Hi guys.
Here’s my current project. The voltage controlled LFO from Meebilt.
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I’m curious: Is the reset the same as a sync?
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Outrageously neat work, what’s your secret?
Can you explain the apparent lower amplitude on the sine wave output? I can’t figure how the sine shaper would do that. (That said my maths is shocking these days). My apologies if this is a daq*.
*Dumb Ass Question
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Didnt test it yet. I just hooked up the pcb with minimal jacks just to test if it works. As soon as i have the panel manufactured, i will connect everything nessesary.
The small black thingy between the trimmer and transistor is the BSS138 mosfet. Apperantly that mosfet is SMD. I managed to solder legs onto the 3 small contacts and bend it like an transistor:+1:
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Yeah. One thing i noticed was the high output. Needed to turn the division knob on my oscilloscope down. Sine waves are always lower in volume. See a sine wave as a triangle wave but with rounded top and bottom. I think you can compensate for the volume loss but at the costs of the wave form’s shape. The trimmer btw rounds off those edges to blocky shaped ones (if you trim to far).
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Maybe the voltage drop over each wave shaper diode?
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The hard clipping diodes should explain the voltage drop, I think.
Some time ago, I bought a couple of SMD JFETs with a plan to treat them like that, but the project was pushed far down the to-do list. Glad to see that this worked though!
I am not familiar with the specific circuit, but couldn’t the MOSFET be substituted for something like 2N7000 or BS170?
Hi K.ostas,
Yes you can use BS170 or other N-channel mosfets. I thought lets try something new.
See the small difference:
The BSS138 and BS170 are both N-channel MOSFETs commonly used for switching applications, but they have some key differences. The BSS138 is typically found in a SOT-23 SMD package and is known for its low on-resistance and low gate threshold voltage. This makes it suitable for low-voltage switching and logic level shifting. The BS170, on the other hand, is usually available in a TO-92 package and is slightly slower but can handle higher currents
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I have a half finished silicone micro jig I started making to make soldering wires to small SMD components. It’s like a lino cut with a hole for the part and channels to introduce the wires. All cut from an old silicon baking mat. The wire channels are simply cuts with a scalpel. You can also cut shapes and bends into the silicon to prep wires for more components.
It’s on the top of the finish pile.
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Great idea. For this i used my “helping hands”with a magnifying led glass.
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