--- In Repeater-Builder@yahoogroups.com, Adi Linden <[EMAIL PROTECTED]> wrote: > > Just breadboard it Chuck. It only uses one chip (the TL084 > > is a quad opamp) along with the passive components. > > If you have a controller that does de-emphasis or you don't want it, a > dual opamp like the TL062 should be sufficient. That's what I'll be using. > > Adi > --
In my particular application, the controller is an RLC-2A. I found that it didn't de-emphasize the RX audio well without increasing the value of the de-emphasis & input coupling capacitors. Rather than hack the controller, I incorporated a workaround in my HPF circult: I did the de-emphasis there with the first TL084 section, then I used a 27K resistor on the output stage to make the output high impedance. Doing this removes the 300 Hz high-pass rolloff that the 0.1 uF cap on the RLC-2A's port audio input would normally add to the response. If you don't need to do all this, you can as originally stated omit the first audio stage. However, don't remove the 27K resistor altogether. Use at least a 220 ohm resistor on the output, otherwise the opamp may oscillate if capacitively loaded (as little as 100 pF can cause this). Bob NO6B Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
