Anyone familiar with a Pearl mic from the 70s known as the SP-84?
It is an omnidirectional that is self-powered from 15V batteries. I have
a chance to borrow a pair. The owner, who hasn't used them in a while,
was told it was possible to phantom power them by putting a module in
place of the battery. However, in an email from Pearl Microphones, they
believe that it is only possible from the battery. But Pearl has changed
hands a few times, so you never know.

(As Mike Rivers will no doubt suggest, I will still try them powered by
batteries...----but I still want to know if they can run off of +48VDC).

I have the data sheet an schematic. From the schmatic, I can't see that
they could run off of +48 by simply replacing the battery with some sort
of module.

Rob

Rob Reedijk wrote:
Anyone familiar with a Pearl mic from the 70s known as the SP-84?
It is an omnidirectional that is self-powered from 15V batteries.

I have the data sheet an schematic. From the schmatic, I can't see that
they could run off of +48 by simply replacing the battery with some sort
of module.

If there's no connection from the center tap of the input transformer
(if there is one, otherwise a "virtual" center tap of resistors) to the
point where the battery connects to the circuit, then it's not likely
that conversion to phantom power will be simple. Better start looking
for a couple of those 15V batteries. Photo shops used to be a
dependable source, but with everyone using digital cameras these days,
they no longer stock "light meter" and "photo flash" batteries. You may
have to find a battery specialist. Batteries Plus has stores scattered
through the US and does mail order, and they can usually come up with
anything that's still being made.

Rob Reedijk wrote:

Anyone familiar with a Pearl mic from the 70s known as the SP-84?
It is an omnidirectional that is self-powered from 15V batteries. I have
a chance to borrow a pair. The owner, who hasn't used them in a while,
was told it was possible to phantom power them by putting a module in
place of the battery. However, in an email from Pearl Microphones, they
believe that it is only possible from the battery. But Pearl has changed
hands a few times, so you never know.

You sure it doesn't require an electronics retrofit?

(As Mike Rivers will no doubt suggest, I will still try them powered by
batteries...----but I still want to know if they can run off of +48VDC).

I have the data sheet an schematic. From the schmatic, I can't see that
they could run off of +48 by simply replacing the battery with some sort
of module.

Is there any easy way to get phantom power off the thing? Say, a center
tap on the output transformer secondary, or a couple resistors that go
to a test point inside the battery compartment?
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."