Help me Geeks - microphone capacitor question

[Geoff_T]

Originally posted by mikelevitt
Hi Guys,

I just picked up an old AKG 451 E. It's a very early version set up for 12v phantom power.

AKG suggests that to operate with 48v phantom, the two caps which are connected between pins 2 and 3 and ground should be swiched from the present 16v 22nf, to 100v 22nf (.022 uf).

I went to the local radio shack, and they didn't have a 100v .022 ceramic caps. They did have 50v .022 mylar.

Will this work? Have any effect on tone?

Thanks!

Mike

Hi

You'd be surprised at how wide the disparity is around the 48v phantom power voltage... some OEMs use voltage multipliers and other unregulated sources of the necessary juice and it can often rise well above 50 volts.....

Radio Shack is not the best place to get components from and you would be better off finding the components on the web at places like Mouser or Digikey.

As a general rule I would always obtain the component that the manufacturer recommends though I will admit my brow furrowed when I saw mention of ceramic capacitors. Those beasties belong in computers and the like and should not be associated with audio paths....

But there again, I'm giving advice and contradicting it at the same time! I guess that with any rule there will be exceptions!

[mikelevitt]

Geoff,

I know what you mean about ceramic caps, and about Radio Shack. Still, it is convenient!

Anyway, curiousity got the best of me, and I went ahead and slammed the mylar caps in there.

There's not much room in the case, and I actually had to move the caps a little bit to get them in there. There's no way a 100v ceramic would fit in that space anyway, so I think these will have to do.

It's pretty interesting looking at the difference between this mic and the later 451s, they seem to have totally redesigned the layout when they added the rolloff switch. It looks pretty handmade in there.

It's no wonder they quit making 451s, it must have taken hours to assemble!

It sounds fine with the mylar caps - so far!

Thanks for the help!

Mike

[Bob Olhsson]

A Mylar is probably better if anything but it may be too big to fit.

[mikelevitt]

Hey Bob,

The mylar was too big to fit, but I would guess that a bigger ceramic wouldn't fit either. It is really tight in there.

I actually turned the mylar on it's side, and tucked it back inside the sleeve inside the cannon connector, and insulated the long leg of the cap. Actually looks pretty slick.

Thanks for your help...

Mike