Pros: surprisingly sensitive; pleasant, neutral sound; has that cool '70s Dynaco look
Cons: switches are clunky feeling and flywheeel is only fairly smooth; FM only
Note: The Epinions photograph of this tuner is distorted for some reason. In reality, the tuner is not square when viewed from the front. It is rectangular, like most tuners of the era.
The FM-5 was Dynaco's first solid state tuner. Intoduced in 1971, it was often mated with the Dynaco SCA-80 integrated amplifier or a Stereo-120 power amplifier and PAT-4 pre-amplifier, which were among Dynaco's moderately priced high-end solid state components of that era. Speakers might have been Dynaco's own A-25s, or perhaps Acoustic Research AR-2axs or Large Advents. Add an AR turntable with a Shure M-91ED cartridge, and you had an excellent system for not very much money. The Dynaco FM-5 is a remarkably small unit, measuring only about 13 1/2" wide x 9" deep x 4 1/4" high, and weighing about 8 lbs. Aesthetically, it is really pleasing in an early-‘70s brushed aluminum kind of way. I believe its face plate is the same size as those of the SCA-80 and PAT-4, meaning you can stack them in a cabinet to nice effect. Cost of the Dynaco FM-5 was $319 in 1971, which was actually fairly expensive for a stand-alone tuner. It could also be purchased in kit form for $199.
The Dynaco FM-5 is an FM-only tuner, and it is quite simple to operate. A small rotary knob in the lower left corner of the faceplate serves as an on-off switch and also as a continuous volume control. Three rocker switches control: 1) mono/filter/stereo; 2) aux/FM; and 3) off/"Dynatune"/mute. Tuning is achieved by a fairly typical large, weighted tuning knob to the right of the (amber or off-white) lighted tuning dial.
On the back are RCA outputs for audio (to your pre-amplifier or integrated amplifier) and tape (presumably directly to a tape recorder), as well as an RCA auxiliary input. Antenna attachments (75 and 300 ohms) are by small flathead screws that were typical of the era. There is also a switched AC outlet on the back. It appears a contemporary user could hook a CD player to this thing and use it as a pre-amplifier, though I'm not sure how much gain it has (I think the gain is rated at 28 db).
Hooking up the Dynaco FM-5 is straightforward, though the flathead screws (for hooking up the antenna) are a bit of pain. Run RCA cables from the tuner to your pre-amplifier, hook up the antenna, plug the unit in, and you're ready to go. The antenna screws are small, and getting the antenna leads hooked up right took a few minutes, but other than that, there were no hassles.
The first thing I noticed about the FM-5 when I fired it up was that the controls feel...well...vintage. The rocker switches operate with considerable resistance and did not "snap" into place. The tuning flywheel is fairly smooth, but not in the same league as the later ‘70s tuners I've been using (including the KT-5500 and KT-7300). There are cool looking blue LED-sized lights that are supposed to indicate stereo and center tuning, but they didn't always light up when I had the best signal. Part of that could be due to the age of the unit I tested. There is also a very small signal strength meter that wasn't particularly easy to read.
But the overall sound of the FM-5 was quite pleasing, and it was surprisingly sensitive overall. Using a regular dipole antenna in my suburban location, I was able to get a good signal from KDFC (the Bay Area's only real classical station), KCSM (the Bay Area's only real jazz station), and a Sacramento NPR station I've been listening to lately. It was more sensitive than the Kenwood KT-5500, and actually quite comparable in sensitivity to the Kenwood KT-7300.
The sound of the Dynaco FM-5 was very neutral, for lack of a better word. Musical instruments sounded real, and I found it easy to forget about the tuner and just listen to the music. Bass was tight and went quite deep, though the overall sound wasn't quite as warm as with the Kenwood KT-7300. The bass did seem to go significantly deeper than that of the Kenwood KT-5500, and the overall sound was a bit warmer and more authoritative than with the KT-5500. In other ways the sound reminded me more of the Kenwood KT-5500 (tight and natural, with a compact but well-defined soundstage) than of the KT-7300 (still warmer, rounder, and more authoritative, with a large but slightly diffuse soundstage), or the Kenwood KT-7500 (which goes over the top in both the bass and brightness regions).
The FM-5's trebles were really nice in that they were not overly bright, yet there was decent high frequency extension. And the midrange was detailed but not etched or clinical. Classical piano sounded especially good through the Dynaco FM-5. There was a nice amount of "plink" to the individual notes, but the notes were suspended in space and never thrust forward, as they were with the Kenwood KT-7500 (but not the KT-7300). As mentioned, the overall soundstage of the FM-5 is comparable to that of the Kenwood KT-5500, with instruments spread in a well-defined but not particularly large space. Background noise was quite low, especially for an older tuner.
Overall, I was pleasantly surprised by the sensitivity and sound of the Dynaco FM-5. It was able to pull in all of my "reference" stations with a clean signal (in mono only for KCSM, as is the case with all tuners I've tested here), and the sound was neutral enough that I found myself "forgetting" the tuner and listening to the music.
If you are putting together a vintage stereo system, especially if you're using some of Dynaco's vintage amps and/or pre-amps, the FM-5 is easily worthy of consideration. It's possible that some Deoxit or other cleaner would make the rocker switches work more smoothly, but I didn't "go inside" the FM-5 I had here.
The current cost on eBay is generally in the $40 to $100 range, which is quite a bargain if the tuner is fully functional.
For those interested, here are some of the FM-5's specifications, gathered from various sources on the internet:
IHF Sensitivity (noise and distortion down 30 dB @ 100% modulation): 1.75 µV
Input required for 40 dB S/N @ 100% modulation: 2.0 µV
Input required for 50 dB S/N @ 100% modulation: 5.0 µV
Frequency Response: 20 Hz to 15 KHz ±1 dB
Harmonic Distortion and IM Distortion @ 100% modulation:
Mono - 0.5% (0.25% typical)
Stereo - 0.9% (0.5% typical)
Capture Ratio: 1.5 dB
Muting threshold: 4 µV
Ultimate signal to noise ratio: 65 dB @ 100% modulation.
Selectivity: 65 dB alternate channel.
Stereo switching threshold: 4 µV.
@ 1000 Hz, 40 dB
@ 50 Hz, 30 dB
@ 10 KHz, 30 dB