Tuners: analogue, synthesized and beyond

[indianajo]

My parents had a couple of FM radios that worked great in 1960-70 and didn't in 2008 after I inherited them. So I replaced the electrolytic caps. All the way up into the territory with the inductors and stuff. Much better. No alignment tools, no manual. If the tuner is working and the sound is bad don't mess with the tuner, but if the sensitivity went away don't be afraid to shotgun replace the dried up wet caps. What is it worth anyway, E1? I had a great working without antenna 1980's analog pocket radio that used for a tuner on my hifi, but then I dropped it, so I spent $35 about 2005 on a Sony pocket radio, probably digital. What a piece of ****. No walkman tape section, a dedicated Sony radio that didn't work. A crystal set would have had more sensitivity. It works okay as a digital watch after the power goes out and the clocks have to be reset. I fished an eighties Luxman pocket tape/radio out of the trash at work that works better than the Sony, after I replaced the E-caps and the trash volume control. Nice unisonic IC, picks up just based on the cable to the mixer as an antenna.
Antennas, the good radios don't need them. Good thing, because roof antennas in Indiana attract lightning, and must be disconnected before every storm. I do that for the television, every time I leave the house for more than a day I disconnect the roof antenna. Yeah, there are ground spark traps on the cable outside etc, here is a hint, they don't work. On FM I'm picking up a 750 W high school station in the next county right now with the 1975 14 transistor radio I inherited from my father and re-e-capped. I re-e-capped all the way up into the tuner sections - 1 uf with a plus end in 1975 does not equal 1 uf in 2011. Uses the built in telescoping rod antenna.

[Mark.Clappers]

Originally Posted by indianajo

Antennas, the good radios don't need them.

All radio communication requires an antenna! otherwise you wouldn't be able to receive/send anything


What type of antenna you need will differ, and will depend on a lot of factors. A important one is tuner sensitivity, but this is by no means the only thing to consider.

[FdW]

Originally Posted by Mark.Clappers

All radio communication requires an antenna! otherwise you wouldn't be able to receive/send anything


What type of antenna you need will differ, and will depend on a lot of factors. A important one is tuner sensitivity, but this is by no means the only thing to consider.

Even he My Favorite Martian - Wikipedia, the free encyclopedia (uncle Martin)

[Karl vd Berg]

Originally Posted by stevecole

Karl,

Spend some time here:-

Tuner Information Center - Vintage Stereo Tuners

Loads of info, particularly for your Sansui. Certainly keep both, in fact get more!

Thanks, Steve. Sounds really good info center.

I have more and more interest on analogue tuners. Wish I could find now a Kenwood L-07TII. Really love that design.

Folks, I had no absolute idea that tuners were suffering from misalignment. It seems that everything is inside those IF inductor, right?

The vintage Sansui TU-317 here has a little hiss whereas the digital Luxman does not! Maybe the Sansui needs a more sensitive antenna or it's a sign that it could be a bit misaligned?

Thank you all

-----

Originally Posted by rsavas

Choose a tuner based on Silicon Labs Si473x series or the newer Si4770, no adjustments necessary, nothing to drift or age. I have a Si4735 running, it works quite well, I like the RDBS information, I get to learn who are the artists etc.

I am in the process of making a Si4770, so will be able to compare the performance.
Some really nice features all done in a DSP. They have brought this part out to compete with the high end tuners, we shall see. It is a $9.00 part = amazing really

How many people actually have FET probes, >350 MHz BW DSO's, FM mpx SG's? = Very few, I do, but it is of no help to Karl, in this case, wish I could help you out, sorry

Rick

How does it work? Is it a DIY kit?

[DF96]

Tuners vary in their sensitivity and in their ultimate signal-noise ratio. These two are related in a tuner with well-designed AGC, but may become decoupled in others.

[Karl vd Berg]

Originally Posted by DF96

Tuners vary in their sensitivity and in their ultimate signal-noise ratio. These two are related in a tuner with well-designed AGC, but may become decoupled in others.

So the Sansui could ALSO be "fine", meaning it could be less sensitive than the Luxman?

I noted also that in some stations the Sansui has an equal reception (signal) to the Luxman. Possible?

[Karl vd Berg]

Originally Posted by Mark.Clappers

I can't help you with a tuner expert in the Netherlands, the people I work with are not into DIY audio..

Mark.Clappers, maybe this guy can do somithing?

[TANDBERGEREN]

There isn't much to do about alignment of theese synthesizer tuners actually.
Unless You have a generatr, a wobler, a oscilloscope and other nice instruments.
There would be to tune up the small coils in the frontend, to get the most out of the signals present. Then the IF wich in this case I think is some SAW-filters, ant not possible to trim. The IF in this tuner is possibly attended by a IC. Strange enough, theese IF-ICs tend to drift off, and replacement could often give several dB advantage on the reception.

'but without the proper instruments this is a fairly "dangerous" thing to start with when You don't really know where to start.

[Richard Ellis]

Frankly if the tuners are working fine, I wouldnt try to improve on them, yes they do require specialized gear $$$$!!
One can go crazy with antennas.........I had a ten element Yagi Uda, two meters long, bought at RS many years ago. Living in Portland Oregon at the time, I missed some stations in Eugene OR. , some 100 miles distant....hooked up to my new Marantz 2220B at an altitude of maybe 500 feet, this antenna brought those stations in like they were right next-door.
You could get a similar multi-element with an antenna rotater & bring in stations in a 100 mile radius, or more, depends on how many elements on your antenna.

__________________________________________________ ___Rick......

[Mark.Clappers]

Originally Posted by Karl vd Berg

Mark.Clappers, maybe this guy can do somithing?

Maybe, I don't know him..

If you want to try simming RF and IF stages (to get a feel for how they work and how sensistive they are) try this SW: AADE Filter Design and Analysis

easy to use & free, good place to start. But I still highly recommend learning how superhet tuners work, once you got that "nailed" you can look at your tuners and try identifying the various circuits and what they should do.

Also interesting and probably usefull is this link (a starting point): http://en.wikipedia.org/wiki/Surface_acoustic_wave

Another good read (basics of AM modulation, imho the most basic form of "modern" radio, sparkgap transmitters are even more basic): http://www.google.nl/url?sa=t&rct=j&...nZ8TIwcJA95Riw

And another one: http://www.ni.com/white-paper/3014/en