Blue Lantern Modules BLM JP JFET MK2 SAW CORE VCO User manual

BLM JP JFET MK2 SAW CORE VCO
Blue Color Input Jacks: 1v/Octave input and Modulation Input. Both of these are 1v per octave
Exponential. Mod input uses an attenuator Knob.
Red Color Input Jack: Sync Input requires a positive Square Wave. Other wave forms will do a very soft
sync. Use a Square wave for best results.
Lime Green Input: Pulse Wave Modulation. This only affects the Pulse Wave. Saw wave does not use this
parameter.
Orange Input: Linear FM input with Attenuator.
Fine Tune Knob brings a perfect musical note down, clockwise brings a musical note up. Flat and Sharp
Notes.

BLM JP JFET MK2 SAW CORE VCO
Calibration: DO NOT MESS WITH THE TRIMMER ON THE BACK!
All calibration for the tracking is done on the front of the panel.
This is using the same calibration like all the other analog vco’s. It involves the LO and HF trimmers.
The back of the module has a 500 ohm trimmer. Do not adjust this! If you adjusted the trimmer you will
have to use a volt meter to re-adjust the internal Reference Voltage for the tracking. There is a small
hole to the right of the trimmer where you can get your reading with a volt meter. It is between the
trimmer and the Ribbon Cable Header. You need to adjust to read 0.274 V.
If you do not have the equipment to perform calibration, please do not try to do this. You will probably
get your vco way out of tune.
Step 1. Apply 0v to the 1v/octave input. Set the Frequency of the vco to 50Hz.
Step 2. Apply 4V to the 1v/octave input, and check the frequency reading on the vco. The goal is to get
800Hz. 799Hz is good also. 801Hz is also good. If the reading is off, for example 832Hz, or 784Hz, you
need to adjust the LO trimmer on the front panel. For each adjustment you are checking your work by
applying 0v 50HZ, 4v->800Hz. When you start getting close, know is the time to check on the High
Frequency.
Step3. Apply 5V and 6V, and the frequency reading should be 1600Hz, 3200Hz.
1598Hz, 3198Hz would be good enough. It is harder to get perfect adjustments on the High Frequency
adjustment. Use the HF trimmer to adjust this. Each time you adjust the trimmer you have to set the vco
back to 50Hz, and check 4v->800hz, 5v->1600Hz, 6v->3200Hz
MODEL: BLM JPJFET VCO
Analog Saw Core VCO
Width: 6hp
Depth: 1 Stack PCB. Skiff Compatible.
Current: -32mA, +32mA
Circuit type: Analog