Henry Kolesnik wrote:
I came across a little black "cube" about and inch thick and 1 x 1.25 inches
on the sides. The top is pitch black and the bottom is gray with four
tinned leads. The top is stenciled PH-7. (Philbrick?) Because it's somewhat
conical and rounded at the top it looks like it might have been cast in an
old style ice cube tray. Google doesn't help so I wonder if anyone out
there has an idea?

It's not in my 1972 Philbrick or 1974 Burr-Brown catalogues. All the Philbrick
stuff starts with P but not PH.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

- - Bill - - exray@coquidotnet wrote:
Scott Dorsey wrote:

You guys are triggering my failing memory. I vaguely remember these
things...something like a black ice-cube with a little wires coming out
of them. Price was something like $1.29-$2.59. I'm struggling to think
of where I saw a magazine article about ho-rigging about three of these
together for something like an AM broadcaster or some such gizmo.
Woulda had to be PE, EI or R-TV-Experimenter in the mid-late 60s since
that was all I had access to.


Everybody and his brother made them. Philbrick, Hewlett-Packard, and
Opamp Labs are some of the ones that are still around today. But
ITI up in Maryland, Solid State Electronics Corporation, Modular Audio
Products. Oh yeah, and Burr-Brown got their start doing this kind of
thing. I think Stephens, the company that later made 2" tape machines,
also started out doing amplifier modules.

Well, in perspective, it sounds like some sort of cheapo stuff that
never really caught on...like those early TenTec modules.

It did sort of catch on, but shortly afterward, monolithics got a whole
lot better. So the lifetime of the discrete module was fairly short.
But they were very popular for a while.

Opamp Labs still makes stuff that looks like something you'd see in 1970.
http://www.opamplabs.com is amazing.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

- - Bill - - exray@coquidotnet wrote:
BFoelsch wrote:
OK, who made the "Mity-Amp"? A 2 watt audio amplifier potted into a block
about 1" x 2" x 3". Worked great, lsted a long time, vanished off the face
of the earth. Wish I had a few left over

Well I'm here to save you. I've got an AIWA bookshelf job that has been
killed from several directions that has such a proprietary chip still
functioning that was good for something like 600 PMPO watts, or 1-2
watts for real people. I can make you a good deal but the postage may
prove to be prohibitive.

The Mitey-Amp was killed by the LM386 and some of the other similar
monolithic amp chips of the late seventies.

I remember those things sold at Lafayette.....
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

- - Bill - - (exray@coquidotnet) writes:
Scott Dorsey wrote:

You guys are triggering my failing memory. I vaguely remember these
things...something like a black ice-cube with a little wires coming out
of them. Price was something like $1.29-$2.59. I'm struggling to think
of where I saw a magazine article about ho-rigging about three of these
together for something like an AM broadcaster or some such gizmo.
Woulda had to be PE, EI or R-TV-Experimenter in the mid-late 60s since
that was all I had access to.


Everybody and his brother made them. Philbrick, Hewlett-Packard, and
Opamp Labs are some of the ones that are still around today. But
ITI up in Maryland, Solid State Electronics Corporation, Modular Audio
Products. Oh yeah, and Burr-Brown got their start doing this kind of
thing. I think Stephens, the company that later made 2" tape machines,
also started out doing amplifier modules.
--scott


Well, in perspective, it sounds like some sort of cheapo stuff that
never really caught on...like those early TenTec modules.

-bm

Well yes.

There were hybrid modules put out by big companies. For years, I
had an op-amp sitting around that was about 1" on each side, and would
indeed be classified as a module. Even as late as the seventies (and
maybe later for all I know), some companies were producing in such modules.
Remember when touch-tone came to amateur radio? The encoders that many
hams built or used were with such modules, until the function was reduced
to an IC.

But, there were also those cheap modules that were in all the popular
catalogs. I don't think they were marked, or at least minimally marked.
They were simple circuits potted in some sort of compound. Code practice
oscillators, "wireless mics", simple audio amplifiers, metronomes and more
than I can remember. With the addition of a few parts, you'd get the
thing up and running in no time. Thirty to thirty five years ago, they
were all over the hobby electronic magazines (less so the ham magazines),
in the ads and in the construction articles.

Michael VE2BVW

Scott Dorsey ) writes:
- - Bill - - exray@coquidotnet wrote:
BFoelsch wrote:
OK, who made the "Mity-Amp"? A 2 watt audio amplifier potted into a block
about 1" x 2" x 3". Worked great, lsted a long time, vanished off the face
of the earth. Wish I had a few left over

Well I'm here to save you. I've got an AIWA bookshelf job that has been
killed from several directions that has such a proprietary chip still
functioning that was good for something like 600 PMPO watts, or 1-2
watts for real people. I can make you a good deal but the postage may
prove to be prohibitive.

The Mitey-Amp was killed by the LM386 and some of the other similar
monolithic amp chips of the late seventies.

I remember those things sold at Lafayette.....
--scott

Actually, the LM386 was a relative latecomer. National had the LM380
in the early or mid seventies, and while it had 14pins, it used the same
amount of external parts as the LM386. In fact, I have a vague memory
that the LM386 is the same die, but in a smaller package.

But even before the LM380 (and I can't recall when it exactly hit),
there were plenty of audio IC amplifiers, though usualy requiring
a fair number of external components.

Michael VE2BVW

Scott Dorsey wrote:

Henry Kolesnik wrote:
I came across a little black "cube" about and inch thick and 1 x 1.25 inches
on the sides. The top is pitch black and the bottom is gray with four
tinned leads. The top is stenciled PH-7. (Philbrick?) Because it's somewhat
conical and rounded at the top it looks like it might have been cast in an
old style ice cube tray. Google doesn't help so I wonder if anyone out
there has an idea?

It's not in my 1972 Philbrick or 1974 Burr-Brown catalogues. All the Philbrick
stuff starts with P but not PH.
--scott

Conover? was another company making these things.

--
1 day!


Michael A. Terrell
Central Florida

I had a few of those modules as a kid; got 'em from Lafayette. Code
practice oscillator, wireless mic; even had one with a tuning control
sticking out of one end that was an aircraft band converter; you placed it
next to your AM radio and it would bring in airband on it!

I'll look through my old catalogs and see if I can find 'em, but I'd bet the
PH-7 is either a phono preamp or a wireless phono oscillator.

John


David VE7ETI wrote in message
...
It sounds like a diode bridge - I've seen a sqaure shiny top and
translucent grey molded underside with 4 large trinned leads that have
holes in them, but, usually, the have a hole through the centre to
bolt it, upside down, to a heat sink. FWIW....

On Tue, 23 Dec 2003 15:32:06 -0600, "Henry Kolesnik"
wrote:

I came across a little black "cube" about and inch thick and 1 x 1.25
inches
on the sides. The top is pitch black and the bottom is gray with four
tinned leads. The top is stenciled PH-7. (Philbrick?) Because it's
somewhat
conical and rounded at the top it looks like it might have been cast in
an
old style ice cube tray. Google doesn't help so I wonder if anyone out
there has an idea?
tnx
hank wd5jfr