Vacuum Radio Tube
Vacuum Radio Tube
 |
 6CG7 6FQ7 AUDIO AMPLIFIER HAM RADIO TV TUBE RCA brand pair  US $3.95
|
 6H6 6H6G AUDIO AMPLIFIER HAM RADIO TV TUBE Zenith brand US $3.95
|
 6AK5 5654 6096 AUDIO AMPLIFIER HAM RADIO TV TUBE Sylvania brand pair US $3.95
|
 6J5 AUDIO AMPLIFIER HAM RADIO TV TUBE RCA brand pair US $6.55
|
 6BW4 audio amplifier HAM radio rectifier tube GE brand US $2.95
|
 6AQ5A 6AQ5 audio amplifier radio TV tubes Sylvania brand pair US $3.95
|
 6K6 6K6GT audio amplifier TV radio tubes RCA brand pair US $2.95
|
 5726 6AL5 audio amplifier HAM radio TV tubes RCA brand pair US $2.95
|
 6J7 AUDIO AMPLIFIER HAM RADIO TUBES RCA brand set of 4 US $4.95
|
 6AU6 6AU6A AUDIO AMPLIFIER HAM RADIO TV TUBE RCA brand pair US $8.51
|
 MATCHED PAIR 6KG6A EL509 TUBESENGLAND JAPAN US $39.95
|
 SEVEN 7 GE 21JS6A 23JS6A NIB NOS US $35.95
|
 MATCHED QUAD GE 6KN6 BEAM POWER NIB NOS US $65.95
|
 Emerson portable vacuum tube AM radio US $9.00
|
 2 NOS General Electric 6JE6C 6LQ6 Vacuum Tubes for Kenwood National Swan Radios US $41.00
|
 2 NOS Delco 6GJ5A Vacuum Tubes for National NCX 3 Amateur Radio Made by RCA US $12.49
|
 2 NOS RCA 12JB6A Vacuum Tubes for Drake TR 3 Radio Transmitter US $19.87
|
 Lot of 28 Mixed Radio Vacuum Tubes in Boxes NOS Used Complete List US $1.04
|
 1947 Magnavox Mono Antique Radio Turntable works for parts or restoration US $10.00
|
 RCA Radio Vacuum Tube New Old Stock Part Number 29LE6 with Original Box US $4.99
|
 Vintage Radio Vacuum Tube 6BN6 Tested Very Good US $2.49
|
 Vintage Radio Vacuum Tube 1V2 Tested Very Good US $2.49
|
 LOT OF 19 VACUUM TUBES 6H6 ALL TESTED ALL GOOD US $15.00
|
 set of 3 vintage radio tv vacuum tube type 6AL5 used tested US $.49
|
 set of 8 vintage radio frequency amplifier vacuum tube type 6J6 used tested US $.49
|
 pair of vintage type 6X8 tv radio vacuum tubes used tested US $.49
|
 set of 7 vintage type 6AG5 radio amplifier vacuum tubes used tested US $.49
|
 Pair RCA 6080 Hickok Tested US $5.00
|
 Lot of 3 JAN 76 VT 76 Printed Base US $5.00
|
 NIB NOS 2 Tung Sol 6SK7 Radio Vacuum Tubes Black Metal Date Code Matched Set US $14.44
|
 NIB NOS 6 Tektronix 12AU6 8426A Radio Vacuum Tubes 2 Date Code Matched Sets US $14.44
|
 NIB NOS Mullard 7189 Radio Audio Vacuum Tube Valve Great Britain US $36.99
|
 NIB NOS Lot of 3 RCA 884 VT 222 6448 Matched Vacuum Tubes Radio Audio Output US $24.88
|
 NIB NOS Set of 6 RCA 12HG7 Radio Vacuum Tubes Gray Plate All Date Codes Matched US $39.99
|
 1 GE NIB NOS 5Y3GT RADIO AMP VACUUM TUBE TESTED VERY GOOD US $4.75
|
 PAIR 1U4 Vacuum Tube RCA Victor USA NOS Pentode Radio US $3.99
|
 VINTAGE RCA 6AK5 RADIO VACUUM TUBE US $1.35
|
 2 vintage RCA type 12SJ7 radio frequency amplifier vacuum tube used tested US $.49
|
 BOX OF VINTAGE RADIO TUBES US $12.99
|
 Vintage vacuum radio TV tubes lot of 69 tubes US $14.95
|
 Electronic Magazines Radio TV News Electronics world US $14.99
|
 6J5 Vint KEN RAD Tests 71 RARE 1 AVAILUSA Low USE BlkMetal Bottle US $9.96
|
 2 Old ELECTRIC ENTERPRISES INC Radio Vacuum Tubes JAN CDZ 811 811A Tested US $20.02
|
 RADIO VACUUM TUBES 6JW8 ECF802 PHILIPS PR pentode triode preamp audio stereo US $11.99
|
 RADIO VACUUM TUBES 6N8 EBF80 PHILIPS PR pentode preamp audio stereo amp ham US $27.99
|
 LOT OF 5 8CG7 RCA SYLVANIA VACUUM RADIO TUBES US $4.99
|
 LOT OF 8 12AU7 RCA VACUUM RADIO TUBES US $49.99
|
 RADIO VACUUM TUBES 14A4 SYLVANIA LOKTAL triode vintage wood radio phonograph ham US $9.99
|
 RADIO VACUUM TUBES 7Z4 HYTRON LOKTAL rectifier vintage wood radio phonograph US $8.99
|
 RADIO VACUUM TUBES 7C7 HYTRON LOKTAL pentode vintage wood radios phonograph US $8.99
|
 Eimac 4 400 RF Power Vacuum Tubes US $75.00
|
 RADIO VACUUM TUBES 7A8 GE LOKTAL octode audio preamp vintage wood radios ham swl US $8.99
|
 RADIO VACUUM TUBES 5AZ4 RCA LOKTAL rectifier vintage radio phonograph ham swl US $9.99
|
 RADIO VACUUM TUBES 14N7 TUNG SOL LOKTAL dual triode vintage radio phonograph US $11.99
|
 RADIO VACUUM TUBES 35Y4 RAYTHEON LOKTAL rectifier preamp vintage wood radios US $8.99
|
 RADIO VACUUM TUBES 35Z3 SYLVANIA LOKTAL rectifier preamp audio stereo ham swl US $9.99
|
 Radio Equipment Hints Sylvania Electric Volume 1 1943 US $10.99
|
 LARGE LOT OF 44 NEW USED Vintage VACUUM TUBES Radio TV Audio TUBES US $35.99
|
 vacuum tubes radio lot of 6 untested G E REALISTIC RCA US $3.99
|
 Vacuum Tubes Lot and misc antique radio parts and tube amp US $29.51
|
 2 vintage 6V6 GTA tubes Realistic and Raytheon Matsushita Japan 1 has gold pins US $9.99
|
 TUNGSOL Type 24 WHITE BOX TESTED US $5.00
|
 PAIR TYPE 43 TRIAD AND RAYTHEON TESTED GOOD US $5.00
|
 ARCTURUS 27 VACUUM TUBE 4 1 2 32 US $9.99
|
 RCA RADIOTRON UY 227 RADIO VACUUM TUBE GLOBE 4 1 2 19 US $9.99
|
 RCA RADIOTRON 80 VACUUM TUBE 4 1 2 45 US $9.99
|
 CUNNINGHAM C 327 RADIO VACUUM TUBE GLOBE 4 1 2 8 US $9.99
|
 RCA RADIOTRON UY 227 UY227 GLOBE VACUUM TUBE 4 3 25 US $9.99
|
 MARATHON MX226 RADIO VACUUM TUBE GLOBE 4 1 2 10 US $9.99
|
 PHILCO 76 VACUUM TUBE 4 1 2 47 US $9.99
|
The Basic Information on the Carbon Microphone
Carbon Microphone is also known as carbon button microphone or a carbon transmitter. It consists of two metal plates separated by carbon granules. One of the plates faces outwards and acts as a diaphragm. When sound waves strike these metal plates the granules change which in turn alters the electrical resistance between the plates.
Direct current passes through the two plates and the changing resistance results in changing current. The current then passes through a telephone system to change the sound into an electrical signal.
Carbon microphones once were known for their high output level performance, low impedance and reasonably low cost. One of the major drawbacks of these microphones was its low quality of sound reproduction and limited frequency response, as well as high hiss noise level. Due to these reasons they became less popular.
One of the merits of carbon microphones is that they can actually be used as amplifiers. This capability was used in early telephone repeaters, making long distance phone calls possible in the period before Vacuum Tubes. These carbon microphones were mechanically coupled with a magnetic telephone receiver.
Another advantage of carbon microphone is that it could be used to boost weak signals and send them down the line. This is possible as it works by changing a current passing through it, instead of generating a signal voltage as in the case of most of the microphone types. These amplifiers were soon abandoned with the development of vacuum tubes as they offered higher gain and better sound quality.
One illustration of the amplification of these carbon microphones was the oscillation caused by feedback. This results in an audible squeal from the old candlestick telephone, if its earphone were placed near the microphones.
The principal advantage of carbon microphones is that they have the ability to produce high level audio signals from very low DC voltages. And it does not need any from of additional amplification or battery.
They are widely used in safety critical applications such as mining and chemical manufacturing where higher line voltages cannot be used, due to the risk of sparking and consequent explosions. Installation of large communication infrastructure base around carbon microphones is already an expensive affair; it is considerably cheaper to maintain the existing structure than to replace it with new technology.
They are also famous as they can withstand damage from high voltage transients such as those produced by lightening strikes and electromagnetic pulses of the type generated by nuclear explosions. They are still maintained as a backup communication system in critical military installations.
In the early days, AM radio transmitters relied on carbon microphones for voice modulation of the radio signal. In the first audio transmissions by Reginald Fessenden a continuous wave from an Alexanderson alternator was fed through a carbon microphone.
Carbon microphones are still used in certain niche applications in the developed world. This is because of its wide compatibility with existing equipment.
About the Author
Victor Epand is an expert consultant for music gear, speakers, and microphones. You can find the best marketplace for music gear, speakers, and microphones at these 3 sites: music gear, music equipment, speakers, and carbon microphones, button microphones.