Problem with SMPS !!!

Minion · 7th December 2009, 11:23 PM

Hi Folks , I have this problem ... At My Jam space my guitarist has a Zoom HD Recorder for recording band practices and song ideas but every time we turn on the zoom recorder the PA puts out a very loud high pitched squeeling wich lasts for about 5 minutes then it goes "pop" and then the volume of the squeeling sound goes down a couple db but it is still quite noisy ....
Nothing else in the studio has an effect on the PA like this , not even the Florescent lights .....

I"m thinking that the 12v 3a SMPS that the Zoom uses might be the culprit and was wondering what you folks think ??

If you think the SMPS might be the problem do you think useing a Linear PSU would be a good idea ?? I was thinking I could build a Regulated 4a 12v PSU with a LM317 and a Pass Transistor ....

Thanx

nigelwright7557 · 8th December 2009, 12:35 AM

Quote:

Originally Posted by Minion

Hi Folks , I have this problem ... At My Jam space my guitarist has a Zoom HD Recorder for recording band practices and song ideas but every time we
If you think the SMPS might be the problem do you think useing a Linear PSU would be a good idea ?? I was thinking I could build a Regulated 4a 12v PSU with a LM317 and a Pass Transistor ....

Thanx

You can either fix the SMPS or the PA.
A lot of amps have a 100pf across the input to short out radio frequencies or high frequencies out of the audio band.

I am surprised the SMPS passed EMC regs if it radiates that badly.

Its worth trying a linear supply to see if it fixes the problem.

Minion · 8th December 2009, 12:39 AM

Hi , Well He won"t let me screw with his equipment so Maybe I"ll try the Linear PSU route ....

Thanx

Enzo · 8th December 2009, 05:15 AM

If the power supply is defective in that it is spewing interference, consider just getting a new power supply. The original supply was clean and quiet, regardless of how it has turned out now. Sure you could invent something, but time and effort versus off-the-shelf?

Minion · 8th December 2009, 10:59 PM

Hi , The zoom has been like this right out of the box , the thing is when you use the zoom without the PA on it sounds fine .....

There is no noise at all on the Recordings accept for the noise that comes through the PA (and the noise we call music) and the noise doesn"t creap into any of the other equipment and none of the other eqiment interacts with one another and causes noise so I"m pretty stumped , maybe it"s the PA ?? or maybe there isn"t anything wrong with either of them but they just don"t like each other ??

Eva · 14th December 2009, 07:20 AM

Ground loop?

7th December 2009, 11:23 PM	#1
Minion diyAudio Member Join Date: May 2006	Problem with SMPS !!! Hi Folks , I have this problem ... At My Jam space my guitarist has a Zoom HD Recorder for recording band practices and song ideas but every time we turn on the zoom recorder the PA puts out a very loud high pitched squeeling wich lasts for about 5 minutes then it goes "pop" and then the volume of the squeeling sound goes down a couple db but it is still quite noisy .... Nothing else in the studio has an effect on the PA like this , not even the Florescent lights ..... I"m thinking that the 12v 3a SMPS that the Zoom uses might be the culprit and was wondering what you folks think ?? If you think the SMPS might be the problem do you think useing a Linear PSU would be a good idea ?? I was thinking I could build a Regulated 4a 12v PSU with a LM317 and a Pass Transistor .... Thanx

14th December 2009, 07:20 AM	#6
Eva diyAudio Member Join Date: Oct 2003 Location: Near the sea	Ground loop? __________________ I use to feel like the small child in The Emperor's New Clothes tale

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8th December 2009, 12:39 AM	#3
Minion diyAudio Member Join Date: May 2006	Hi , Well He won"t let me screw with his equipment so Maybe I"ll try the Linear PSU route .... Thanx

8th December 2009, 05:15 AM	#4
Enzo diyAudio Member Join Date: Sep 2004 Location: Lansing, Michigan	If the power supply is defective in that it is spewing interference, consider just getting a new power supply. The original supply was clean and quiet, regardless of how it has turned out now. Sure you could invent something, but time and effort versus off-the-shelf?

8th December 2009, 10:59 PM	#5
Minion diyAudio Member Join Date: May 2006	Hi , The zoom has been like this right out of the box , the thing is when you use the zoom without the PA on it sounds fine ..... There is no noise at all on the Recordings accept for the noise that comes through the PA (and the noise we call music) and the noise doesn"t creap into any of the other equipment and none of the other eqiment interacts with one another and causes noise so I"m pretty stumped , maybe it"s the PA ?? or maybe there isn"t anything wrong with either of them but they just don"t like each other ??

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