jwachman
New Member
Dear Dynon,
Here comes my diatribe and fault finding on an issue with the HS-34 Audio Warnings.
The setup. I have the HS-34 Audio output connected to an SPA-4 intercom. There is no seperate input for audio warnings, so I initially connected this to the common headset line. (You will see as you read - I have tried other connection points).
The problem - When the HS-34 is turned on the radio volume level drops by about 50%. My HS-34 and EMS happen to be connected to a seperate switch so I can turn them off with all other avionics on.
The audio warnings work fine. If I turn on the radio I can listen to various transmissions, all loud and clear. But when I turn on the HS-34, the radio audio level drops, and remains dropped, even when the warnings have finished.
It is like there is a continuous side-tone on the HS-34 output.
So onto the fault finding. I disconnected the HS-34 output. The radio volume returns to normal. If I connect the HS-34 to the left headphone output, the volume to that ear drops. Same to the right.
I connected a 250 ohm resistor, in series, this lowers the volume of the HS-34 warnings, and also reduces the impact on the volume of the radio.
If I connect the HS-34 to the same input to the intercom as the radio, it again drops the volume. This input location seems good, as it does stop the iPod sounds when warning tones are transmitted. This also indicates the intercom is working correctly.
So I purchased a Flight Data Systems - AP-60 Audio Mixer. Which mixes and amplifies up to six signals. When I connect the HS-34 output and radio to this and turn on the mixer, the HS-34 output causes a loud 'sream' which is only removed when I remove power from the mixer, or disconnect the HS-34 input to the mixer.
Conclusions: What appears to be happening is that the HS-34 audio output has a continuous sidetone. This side tone appears to cause a reduction in the volume of the radio. When I use the mixer it amplifies the sidetone, until it becomes a 'scream'.
Questions:
1. Have you got any idea whats going on?
2. Does the HS-34 produce a continuous sidetone on the Audio Warning output line.
3. Any other ideas?
Thanks
Jon :-/
Here comes my diatribe and fault finding on an issue with the HS-34 Audio Warnings.
The setup. I have the HS-34 Audio output connected to an SPA-4 intercom. There is no seperate input for audio warnings, so I initially connected this to the common headset line. (You will see as you read - I have tried other connection points).
The problem - When the HS-34 is turned on the radio volume level drops by about 50%. My HS-34 and EMS happen to be connected to a seperate switch so I can turn them off with all other avionics on.
The audio warnings work fine. If I turn on the radio I can listen to various transmissions, all loud and clear. But when I turn on the HS-34, the radio audio level drops, and remains dropped, even when the warnings have finished.
It is like there is a continuous side-tone on the HS-34 output.
So onto the fault finding. I disconnected the HS-34 output. The radio volume returns to normal. If I connect the HS-34 to the left headphone output, the volume to that ear drops. Same to the right.
I connected a 250 ohm resistor, in series, this lowers the volume of the HS-34 warnings, and also reduces the impact on the volume of the radio.
If I connect the HS-34 to the same input to the intercom as the radio, it again drops the volume. This input location seems good, as it does stop the iPod sounds when warning tones are transmitted. This also indicates the intercom is working correctly.
So I purchased a Flight Data Systems - AP-60 Audio Mixer. Which mixes and amplifies up to six signals. When I connect the HS-34 output and radio to this and turn on the mixer, the HS-34 output causes a loud 'sream' which is only removed when I remove power from the mixer, or disconnect the HS-34 input to the mixer.
Conclusions: What appears to be happening is that the HS-34 audio output has a continuous sidetone. This side tone appears to cause a reduction in the volume of the radio. When I use the mixer it amplifies the sidetone, until it becomes a 'scream'.
Questions:
1. Have you got any idea whats going on?
2. Does the HS-34 produce a continuous sidetone on the Audio Warning output line.
3. Any other ideas?
Thanks
Jon :-/