marcfrom said:Ok Keith, but do you talking about the two 15K resistors wich feedback the NE5532 (just at the ouput of the VCAs)?
Or do you talking about the 127K* that we usualy adjust to calibrate the ratio?
Substituting the 127k* would be more like 1Mohm to get a 6mV/dB instead of 50mV/dB controlV and the 620k at the makeup pot would need a sizeup as well. I'd probably decrease the 100k feedback resistor to 12k for the needed 0.12 scale down factor and keep the 127k* and 620k in front. The 100pF compensation cap might increase to 470pF. If I encrypted the DBX202 schematic right, max.allowed signal current is 500uA for Iin+Iout, so the 27k Rin would at least better be doubled up to withstand 250uA @ 13Vpk from the debalancing NE5534. The suggested 100k for Rin might be the safer bet and give less distortion at the cost of noise. YMMV.SSLtech said:marcfrom said:Ok Keith, but do you talking about the two 15K resistors wich feedback the NE5532 (just at the ouput of the VCAs)?
Or do you talking about the 127K* that we usualy adjust to calibrate the ratio?
The 127k.
I reckon the new value will be in the 15kΩ region... Try 12kΩ with a 5kΩ trim-pot, although you might have MASSIVE makeup gain range, in which case you'd also have to reduce the feedback around the op-amp following the makeup gain pot, by about the same degree (a factor of 8.3333 etc.)
Keith
marcfrom said:I will swap the 100kΩ resistor between pins 6 and 7 of the TL072 for a 12kΩ resistor, and then change the 100p capacitor to an 820p capacitor.
Other things, look this schematic:
i saw the 202 Black can specs, it seems i have to put 2.2Uf cap. /100k res.(blue) at input and 10pF cap. /100k res. (red) at output of the VCA to adapt impedance.
Could you confirm ?
marcfrom said:jumper the 1K going to pin3... Where does it go? Do i put 1K resistor or just jump the signal?
Added Resistors are under the Black Can?
I'm not shure to understand, can you post something like a schematic showing the board?
Enter your email address to join: