I was thinking of building a new receiver (only FM stereo needed) to replace the innards of a old sentimental "receiver". Hoping to keep the existing mechanical dial working.
I have found a few articles on the internet, on a couple of chips CXA1619BS and a TEA5711 based build. Anyone know of some other chips I should look at? Or how good the two I have found are?
What started all this is my working on fixing an old Marantz SR4000, the tuner sounds great, so much better than anything else I have, I was surprised.
I have found a few articles on the internet, on a couple of chips CXA1619BS and a TEA5711 based build. Anyone know of some other chips I should look at? Or how good the two I have found are?
What started all this is my working on fixing an old Marantz SR4000, the tuner sounds great, so much better than anything else I have, I was surprised.
The guts you seek are listed on fleabay right now for super cheap:
Marantz SR 4000 Receiver complete tuner and input board - fully functional | eBay
Whether it will fit or not depends on what revision/sub-model you have. For speed and ease, I would definitely try to make the stock tuner work, rather than engineering another circuit into the existing unit. RF circuits are really dependent on layout and component selection.
No matter which way you go, an alignment of the front end and IF stage(s) is vitally important for acceptable or better performance. Some radio-specific instrumentation is needed to accomplish this. Due to the age of the unit, some of the interstage transformers may be tricky to adjust, and special care must be used not to destroy them.
I found a service manual online, as with the above board it all depends on what sub-model you have.
Marantz SR 4000 Receiver complete tuner and input board - fully functional | eBay
Whether it will fit or not depends on what revision/sub-model you have. For speed and ease, I would definitely try to make the stock tuner work, rather than engineering another circuit into the existing unit. RF circuits are really dependent on layout and component selection.
No matter which way you go, an alignment of the front end and IF stage(s) is vitally important for acceptable or better performance. Some radio-specific instrumentation is needed to accomplish this. Due to the age of the unit, some of the interstage transformers may be tricky to adjust, and special care must be used not to destroy them.
I found a service manual online, as with the above board it all depends on what sub-model you have.
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I guess I did not state things clearly. The Marantz works fine, except for the power amp section (still working on that). I picked it up broken and cheap as a learning project. The point was, that I was just astounded by how much better the tuner sounds.
I am looking to build my own tuner for another receiver, a Realistic Modullette, which in terms of audio quality was just a step up from a clock radio. The only reason I like it is because I had one as my first receiver, so it has the nostalgia factor in it's favor. I have already replaced the amplifier in it, which has been a fun project.
The ebay listing is intriguing, but I think the board would be a bit too large to fit in the Modulette's box.
Here are the links to the two DIY tuners that I have found, but I am not sure how they would stack up next to the sound of the Marantz
MidCenturyRadios.com
https://elect.wikispaces.com/Low+Cost+and+High+Quality+Stereo+FM+Radio+Receiver
I am looking to build my own tuner for another receiver, a Realistic Modullette, which in terms of audio quality was just a step up from a clock radio. The only reason I like it is because I had one as my first receiver, so it has the nostalgia factor in it's favor. I have already replaced the amplifier in it, which has been a fun project.
The ebay listing is intriguing, but I think the board would be a bit too large to fit in the Modulette's box.
Here are the links to the two DIY tuners that I have found, but I am not sure how they would stack up next to the sound of the Marantz
MidCenturyRadios.com
https://elect.wikispaces.com/Low+Cost+and+High+Quality+Stereo+FM+Radio+Receiver
Thinking about it some more, and doing a bit of measuring, that ebay board might fit.... I already have the working tuner section on the Marantz SR 4000 and schematics to use as a guide. I can use that to track down the output of the tuner board and run that to my input selector switch in the Modulette. Just a matter adding the needed power and changing the size of the pulley on the tuning capacitor and rigging the string to it.
This is turning into quite an amusing project. Imagine this unassuming receiver with 25 watts, a Marantz tuner and a pre-out/in loop. I have also desolderd the input selector switch so I can use the postions as I please, turning the FM mono and AM positions into additional inputs, plus another postion that was locked out. Six inputs, minus one to take the FM tuner and I can hook up my cassette decks, reel to reel, turntable and CD player.
It was all I could afford as a kid, back in the mid 70's a whopping $78. I would have been better off saving a bit more and going for Realistic STA-15 for $119, but $40 was a lot back then ;D
This is turning into quite an amusing project. Imagine this unassuming receiver with 25 watts, a Marantz tuner and a pre-out/in loop. I have also desolderd the input selector switch so I can use the postions as I please, turning the FM mono and AM positions into additional inputs, plus another postion that was locked out. Six inputs, minus one to take the FM tuner and I can hook up my cassette decks, reel to reel, turntable and CD player.
It was all I could afford as a kid, back in the mid 70's a whopping $78. I would have been better off saving a bit more and going for Realistic STA-15 for $119, but $40 was a lot back then ;D
Well, the surgery was a success. I also managed to get the Stereo indicator working. I had the "genius" idea (duh, should have tried that first) to replicate the LED circuit and hook it up to see if it would work, even though my volt meter was telling me nothing much was happening.
Before - The old Radio Shack AM/FM Tuner and amplifier (with a whopping four little transistors )
The Marantz tuner grafted inside. A spool from a spool of thread turned out to be the perfect size for the tuning capacitor wheel so that the scale on the front would mostly line up. But with the FM section only being about 4 inches long, that feeling of precision tuning that the Marantz has, is not there, just a bit of careful turning till the stereo light comes on.
I still have to work out a tone circuit. I think I will just make is a bass adjustment.
New back side with pre-in/out for a graphic EQ and whatever else. Cooling fins are for the new amp.
I am sure most people will say that was a lot of work for nothing, but I found it fun to turn a sentimental thing into something that works so much better than before and makes it usable.
Before - The old Radio Shack AM/FM Tuner and amplifier (with a whopping four little transistors )
The Marantz tuner grafted inside. A spool from a spool of thread turned out to be the perfect size for the tuning capacitor wheel so that the scale on the front would mostly line up. But with the FM section only being about 4 inches long, that feeling of precision tuning that the Marantz has, is not there, just a bit of careful turning till the stereo light comes on.
I still have to work out a tone circuit. I think I will just make is a bass adjustment.
New back side with pre-in/out for a graphic EQ and whatever else. Cooling fins are for the new amp.
I am sure most people will say that was a lot of work for nothing, but I found it fun to turn a sentimental thing into something that works so much better than before and makes it usable.
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