Low Tide Modulator: led and bypass works, but no audio otherwise

[sven59372]

Hi guys,

I have built the Low Tide Modulator with a kit from Musikding. When I engage the pedal, the LED comes on, but there is no audio coming through (not even hum or noise). I have tried turning up and down all the knobs, the two trim pots and the dip switches, but this does not result in audio output. When bypassed the audio works fine.

Any ideas of where I should start troubleshooting? This was my first pedal build, but I have soldered before and while building I didn't really encounter any difficulties. The only problem was that there was one component in smd format (2SK208-Y). I had no experience with smd, is there a way to check if that at least is properly connected?

-Sven

 

[zgrav]

record voltages and ground connections on the ICs to make sure those are OK. seems like something could be wrong there since no sound is coming through at all.

are your transistors secure in the sockets? don't hesitate to shorten the leads on them if you want to fit them in without bending them over. go ahead and measure the voltages on the leads for the transistors too and share all of the results in the forum if things are still not working.

your smd chip looks like it took a bit of heat. you might want to try to clean it up a bit with some isopropyl alcohol. the leads look like they are soldered OK but you could confirm by testing for continuity for each lead using the schematic to confirm they connect to their counterparts.

if the power and grounds are OK, use the schematic and an audio probe to start following the audio through the different parts of the board. do a search for "audio probe" on the forums and internet if you are not familiar with making them or using them.

 

[PJS]

In order to get this working properly you will need to adjust the bias trimpot for the BBD to work properly. I would think that you should be getting dry signal even without that though. The audio probe idea will at least track down where you are losing that.