EG&G Princeton Applied Research made a very low noise preamp unit, the 113, which was pretty much the industry leader for years. It was often used with Lock-In amplifiers. The unit used NiCds, I believe for that, among other, reasons. I'd expect Ithaco and SAE have similar products.
-John =============== > David Kirkby wrote: >> On 9 July 2013 04:52, Mark Spencer<[email protected]> wrote: >> >>> Hello, I've just reviewed the thread from earlier this year regarding >>> low noise power supplies and some related information about the noise >>> levels of certain batteries. Has anyone ever come across any data >>> pertaining to the noise levels of common gelled lead acid storage >>> batteries ? >>> >> Have you come across the volt-nuts list? >> >> https://www.febo.com/cgi-bin/mailman/listinfo/volt-nuts >> >> I see a bizzare review of an HP 3457A meter on utube >> >> http://www.youtube.com/watch?v=HfxpJCdgVwc >> >> where the guy determines the noise level of the 6.5/7.5 digit meter by >> measuring the voltage of what he describes as a "general purpose lab >> power supply". Is it me, or is it a bit dumb to try to "measure" the >> noise level of a laboratory multimeter by using a general purpose lab >> power supply. >> >> I must admit, I thought that using a battery would have been stable at >> least short term, but it seems there is noise on a battery - something >> I was not aware of until today. >> >> Dave >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> >> > A battery is noisest when current is flowing in the battery. > With no current flow (or electrolyte disturbance) the noise is very low. > NIST has measured the noise of unloaded NiCd cells for example and it is > extremely low. > > Bruce > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
