Preamp interference

kawpoet

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Aug 29, 2011
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I have a gemini 7000 preamp connected to a 2 channel marantz receiver and I get cb or ham radio interference. I call gemini and they said it was impossible for that to happen but suggested I use sheild cable and it did help I think but hasn't totally eliminated the problem. Please help if you can. Thanks
 

soundguruman

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Kit RFI-4 contains ferrite toroids and beads selected to eliminate RFI from 1 to 1000 Mhz. Enough to cure a normal household of RFI..



What causes RFI? Strong signals from nearby amateur radio, CB, FM and other transmitters are picked up by long wires running through the house: electric power wiring, telephone cables. alarm system wires, etc. They feed the signals into the TV, the telephone, and the stereo. Long leads to the stereo speakers do the same. Electronics in these appliances are upset by the RF and you hear the radio transmitter in your telephone and TV and the alarm goes off.



How to cure RFI - Run the wires through ferrite cores right next to the affected appliance (the Tip Sheet gives details). Ferrites do not affect the signals going through the wires but they resist the passage of RF. So they keep the RF out of the appliance and stop the RFI.



What is in the kit? 12 beads with 0.2” holes for small wires and cables, 4 toroid (donut shaped) cores with 1/2” holes, 4 with 3/4” holes, 4 split beads (toroids cut in half so you can put them over cables without disconnecting them). Two of them fit over RG-58 (1/4” hole) and two fit over RG-8 (1/2” hole).



Also included is our RFI Tip Sheet that explains the use of ferrites in detail and tells how to use them to keep RF out of computers, stereos, VCRs, alarm systems, and telephones.



What does it cost? Kit RFI-4 is $35.00 + $8 S&H in U.S. and Canada. (Plus Sales Tax in California.



How to order? Use VISA, Mastercard, check or money order. Call, FAX, write or send e-mail request.





www.Palomar-Engineers.com Updated 12-15-08
 

musical marv

Distinguished
Feb 26, 2011
408
1
18,960
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Where do you live near? That has quite a bit to do with this interference. Is this Pro equipment?
 
You need to determine where the RF is getting into the system. Does it happen with different sources? Does it happen when you go directly into the Marantz receiver without the Gemini preamp? You can try using ferrite core filters on the cables between the components. These are cheap. If it is getting into the Gemini itself then maybe you can do without it?
 

musical marv

Distinguished
Feb 26, 2011
408
1
18,960
7
Are you talking about ferrite bead filters which can sometimes cut out the interference.
 

soundguruman

Distinguished


Kit RFI-4 contains ferrite toroids and beads selected to eliminate RFI from 1 to 1000 Mhz. Enough to cure a normal household of RFI..



What causes RFI? Strong signals from nearby amateur radio, CB, FM and other transmitters are picked up by long wires running through the house: electric power wiring, telephone cables. alarm system wires, etc. They feed the signals into the TV, the telephone, and the stereo. Long leads to the stereo speakers do the same. Electronics in these appliances are upset by the RF and you hear the radio transmitter in your telephone and TV and the alarm goes off.



How to cure RFI - Run the wires through ferrite cores right next to the affected appliance (the Tip Sheet gives details). Ferrites do not affect the signals going through the wires but they resist the passage of RF. So they keep the RF out of the appliance and stop the RFI.



What is in the kit? 12 beads with 0.2” holes for small wires and cables, 4 toroid (donut shaped) cores with 1/2” holes, 4 with 3/4” holes, 4 split beads (toroids cut in half so you can put them over cables without disconnecting them). Two of them fit over RG-58 (1/4” hole) and two fit over RG-8 (1/2” hole).



Also included is our RFI Tip Sheet that explains the use of ferrites in detail and tells how to use them to keep RF out of computers, stereos, VCRs, alarm systems, and telephones.



What does it cost? Kit RFI-4 is $35.00 + $8 S&H in U.S. and Canada. (Plus Sales Tax in California.



How to order? Use VISA, Mastercard, check or money order. Call, FAX, write or send e-mail request.





www.Palomar-Engineers.com Updated 12-15-08
 

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