EA Trem Trimpot Troubles

[Alex C]

Hi, I've searched the forum for references to a similar problem, but couldn't find any.  

I used the Runoffgroove schematic for this.  My LED lights and pulses according to the settings, and the rate, volume, and depth controls work as they should.  However, when adjusting the trimpot (100k) I can get either a clean, uneffected sound (just boosted), or distorted tremolo (has the tremolo pulsing sound, but has the "mis-biased" sound too, like a sputtering fuzz).  There is very little "adjustment distance" between the two (meaning that a very slight turn of the pot will change it from one to the other, and I can't get an acceptable mix of the two).  
I checked the orientation of the transistors, and all are correct, as are the electrolytics.  
Should I try a smaller trimpot for more precise adjustment?  Or is something else my problem?  I used a 2N5089 instead of the specified 5088, because that's all I had on hand, and I believe I read that the two are basically identical, but the 5089 has lower noise, etc.   I am most likely wrong, but it seems to be peforming a non-audio job, just manipulating the depth/rate (I forget which).   The other values are as specified, except for the trimpot, for which I substituted a regular pot which happens to be audio taper.  Could this be contributing to my difficulty in locating the proper setting?  

Any ideas?  Thanks.

Alex