Bottlehead Forum

Bottlehead Kits => Legacy Kit Products => Quicksand => Topic started by: brightcity on September 13, 2017, 02:29:35 PM

Title: Quicksand hash noise
Post by: brightcity on September 13, 2017, 02:29:35 PM

Hello, I need some help with a Quicksand build. I am running it with a Quickie pre-amp driven via laptop headphone out.

I am getting some intermittent hash coming out of the right channel. It has gotten worse as the batteries have run their course but existed at first power up. Touching the speaker binding posts can sometimes makes it worse.

Shifting my laptop can affect it. Does anyone think it could be the wifi in the back of the laptop? The solder connections between the headphone jack and binding posts look a good shiny silver.

Edit: The cellphone makes it really bad, but just the right channel.

Title: Re: Quicksand hash noise
Post by: Paul Birkeland on September 14, 2017, 03:43:21 AM

If you do not use a computer into the Quicksand and you turn your cellphone off, do you still hear the noise?

Title: Re: Quicksand hash noise
Post by: brightcity on September 16, 2017, 02:19:24 PM

Yeah, it goes away. Loading webpages, Bluetooth mouse, and grounding the laptop chassis with my hands cause it. The wifi is probably connected in a ray across the right channel.

Ill find a better location for it.

Title: Re: Quicksand hash noise
Post by: Paul Birkeland on September 16, 2017, 03:37:59 PM

Using a toslink based DAC or a USB DAC with its own power supply may solve the problem also.

Title: Re: Quicksand hash noise
Post by: aragorn723 on September 22, 2017, 05:14:52 PM

The audioengine d1 can do toslink and needs a separate power source (you can use an old phone charger with the right Usb cable).  It works great with the Quickie too.  This is my main source (I connect it straight from the laptop Usb for power and then use an rca cable to the Quickie).  They go for $170 and sound great too.  Might be a solution for you.

Dave

Title: Re: Quicksand hash noise
Post by: brightcity on January 19, 2018, 03:55:47 PM

Purchased a Behringer USB UCA202. It helps with the hash noise but not perfect, mostly when I use the mouse now it occurs and not the WiFi.

The plus is that it sounds significantly better than the headphone out from my laptop.

EDIT: Modifying the output filter inductors to some sizeable Solen air gap. Maybe this will help the hash noise. WHOOPS, need to source 47uH not mH. Reinstalled the original inductors.

Found some plastic core axial inductors on digikey. Maybe some shielding like ERS tape will help. Maybe the lack of a magnet and the increased coil size will make things worse.

Title: Re: Quicksand hash noise
Post by: Paul Birkeland on January 22, 2018, 06:10:35 AM

Messing with the parts in the Quicksand isn't going to solve the issue.  The noise is at the input of the Quicksand, and will require a DAC that isolates the USB power supply in the computer from the audio signal appropriately, or using a Toslink cable.

Title: Re: Quicksand hash noise
Post by: brightcity on January 25, 2018, 12:12:36 PM

Ok, the USB dac I purchased helped some but not completly. Ill try using its optical out to a different DAC I have.