Re: Hot Rod Mic - More Details

[Mike Curtis <wd6ehr@xxxxxxxxxx>]

Thanks from all of us for all your hard work.  We all appreciate it, and 
especially your sharing it with us.

> It is 5 Meg, and much to my surprise, it seems to be a linear taper.
> As I said before, I've put several volumes on Astatics and Shures, and
> I've always used audio taper; however, I've never used a capacitor.
> Also, one minor note about the markings on the pot.  It had a 'C' w/a
> circle around it (like the copyright symbol) and 'B5M'.  I left out the
> 'B' in my previous post.  (Does anybody know if that signifies linear taper?) 

Sounds like a manufacturers number.  The "5M" is pretty obvious (5 meg), 
but the (c)B doesn't ring a bell here.

> Also, when playing thru the mic, w/the volume on the bottom, turning
> the volume knob from the right to the left (counter-clockwise) will turn
> up the volume.  With a linear pot is shouldn't matter if you wire it up
> the other way around, but with an audio taper pot (w/o the capacitor at
> least) it would matter.  With all the audio taper pots I've used in
> the past, it has worked the same way (counter-clockwise to turn up
> the volume).  

Or, if you put the pot facing you, clockwise is higher volume.  I had to 
think on this one a minute :-)

With audio taper, the resistance is graduated, with the least change 
being in the first portion, and gradually increasing as you go higher.  
this gives a logarithmic taper.  While this sounds strange initially, the 
ear responds logarithmically, so this gives a more "linear" perceived 
volume.

But I've found that audio taper isn't good for musical instruments.  
Linear taper gives a much better "touch", allowing finer control at 
higher volume.  Audio taper "condenses" this to a much smaller portion of 
the pot rotation.


> OK.  I measured the capacitor, and it is .15 ufd  (AKA 150 pfd) ceramic cap. 

Picofarad is .000001 micro (one millionth); ergo .15 uF = 150,000 pF.
Oh, well - it's just a silly decimal anyway :-)

Thanks once again, Elliott, for taking (considerable) time to check and 
verify this.  I've benefited from your work, and I'm sure many others 
have as well.

 -- mike