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Author Topic: Best 9v rechargeable setup?  (Read 7212 times)

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Offline Gordon

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Re: Best 9v rechargeable setup?
« Reply #60 on: March 15, 2017, 06:32:30 PM »
I'm a dumbass.  that was phantom off.  with it on powering beyer 950's the voltage started at 20 or so.  so still a little higher than rec but not much.
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or

Neumann ak40 > lc3 > km100 > Lunatec V3 > Edirol R-44 @ 24/48


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Offline Gordon

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Re: Best 9v rechargeable setup?
« Reply #61 on: March 16, 2017, 08:28:47 PM »
I ran them in my Femto 5 or 6 times and never had a problem.

so I just put two fresh off the charger powerex 9.6v in my new femto and it reported 23.2 volts!  I checked with a multimeter and sure enough they are 11.6v on a fresh charge.  The femto specs say "Powering: 2 x 9V batteries (type 6LR61) or external (12-18V)"

So is this a no-no to use these in the femto?  I plan to send them an email and ask but thought I'd ask here.  I've used these a handful of times in the littlebox without issue.


Hmm.  So testing last night just running pandora on my computer though my monitor speakers.  4 hours or less with the Beyer 950's.  These are borrowed mics as mine are out for service.  I noticed at Son Volt the other night that the Beyers seem to run way hotter than my Neumann's (with same battery but in the littlebox).  So the next part makes is stranger....

With normal Duracell 9v's the femto ran much hotter than with the powermax in it.   In fact with the powerex it would not even peak with full gain and me tapping the caps!  That is not right.  With normal Duracell it seemed fine.

So my non scientific testing leads me to believe the powerex are not ok in the femto.
« Last Edit: March 18, 2017, 11:23:02 AM by Gordon »
Neumann ak40 > lc3 > km100 > Naiant Littlebox v1 (2015 edition) > Sony PCM-M10 @ 24/48

or

Neumann ak40 > lc3 > km100 > Lunatec V3 > Edirol R-44 @ 24/48


http://www.archive.org/bookmarks/gordonlw

Offline Gutbucket

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Re: Best 9v rechargeable setup?
« Reply #62 on: March 17, 2017, 08:57:59 AM »
How old are your Powerex 9.6V batteries?
Are you measuring their voltage with them in an open circuit condition (not powering anything) or while under load?

As the batteries age, their internal resistance increases, which is essentially what causes them to no longer perform correctly.  Measured directly out of the charger in an open circuit condition, and old battery with high internal resistance will often indicate correct fully charged voltage, but as soon as it is put under load the voltage will drop very quickly to questionable levels.  Figure a way to test voltage with the battery in the preamp with the preamp running.  Alternately you could measure the battery's voltage with an appropriate sized load resistor across the terminals.

This may not be the problem in your case, but it's the first thing that comes to mind, and I've experienced it myself numerous times.  It was confusing until I understood what was going on.
volition > vibrations > voltages > numeric values | numeric values > voltages > vibrations > virtual teleportation time-machine experience

"Narrow or widely spaced microphone configurations are preferred. It is well-known experience that pure coincidence microphone concepts are not able to produce a satisfying natural spatial impression, due to the lack of adequate interchannel temporal relations (time-of-arrival, phase, correlation)" -Günther Theile
"The mix of the Double M/S signals with a large A/B configuration of omnis results in the spacious sound that is often desired. This option also provides decorrelated low-frequency signals." -Helmut Wittek

Offline Gordon

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Re: Best 9v rechargeable setup?
« Reply #63 on: March 17, 2017, 12:30:42 PM »
I bought them new right before Christmas.  I've used them in the Littlebox once or twice and we had one my daughters remote control car.  So new and barely used.  I could see not being power cycled a few times being an issue.  To me that doesn't explain why the mics were not running nearly as hot.  Like I said with the powermax it would not even peak with full gain and me tapping the caps!

Testing was done "open circuit" right off the charger with a multimeter.  The Femto actually has a battery voltage display.  That's how I first noticed the high voltage.
Neumann ak40 > lc3 > km100 > Naiant Littlebox v1 (2015 edition) > Sony PCM-M10 @ 24/48

or

Neumann ak40 > lc3 > km100 > Lunatec V3 > Edirol R-44 @ 24/48


http://www.archive.org/bookmarks/gordonlw

Offline Gutbucket

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Re: Best 9v rechargeable setup?
« Reply #64 on: March 17, 2017, 12:57:54 PM »
Hmm. Not sure what to suggest then, except to emphasize checking battery voltage under load to assure an accurate reading, yet the internal Femto display should be doing that. Good luck with trouble shooting it.

Powerex also offers a standard 9V version (8.something volts nominal I think) which has a higher mAhr rating than the 9.6Vs

volition > vibrations > voltages > numeric values | numeric values > voltages > vibrations > virtual teleportation time-machine experience

"Narrow or widely spaced microphone configurations are preferred. It is well-known experience that pure coincidence microphone concepts are not able to produce a satisfying natural spatial impression, due to the lack of adequate interchannel temporal relations (time-of-arrival, phase, correlation)" -Günther Theile
"The mix of the Double M/S signals with a large A/B configuration of omnis results in the spacious sound that is often desired. This option also provides decorrelated low-frequency signals." -Helmut Wittek

Offline Gordon

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Re: Best 9v rechargeable setup?
« Reply #65 on: March 18, 2017, 12:28:11 PM »
Just ordered a couple of the 8.4v 300 mAh to test out.  Thanks
Neumann ak40 > lc3 > km100 > Naiant Littlebox v1 (2015 edition) > Sony PCM-M10 @ 24/48

or

Neumann ak40 > lc3 > km100 > Lunatec V3 > Edirol R-44 @ 24/48


http://www.archive.org/bookmarks/gordonlw

 

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