Lancing a wall-wart.

raypalmer · 19th May 2011, 12:06 AM

I have the Pro-Ject Phono Box II. I am a bad diyer, I still have store-bought pieces...

Anyway, no matter what I do the thing hums. No matter what amp it's plugged into, interconnects, etc. it hums.

Is it at all possible that the pathetic little 16v wall wart is to blame? That is to say, if I took the this wall-wart out of the equation. Made a good, solid, grounded, PSU, bypassed the rectifier inside the pre-amp in favour of a beefier one in the PSU, and grounded the pro-ject proper (you have to attach it to a grounded device with a little wire right now). Would it sound better?

I think it would.

P.S. I've grounded the thing to a lot of stuff, also ran it ungrounded, and it hummed the same way in my past two homes so it's not a grounding issue in the building.

sawreyrw · 19th May 2011, 12:33 AM

The User Manual says the input cable needs to be shielded.

infinia · 19th May 2011, 01:26 AM

It's doubtful the wall wart is to blame. I bet it doesn't hum without your turntable connected. Usually a ground / shield interconnect problem on the turntable / headshell. or better yet try a known good unit, ie more troubleshooting.

19th May 2011, 12:06 AM	#1
raypalmer diyAudio Member Join Date: Dec 2008 Location: Burlington	Lancing a wall-wart. I have the Pro-Ject Phono Box II. I am a bad diyer, I still have store-bought pieces... Anyway, no matter what I do the thing hums. No matter what amp it's plugged into, interconnects, etc. it hums. Is it at all possible that the pathetic little 16v wall wart is to blame? That is to say, if I took the this wall-wart out of the equation. Made a good, solid, grounded, PSU, bypassed the rectifier inside the pre-amp in favour of a beefier one in the PSU, and grounded the pro-ject proper (you have to attach it to a grounded device with a little wire right now). Would it sound better? I think it would. P.S. I've grounded the thing to a lot of stuff, also ran it ungrounded, and it hummed the same way in my past two homes so it's not a grounding issue in the building. __________________ Wherever you go there you are.

19th May 2011, 01:26 AM	#3
infinia diyAudio Member Join Date: May 2005 Location: Californication	It's doubtful the wall wart is to blame. I bet it doesn't hum without your turntable connected. Usually a ground / shield interconnect problem on the turntable / headshell. or better yet try a known good unit, ie more troubleshooting. __________________ like four million tons of hydrogen exploding on the sun like the whisper of the termites building castles in the dust

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19th May 2011, 12:33 AM	#2
sawreyrw diyAudio Member Join Date: Apr 2006 Location: Minnesota	The User Manual says the input cable needs to be shielded.

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