Build Your Own Clone Message Board

First build, and working out the kinks.

I'm getting a good boost in the linear and clean modes, but my germanium boost is only slightly higher than unity.

I made sure I didn't have the transistor in backwards - even installed it backwards to be sure, and that was definitely worse. but it back the right way and still have the problem. I'm getting 9v on all the input ends of the resistors in this circuit, and various reduced voltages to all the transistor leads. (2.5 at the collector, and close to 8 on the base and emitter - I have no idea what to expect here)

I notice also that I get a pop when I turn the footswith on in this mode, and sometimes when I change the treble/mid/full selection - not sure if that is relevant or a different problem.

Is there a simple way to check if the transistor is working correctly? What else should I check to troubleshoot this? I feel pretty comfortable looking at the schematic and the pictures of the PCB to figure out which component is which, and how it is wired, so if there are voltages I should check, that is fine. I didn't do the math to determine what attenuated voltages to expect, but the figures I was seeing seemed reasonable.

OK, I reflowed all the solder joints. At this point, I am getting a noticable boost, but it is the weakest of the three. With my amp at a very low setting, and the guitar volume at 10, I guess I'm getting close to twice the perceived volume with the pedal on (and volume at 10). Is this about right? I thought somebody posted it should be 20dB, and I thought 3dB is double volume - I'm either remembering those figures wrong, or I'm still not getting full boost here.

I posted pics under my thread about the fuzzy clean boost - I won't re-upload on this thread unless that is preferred, to save server space.

That sounds about right; the germanium devices always provide much less gain than the BJT or mosFET variety. And if you have it set to treble boost, it's blocking many of the lower frequencies before the boost, so there is even less signal to boost.

One thing I recommend is comparing your resistor color bands to some of those in the Tri Boost gallery to make sure you haven't swapped resistor values somewhere. It's difficult to compare your photos to other photos; much easier to compare the real thing to photos.

If you still have no luck, you can measure the gain and leakage of the OC75 using this method: http://freestompboxes.org/viewtopic.php?f=44&t=9851