I swapped the stock IC3 for a Burr Brown the oher night. It took about 3 hours all said and done. What I have found is that the clean tones do open up quite a bit. There is a lot of "air" present that was stiffled before. However, it is apparent that the chip overdrives at a MUCH lower signal level. In order not to run into distortion (even on the cleanest of settings), I've either had to either lower the gain on the Rythym Yellow and Green by about half (from 5 .5 to 3), OR use a single coil pickup rather than humbuckers.
The initial soldering of the IC socket proved to be intermittent, (tapping on the PCB cut the signal in and out), so I re-soldered and the intermittent connection was resolved. The question that I hope someone might help me with is to those who are familiar with the nature of the chip and how it works. Does this early clipping sound like it could be a short or an open on any of the IC pin connections? Obviously, the bottom of the circuit board is easy to test and I can do a visual check for a clean solder joint. The component side of the circuit board is not so easy to diagnose as the IC socket sites on top of the PCB traces.
It would appear to me that the positive and negative supply voltages are connected (V+ and V-) or the IC wouldn't work at all, no? Perhaps an open feedback connection to the chip on OutA back to -InA or an open or short on other pins? I will get the old Ohmeter going on this to check for continuity, but was hoping someone might have some other insight as the disassembly of this box is a mini project in itself and knowing what one might look for would be a tremenous help.
I am also going to swap back in a TI TL072 to see if the OPA2134 does indeed clip early. From what I have researched on this subject however, the 2134 should have more, not less headroom.
Man.
The initial soldering of the IC socket proved to be intermittent, (tapping on the PCB cut the signal in and out), so I re-soldered and the intermittent connection was resolved. The question that I hope someone might help me with is to those who are familiar with the nature of the chip and how it works. Does this early clipping sound like it could be a short or an open on any of the IC pin connections? Obviously, the bottom of the circuit board is easy to test and I can do a visual check for a clean solder joint. The component side of the circuit board is not so easy to diagnose as the IC socket sites on top of the PCB traces.
It would appear to me that the positive and negative supply voltages are connected (V+ and V-) or the IC wouldn't work at all, no? Perhaps an open feedback connection to the chip on OutA back to -InA or an open or short on other pins? I will get the old Ohmeter going on this to check for continuity, but was hoping someone might have some other insight as the disassembly of this box is a mini project in itself and knowing what one might look for would be a tremenous help.
I am also going to swap back in a TI TL072 to see if the OPA2134 does indeed clip early. From what I have researched on this subject however, the 2134 should have more, not less headroom.
Man.