Hey all! First off, i just want to thank everyone on this board who has helped me with excellent informative and patient responses to my vibe questions.  This place is an invaluable source of information and support! So...i've finally gotten my neovibe boxed up and finally working! I've had so many things go wrong with this build, but i've learned a lot about debugging with voltages and audio probe etc...so in the end i guess i've gained some good insight and knowledge to work with in the future.     

Now, i have one more issue here which is the lfo is audible through the amplifier.  I've even unplugged the guitar and just had the out of the effect going into the amp...the oscillation of the lfo is at a pretty high level through the amp.  I'm wondering how i can go about debugging this...           i can use the audio probe, but where on the circuit should i hear the lfo and where not, or should i not be hearing it all anywhere?

Much thanks and appreciation!!!

The LFO is very isolated from the circuit in the Neo. The only 'sposed-to-be connections are through the power and ground, as the output is isolated by that lamp and the LDRs.

I believe this is the first issue with hearing the LFO I've had come up in the decade or so the Neo has been available.

First thing to check is whether your power supply voltage is sufficient for the regulator to not fall out of regulation with the pulsing of the LFO. That might do this.

Measure the DC voltages before and after the regulator IC.

Thanks R.G.  Okay, i have another board up and fully populated that i'm building for a friend.  It also has similar issues, so i figured i'd measure the voltages on this first and then open up my boxed one and compare.  I measured the DC voltages first from the two points just before the current enters the diode bridge...I'm using an ac source.     

1st pin of diode bridge: 8.54 VDC
2nd pin of diode bridge: 8.37VDC
Output of Regulator: 15.04VDC

Another strange thing is that with this board which is hooked up to a breadboard for all the pot connections (the finished one is all boxed up, so the breadboard can't be the issue)...i had the lamp and ldr's uncovered, when i went to put a light box on top, in fact whenever i moved my hand over the area, i would hear a louder pulsing of the lfo through the amp...

I'll check the other box now...but i think the results will be the same in terms of voltage...actually i seem to remember checking this once before and coming up with a total closer to 18VAC off the power supply and the same 15.04VDC off the regulator...

Thanks again R.G.! Any response is greatly appreciated!

I'm going to try switching to a 24VDC power supply and see if that helps...i'll report back for anyone interested

Just chiming in here cause I want to follow this thread...

Okay report: tried 24VDC power and same as with AC power...still lfo oscillation coming out of amp even with guitar unattached...have to try some other stuff and will report back