Home |
Search |
Today's Posts |
|
#1
|
|||
|
|||
"Rich Grise" bravely wrote to "All" (03 Mar 05 23:00:40)
--- on the heady topic of " 1/4 vs 1/2 wavelength antenna" RG From: Rich Grise RG Xref: aeinews rec.radio.amateur.antenna:26329 RG sci.electronics.design:1386 RG On Thu, 03 Mar 2005 20:53:48 +0000, John Woodgate wrote: I read in sci.electronics.design that gwhite wrote ... Doesn't everyone know that an audio amplifier that id designed to feed an 8 ohm load MUST have an output source impedance of 0.0000001 ohms or less. An output source impedance of 8 ohms would dramatically decrease the electromagnetic damping on the loudspeaker voice-coil - by the huge factor of .... two!(;-) RG Yeah - isn't that why the TOOB amps had those taps? So you could get RG that rich, full-bodied TOOB sound? ;-) No, the taps are there to maximize the power output. If one uses the 8 ohm tap with a 4 ohm speaker the power is reduced and the same if one uses a 16 ohm speaker. Audio output matching has little to do with plate resistance in a beam tube or pentode. It has everything to do with plate voltage swing and maximum plate current. The less plate resistance the more power can get to the load. Beam tube curves look a lot like a transistor's collector saturation curves. However, some tube amplifiers had a current feedback control which would increase the output impedance to equal the speaker's. Needless to say it severely reduced the speaker damping resulting in exagerated frequency response artifacts. A*s*i*m*o*v .... Without ignorance, knowledge is powerless. |
Reply |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
Discone antenna plans | Antenna | |||
The "TRICK" to TV 'type' Coax Cable [Shielded] SWL Loop Antennas {RHF} | Antenna | |||
Poor quality low + High TV channels? How much dB in Preamp? | Shortwave | |||
X-terminator antenna | CB | |||
Outdoor Antenna and lack of intermod | Scanner |