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Username: mica

Post Number: 4563
Registered: 6-2000
Posted on Wednesday, May 09, 2007 - 7:42 pm:   Edit Post

10k resistor mod for F-1X direct out

You can modify your F-1X if the POST output is at line level and you prefer it at mic level. Add a new 10K resistor where indicated in above photo. We use 1/4 watt 1%, but 1/2 watt and 10% tolerance will work fine in this application.

Note: the horizontal resistor where the new 10K resistor connects at the top is 36.5K (orange, blue, green, red, <brown>). Some earlier versions had 30K (orange, black, orange, <gold>), which works fine with the modification.

Some versions had a 10K resistor in that position (brown, black, orange, <gold>) and you'll only get 6dB reduction in level when you add the new 10K resistor. If the unit has 10K in this position, substitute a 30K or 33K resistor instead.

The purpose of the modification is to change the "POST" signal level to microphone level. Early units were like this, but we purposely changed the post to line level. Feedback from most users indicates that microphone levels for both switch position is expected and preferred. After the modifications, the signal levels for both
"PRE" and "POST" are similar (depends on the settings of the volume and tone controls and the sensitivity of the power amplifier and speakers).

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