not designed from the start to have these parts, the solutions are less than ideal. It would take a very catastrophic failure (like say replacing the power cord on your electric clothes dryer with the power cord plugged into the wall, then dropping the bare end of the power cord onto your Foreplay's chassis plate) to cause problems with the diodes installed, but it is remotely possible.
Paul "PB" Birkeland

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Offline Tomunizum

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Background static when external DAC USB is connected
« Reply #108 on: April 12, 2021, 10:53:58 PM »
Hello,

Just finished my stock Crack build and I’ve discovered through process of elimination that my crack produced a static noise whenever my FIIO K5 Pro external DAC/amp’s USB is connected to my desktop computer. The static increases in volume when the volume on the crack is increased but not when the DAC/amp’s volume is increased.

I’m pretty confident that my solder joints are good, as tapping on the unit produces no distortion or anything audible.

I’m wondering if using an optical connection would resolve the issue.

I would greatly appreciate any advice or help anyone is able to offer regarding this issue.

Thanks I’m advance.

Tom

Offline Paul Birkeland

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Re: Background static when external DAC USB is connected
« Reply #109 on: April 13, 2021, 05:33:58 AM »
An optical connection will resolve the issue, or there's this:
https://forum.bottlehead.com/index.php?topic=11676.0
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Tomunizum

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Re: Background static when external DAC USB is connected
« Reply #110 on: April 13, 2021, 05:49:38 AM »
Aha!

I had read that thread as it sounded similar and wondered, but did not want to assume.

I think I will move forward with adding a ground breaker, thank you much!

Would you mind explaining why this is happening and how this fixes it? I found it interesting because whenever I moved my computer mouse I could cause a noise in addition to the background static.

Tom

Offline Paul Birkeland

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Re: Noise with Computers, USB DACs, and Powerline Ethernet Kits
« Reply #111 on: April 13, 2021, 07:18:31 AM »
The diodes create some separation between the Crack earth and the earth of the computer, which will interrupt the flow of low level noise that would otherwise be there. 
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline Tomunizum

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Re: Noise with Computers, USB DACs, and Powerline Ethernet Kits
« Reply #112 on: April 13, 2021, 04:34:48 PM »
Okay gotcha. Was trying to read a bit about the anti parallel diodes.

Thanks a bunch Paul!

Tom

Offline vaplen

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Re: Noise with Computers, USB DACs, and Powerline Ethernet Kits
« Reply #113 on: June 15, 2021, 01:28:00 PM »
I want to try this on my SEX kit.  I also have USB noise on my odac.

I drew a picture of what I think needs to be done.  So basically I solder the twisted diodes at the red points and the black line represents the twisted diodes. Anything I am missing?

Also currently looking at the 1n4007 for this mod.  Anyone have a better recommendation?  I guess the ones Paul mentioned are all good for this.

Does this look correct?

Offline Paul Birkeland

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Re: Noise with Computers, USB DACs, and Powerline Ethernet Kits
« Reply #114 on: June 15, 2021, 02:34:16 PM »
1N4007 will do the job.  The little piece of bus wire going from the solder lug on the chassis up to the IEC power entry module needs to be removed in the process as well, as the diodes are taking its place.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline vaplen

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Re: Noise with Computers, USB DACs, and Powerline Ethernet Kits
« Reply #115 on: June 17, 2021, 09:21:22 AM »
Thanks Paul, if I understand correctly just the single piece of bus wire going up to the IEC power entry module should be removed. 

The 2 other pieces of bus wire should remain, correct? 
Also should I reverse the polarity of the diodes like in your original picture?

Much appreciated.

Offline Paul Birkeland

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Re: Noise with Computers, USB DACs, and Powerline Ethernet Kits
« Reply #116 on: June 17, 2021, 09:29:35 AM »
Yes, the piece of bus wire wire going to the earth lug on the IEC power entry module is removed and replaced by the pair of diodes.  The diodes need to be wired antiphase.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man