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#11
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Larry Dighera wrote:
On Sun, 18 Mar 2007 08:02:34 -0600, "John Berenyi" wrote in : When the volume knob is turned down = all the way I still hear audio coming from my speaker or headphones. Is = this typical of these units? The same thing occurs with my Drake R8B. Mine too. It's my second R8B and the first one also did it. I'm pretty sure it's caused by high impedance leakage around the pot. I discovered this when I had the receiver apart for some maintenance. I removed the connector to the volume pot and I could still hear some weak audio. Since I use the R8B close to my bed, I installed a mute switch in the speaker circuit so I don't hear any sound when the volume is down all the way or up too. |
#12
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On Mon, 19 Mar 2007 09:19:32 GMT, HFguy wrote in
EAsLh.8578$282.8431@trndny04: Larry Dighera wrote: On Sun, 18 Mar 2007 08:02:34 -0600, "John Berenyi" wrote in : When the volume knob is turned down = all the way I still hear audio coming from my speaker or headphones. Is = this typical of these units? The same thing occurs with my Drake R8B. Mine too. It's my second R8B and the first one also did it. I'm pretty sure it's caused by high impedance leakage around the pot. I discovered this when I had the receiver apart for some maintenance. I removed the connector to the volume pot and I could still hear some weak audio. With the pot out of the circuit, I wonder what the signal path might be? I presume the 5K AF Gain pot grounds the input to U4 when it's in the Min position. When the pot plug is removed from jack P4, the U4 amp input floats. Since I use the R8B close to my bed, I installed a mute switch in the speaker circuit so I don't hear any sound when the volume is down all the way or up too. According to the R. L. Drake R8B Owners Manual http://www.hamradio.no/la3tq/r8b.htm, there is an RCA jack on the rear of the receiver labeled Mute: MUTE - The RCA connector provides a method of muting the receiver for use with a transmitter. Ground center pin to mute. Grounding the center pin of this jack fully mutes the receiver. Just out of curiosity, why don't you just turn the receiver off when you don't want to hear it? |
#13
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In article EAsLh.8578$282.8431@trndny04, HFguy
wrote: Larry Dighera wrote: On Sun, 18 Mar 2007 08:02:34 -0600, "John Berenyi" wrote in : When the volume knob is turned down = all the way I still hear audio coming from my speaker or headphones. Is = this typical of these units? The same thing occurs with my Drake R8B. Mine too. It's my second R8B and the first one also did it. I'm pretty sure it's caused by high impedance leakage around the pot. I discovered this when I had the receiver apart for some maintenance. I removed the connector to the volume pot and I could still hear some weak audio. Since I use the R8B close to my bed, I installed a mute switch in the speaker circuit so I don't hear any sound when the volume is down all the way or up too. Build a small attenuator pad in line with the headphones. -- Telamon Ventura, California |
#14
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Larry Dighera wrote:
On Mon, 19 Mar 2007 09:19:32 GMT, HFguy wrote in EAsLh.8578$282.8431@trndny04: Larry Dighera wrote: On Sun, 18 Mar 2007 08:02:34 -0600, "John Berenyi" wrote in : When the volume knob is turned down = all the way I still hear audio coming from my speaker or headphones. Is = this typical of these units? The same thing occurs with my Drake R8B. Mine too. It's my second R8B and the first one also did it. I'm pretty sure it's caused by high impedance leakage around the pot. I discovered this when I had the receiver apart for some maintenance. I removed the connector to the volume pot and I could still hear some weak audio. With the pot out of the circuit, I wonder what the signal path might be? I presume the 5K AF Gain pot grounds the input to U4 when it's in the Min position. When the pot plug is removed from jack P4, the U4 amp input floats. Since I use the R8B close to my bed, I installed a mute switch in the speaker circuit so I don't hear any sound when the volume is down all the way or up too. According to the R. L. Drake R8B Owners Manual http://www.hamradio.no/la3tq/r8b.htm, there is an RCA jack on the rear of the receiver labeled Mute: MUTE - The RCA connector provides a method of muting the receiver for use with a transmitter. Ground center pin to mute. Grounding the center pin of this jack fully mutes the receiver. Just out of curiosity, why don't you just turn the receiver off when you don't want to hear it? I didn't spend much time studying the problem so I can't say with any certainty how the audio may be leaking around the pot. It could have something to do with the design of the PCB traces or maybe the wiring lead dress. I do remember trying to make the audio silent by substituting some resistors for the pot but it didn't have any effect. I solved the problem by adding a mute switch (button) on the front panel for convenience. I prefer to mute the audio because I don't like to be cycling the receiver on and off every time I want the audio to be completely silent. This situation usually happens when I'm in bed at night listening to the television on low volume and the R8B is closer to me than the TV. |
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