Message Board

The preamp circuit in this unit is very similar to the mic pre design shown in the Jensen schematics on their website. The main difference is that they use a reverse log, not log, 10K pot in the location of R103,203,303,403. This is the same type of taper used in most preamp designs. It may be worth...

Im also a little confused about changing the location of the output control in the circuit. Rod suggested removing the connection between R136 and C108 then running from r136 to the center leg of the output pot. Gabreal removed R136 all together.

Hey guys, This is some great info. I just ordered a 1678C and can?t wait to try it out. I have a couple of questions though. According to the schematic, the 560 ohm resistor reduces the gain by 14db. and after you installed a 1K pot in it?s place the signal was still too hot for most applications an...