[time-nuts] HP58535A to Line Amp

Bob Camp lists at rtty.us
Mon Apr 5 01:28:37 UTC 2010


Hi

Thanks a fine deal on some 58535's I've been poking around inside one. Line amps with all the "right stuff" are massively expensive, so converting a two channel unit into a line amp has some financial benefits. It has the bandpass filters, connectors, and low noise amp in it already. Exactly what's different between the parts in a two way and a line amp would be an interesting thing to dig into. I don't have any schematics so I can't do that. 

From previous posts and looking at the one in my hand, there appears to be about an 8 db pad on the output of the two way devices. The pc board is setup to be either a 2 way or 4 way splitter. Since it's a resistive splitter, the 4 way would have 6 db more loss. 8 db on the 2 way would let them use the same amp on the 4 way and just switch around resistors. Based on all that, simply taking out the pad should give me a "line amp" function with the 2 way splitter. 

I'm guessing I'm not the first to notice this. Has anybody tried this before? Did anybody ever find an actual schematic to confirm all this against?

I realize that a line amp is not the idea answer to every problem. In my situation I have 10 db of loss past where this device would go. Even with 8 db of "extra" gain, I will have 2 db of net loss. This is not a situation where the downstream devices will be over driven. 

Thoughts?

Bob





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