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I inadvertently posted this to the ITMD3 forum, my aplogies, and I can't figure out how to delete it from that forum.
Years ago, I bought a 4 inch snooper, and it had an inline amp that made it very sensitive. Screwed up the ID a bit.
I have been hunting for a 5900 SL for a while, and found one, but it has a huge current draw.
Last week, I scored one off ebay, with no coil.,
Hooked it up and it works, except that in tr mode, one can't get the sound to go silent, which is the mode I prefer to hunt in.
I was under the impression that sigbal was essentially an amplifier, but now I am not sure.
Exactly what is the sig-bal block doing?
It looks like sigbal is used as a non inverting amp with a fixed gain. R2 is 6.34K R1 (Rf for the equation) is 34.8K 1+(rf/R2) looks like the gain is 1+(34.8/6.34) seems that the gain is 6.48. What does the pot on the + lead do?
What would happen if one changed R1 (34.8K to a similar configuration as the preamp to allow for a bit more gain?
What doe the R5 R3 resistor combination do here?
The output of the preamp is passed into sigbal, and it appears that R5 attenuates the signal some.
Second question, There is a pre-amp U1, a NE5534 that feeds everything. Looking closer, there is an R2 which is a 25K pot, and it appears to vary the feedback on the opamp. R3 is a 30K and feeds into the variable resistor R2. That would allow you to set the feedback from 30.1K up to 55.1K
given R1 is 825 1% resistor I am assuming that the gain of the amp is controlled by R2. IF R2 is removed, and measured, then attached to the box so it is accessible, can it be used to amplify the signal a bit more to get more depth like the external amp on the 4" sniper coil?
It looks like the gain can range from:
1+(55000/825) = 66.6
1+(30100/825) = 36.48
I have no idea what the actual setting is, and I assume it was set for specific output value by whites, and it is an on board trimmer.
IF R2 is removed, and measured, then attached to the box so it is accessible, can it be used to amplify the signal a bit more to get more depth like the external amp on the 4" sniper coil?
Carl, I am looking for your input here specifically.
Based on MR. Bills mods , I understand that changing R56 (a 220K) on the audio tuner will change the rate of the SAT signal is that correct?
I notice also, that there is no volume control.
based on the 6000 DI pro CB, it looks like one could lift the end of R59 or R114 and insert a pot in there to get a volume control to work. basically R114 14K ----100K pot----16.5K gnd