My brother just gave me some stereo equipent that he got back in the late 70’s (including all his vinyl) and I’m loving setting it up and listening to it.
However he included one piece of equipment and I have no idea what its purpose is.
Its a pioneer system with receiver, equilizer, phono and a couple of big kenwood speakers. The other piece is an “Pioneer RG-1 Dynamic Processor”. I have no idea what it is or what it does. I can’t find much info on the web and I’m not sure how to test it because I don’t know the correct way to hook it up.
It’s an expander, the opposite of a compressor. Due to various complicated reasons, the dynamics of music must be compressed to get them onto a record for reproduction. The goal of the engineer was to make this compression as transparent as possible, but it’s still compressed. An expander looks ahead at the program content in milliseconds, and attempts to undo the compression, thereby increasing the dynamics of the music. Loud parts will be louder, soft parts will be softer.
There are two sets of connections on the back. It can be configured to work between the preamp and the power amp, or through the tape monitor circuit. Let’s say you connect it to the Tape 2 in/out on the receiver. You’d play a record with the selector knob on Phono, and the Tape Monitor 2 button ‘in’. That way, the signal from the TT goes out the tape monitor’s REC jacks to the expander, gets expanded and comes back in the tape monitor’s PLAY jacks, once you turn the function on, on the front panel.
Alternately, the In/Out jacks on the back will connect to the receiver’s Tape Monitor circuit, and the other set of jacks on the expander will be used to replace the tape deck input that’s being used on the receiver. You’d plug your second tape deck into the back of the expander, and when you want to hear it, you’d switch it on from the expander’s front panel.
I could be mistaken, but it sounds like a “preamplifier”. My father has one totally badass 70’s-era stereo system, mostly Harmon/Kardon, with some ancillary pieces from other high-end makes. (Unfortunately, he also bought Bose speakers, but that’s subject for a different thread in another forum altogether.)
The amplifier has steel handles bolted to the front to assist with moving it, since it weighs as much as a good-sized window A/C. But the system also has a preamp, almost comically tiny and flyweight by comparison.
Sounds like a variant of dbx, which comes in two flavors.
The one that was semi-popular on tape recorders was a noise-reduction system that worked similarly to Dolby.
The other version was more commonly seen in PA systems at dance clubs, bars, etc., nd was an active semi-intelligent bass boost (dynamic bass expansion) that kicked up drums and bass guitar, but managed to leave male voices alone, more or less. I’m guessing this is closer to what your gizmo is for.