* The following comments were posted by Meduci LLC on my Youtube channel, in response to a video where I played records into an AM stereo transmitter. They are preserved here, in case they are later removed. All comments were posted to a public forum. * You are relatively new to the AM stereo scene. I became involved and associated with AM stereo in 1982 and worked with all four AM stereo formats that were competing for listeners. I know all of the shortcomings for virtually all AM stereo tuners and receivers. Be wary of the Denon TU-680NAB--there were quality control issues with tuners opened by users brand new and stillborn out of the box. - - - - Fortunately, you received one of the few working Denon TU-680NAB models. They were introduced for a short time period in 1992 at a cost of $700 USD each. Any Denon's now in existence are pushing 20 years age. Top end for audio response only goes to 10kHz, due to ceramic filter limitation. Something else to be careful about is the rather aggressive stereo blending in the Mot C-QuAM chip. Narrow band selection doesn't use I.F ceramic filters either. - - - - Delco UX-1 are even older (1985-1992); not all Delcos have AM tuning range to 1700kHz; and like the TU-680NAB, only have 10kHz AM audio response. The UX-1 were only available in certain GM vehicles. Chrysler at least put AM stereo in nearly all their vehicle introductions from 1985-1993. - - - - Realistic TM-152 (1985-1987) tuners do not tune past 1620kHz and use the first generation Mot C-QuAM decoder chip. TM-152 audio fidelity extends to 4.5kHz due to I.F ceramic filter and other limitations! This is high fidelity? These tuners, when found on eBay, are 25 years old; can you say electrolytic aluminum capacitor replacement will be likely? - - - - Our new meduci PRO1k tuner model is a new hand-built AM stereo tuner, and each purchase costs nearly the same as TM-152 in 1985 dollars! PRO-1k tuners offer third generation Mot C-QuAM decoder chip,15kHz audio frequency response, digital tuning display (thanks to precise frequency counter). - - - - PRO-1k has many other features too numerous to list here. Since the PRO-1k is an analog AM stereo tuner, there will some microphonics found when the tuner is moved. This issue is discussed in the PRO-1k owner's manual. Unlike the digital tuned brethren, our PRO-1k is a very quiet analog tuner. We do not use any PLL frequency synthesizers, microcontrollers, or other similar noise-producing parts. - - - - MCS 3050 has I.F ceramic filter capable of 3kHz audio frequency response! There is not wide/narrow bandwidth selection either. Also, none of the MCS3050 will tune past 1620kHz. If you have a favorite AM station in the extended band past 1620 kHz, such as KCJJ, forget it. These tuners are nearly 30 years old; the microprocessor is known to fail at some point; replacement parts cannot be obtained to repair this tuner. I know, as I have worked on these tuners in the past. - - - -