| K150-8 Loud Thump [message #26066] |
Thu, 20 April 2017 09:34  |
ReverbJoe
Messages: 37
Registered: October 2012
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Hi guys, some time ago I had asked about a few things I thought needed fixing in my K150-8 combo, and I was told I might need two new power supply rail filters. I was suggested that because when I turn on the amp, it makes a loud thump after a few seconds. So I was hoping you guys could tell me what these power supply rail filters look like. Or where they are locates in the amp. Thanks in asvance.
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| Re: K150-8 Loud Thump [message #26072 is a reply to message #26066] |
Fri, 21 April 2017 15:37  |
stevem
Messages: 4775
Registered: June 2004
Location: NY
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Senior Member |
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Yes, and the better and bigger your speakers are the louder the thump will be!
It's when you do not hear a turn on thump that is a sign that the two main rail filters are taking longer then normal to charge up .
[Updated on: Fri, 21 April 2017 15:39] Report message to a moderator |
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| Re: K150-8 Loud Thump [message #26074 is a reply to message #26066] |
Fri, 21 April 2017 23:44 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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No, when the amp is on the pilot should stay on until the amp is turned off.
Check to see if the bulb is not correctly seated in the socket or the socket might need to be cleaned.
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| Re: K150-8 Loud Thump [message #26077 is a reply to message #26066] |
Sat, 22 April 2017 12:17 |
chicagobill
Messages: 2006
Registered: April 2003
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Senior Member |
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If the sound stops when the light goes off, then the amp might be turning off when this happens. You might have a loose connection in the ac wiring, like to the thermal shut off switch.
Be careful when checking those connections, make sure the amp is unplugged and off before touching anything.
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| Re: K150-8 Loud Thump [message #26080 is a reply to message #26066] |
Sun, 23 April 2017 06:14 |
stevem
Messages: 4775
Registered: June 2004
Location: NY
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Senior Member |
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From what you have posted up now , and like Bill has commented on you may have a bad AC connection in the amp, or it could be your power cable on the amp.
A grounded power cable will not fix anything , but it will keep you from getting a shock when touching another item of gear, in fact since your are deactivating the polarity switch when doing this Mod if you are plugged into a grounded outlet which is not grounded ( as in a new outlet in a old wired House) you will not beable to get rid of the ground buzz you may have .
Before you do anything new power cord wise see if you can get the power cord grommet out from the rear of the amp with a real big Ass Needlenose plier, as if you do not have the special made tool to do such this is the only way to get that grommet out.
What I do for a new cord when I want to keep a long one on the amp I head out to the hardware store and buy a small diameter extension cord and just cut the end off.
The potential issue with this is that many times these cables are a bit thicker than the original cord.
In a case like this a carefully slice some off the cords jacket down with a brand new single edge blade.
If you do not want to mess around like that and can live with a 6 ft cord then just use a IEC cord which you likely already have tons just sitting around the house!
[Updated on: Sun, 23 April 2017 06:16] Report message to a moderator |
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| Re: K150-8 Loud Thump [message #26087 is a reply to message #26066] |
Mon, 24 April 2017 12:16 |
stevem
Messages: 4775
Registered: June 2004
Location: NY
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Senior Member |
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The K 50s and 25 models carry the lamp voltage in far more hum prone section of there circuit boards then any other Kustom model, so in light of this I do not think that having a wrong higher current pulling bulb in stalled in a K150 will do much.
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