flemming
Well-known member
I've poked at this one several times now, boxed it up, unboxed, rinse, repeat and I'm finally throwing it out there to see if anyone has any tips. This isn't the first time this has been mentioned:
forum.pedalpcb.com
The ticking only occurs when the Oscillator is turned up (or when the Subharmonic is toggled to use the Oscillator as the root). My prior experience with ticking has either been because of noisy power (but this also happens on battery) or running the output too close to the LED/LDRs in the Phase II. I read a couple things Chuck wrote on the topic of LFO tick:
forum.pedalpcb.com
But there's a lot going on in this circuit so testing out some of the ideas in here are currently a bit above me. I believe the pedal works fine, aside from this. Though I don't know if my angry robot sounds are the intended angry robot sounds
. One thing that I have noticed while testing on a battery is that if the voltage of the battery drops a bit to ~8v then the ticking disappears. I don't have a power supply to test this more precisely. I'm inclined to throw some diodes on the input power to knock it down a bit and see if that "solves" the problem. I tinkered with a voltage divider on the input power but that didn't really work. Another thing that I've noticed is that with the oscillator turned up there is a bit of DC bouncing up and down the output (~.3V) and with it down there is not. I replaced both the 1u coupling caps out the oscillator pot as well as right before the volume with 1u tantalums just to see if either of those helped and they did not.
I've probed the circuit the best I can, but there's a lot going on in here and it's really hard to say for certain if a tick is present or not in some places since the volume may be super low and it's just being amplified elsewhere. There appears to be a faint tick pretty much everywhere starting even before the power input diode if you listen closely, even while on battery. Is that the same loud tick that I'm ultimately hearing from the oscillator? I have no idea. The tick is only present in the output when the oscillator is turned up, so even though I may faintly here it for example on the square pot I don't here it in the output. I noticed the tick from the square pot is gone on the opposite side of its coupling cap. Would changing the coupling cap size from the oscillator make a potential difference? I don't really want to desolder more things randomly, so looking for a bit of insight if you have any to offer. I do have a cheap digital scope, though I'm not entirely certain where and what to look for to help narrow it down.
Thanks for the help.
Mini Heterodyne Receiver
First time posting, first time SMD’ing, loved every minute of it. Sounds great! Forgot to order a 10M so I had to parallel a few and mount them under the board.
forum.pedalpcb.com
The ticking only occurs when the Oscillator is turned up (or when the Subharmonic is toggled to use the Oscillator as the root). My prior experience with ticking has either been because of noisy power (but this also happens on battery) or running the output too close to the LED/LDRs in the Phase II. I read a couple things Chuck wrote on the topic of LFO tick:
LFOs - part I
LFO stands for Low Frequency Oscillator. We use LFOs in modulation and delay pedals to vary some parameter, such as phase, volume, delay time, etc., to create movement and give our guitar signal more life. Oscillators are a really interesting subject and they're all around us. You're probably...
forum.pedalpcb.com
How to fix the LFO tick in the Sea Horse and Dark Rift
I've found a simple circuit mod that gets rid of the LFO tick in the EQD Sea Machine (Sea Horse) and Space Spiral (Dark Rift). It has been tested on both pedals. It's the same mod for both pedals, only the ref designators are different. Sea Machine: Remove C19. Connect a 10nF cap between pins...
forum.pedalpcb.com
But there's a lot going on in this circuit so testing out some of the ideas in here are currently a bit above me. I believe the pedal works fine, aside from this. Though I don't know if my angry robot sounds are the intended angry robot sounds
. One thing that I have noticed while testing on a battery is that if the voltage of the battery drops a bit to ~8v then the ticking disappears. I don't have a power supply to test this more precisely. I'm inclined to throw some diodes on the input power to knock it down a bit and see if that "solves" the problem. I tinkered with a voltage divider on the input power but that didn't really work. Another thing that I've noticed is that with the oscillator turned up there is a bit of DC bouncing up and down the output (~.3V) and with it down there is not. I replaced both the 1u coupling caps out the oscillator pot as well as right before the volume with 1u tantalums just to see if either of those helped and they did not.I've probed the circuit the best I can, but there's a lot going on in here and it's really hard to say for certain if a tick is present or not in some places since the volume may be super low and it's just being amplified elsewhere. There appears to be a faint tick pretty much everywhere starting even before the power input diode if you listen closely, even while on battery. Is that the same loud tick that I'm ultimately hearing from the oscillator? I have no idea. The tick is only present in the output when the oscillator is turned up, so even though I may faintly here it for example on the square pot I don't here it in the output. I noticed the tick from the square pot is gone on the opposite side of its coupling cap. Would changing the coupling cap size from the oscillator make a potential difference? I don't really want to desolder more things randomly, so looking for a bit of insight if you have any to offer. I do have a cheap digital scope, though I'm not entirely certain where and what to look for to help narrow it down.
Thanks for the help.
If I'm sufficiently motivated I may try pulling the power pin on the Oscillator IC and see if just dropping the voltage there makes it better without effecting the voltage elsewhere.
