Reply 120 of 448, by dreamblaster
here are the schematics for CVX-2 (SMD version) and CVX-1 (through hole version), this may be helpful for the investigation.
Although CVX-2 seems to sound better than the clone versions, the schematic is very similar to the clones and circulating schematics, where I in fact inspired on for this first revision.
Many clones may practically omit some components, use different resistor values, combine resistors to one value, use lower tolerance resistors, or worse pcb layout (or no pcb at all -> may get more noise picked up). There is not much to it. CVX-2 uses all the same resistor values to have a close tolerance. (I also used 0.1% resistors initially, compared to 1% resistors, but most important, all resistors from same batch/strip, so the values are close to eachother). So the original covox still sounds better : CVX-2 may still have a difference or mistake, compared to the original covox, let's find out !
Maybe it is just a matter of getting the optimal values :
Resistor value : once we determine the value of 2R in covox, I can try using the same here.
C1 = low pass filter --> filters out the high frequencies. --> We played with this value and determined 4.7nF sounded best for the current setup. (actual filter freq. depends on resistor values as wel as cap value, so we may tweak this again if the resistor value changes)
C2 = decoupling cap --> filter out the DC component from the audio signal. ---> the original covox doesn't seem to have this, so we can short C2 as a test.
The pins used (for example for ground connection), may differ from the original covox, not sure if that matters at all.
Other differences you can trace ?
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