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K100C-8 hum [message #12419]

Mon, 30 November 2009 07:15

willism
Messages: 4
Registered: November 2009
Location: Edmonds, WA

Junior Member

Hi all,

My Kustom K100C-8 has no hum unplugged from a guitar. When connected to the instrument it has a hum which stops when the metal plug on the coax cable is touched. I tried several different coax cables. Is there anything that can be done to eliminate the hum? TIA.

- Michael

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Re: K100C-8 hum [message #12420 is a reply to message #12419]

Mon, 30 November 2009 09:58

stevem
Messages: 4758
Registered: June 2004
Location: NY

Senior Member

A hum from a amp would be 60Hz or 120Hz, both of which are lower in frequency than the low E note on a guitar which is around 200Hz. low E on a bass guitar is 40Hz, so is this a hum or a ground Buzz noise? has the AC cord on the amp been changed out to a 3 prong type?
The way to test for amp made noise is to plug in your axe and trune the amp up full with the guitars volume(s) down. Any noise or hum difference from having the guitars volume up or down is from (1) the cord used. (2) the guitars pickups and or sheilding(3) both number 1 and 2.
(4)Other equipment stacked on top of your amp can induce 60 HZ hum into your amp from the other gears power transformer.
(5) grounding buzz that stops when you touch the strings can be stopped by using a 3 prong ground lift adapter, but then you have may have a shock issue when touching other equipment or playing while standing on the ground or concret with bare skin.
Does your amp have reverb, as this can add 60Hz hum to one degree or another when turned up.

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Re: K100C-8 hum [message #12421 is a reply to message #12419]

Mon, 30 November 2009 10:43

willism
Messages: 4
Registered: November 2009
Location: Edmonds, WA

Junior Member

Thanks very much for your reply. Earlier this morning I was wondering if perhaps the lack of the 3-wire power cord might be the issue. I just figured out a method of safely connecting the amp ground to the house ground and the hum disappeared. I'll have that cord changed out.

- Michael

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Re: K100C-8 hum [message #12529 is a reply to message #12420]

Sun, 20 December 2009 13:09

willism
Messages: 4
Registered: November 2009
Location: Edmonds, WA

Junior Member

That 2-wire power cord got changed out for a 3-wire and the .22mfd/600V cap was removed to prevent a ground loop. Result: no hum.

My blue sparkle T&R amp was purchased by my brother in the late 60s and used very, very little so is still in excellent condition. It was inherited by myself when he passed away in 2001. I only recently became interested in putting it back in playing condition. Besides the hum it would spit noise bursts randomly but this seems to have been fixed by cleaning all the pots with electronic contact cleaner spray. I've got some photos up on my website.

http://home.comcast.net/~willism98026/site/?/photos/

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Re: K100C-8 hum [message #12530 is a reply to message #12419]

Mon, 21 December 2009 06:02

stevem
Messages: 4758
Registered: June 2004
Location: NY

Senior Member

Please note that as in my last post the problem you thanlfully worked out was a ground BUZZ, and not a hum.
Proper discriptions great;y aid us in helping folks out.
I took a look at you site, that a nice clean amp!
I am glad you enjoy playing it and that it has warm vintage meanings for you in regards to your brother.

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Re: K100C-8 hum [message #12531 is a reply to message #12530]

Mon, 21 December 2009 10:02

willism
Messages: 4
Registered: November 2009
Location: Edmonds, WA

Junior Member

Sorry Steve, but all I could do is describe the symptoms as best as possible. How can one differentiate a ground buzz from a hum?

I did spend a good deal of time searching the site trying to determine the correct wire size for the cord when I encountered the thread regarding removing the capacitor. Also the use of contact cleaner on the pots. I highly commend all your efforts as without this help the task would have been next to impossible.

As to playing, it won't be possible for me anymore as arthritis in both hands and a "trigger finger" condition in my left hand makes that nearly impossible. I will have to part with the blue sparkle beauty and keep only the memories.

Thanks again for your help.

Best Regards,

Michael Willis

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Re: K100C-8 hum [message #12532 is a reply to message #12419]

Mon, 21 December 2009 12:12

stevem
Messages: 4758
Registered: June 2004
Location: NY

Senior Member

Sorry to hear about your condition, but it may be worth while if not for you, but for others in your life you care about to do a search ofr Aspertame poisoning and read up on it as it effects many millons now and they know nothing of it!

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