Microphone Holders
Interference/crackling on a transmitter microphone?
I have just modified an FM transmitter, it has an inbuilt mic, but i decided to add an extra Jack in case i needed to add an external one. I added the Jack wires to the mic input, so it has two mics in one input lead, and added a switch to the original mic to stop a mix in signals. The system does work, the Original mic works a treat, but the added mic has a crackling sound, unless I hold the lead, or touch the Battery holder, I presume that I am grounding it by doing this, the original mic does not need any grounding to work, do not know why this is happening, I thought of adding a diode to the negative lead, but am not sure, does anyone have any ideas?
Thanks Mick
Also the 2 mics are the same, and how could I screen the wires?
The added mic works fine, I have tested it on a computer
Crackling normally comes from a poor contact, so normally I would suggest you try cleaning the jack socket and / or switch.
However, what you said about the crackling going away when you touch parts of it makes this doubtful. It could be high frequency instability in the microphone pre-amplifier because you are using a different type of microphone, or it could be picking up RF interference because you have not screened the mic wires properly, or you could be getting feedback from the transmitter output back to the mic input.
If this is an electret capsule type mic, you should be aware that these have a small amplifier built into them which takes DC power from the 2 wires. Therefore it has to be connected the right way round. Try reversing it.
Things you could also try:
Make sure the mic lead is screened correctly.
Connect a small value capacitor (~100pF) across the microphone.
Put ferrite beads on the wires to the microphone.
Edit:
The cable to the mic should be single screened or twin screened cable. It has one or two wires inside surrounded by a screen of foil or thin copper wires. Make sure the screen is connected to circuit ground, which is probably the battery negative voltage.
 New Mic Holder works well with Shure SM58 and others  US $4.49
|
 New Expandable Mic Holder for Most Cordless and Corded US $6.49
|
 5x Black Plastic Microphone MIC Clip Stand Holder US $18.99
|
 Black Plastic Stage Microphone MIC Clip Stand Holder US $.99
|
 Slide Mic Holder works well with Shure SM58 and Others US $6.49
|
 2 Pcs Plastic Microphone Mic Clip Stand Holder Mounts Black US $4.95
|
 GRAY MIC BASE MICROPHONE BOOM HOLDER GREY 2 RISER US $10.00
|
 Quad 4 Microphone Holder Recording Studio Sale US $6.99
|
 Universal Studio Mic Holder US $4.99
|
 Microphon holder holders stands mounts magic tricks US $17.99
|
 Flexible Microphone Holder US $3.99
|
 6 PACK Lot Microphone Mic Boom Stage Stand Holder Clip US $107.95
|
 2Pack Microphone Boom Stand Holder Cable Mic Clip Bag US $59.95
|
 Microphone table stand holder Flexible Gooseneck Chrome used US $12.99
|
 4 Plastic Microphone Mic Holder Stand Clamp Clip Black US $6.99
|
 Steren MS 040 Microphone MIC Clip Clamp type Holder US $.99
|
 Mic Stand Holder for iPad2 US $29.95
|
 10 Mic Clips Holder Microphone Slide Type Black US $12.99
|
 Mic Shock Mounts Holder For MXL M audio Nova Blue 01 US $14.89
|
 10 Plastic Microphone Mic Holder Stand Clamp Clip Black US $12.99
|
 Metal Screw on MIC Holder US $.99
|
 4 Pack Microphone Boom Arm Stand Tripod Holder Mic Clip US $76.95
|
| Powered by phpBay Pro |
 |
Dream Essence Designs Valentines Day - Large red heart, musical notes, microphone, Sing From the Heart text, dark background - Tile Napkin Holders
 |
DescriptionLarge red heart, musical notes, microphone, Sing From the Heart text, dark background Tile Napkin Holder is measuring 6w x 6h x 4d. Made from high quality solid maple wood with satin finish and two 4.25 commercial grade mirror gloss ceramic tiles... |
 |
Dream Essence Designs Music - Large red heart, musical notes, microphone, Sing From the Heart text, light background - Tile Napkin Holders
|
DescriptionLarge red heart, musical notes, microphone, Sing From the Heart text, light background Tile Napkin Holder is measuring 6w x 6h x 4d. Made from high quality solid maple wood with satin finish and two 4... |
 |
Perkins Designs Animals - Micro Flight Butterfly creative butterfly designed using several microphones - Tile Napkin Holders
|
DescriptionMicro Flight Butterfly creative butterfly designed using several microphones Tile Napkin Holder is measuring 6w x 6h x 4d. Made from high quality solid maple wood with satin finish and two 4.25 commercial grade mirror gloss ceramic tiles... |
 |
Solid Wood In-Wall Toilet Tissue Holder
|
DescriptionNEW: This unit now comes with our Full Wall Depth Option (3.5" deep) standard! This means that is easily has enough room to handle both single and double size rolls. If you need an even larger unit, check out our MEGA Toilet Paper Holder which can handle any roll on the market today with ease! Hand crafted from solid whitewood... Features
|
 |
Digital Voice Recorder Key Chain. Buy 1 Get 1 Free
|
DescriptionDigital voice recorder is perfect for reminding yourself of important dates, appointments, directions, shopping lists, parking locations, times for medication etc. Play back when needed. Handy device helps you save time, energy and extra trips to the store... Features
|
 |
Compact Contact Lens Case Tweezers w/ Mirror Set
List Price: |
Description·A pair of tweezers and of contact lens cases, a tiny bottle for liquid medicine, and a case with mirror as one set ·Lens cases, tweezers and bottle can all be put in the mirror case, convenient to carry around ·With pictures of musical notes on both mirror case cover and lens case covers ·Compact case provides safety and easy access Features
|
 |
ChargerCity 360° Swivel Adjustment Apple iPad iPad 2 Kindle Fire Nook Color Universal Tablet Handle Bar Mic Microphone Stand Exercise Machine Shopping Cart Wheelchair Golf Push Cart Strap Lock Mount (Fits aany shape handle bar from .75" to 1.5")
List Price: |
DescriptionNeed a cost efficient mounting Solution for your tablet? ChargerCity Universal tablet mount offers an easy solution for mounting your tablet on to a Microphone Stand, golf cart, wheelchair or any standard size round bar ... Features
|
 |
Connectland CL-NBC-STDFAN Plastic Ergonomic Laptop Cooling Stand for 12-Inch-17-Inch Notebook PC
|
DescriptionSYBA ERGO NOTEBOOK STAND W/ FAN Features
|
Uhf Dual
Xlr Cables
Dual Wireless
Professional Microphone
Ribbon Microphone
Microphone Akg
Stereo Pair
Condenser Microphones
Hughes Kettner
Microphone Mic