Four steps to troubleshoot your Earthworks Microphones
If you are experiencing an issue with the performance of your Earthworks microphone, do this first:
#1 Check your microphone cable or try another cable
A cable with a cold solder joint or other defect can sometimes appear to be fine when tested with a dynamic microphone or condenser that draws less current, but fail to work with an Earthworks microphone because it can’t deliver the full amount of power required or cannot do so continuously.
#2 Check Phantom Power
Earthworks microphones require 24 to 48 volt phantom power with 10mA of current to operate properly.
Symptoms of inadequate phantom power supply:
- No signal from microphone – seems like it hasn’t powered up
- High noise floor
- Audio signal low in level and distorted
What to do:
- Check your microphone cable or try another one (see above)
- Check the phantom power specifications for your preamp/interface/mixer/stagebox. If it does not provide between 24 and 48 volts, or is not rated to provide 10mA of current or more, you may need to use an external phantom power supply.
- Check that your device can provide enough current to power all of the Earthworks microphones you want to use at the same time. Some devices are rated for 10mA of current per channel, but don’t have enough total capacity to provide 10mA to all inputs simultaneously. You may need to use an external phantom power supply for some of your microphones.
Power Considerations for all Phantom-Powered Microphones
Don’t plug in “hot”
Make sure that phantom power is switched off before you plug in a phantom-powered microphone
Some preamps/interfaces/mixers/stageboxes with large capacity phantom-power supplies designed to power many microphones at once can generate a damaging spike or surge when a microphone is plugged into an unloaded channel that already has phantom power engaged, rather than the smooth, controlled ramp-up that normally occurs when you connect the microphone first and then turn on phantom power.
When AC power is unstable, use a UPS or switch off phantom power when not needed
When AC power supply is unstable (ie: rural areas, live-sound with generator power, marine environments), some preamps/interfaces/mixers/stageboxes can deliver a damaging phantom power spike or surge to connected microphones if their phantom power switch is still in the ON position when power is first restored.
- When not in the studio, or between performances, if the microphones aren’t needed and there’s a possibility of power failure, switch off phantom power
- If the power is currently out, or if you know in advance that power will be interrupted, turn off phantom power or disconnect the microphones to ensure that they aren’t affected when power is restored
- Power the preamp/interface/mixer/stagebox with a UPS (uninterruptible power supply) to ensure that it always receives stable power
- If the preamp/interface/mixer/stagebox is too large to be powered with a UPS, use an external phantom power supply for the microphones and power it with a UPS
#3 Check for transformers
Earthworks microphones are incompatible with some devices that use input transformers. The sheer variety of different transformers and circuit designs, combined with component tolerances and age (especially with vintage equipment) makes it difficult to provide a list of compatible preamps, mixers, broadcast splitters and other transformer-based devices. It also means that there can be different symptoms of incompatibility with different devices.
Symptoms of Transformer-Related Incompatibility:
- No signal from the microphone
- High noise floor
- Distorted signal
- High-pitched oscillation or whistling sound
- Reduced low or high-frequency response
What to do:
- Give the microphone extra time to fully power up
- With some Earthworks microphones and some transformer-based devices this can take two minutes or more
- Once powered up the microphone should perform normally
- Check your cable length – With transformers, the use of very long cables can be a problem. In some live sound and studio situations, the total length of microphone cabling including snakes or in-wall wiring can be hundreds of feet.
- Try connecting directly to the preamp with a shorter cable (50 feet / 15 meters or less) if possible
- Relocate the preamp closer to the microphone
- Check your input impedance – Transformers with very low input impedance (1k ohms or less) can be an issue with Earthworks microphones
- If your preamp has switchable input impedance, choose a higher impedance setting (ie: 6.8k ohms)
- If input impedance is very low and cannot be switched, the use of an external phantom power supply may possibly help
- In a live sound setup with a transformer-based splitter to feed input signals to separate FOH, monitor and broadcast consoles:
- Try an external phantom power supply for the Earthworks microphones
- Try swapping which of the consoles is feeding phantom power through the splitter’s direct output
#4 Check the Microphone Output Level
Like most other condensers, Earthworks microphones are more sensitive than most dynamic microphones and thus have higher output levels. When miking drums, guitar amplifiers, and even sometimes with loud vocalists singing very close to the microphone, a negative amount of overall gain is required from the preamp to avoid distortion.
On many preamps a switchable pad provides the necessary attenuation; however, in some cases including the following it may be necessary to use an external pad connected inline between the microphone and the preamp:
- With audio interfaces/recorders/mixers that do not feature pads and have gain controls that don’t go far enough down to provide negative gain
- With some vintage and vintage-inspired preamps that have positive gain even with their pad engaged and gain control at minimum
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