Help: AM antenna and AM reception


Hello all: I would like some suggestions and advice on AM reception. I know this may not be a popular format but a couple of the stations I enjoy broadcast in AM only.
My experience with AM reception using the "mainstream" FM/AM tuners has been very dissapointing (said tuners being JVC FX1010, SONY SA5ES and Denon TU-800). I tehn bought the Denon TU-680NAB (supposedly optimized for AM performance) but still no luck. OTOH, a pre-wired whole house intercom system with am/fm radio does a FAR better job with the AM stations! This creates a problem with my spouse who says that I spend so much on tuners which are unable to compete with much cheaper syatems! So, what gives? Why does a $300-$600 tuner fail miserably while an "el cheapo" combo am/fm/intercom does so much better? I should say that the antenna used for separate tuners has been the Terk AM indoor type. How do I improve upon this? My location is central NJ. Thanks.
PS: Do let me know if I need to provide additional info.
upgrade1394
The best AM section I've found in a tuner so far was, unfortunately, in one of the most expensive tuners out there as well. I won't go into full technical detail, but suffice to say the AM section in the Sansui TU-X1 with its synchronous AM detector is simply one of the very best ever produced. Reportedly, Carver also did a decent job with the AM section in their TX-11a and TX-11b as well, although I've never used one. I've also gotten good AM out of my Sony ST-S730ES which has selectable bandwidths, although it was by no means as good as the TU-X1, with its wide/narrow, selectable filters, and synchronous detector. The Philips AH673 also had a good AM section, reportedly. Sansui and Pioneer also put decent AM sections with selectable bandwidth in a few tuners, Pioneer specifically in the TX-7800 and TX-9800. The most economical might be the Carver, where I'd take a second look for sure. The lower end Pioneers and Sansuis don't seem to have had the filters often necessary for good wideband AM reception. Hope this helps.
Thanks for all the responses. I do agree that older AM tuners had good performance BUT I want to stick with tuners from late 1980's to current. One of the posts also confirmed that Car head units have better AM performance- I totally AGREE! This is another sore point, I can get the same station MUCH better in my car with its cheap $150 head unit BUT my dedicated JVC/SONY/DENON [FX1010, S707ES, TU-800] are lousy at getting the same station. I have even tried taking the tuner outside (OR putting the Terk antenna outside window) but still no improvement. BTW, [Ryammh1]: I have also owned Sony S730ES 2 times and it was not very good with AM reception - too much static and a continuous droning noise in background.
For those of you recommending Grundig/Sangean models: I have tried that route also. Currently have a Sony SW-777 (very pricy) and also a Grundig (Model 2000?) but both have same problem. And yet the cheap $100 unit which builder installed as part of whole house intercom system continues to beat all these pricy units! As the weather improves I will install a "long wire" antenna and see if it makes a improvement. Regards to all those who posted.
I've found that the GE Superadio II portable is superb on picking up am signals. It also has a good sound with adjustable bass and treble. They usually go for $75-100 on Ebay.
I use the CCrane Twin Coil Ferrite AM antenna to pick up my favorite sports talk.. http://www.ccrane.com/am-antenna.aspx Much better than the Terk AM/FM I used to have.

I've measured about 40 db SNR on a distant station using that and their Select-a-tenna in tandem.