greg@olivej.UUCP (Greg Paley) (01/18/84)
I'm hoping someone might have suggestions that will help me improve the sound of FM on my system. I am using a Telefunken TRX-3000 receiver I brought back from Germany at the end of 1980. While using it in Europe, the FM performance was flawless - really quite extraordinary sound (it was Telefunken's top of the line and listed at that time for approx. $1500). Since I've been back in the U.S. the FM sound has been completely different - noisy, overmodulated, and generally distorted. There seem to be a large number of variables involved which someone with more knowledge might be able to zero in on with some insight. (1) Being a European receiver, the built-in de-emphasis is 50 milliseconds (not switchable on this unit) whereas the U.S. standard (except for Dolby FM) is 75. From my understanding, the only side-effect of this mismatch should be a slight emphasis of the highs. Is there more to this than I understand? (2) I rent a townhouse where outdoor antennas are not allowed. As a result, I get my hookup from the local TV cable company. I have the coaxial cable from the CATV connected to a 300-75 ohm transformer which, in turn, feeds the 75 ohm input to my receiver. This step appears necessary since I've been completely unable to find a connector that will mate with the peculiar one built onto the 300-ohm input on the receiver. One symptom that might give someone knowledgeable a clue is that the "signal strength" indicator on the receiver seems always to be at its maximum position. Do any of the following seem a likely cause and, if so, can anybody suggest a solution? (a) Some inherent incompatibility between the European receiver and U.S. broadcast methods? (b) Are the Cable TV FM signals generally inferior in quality? (c) Would the signal-strength setting indicate that the signal from the CATV is overloading the tuner section of the receiver somehow? (d) Have I just been spoiled by European FM quality to the degree that the U.S. stations just sound that much worse? The last might be true to a degree, but I don't think it accounts for the fact that all stations exhibit the same problem. The actual distortion I'm hearing, if this is any help, is much like the kind of sound a cartridge makes when it can't track a heavily modulated passage or when it's improperly aligned. Thanks in advance for any help. Greg Paley Olivetti ATC, Cupertino, Ca
leichter@yale-com.UUCP (Jerry Leichter) (01/24/84)
The description you give sounds very much as if the signal coming out of the cable is way too high, and is overloading the front end of your receiver. What you most likely need is an attenuator. I believe they are available from the likes of Radio Shack. -- Jerry