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Topic: 60hz noise capastitor in Amps??? |
Dag Wolf
From:
Bergen, Norway
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Posted 21 Mar 2001 10:00 am |
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Does anyone know if there`s a thing called noise capasitor in amps? Reason I ask is I have converted a couple of Mosvalve 500`s from 110volt to 220volt but I get some noise in the midrange area.
I was thinking the problem might be that the capasitors should take care of the 60hz noise and if thats the case I would need to change them to 50hz that we have over here in Norway.
Any thoughts on this are welcome.
Thanks, Dag
[This message was edited by Dag Wolf on 21 March 2001 at 10:02 AM.] |
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Jack Stoner
From:
Kansas City, MO
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Posted 21 Mar 2001 12:40 pm
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Dag, e-mail genz-benz and see what they say. I don't know if there is a different AC Mains line bypass capacitor needed for 50Hz.
http://www.genzbenz.com
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 21 Mar 2001 3:39 pm
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| Dag, Iam confused by your saying..."I get some noise in the midrange area...". AC line hum is low in frequency, and will show up most when you advance the bass control. One way to make sure the problem isn't coming from outside the amp is to turn up the amp volume with nothing plugged into the amp. If you still get hum with nothing plugged in, it's a filtering...or a shielding problem. You can increase the size (capacitance) of the large filter caps in the amp to help filtering. This may raise the operating voltages slightly, but it usually won't cause a problem. Did you eliminate any "grounding switches" when converting the amp? |
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Dag Wolf
From:
Bergen, Norway
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Posted 21 Mar 2001 6:33 pm
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The noise is not in the low area and would not change much if I boost bass.
However, I have no noise if I disconnect my profex II leaving the speakers connected at full volume. I connected my DPC 750 amp and it didn`t have any noise. My Profex has an outboard power supply.
There`s a flat "capasitor" ,I think, going from one of the power leads to ground what does it do?
Genz-Benz people said the converting should work and the noise comes from somewhere else but I`ve tried to disconnect the ground as well.
Donny, I was thinking the same about disconnecting the preamp and have done that - no noise - but was wondering if the first step of the Mosvalve maybe goes to a sort of standby without jacks in the inputs?
As you can see I don`t know too much of this technical stuff so keep `em comeing.
Thanks, Dag[This message was edited by Dag Wolf on 21 March 2001 at 06:38 PM.] |
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Keith Hilton
From:
248 Laurel Road Ozark, Missouri 65721
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Posted 21 Mar 2001 8:55 pm
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| Dag, I would not think that the filter capacitors would be a problem considering 50Hz in Europe, and 60Hz in the USA. You would get a LOT of noise if the filters were not right. Sounds like one of the following: Ground loop--The ground potential between the different pieces of equipment is probably different.You may have to lift a ground. Make sure the transformers are not near your pickup, effect units or amps. Move all transformers away from electronics and pickup. Make sure transformers are not near each other. Make sure your effect unit is not near your pickup. Dag, try what I have suggested. I hope this helps! |
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Dag Wolf
From:
Bergen, Norway
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Posted 22 Mar 2001 3:22 am
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Thank you all for helping me out. I did once again hook up the equipment. I turned up the Mosvalve and the Profex II and......NO NOISE!
I did not plug in the steel to the Profex II so I guess the noise did come from the steel.
Thanks again, Dag |
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Blake Hawkins
From:
Florida
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Posted 22 Mar 2001 8:49 am
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Dag, If the noise is coming from the steel,
check to see if you have any lamp dimmers nearby or anywhere in the house. They can cause a midrange noise. Also check to see if you have any speed controls on fans, or a fish tank with an aeriator attached.
Anything with solid state power control can cause an Radio Frequency field which can be picked up by the steel guitar.
Blake |
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