First of all...Howdy to all of the "old souls" still on the forum (and, of course, to all of you just starting out).
While I may have been AWOL for a few years (?), I'm back.
Soooo....
Dual front ends and my take. I have replaced my NE5534 single op-amp front end with a dual op-amp LM4562 ( http://www.ti.com/lit/ds/symlink/lm4562.pdf ) as per my old post on the "show us your HH build" thread ( http://www.geotech1.com/forums/showt...ed-HH-detector ) {P.S.- don't forget to remove R13-1Meg!}.
I also replaced the 'back-end', IC8-TL072/082 with another LM4562. I may be suffering from the," I washed my car so no wonder it runs better" complex - OR - Having matched front and rear amps really does make a difference. The scope says the noise is lower, but did I really GAIN anything? Hmmmm. The lower first stage gain did help the noise issue. What should I look for on the scope in time domain to empiricaly define the difference between the setups? Just a thought...
I suspect that the LME49710 single amp version ( http://www.ti.com/lit/ds/snas376b/snas376b.pdf ) would be a great alternative to the NE5534 for a single amp front end. Just pricey.
As of this post the LM4562's are not cheap (about $4.20 U.S.}. But if you are going for the shortest samples and quietest background noise, they might be the answer for your app.
Just my thoughts... GTB
While I may have been AWOL for a few years (?), I'm back.
Soooo....
Dual front ends and my take. I have replaced my NE5534 single op-amp front end with a dual op-amp LM4562 ( http://www.ti.com/lit/ds/symlink/lm4562.pdf ) as per my old post on the "show us your HH build" thread ( http://www.geotech1.com/forums/showt...ed-HH-detector ) {P.S.- don't forget to remove R13-1Meg!}.
I also replaced the 'back-end', IC8-TL072/082 with another LM4562. I may be suffering from the," I washed my car so no wonder it runs better" complex - OR - Having matched front and rear amps really does make a difference. The scope says the noise is lower, but did I really GAIN anything? Hmmmm. The lower first stage gain did help the noise issue. What should I look for on the scope in time domain to empiricaly define the difference between the setups? Just a thought...
I suspect that the LME49710 single amp version ( http://www.ti.com/lit/ds/snas376b/snas376b.pdf ) would be a great alternative to the NE5534 for a single amp front end. Just pricey.
As of this post the LM4562's are not cheap (about $4.20 U.S.}. But if you are going for the shortest samples and quietest background noise, they might be the answer for your app.
Just my thoughts... GTB
Comment