The Trek II electronic crossover also cut off at 150 Hz with a 12 dB per octave roll off and uses a single power source right from the Leslie. The master volume is located on the circuit board, but can be modified to mount elsewhere.
For a simple clarification the more dB per roll off, the faster those frequencies are not transferred to the place it should no t go.
-I used the Trek II and modified it not only because of the good design but the ease of the modification. By replacing and adding only five
components (resistors and capacitors) now I have a 800 Hz electronic crossover with 12 dB per octave roll-off. It uses the Leslie's power supply which is a less of a hassle. The
-
+I used the Trek II and modified it not only because of the good design but the ease of the modification. By replacing and adding only nine
components (resistors and capacitors) now I have a 800 Hz electronic crossover with 12 dB per octave roll-off. It uses the Leslie's power supply which is a less of a hassle. The instruction that are supplied with it are clear and easy.
!! The parts to alter the Trek II LC0-1 are:
Warning! |
A reliable source has reported that the component values listed here
will result in a crossover frequency of 80 Hz rather than 800 Hz.
Please double-check the calculations before attempting the modifications described here.
(Not having access to the full schematic for the LC0-1, I can not check
- the calculations myself.) -- JeffDairiki
+ the calculations myself.) -- JeffDairiki Part change and additions corrected below -- Mike Casino
-1) 28K ohms 1/4 watt. mouser pt# 271-28K min order of 10 @ $.09 each
-3) 14K ohms 1/4 watt. mouser pt# 271-14K same min order & price
-
-2) .1 micro farad caps. mouser pt# 146-250V 1K about $.27 each
+5) .01 micro farad caps.
Replace R2, R3 & R6 with 14K ohm resistors.
Replace R7 with 28K ohm resistor.
-Replace C3
with two .1uF
caps in parallel.
-
+Replace C2
with two .01uF
caps in parallel.
-This will give you a crossover of 803 Hz (close enough for government work)
.
+Replace C3, C5 & C6 with .01uF caps
.
+This will give you a crossover of 803 Hz.
!! The Lower Rotor
Now for the lower Rotor assembly:
