• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Quadradial Guts Gone!?!?

greybeige

greybeige

Active Member
I got this little 104 tuner and opened it up and lo and behold there was a set of wires running on the underside of the main chassis board that were cut and taped with black electrical tape! I traced them back to the rear of the unit and they were connected to the Quadradial Output jack.

I know the Quad technology was designed for FM and is now obsolete. But why would anybody want what was inside that connects into the receiver function? There seems to be a "gap" there where something used to be.

Curious. Unit still seems to work, though I didn't have a chance to hook it up to an amp yet.
 
Register to hide this ad
Hello greybeige,

there is no quad circuitry in your tuner. The quadradial output jack adapts the FM tuner MONO output (pre deemphasis) before the signal goes to the tuner's integrated stereo decoder.
That signal was supposed to drive an external FM-Quad Decoder. But AFAIK, FM-Quad was a dead birth, at least here in Europe.

Helmut
 
RCA Jack is OK

Yeah, the wires (1 black, 1 white in purple sheath) run from the RCA Jack which is intact and in fine shape, under the center plate of the chassis up toward the front of the unit and then just stop. It's evident that they were once connected to something because there are solders and smaller wires which are cut and the whole thing taped up with electrical tape.

So I just wondered at the time where they had once run TO. But since I wrote the original thread, I checked out the unit and both the FM, FM stereo, and AM seem to work fine. I guess the wires were once an output from the FM discriminator to the RCA jack rather than connecting to some other electronic gizmo that I thought might now be missing. At least after some searching on AK, that's how the function of the FM Quadradial technology was intended to work.

Sorry no pics since my digital camera is in repair. :no:
 
Interesting..... I haven't opened my 2385 yet, as everything works and sounds as if the unit were brand new. I am guessing then that the quadradial output is simply a mono signal, or rather a mulplexed signal?
 
As I mentioned above, the quadradial output is a mono signal coming directly from the FM discriminator. It bypasses the MPX stereo decoder, also, deemphasis is not aplied to that signal.
If you have an external RDS-decoder, this is the best way to connect it.

Helmut
 
You must log in or register to reply here.
Back
Top Bottom