Help with T&R HEAD [message #24911] |
Sun, 17 April 2016 12:44 ![Go to next message Go to next message](/FUDforum/theme/vk30/images/down.png) |
bproctor
Messages: 11 Registered: December 2015 Location: BOSTON
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Junior Member |
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Hello,
I am hoping for some help in diagnosing issues with my vintage blue tuck and roll head.
I believe this is an early head, which has a bright switch, and separate inputs for low and high.
The model number is 3-15J-1 and is marked 'Kustom by Ross, inc.'
For starters,
When i plug into the low inputs, I get a machine / hum modulation. This is with no sound coming through the quarter inch jack into the unit. It sounds a bit like an engine idle.
Any feedback on where i should start troubleshooting the amp would be appreciated.
I did switch over to a grounded cord and replaced the death cap.
Thanks,
Brian
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Re: Help with T&R HEAD [message #24918 is a reply to message #24911] |
Mon, 18 April 2016 06:26 ![Go to previous message Go to previous message](/FUDforum/theme/vk30/images/up.png) ![Go to next message Go to next message](/FUDforum/theme/vk30/images/down.png) |
stevem
Messages: 4758 Registered: June 2004 Location: NY
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Senior Member |
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Early Kustoms could have a problem with radio interference and there is a factory fix for it that involves placing a resistor and small value cap in series after each input jack.
Your hum issue sounds like a ground loop and is caused by having two grounds.
If both the mixer and the Kustom have a grounded power cable you need to get a ground lift adapter and place it on one of the power cables, and even further than this the wide tang of the adapter may need to get cut back so you can pivot it around the other way in the outlet.
Another source of your hum could be due to having the mixer and or turn table stacked up on top of the Kustom which can make for one units 60 HZ hum from its power transformer radiating out and getting into the preamp circuit of the other unit or into the turn tables Mag cartridge, or its RCA cables which are all too many times crappy cables to start with.
[Updated on: Mon, 18 April 2016 06:28] Report message to a moderator
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Re: Help with T&R HEAD [message #24920 is a reply to message #24911] |
Tue, 19 April 2016 14:40 ![Go to previous message Go to previous message](/FUDforum/theme/vk30/images/up.png) |
stevem
Messages: 4758 Registered: June 2004 Location: NY
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Senior Member |
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The radio interference can be blocked by placing a .005 cap feeding a 47k resistor to ground off of the hot terminal of a input jack.
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