The receiver is from a Quadrophonic system Sanyo DC6100K (circa early 70's)
Ive been looking to see if any other Sanyo Receivers of that time had this but no luck yet...it seems an quite the oddball.
Could this signal be amplified used directly via aux and what would be the result!
This receiver does not have a Stereo to Mono Switch and it would be nice to have a Mono option.
Ive been looking to see if any other Sanyo Receivers of that time had this but no luck yet...it seems an quite the oddball.
Could this signal be amplified used directly via aux and what would be the result!
This receiver does not have a Stereo to Mono Switch and it would be nice to have a Mono option.
Try it. But if it is designed to receive any kind of extra decoder, this signal may be taken prior to the deemphasis of 75uS of the FM transmision. This means you can use this signal but you will note it very poor in bass and heavy high frequency contents. This was deleverately done and I suggest to read any book or web page about FM and stereo signal handlings.
It sounds like it might not provide what I hoped for - Pure Mono FM Output - so if one wanted a pure Mono FM signal from a stereo receiver - what could be the easiest way to create a mono/ stereo switching....how is it done on some receivers?
Would it be something like grab one channel output from the FM board and share the one channel across the both amplifier channels, via switching.?
Would it be something like grab one channel output from the FM board and share the one channel across the both amplifier channels, via switching.?
"note: a CD4 demodulator to be be connected" https://www.radiomuseum.org/r/sanyo_dc6100k.html
This is a 4-channel set.
There WAS an FM-CD4 system; not in the USA where our FCC didn't make a decision. So the un-equalized FM may have been to feed the CD4 decoder.
Then the 'mono out' will be mono with strong boost above 2kHz. (Not poor bass, except in comparison.)
Why don't you post more information? Pictures of controls and jacks? Links to web pages where you did or did not find information?
Thanks for the info
Not much more info I can post about the DC6100K..we have the FM Mono RCA Jack as seen in the OP ...the Source Selector Switch has only one FM selection 'FM Auto'...but thats all there is as far as FM Controls....I do know this model did not come with an inbuilt CD4 Decoder (the next model up the DC8500K did and had no FM mono output)..Looking at the FM Circuit Board it is very similar to other Sanyo Receiver models of that time. This Sanyo DC6100K Quadrophonic System/Receiver seems to have been available only in Asia/Australia not US...try as I might have not been able to find as yet a Schematic/manual.
So could I try the FM Mono Output into an Aux and amplifiy ? I just heard from someone on the Quad forum that there is a higher frequency (38khz) outputted that may harm tweeters. IF not is it possible to implement an FM Mono switch - how are they done in old receivers?
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The chip used is a Sanyo LA3301 Datasheet is Japanese...attached a Pin config...not sure what could be MPX disable pin?
Attachments
For ref I did try the FM Mono RCA output through a test amp and speakers and it did work....it was slightly degraded to the ear compared to normal FM output....I could make out higher frequencies. Certainly not an improvement and not what I could use to improve the quality of some FM stations with.
I believe the "Mono" output is actually a Composite broadband output post-discriminator carrying not only the baseband mono but also subcarriers. As such it will not have de-emphasis. While it could be used for SCA and other sub-carriers it was likely for the FM CD-4 decoder. I say this in the absence of any documentation other than what PRR provided.
A 96 or 192 kHz sample rate FFT of the mono output would be interesting to see.
A 96 or 192 kHz sample rate FFT of the mono output would be interesting to see.