AM tuner performance?


I sold a Marantz 150 AM/FM tuner to a buyer who's now disgruntled that the AM performance is so dismal, and that I didn't disclose this up-front. My response is that I've never known an AM/FM tuner to pull any AM signal whatsoever in an urban setting, that many manufacturers show they concur by making FM-only boxes, and that I'd just assumed he wasn't expecting to use the Marantz to hear AM. Who's right here?
sbass
Unfortunately, the vast majority of AM tuners historically have used diode-type envelope detectors, which have inherent distortion, noise, and sensitivity problems. Most roll off the high end at 5 to 10 kHz to reduce adjacent-channel interference.

I don't blame the manufacturers much; there's not been much demand for good AM receivers. Most people think of talk radio, sports, and news when they think of AM. I haven't been following lately who's making what types of AM receivers, but if you can find one with a decent product detector instead of a diode detector, they can sound really nice. Not many people know that despite the 10 kHz spacing on the band, AM stations can actually broadcast up to 15 kHz audio bandwidth. And some do so.

I've been meaning for years to get around to building my own product detector and tap it into the IF stage on one of my receivers. But it slipped behind a lot of other projects, and thanks to this thread, I might get back into it.
My parents still have an old Tube Sylvania AM table radio. Still works and reception is very very good (just the internal ferrite bar antenna). Automobiles radios have good AM reception also, so it is just the audio companies saving money. The Creek and Cambridge Audio Tuners (both designed by Mike Creek) use a high-end car stereo chipset. I wonder if the AM is good on those tuners?
Citation is correct. AM reception can be decent on any tuner, but the antenna connection needs to be more than the wire that comes with most tuners if anything at all. Some old analog receivers (Rotel is one) had an internal ferrite bar that worked pretty well.
Perhaps you could suggest he locate the tuner well away from all other equipment & electrical fields & buy an AM loop antenna from Radio Shack. These basic steps will do wonders for reception with any AM tuner/radio/reciever.
I owned a Model 150 throughout the 1980's. I wouldn't characterise it's performance as "dismal". The AM section was average for it's time. The best AM section I've owned was a Dynaco AF-6: Wow! it sounded like FM mono.
Anyway, I agree with Onhwy61; as long as you didn't hype AM performance you're in the clear.
I agree with you all. I cannot think of an Audio tuner that has good AM. If someone wanted good AM, I would tell them to get a Short Wave / Long Wave Tuner at a specialty shop. These tuners always encompass the AM band and are excellent. Brands to consider are Grundig, Alinco, Drake, Icom, Jandek, Kenwood, Lowe, Sony, and Realistic (Radio Shack),
There are some tuners with good AM performance, but did the buyer make clear to you that he was buying the tuner to listen to AM? Like Onhwy61 said, the buyer has no one but himself to blame if he did not. I, like you, would presume a person was buying a tuner for FM listening.
Good post, Onhwy61. Most high-end tuners seem to have AM as an afterthought, and I thought most people knew that. Would also be interested in the buyer's side....
Assuming the Marantz is functioning as designed, then the buyer has nobody to blame but themself. When you offer to buy a product you should have a very clear idea of its performance. SBASS, unless you raved about the AM performance is your ad, you should have no remorse. As always there's two sides to a story. I'm interested to hear the buyer's side.