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THE AM BULLETIN BOARD => Technical Forum => Topic started by: KU8L on February 27, 2013, 11:33:17 AM



Title: Line-Level pick-off point in R4B
Post by: KU8L on February 27, 2013, 11:33:17 AM
GM All:

I am setting up a recording capability and want to pick-off some line-level audio in the R4.  I'm sure many have already done this.  Favorite pick-off point?

There are three transistor amps ahead of the Hollow-state audio output amp.  Would like to go as early in the chain as possible.  Maybe right at the top of the Volume control?

Thanks
Curt


Title: Re: Line-Level pick-off point in R4B
Post by: W3GMS on February 27, 2013, 11:49:52 AM
I don't have the schematic, but I think your approach is a good one.  Right across the top of the AF Gain pot and ground. That's usually buffered one stage in from the detector and will eliminate any loading effects on the detector.  Just make sure the coupling caps between it and the detector are large enough to pass the low end response your looking for.

Joe, W3GMS
AMfone - Dedicated to Amplitude Modulation on the Amateur Radio Bands