The Behringer 305 module is my favorite eurorack module. If I lost everything and had to start again I would get this one first. It has an amazing list of fantastic features all in one module:
4 inputs with level and pan
4 Band Parametric EQ
1/4 inch outputs
Master Volume Control
Standard Oscillator (A 440) for tuning
I can’t understand why ANY musical instrument would have a 3.4mm output jack! It makes no sense at all (I’m looking at YOU, Korg!!) so this module is absolutely the most important one to own, in my opinion!
HOWEVER…. one day I recorded something and noticed it was not in tune with everything else. After comparing the standard oscillator to the A440 oscillator in my Minimoog I realized it wasn’t in tune! That really kills it’s usefulness.
I searched around the internet and only found other people asking the same question: How do you tune the standard oscillator in the behringer 305 module?” So finally I pulled the module out and it’s actually very simple and obvious. There’s a blue multi-turn pot right beside the oscillator switch.
Get out a tuner, or use another very reliable source, get a small screwdriver and just turn the screw until it’s in tune. It might take several turns since it is a very fine tuning pot but, at least in my case, I was able to tune it.
Just make sure you let it warm up for 15 minutes first.
However… I checked it again the next day after I had left it all turned on for over an hour and it was significantly sharp again. So I tuned it again but this time I turned the screw all the way to the end and still couldn’t get it perfectly in tune. It’s still just a tiny bit sharp (3 or 4 cents maybe), close enough I guess, but it would be nice if I could bring it down a tiny bit more. I also tested it the next day and found that when I turn the system on the oscillator is well below 440 and needed about 10-15 minutes to come up to pitch. It’s a bit disappointing but I still love the module otherwise.