Hi,

There are basically two issues dealing with the Ring Frobnicator.

1) Getting the oscillator to work

2) Adjusting the trimpot TR2, in the schematics also called TR1 (100 k).

The first issue, getting the oscillator to work, can be solved two ways. The preferred way is to replace R11 with a 20k trim and set the voltage across LED1 and LED2 to 3.2 to 3.4 volts. An alternate solution is to add an extra diode to LED1 and LED2. Mind the polarity.

The second issue, is the adjustment of TR2. For me there was no effect adjusting the trimpot. The clicking sound was quite annoying, and in the Ring Modulator mode it was just the same, annoying. The solution in this case is to replace R6 with a lower value of the resistor. In my case I tried replacing the R6, 10 Mohm with a 910 kohm resistor. Why 910 kohm? Somewhere here I read that somebody replaced the 10 Mohm resistor with a 1 Mohm resistor, and got it working, but still not perfect. As 1 Mohm is close to no connection, I was doing a little math. 1 Mohm minus 100 kohms (trimpot) is equal to 900 kohms, this way I got the 910 kohms value of R6. I replaced the resistor and, voila, it was now adjustable. and I got it to work beautiful. However, I would like to say that this is pure experimental, and this value might not work for others. Also be careful with the solder iron, the heating might easily break the printed curcuit. I can't trace any bad thing happening or any malfunction by lowering this resistor to 910 kohms.

The tremolo is now incredible! Works nice and quiet. The Ring Modulator is really nice. I can use the Ring Modulator several ways. The most evident is the Ring Modulator-effekt with the amplitude modulation just audiable, or adjust it to be inaudiable, and it will work as some sort of filter that will surpress the frequency in a chord, set on the Ring Modulator.

BR,
Hans

I was able to get my Frobnicator to oscillate by using the same type of LED for all three LEDs. The bleed through of the oscillator in the tremolo mode is in audible. In the Ring mode the trimmer almost gets rid of it but not quite. So in the ring mode there is a tone you can hear if the instrument is quiet.

Hi,

Your post made me get mine back out again.  I got the trem to work by adding a dio between the battery and the board.  Mine never ticked but the overtone on the ring mode made it unusable.  My 100k trimmer never seemed to do anything.  I tried what you have above and it did not work for me.  In fact I put several different values in the (R6) 10M spot and found that they all did nothing for me.  Even leaving the (R6) res. out of the circuit did not change the effect.  Then I messed around with different values to ground out the other end of the 10M res.  Which I guess is grounding out pin 5?  I found that a (R6) 4.7M res to ground cuts out about 95% of the overtone.  But the effect is not super strong.

Is your ring effect strong?  The tremolo effect does not seem to care what value is in the R6 slot. 

Questions:  Would changing the Tr2 to a 4.7M value help out?  Does it matter which way the 100k trimmer is placed in the circuit?  Is it strange that leaving R6 empty does not effect anything?  And what am I doing when I put a 4.7M res to ground?  How is that making the overtone almost go away?

I hope this is somewhat clear,
Paul.

I'm not sure what you're describing I'll have to get out the schematic and take a closer look. I like the Trem effect it's very nice. The Ring effect might be worth using sometimes if the sound of the oscillator could be removed. I can get the sound pretty quiet but it never goes away.