Tink,
I know what Hi-Fi is and can easily achieve more bandwidth with flat response then we normally find on the broadcast bands. Once you know how to spot bypassing caps, coupling caps, and negative feedback loops in the audio chain, this is no difficult task.
Years ago I use to modulate radios from the outside using Hi-Fi stereo audio amps. Then I learned how to modify the radios internal audio stages to achieve the same results. It's a simple audio amplifier not rocket science. With a signal generator, a scope, and a schematic results are easy.
I enjoy AM and sharing what I've learned with others free of charge. At the recommendation of WA1HLR and W2NBC I will be posting one of my more popular modifications on the The AM Window site. The TS-940S is a very common radio that can be purchased used inexpensively now. You probably know they sound fairly bad on AM stock.
You don't need to travel all the way to Connecticut just to see mine. You can copy my modification and have you're very own. You can sweep it, look at it on the spectrum analyzer, and scrutinize the entire modification if you wish. Bottom line is it will provide every bit of fidelity you can get by modulating a rig from the outside and you can prove it to yourself.
The best part is my modification does not require the use of any external equipment that could introduce new places for RFI to migrate into the audio chain. Once the moderator on the amwindow site uploads the modification, I will post the links here. My documentation includes step by step instructions with photos. It renders old school outboard modulators obsolete by using Hi-Fi low level RF modulation as opposed to restricted IF modulation.
