Hi!
I have an issue with the ez1073.
I have it connected to an Alphalink converter. That's it. No computer no anything, powered through the same extension cable.
When I engage the eq on the MIC input, I get a ton of noise but not any kind of noise, if I boost the low end, I get noise tuned to this frequency, if I boost midrange, same, etc.
The signal level also raise a lot with MIC vs LINE.
Also something seem to become "microphonic". If I tap the input transformer (or anything touch the pcb) I hear it amplified. Leaking in the audio path. A bit like the sound a mic is hearing when tapping it's mic stand.
There's no input connected, all floating (Mic and Line) except the line output. The screen of the output is connected to the pcb.
I made sure the enclosure is grounded everywhere with a ohm meter (0.3 ohm at worst), connected the power transformer's green/yellow wire , the "Mains Safety Earth" point on the pcb and the Main Ac ground to the chassis. The pots goes through the front panel and are grounded too.
When I disengage the eq the noise level drop dramatically but there's still a faint hum.
Switching to Line input everything goes quiet, even with the eq engaged.
I checked all and every soldures twice, checked with an ohm meter to be sure there's no shorts and made sure the transformers are wired properly.
Anyone have a suggestion? I think "microphonic" is the key word, maybe the inductors? The transformer?
I have no clue so far, thanks for any help!
I have an issue with the ez1073.
I have it connected to an Alphalink converter. That's it. No computer no anything, powered through the same extension cable.
When I engage the eq on the MIC input, I get a ton of noise but not any kind of noise, if I boost the low end, I get noise tuned to this frequency, if I boost midrange, same, etc.
The signal level also raise a lot with MIC vs LINE.
Also something seem to become "microphonic". If I tap the input transformer (or anything touch the pcb) I hear it amplified. Leaking in the audio path. A bit like the sound a mic is hearing when tapping it's mic stand.
There's no input connected, all floating (Mic and Line) except the line output. The screen of the output is connected to the pcb.
I made sure the enclosure is grounded everywhere with a ohm meter (0.3 ohm at worst), connected the power transformer's green/yellow wire , the "Mains Safety Earth" point on the pcb and the Main Ac ground to the chassis. The pots goes through the front panel and are grounded too.
When I disengage the eq the noise level drop dramatically but there's still a faint hum.
Switching to Line input everything goes quiet, even with the eq engaged.
I checked all and every soldures twice, checked with an ohm meter to be sure there's no shorts and made sure the transformers are wired properly.
Anyone have a suggestion? I think "microphonic" is the key word, maybe the inductors? The transformer?
I have no clue so far, thanks for any help!