Which Fisher tube receiver had the best FM stereo tuner?
- Thread starter monkboughtlunch
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The number of IF stages is important to be sure, but all the "extra" IF stages provided beyond those needed for basic amplification duties (typically two) are there to improve the selectivity of a given design, and the ability for the limiter to fully function on the weakest signals.
Also, the tubes used make a difference as well. The early version 400 receivers used only a three tube IF strip, one of which was a 6HS6, which is a high Gm tube. In later versions, Fisher converted to a four tube IF strip, using all 6AU6 tubes -- which are lower Gm tubes. The gain of both IF strips however, is about the same. The potential advantage of the latter design then is with improved selectivity, and possibly improved limiting action as well, but the basic performance of the two designs will largely be the same.
The 400 was a wonderful effort to achieve most of what the 500C provided in performance, but at a reduced price point. This undoubtedly led then to the original three tube IF strip design used in these receivers. But production of specialty vacuum tubes was winding down quick back in the mid 60s, since their wide spread use was quite small compared to that of main line tubes. Therefore, I believe that Fisher wisely moved to a four tube IF strip in this receiver not for improved performance, but primarily due to large scale availability concerns for "real" 6HS6 tubes. The move to use more main stream tubes then (and the resulting extra IF stage), was likely a stopgap measure to allow continued production of the 400 receiver, with performance credentials that the company could still stand behind, at a time when it was quickly moving to change over to the new SS format.
Dave
Also, the tubes used make a difference as well. The early version 400 receivers used only a three tube IF strip, one of which was a 6HS6, which is a high Gm tube. In later versions, Fisher converted to a four tube IF strip, using all 6AU6 tubes -- which are lower Gm tubes. The gain of both IF strips however, is about the same. The potential advantage of the latter design then is with improved selectivity, and possibly improved limiting action as well, but the basic performance of the two designs will largely be the same.
The 400 was a wonderful effort to achieve most of what the 500C provided in performance, but at a reduced price point. This undoubtedly led then to the original three tube IF strip design used in these receivers. But production of specialty vacuum tubes was winding down quick back in the mid 60s, since their wide spread use was quite small compared to that of main line tubes. Therefore, I believe that Fisher wisely moved to a four tube IF strip in this receiver not for improved performance, but primarily due to large scale availability concerns for "real" 6HS6 tubes. The move to use more main stream tubes then (and the resulting extra IF stage), was likely a stopgap measure to allow continued production of the 400 receiver, with performance credentials that the company could still stand behind, at a time when it was quickly moving to change over to the new SS format.
Dave
My Fisher late model 400 uses one 6BA6 and three 6AU6. But, as fore-mentioned a total of four IF stages.
IMO LC type IF based sections provide best sonics vs ceramic or crystal filters used in some Scott broadcast monitor series.
LC type IF circuits are not as selective per section compared to ceramic or crystal band pass filters. The LC filter skirts provide less attenuation of unwanted signals vs ceramic and crystal IF filters. Most newer SS tuners use ceramic IF filters.
FM broadcast station frequencies are not close spaced anyways as set forth by the FCC band plan. Thus two IF sections will perform reasonably well without adjacent FM station interference.
I prefer four IF sections, five is a luxury as the Fisher 1000 is expensive. I like FM broadcast, however the Fisher FM tuner section is not as important to me as the amplifier section. All Fisher tuners are excellent.
If your favorite FM station is not performing well at your location using a Fisher FM tuner with good alignment and healthy tubes, use of a rotatable Yagi type multi-element outdoor antenna is the solution as long as a mountain side is not in-between you and the FM station. Further, FM stations are mostly horizontally polarized. Place the antenna elements in the horizontal position.
Just to be even more correct- Some FM stations do have circular polarization. In that case slightly better reception may come forth by placing the elements in a 45 degree position from the standard horizontal position.
IMO LC type IF based sections provide best sonics vs ceramic or crystal filters used in some Scott broadcast monitor series.
LC type IF circuits are not as selective per section compared to ceramic or crystal band pass filters. The LC filter skirts provide less attenuation of unwanted signals vs ceramic and crystal IF filters. Most newer SS tuners use ceramic IF filters.
FM broadcast station frequencies are not close spaced anyways as set forth by the FCC band plan. Thus two IF sections will perform reasonably well without adjacent FM station interference.
I prefer four IF sections, five is a luxury as the Fisher 1000 is expensive. I like FM broadcast, however the Fisher FM tuner section is not as important to me as the amplifier section. All Fisher tuners are excellent.
If your favorite FM station is not performing well at your location using a Fisher FM tuner with good alignment and healthy tubes, use of a rotatable Yagi type multi-element outdoor antenna is the solution as long as a mountain side is not in-between you and the FM station. Further, FM stations are mostly horizontally polarized. Place the antenna elements in the horizontal position.
Just to be even more correct- Some FM stations do have circular polarization. In that case slightly better reception may come forth by placing the elements in a 45 degree position from the standard horizontal position.
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Thanks Sony -- you're correct on the tube compliment for the IF strip in the later 400s. That 6BA6 in there always slips my mind......
Dave
Dave
audiodon
Addicted Member
Where some of us live, there's an oasis of area stations so tuner quality matters.
In other places, there's less worth listening to.
As far as tuner tech goes, it's a somewhat academic argument from my perspective as a listener, since all of the tuners mentioned are adequate for my needs. Some hold FM stations better in the transition from day to night.
WOT - Nice to see you posting. It has been a while.
In other places, there's less worth listening to.
As far as tuner tech goes, it's a somewhat academic argument from my perspective as a listener, since all of the tuners mentioned are adequate for my needs. Some hold FM stations better in the transition from day to night.
WOT - Nice to see you posting. It has been a while.
FauxHall
Super Member
The 1964 Fisher catalog says this about the 400:
"three wideband IF stages"
http://www.hifimuseum.de/the-fisher-book-1964-1.html
"three wideband IF stages"
http://www.hifimuseum.de/the-fisher-book-1964-1.html
Yes, as mentioned in previous posts the early 400s had three IF stages, later 400s have four IF stages.
Listened too my FM 200B this evening and a great college station nearby was playing Sonny James and Carl Perkins etc...enjoyed it. Ticks me off FM isn't what it used to be. These days I use a DAC to stream threw my Fisher gear a lot. Sigh..
Interesting, we have many good (quality signal) FM stations in South Florida. The problem is they play the same songs over and over again. My Fisher 500-C and TA-600 have very good FM receivers, Though Jim (Sony6060) probably has something to do with that too. :thmbsp:
I really can't stand to listen to radio anymore, I have over 2,800 songs on my I-pod that I use most of the time. Everyone gets a kick out of the old tube gear hooked to the modern source. I do spin vinyl at certain times, the phono sections are top notch! :thmbsp:
Been using Spotify to stream to a Aune T-1 DAC thru the 800C then to LaScalas. Sounds good Anyone tryed them?