On 6/21/2016 8:01 PM, amdx wrote:


Did you complete the audio compressor/limiter you were working
on for
a bit?
Mikek

I don't even remember that ;-)

...Jim Thompson


As I recall it was a personal project, you had ask a question
here about it.
I'm interested because I use an FM transmitter to transmit my
internet
radio audio around the house/yard. Some internet radio signals
have high
volume some have low, and sometimes it's different between
programs*.
I'd like to level this, without adjusting the transmitter input
level
each time I switch internet stations.

Did you ever listen to these radio shows as a youngster?
Gunsmoke, William Conrad voices Matt Dillion, The Six Shooter with
Jimmy Stewart, Dragnet with Jack Webb, Bold Venture staring Humphrey
Bogart and Lauren Bacall, The Adventures of Philip Marlowe,
Our Miss Brooks with Eve Arden, and of course The Shadow?

* I often listen to Old Time Radio Programs, and there can be a
level
difference between shows.

Mikek

I'm much older... I'm of "The Fat Man" and "The Lone Ranger" era.

I guess you missed this part of the compressor thread...

From: Jim Thompson

Newsgroups: sci.electronics.design
Subject: Best Audio Clipping Ind Circuit
Date: Thu, 10 Feb 2011 08:19:18 -0700
Message-ID:
References:
X-Newsreader: Forte Agent 6.00/32.1186

[snip]

Use a compressor instead, like...

http://tinyurl.com/4npqpcl

I use one to level everything out of my Roku Soundbridge before it
goes to my sound system... since streaming feeds on the Internet are
so variable in amplitude.

...Jim Thompson


I did miss that part, or forgot it because I didn't want to spend
that
much.
So I take it that's what you bought, and you are happy with it?

Yep. Works for radio, but not so well for TV movies which can have
significant pauses between speaking... thus the volume runs up and
down.

One reviewer of your selection comments short attack (good), short
decay (bad).

I noted that, also saw it was the only review like that. If it is
objectionable, I'll return it, if it works reasonably well it can always
be tweaked.
If it wasn't for buying enclosures, variable resistors and connectors,
it would be cheap to build. :-) There is a schematic online, although
someone said it has a few errors.




Yes the "Fat Man" and "The Lone Ranger" have also played on the
Internet
stations I listen to, I'd rather listen to "Fat Man" than
"The Lone Ranger", Gunsmoke would probably be my favorite, but I
enjoy
most of the detective stories, Dragnet and Philip Marlowe etc.

Went on a search and found this compressor.
https://www.amazon.com/rolls-SL33B-S...dio+compressor

I'll search a bit more but think I'll buy that one.


Mikek

...Jim Thompson


I designed a compressor for a hearing aid about 48 years ago...
testing it before I got it working correctly... blew a hole in my left
eardrum :-(

...Jim Thompson

Bummer about the eardrum!
I reviewed again that negative review on Amazon, she said by adding
10uf to 100uf cap from emitter to collector of Q1 eliminated the raspyness.
Only problem is, as I see it the units has 1 single IC and no
transistors. I wonder if it she has an older or newer unit.
Her review is recent, the published schematic is May 2009.
I think she just may be confused.
Mikek

I need to apologize to the reviewer.
I received the Rolls SL338 program Limiter.
It has a schematic and shows the unit has been revised from their
original schematic that was posted online. The new schematic has a
couple of optoisolators, and most important, one transistor labeled Q1!
I have it hooked up, but I'm not ready to make any comments yet. I
need to solve some hum and breakthrough problems, possibly caused by the
FM antenna to close to the limiter.
Listening to Dragnet, Jack Webb is advertising Chesterfields. :-)
Also an ad asking for blood donations to get gamma globulin to help
fight polo.
It also had an ad for Fatima cigarettes, that's one I never heard of.
http://graphic-design.tjs-labs.com/s...?id=1174783428


Mikek