Does your Drake R7A Do This?
 

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.

Does your Drake R7A Do This?
 

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?

Does your Drake R7A Do This?
 

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

Does your Drake R7A Do This?
 

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.