Read message #254 in the McIntosh Audio group in www.my.yahoo.com. If you don't want to go there, here's a reprint from the group: There's been considerable discussion in the group lately about the merits of the MR77 tuner versus the MR78 tuner. Well, we'd like to add "Don't overlook the MR74 tuner as it's a keeper too." We happen to use one as our primary tuner and we did some research on the history of this model and wanted to share what we learned with you. To begin, there has been some lively discussion in the Tuner Information Group (http://www.fmtunerinfo.com/) over their relatively low ranking of the McIntosh MR78 relative to other vintage tuners. We happen to agree with their ranking of the MR78 and here's why: We live in the boondocks (where the TN/NC/VA borders come together) and *cannot* get any TV stations with an outdoor antenna, rotor and antenna amp. So we're "DISH Network" people. However, we *can* get about 10 public radio stations, four of which are broadcast off translators/repeaters and six directly using a dedicated outdoor FM antenna, rotor, and antenna amp. When we moved here in 1995, we were using a Pioneer F-91 Elite digital tuner (ranked much higher than the MR78 by the Tuner Information Group) which worked fine, but about 18 months ago, we got to wondering could we do better? So we did out own little "shootout" at casa Britt/Weatherwax and brought in a stock McIntosh MR74, a Modefferi-modded MR78, a stock Sansui TU-919, and a stock Sony ST-730ES. The MR74 won by a nose - The Sony ST-730ES was REALLY CLOSE to the MR74, but the MR74 was slightly more sensitive and had slightly more depth on live studio broadcasts by the NPR stations. This may have been because the MR74 had been completely rebuilt and aligned by McIntosh Labs AND also by an acquaintance who owns one of the companies that rebuilds and refurbishes vintage McIntosh: We think he did it (at no charge to us) to see if he could improve on what McIntosh did, and he says he got 3 dB more separation and slightly lower stereo distortion, but it might have been a testosterone thing with him vis a vis McIntosh (He's also a really large McIntosh dealer). Now, our friend happens to like the MR71 as the best sounding of all the McIntosh tuners after it's been cleaned, aligned, and checked out with all leaky caps, etc., replaced. We didn't try a MR71 as we didn't want to deal with tubes. As to how the other tuners did in our little test, we were surprised at just how average the Sansui TU-919 was (it's considered to be a very "hot" tuner): It was very "warm" sounding and it sounded like there was a "loudness contour" control engaged when it was playing. It *was* more sensitive and selective and quiet on weak stations than our F-91 but it didn't sound as good as the F-91, at least to us. And we thought the MR74 and Sony ST-730ES were better than the TU-919. The MR78 was borrowed from a friend and it was only six months old from the Modafferi Mod. It was more "electronic" sounding than the MR74 and the Sony, was no more sensitive than the MR 74 and the Sony, and didn't have as much bass response as the MR74 and Sony. And the MR78 highs seemed slightly rolled off. Adjacent channel selectivity *was* better than the MR74 and Sony, but this is not an issue for us. Picking between the MR78 and the F-91 would be a hard choice, but ultimately, we'd pick the F-91 for it's sound quality unless we absolutely needed the superior sensitivity and selectivity of the MR78. Our F-91 had replaced a stock Kenwood KT-815 and it was significantly better sounding *and* more sensitive, particularly at in the public radio range than the KT-815: The KT-815 was very "electronic, "harsh," and "two-dimensional" sounding relative to the F-91, which seems consistent with the Tuner Information Group's findings. And we tried out a Magnum Dynalab (whatever their top model was) when we bought the F-91. The Magnum was a teensy bit better sounding, but the F-91 was much more sensitive and much more quiet on weak signals, so we bought the F-91. After living with and enjoying the MR74, we became curious about who designed the MR74 and its development, etc. relative to the MR77, MR78, and the MR75. So we did some research, made some inquiries, and the following information was kindly provided to us by Jeff Joseph and he got the answers directly from Richard Modafferi who he works with at Joseph Audio. The design of the MR74 was group effort. Jean Filon designed the RF front end and MPX decoder. Richard Modafferi did the FM IF. Ron Evans did the AM circuitry. Mile Nestorovic did the Audio & Power Supply. Some of you may remember that Mile Nestorovic designed many of the early Macintosh tube amplifiers which may account for why we happen to like the sound of our MR74 so much. We don't know if Mile or someone else designed the Audio and Power Supply of the MR77 and the MR78, but we can only speculate that perhaps Richard Modafferi did more of the total design work on these two tuners since they were his "babies." From a filter perspective, McIntosh literature states the MR74 has a 10 pole filter in the "Wide" setting and we incorrectly assumed this meant the MR74 used a 10 Pole RIMO filter, but this is not the case: The MR74 uses exactly the same 8 pole RIMO filter as found in the MR77, but it is preceded by a 2 pole bandpass filter. They're two separate filters and they are cascaded. This explains why the specified distortion is slightly higher on the MR74 than on the MR77. The MR74 in "Narrow" mode switches in a single ceramic filter. This adds a little extra selectivity - not much. It is thought to be a \2 Pole interspersed between the 2 Poles in the RF and the 8 Poles in the IF filter. The original MR77 prototype used a 10 Pole RIMO – but there's only one in existence – and Richard Modafferi has it. The production MR77 used only an 8 Pole RIMO filter and Jeff advised us the MR-77 does have slightly better phase linearity than the MR-78, which may account for the slightly better sound quality associated with the MR77 relative to the MR78. We had also heard rumors of a tube front end MR78 and we learned that Richard Modafferi did build a tube tuner (not an MR78) with RIMO filters for his Master's thesis in 1965. However, he *did* build an experimental MR-78 in 1991 with a tube front end that he still has. Richard also made a battery-powered MR78, which was actually the most sensitive and "hottest" of all the MR78 tuners, but only one was manufactured. We also asked Jeff a question about the MR75 (relative to the MR77, MR74, and MR78) and he commented the MR75 is based on IC chips, and is no match for the 74, 77 or 78 since it lacks the RIMO filters. And the MR75 is also much more sensitive to front end overload. We were left with the impression that he was somewhat underwhelmed by the MR75. After mulling all this over, we're left with the impression that the MR77 is the best sounding of all the vintage McIntosh solid state tuners, while the MR78 might the best one for use in impossible reception conditions, with the MR74 kind of in-between the two. As mentioned above, when we compared our MR74 to a Modafferi'd MR78 we preferred the sound of the MR74 to the MR78 but recognized that the MR78 was much more selective than the MR74, but we didn't need the selectivity performance in our location. Now we're wondering if we should have also included an MR77 in our little "shoot-out" since we have some very good public radio station signals in our broadcast area. And finally, we're *really* curious what the final bid would be if Richard Modafferi ever decided to auction his "one of" 10 Pole RIMO MR77, or the experimental (and only) MR78 he built in 1991 with the tube front end, or the battery-powered MR78 he owns? Oh well, live and learn. Hope you found this interesting. Tim & Ann Copyright 2003 by Tim Britt & Ann Weatherwax
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