Topic: Powering a 1.5V mic with 12V?

[sunjan]

Hi all,

One of the Nak team members suggested powering my stock Nak CM-100's with 12V, 9V or 7.2V internal batteries, instead of 1.5V as designed:
http://taperssection.com/index.php/topic,61569.msg1289627.html#msg1289627

I'd like to get a second opinion before I potentially fry them. ;-)
Are there other mic brands that also are run over-powered? Where is the "sweet point" when selecting different voltage options? Is there any benefit to this in general?!

The way it was explained to me is that more juice than the official specs will lower the distortion at high SPL, but maybe that not an issue in the first place?

If higher voltage improves the handling, how come the original manufacturer/designer decided to go with 1.5V?

/Jan

[oleg]

most of back electert mics desighned work with 1-10 or maybe abit higher voltage , usially they would preform better with higher voltage
usially mic preformers going better with higher voltage , as it happence with self powered mics which also have ph  12-48 power converters  inside .
they would get better preformers ( hang higher spl befor distortioN0with phantom as the dc to dc converter suply higher then 1-15 then internal battery .
so i personaly wouldnt go with 12 v which maybe the highes t poit , but dont see anyproblem with 7.2 v

[busterr]

I would agree with what Oleg is describing...I use to do that with some modified PZM's I ran in the mid to late 90's. The mics themselves where powered with one AA(1.5v) each, and we would swap that out with either 6v or 9v camera batteries, and since they were 1/2 the length of AA's, a small metal conductor to pass the voltage. It seemed to act as a psuedo preamp of sorts with improved handling at high spl's as you've described. It just cleaned up the sound of them overall, not dramatically but it did help a bit.

I won't go as far as to recommend that you do it as I am not familiar with those mics. The ones we used were cheap enough that they could be easily replaced if something went wrong, and experimentation was what we were after at that time.

[flipp]

I'm also interested in whether 100s can be run on a higher voltage. Sometime back I asked about replacing a 1.5v AA with a 3.6v AA but never got an answer either way. At the time those were the only mics I had so I didn't experiment. Now that I have some other mics I might give it a try in the not too distant future.

[sunjan]

The original thread I referred to suggested using two of these, to achieve 7.2V:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=140201858972

AFAIK, the Franken-Nak (leegeddy or Sank) mod feeds the caps with phantom power, converted down to something in the range of 9V-10V, right? So it can't be harmful to the components?! I'm just speculating here...

/Jan

[Roger Gustavsson]

According to Stephen Sank you can have up to 28 V with the 2SK118 JFET. I am feeding mine with 15 V (that fits the battery compartment well). Above 10 V should not give any advantages. A higher voltage raises the overload level.

Roger