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Antenna for Marantz 10B

I recently installed a Marantz 10B into my system. It has an antenna "block" with a ground screw and two other screws net to the ground that are labeled for 300ohms. I have a 75 ohm cable coming in from the outside antenna or a 75 ohm cable from Charter. I have hooked up the Charter cable to the ground and one of the 300 ohm screws and it works but is it the best way? I live in an area with few FM options so the best approach will have to be good enough. Sure is fun to see the 10B sitting in the system. The tubes have all been checked with a few marginal that I will have replaced soon. Who serves as "the oracle" for this "holy grail" of tuners? Probably worth having it gone through by an expert so I can listen to the few available stations with confidence. Thanks...
kkurtis

Showing 2 responses by crooner

crooner
11 posts
 
Onemug is right recommended a simple folded dipole. Works wonders in strong reception areas where there is not a whole lot of multipath.

The original Audio magazine reviewer back in 1965 went one step further and glued the dipole to a wooden cross piece that could be rotated to reduce multipath. Excellent idea.

Marantz developed a couple of antennas for the Model 10B but unfortunately were never released.
crooner
11 posts
 
You need a standard balun or matching transformer. They are available at any big box electronics store or your local RadioShack. One end goes to the tuner 300 ohm antenna terminals (ground is not used), the other to the 75 ohm coax.

I am curious to know which tubes tested marginal. I have an original Marantz Model 10 and Model 10B and both had strong tubes in them at the time of purchase.

If the unit works fine, I would leave it alone. Run it with a VARIAC set at 117V to prolong life of the tubes and filter caps. I installed a thermistor in line with the AC, that provides soft start and reduced AC voltage fed to the tuner.

Once you have the tuner operating, put your hand on the three aluminum filter cans located in the back of the chassis. They should never get hot to the touch. If they do, you will have to replace them at some point.

Since these filter cans are no longer available, I usually stuff them myself with modern electrolytics to preserve the original look. Any "expert" out there will simply add axial caps underneath the chassis which destroys the original look.
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