jasonallenh said:I do have a couple questions though-
1) what do you do if you don't have VR2?? I used the THAT chip instead and the schematic references the other chip in the notes you're referring to.
2) I was able to set the same reference level, but I cannot reduce VR'2 to get -5VDC at TP2. Instead, I just set my reference level per your instructions, and then used the SSL procedure to set 0DB (Create a 4db decrease when switching in). The THAT portion of Igor's schematic does refer to this point as "set 0db, so I am assuming this is still ok even though this ended up giving me about 4.8VDC at TP2 instead of -5VDC. I thought maybe the PCB was arranged so that either option you choose uses one half of an opamp, but the schematic says that's not the case. It's behaving like a compressor though! and you're right, the comp does behave better.
Just had a look a the Schematic. You should have VR2. I think you are referring to VR1
The THAT chip has a fixed resistor (R1) instead of a trimmer (VR1) data sheets might show the THAT chip is fixed and can not be adjusted. I do not have time to compare data sheets at the moment, but if DC can be adjusted on the THAT I would have expected Igor to put a trimmer at position R1 as it is on the the AD536.
jasonallenh said:I was able to set the same reference level, but I cannot reduce VR'2 to get -5VDC at TP2. Instead, I just set my reference level per your instructions, and then used the SSL procedure to set 0DB (Create a 4db decrease when switching in).
This is my thoughts, but could be wrong and do not have the THAT version to experiment!
What DC measurement do you get at TP1 at 1.55VRMS. I presume this will 0.2VDC
This ideally would be 0VDC. However as you are fixed you probably will not be get exactly 0VDC. I think you want to get -5v difference. So if TP1 reads 0.2VDC set TP 2 to -4.8VDC to achieve the the -5VDC.
I think this will then create the 4db difference as per the SSL manual?