Well, I am finally back with my comparison. It sure took a while. It all came down to a very sharp utility knife, a trip to the ER, eleven stiches in my hand, and waiting for it to heal enough so I could get the stupid bulky bandage off. The hand will be just fine. The woodworker's ego is still having a few issues.
I completed the build of the pcb version and used sockets for the chips so I could compare the NJM13600 chip that Steve sent to me with the surface-mount LM13700 I purchased from him at Smallbear. This was my first attempt at a pedal in this size enclosure and that brought its own issues to bear. I did incorporate the two protection leds to minimize distortion, I used a trimpot to replace the resistor to have the threshold capability, and I temporarily added a switch to control the treble boost.
First off, the 13600 IC did work as anticipated. I tried the treble boost switch here and did not find a lot of difference. As has been discussed, the threshold trimpot is not really that useful over just the release pot. I really like the compression and especially the sustain. However, there was quite a noticable amount of distortion at higher settings of the release control and the pedal reduced the output to the extent that I had to have the level pot at about 80+ % to equal the bypass level.
I tried to solder some leads to the legs of the surface-mount IC with the expected negative results. I decided I had to make a mini pcb to mount the board and provide contacts for regular leads (not many leads are required). My first attempt at this involved running leads from this board to the sockets of a millmax socket. I built it, epoxied it all together and had my own chip ready to plug in. It worked great, but it was too thick with the other socket already in place and I couldn't get the bottom of the box on
I made another pcb with the LM13700 and just bent the leads into the desired locations (using a socket for alignment) and then applied some epoxy. The resulting "chip" worked just fine!
These are subjective "ears only" comparisons at this point. The REAL LM13700 improved the level issue. I know that this is true from AB comparisons with the pots held constant. The distortion issue seems much better with the 13700. I really need to explore this with my oscilloscope to see if my ears are fooling me or not. I had removed the treble boost switch so I cannot report on that.
I may have a go at modifying the pcb layout to incorporate the surface mounted chip. This will not be trivial since all of the connections are mirror images and there are already several traces running under the chip.
Here's a quickie photo of the Rube Goldberg IC chip in the pedal. The picture gives some funny color cast to the solder joints. It is not there in the real pedal.
Oh yeh... I should add that the reason the 47 uf cap is laying on its side is that some dummy cut the notch for the DC plug on the wrong side of the box.
