Yay I got my Dynaco FM-3!!!

[Binski99]

I just got my Dynaco FM-3 , but their is one problem the power switch is broken.

How many amps should the switch I get be rated for?

I have already replaced the dial bulb with an LED using a 150 ohm resistor and a white led from radioshack. I did this because I could not get the original light to stay on even after resoldering it so I took it out and put the led in.

The led mod (Look behind the bluish green circle)

 

[JonL]

Congratulations! Where did you get it from? I just pulled mine out of storage today, getting ready to get it into my system. I've been looking into capacitor upgrades and some other mods that are available. Are you planning on doing anything on yours? I'd think that can cap really ought to be replaced....

Regarding the switch, mine is stamped 125V 3A AC, 125V .5A DC.

Yours is a whole lot cleaner inside than mine. I've got 1/4 inch of caked on dust on everything, I've been brushing (gently) and vacuuming for a while tonight.

 

[Binski99]

Congratulations! Where did you get it from? I just pulled mine out of storage today, getting ready to get it into my system. I've been looking into capacitor upgrades and some other mods that are available. Are you planning on doing anything on yours? I'd think that can cap really ought to be replaced....

Regarding the switch, mine is stamped 125V 3A AC, 125V .5A DC.

Yours is a whole lot cleaner inside than mine. I've got 1/4 inch of caked on dust on everything, I've been brushing (gently) and vacuuming for a while tonight.

I got mine from ebay. I have also been looking into the capacitor upgrade boards.

As for mods check out this site

http://home.comcast.net/~netminer/FM3ZONE.html

I've been looking at the Selectivity/Sensitivity Module which helps you recieve weaker stations.

Thanks for the info on the switch.

 

[Punker X]

Main caps on tube tuners were usually over rated and most times still test good on tube tuners. You may see some gain from power supply upgrades. You will see more from the selectivity/sensitivity module, the PEC replacement boards and changing the audio coupling caps.

 

[bordeno]

So how does it sound?

 

[JonL]

Mike... I was about to get caps of the same value as the can cap (20/20/40/40) and put them under the chassis, then I saw the upgraded cap boards that are available and decided to hold off. It seemed to me that with all low-level tubes (no power tubes) there wouldn't be any need for additional power supply capacitance, yet the upgrade boards add quite a bit. I'd love to save my time and money and simply do what I had originally planned, but if there's a real sonic improvement with the cap board, I'd do that. I was planning on doing the other upgrades in the near future, but really wanted to get the tuner up and going right away. Can you offer an opinion on the cap board?

 

[Binski99]

So how does it sound?

It is very sweet sounding especially going through my Dynaco SCA-35 amp and my Dynaco A-25 speakers.

 

[Punker X]

Mike... I was about to get caps of the same value as the can cap (20/20/40/40) and put them under the chassis, then I saw the upgraded cap boards that are available and decided to hold off. It seemed to me that with all low-level tubes (no power tubes) there wouldn't be any need for additional power supply capacitance, yet the upgrade boards add quite a bit. I'd love to save my time and money and simply do what I had originally planned, but if there's a real sonic improvement with the cap board, I'd do that. I was planning on doing the other upgrades in the near future, but really wanted to get the tuner up and going right away. Can you offer an opinion on the cap board?

I'm a firm believer in adding as much capacitance as you can to the power supply. The cap boards are a much cleaner solution than tacking caps under the chassis. The funny thing is, I've never had a completely stock FM3 come through my shop. All have been modified in one way or another. If one came my way. I would probably buy the complete kit and do all the upgrades. I would probably opt out of the coupling caps and use a nicer cap, like Russian film and foils or Auricaps.

 

[bronco]

I just purchased my third FM-3 tuner, and am awaiting its arrival. This one has all three of the upgrade modules, and the upgraded capacitance board. I will be curious to compare it to my main system FM-3 tuner. The current FM-3 I am listening to, has just a few upgrades I performed on it: replace can capacitor with individual electrolytics, replace some of the capacitors with paper-in-oil types, and perform a tuner alignment. It has the Telefunken 12ax7 tubes in it, I have tried several others in it and the Telefunken were my favorites. So, it will be interesting to compare it with my new FM-3 with the full upgrades. Think I will replace the capacitors in it with paper- in-oil so it will be an apples to apples comparison between the tuners. I will let you know which tuner I prefer!

 

[59volvo]

does anyone have any experience with an FM5? how does it sound and grab stations?

 

[Binski99]

I just purchased my third FM-3 tuner, and am awaiting its arrival. This one has all three of the upgrade modules, and the upgraded capacitance board. I will be curious to compare it to my main system FM-3 tuner. The current FM-3 I am listening to, has just a few upgrades I performed on it: replace can capacitor with individual electrolytics, replace some of the capacitors with paper-in-oil types, and perform a tuner alignment. It has the Telefunken 12ax7 tubes in it, I have tried several others in it and the Telefunken were my favorites. So, it will be interesting to compare it with my new FM-3 with the full upgrades. Think I will replace the capacitors in it with paper- in-oil so it will be an apples to apples comparison between the tuners. I will let you know which tuner I prefer!

Nice!!!

Let us know how its sounds.

 

[Dr Tinear]

does anyone have any experience with an FM5? how does it sound and grab stations?

The FM-5 and its AM/FM cousin, the AF-6, are both solid-state tuners. I built an AF-6 in 1976 and have included it in my main system ever since, so I can offer some insights on how it compares to my FM-3s. I also have two FM-5s that I picked up over the years and restored to health. My references to the FM-5 apply to the AF-6 as well, as the FM sections of these two tuners are functionally and sonically identical.

The FM-5's selectivity is quite a bit higher than the FM-3's, so it does better at receiving signals in urban areas with crowded FM bands. The FM-5 also has slightly better sensitivity than the FM-3, which helps it in fringe reception. The FM-5's FM muting and automatic fine tuning (Dynatune) make it easy to tune in the desired station.

Sonically the FM-5 is more detailed in the highs than the FM-3, but less harmonically rich. Think solid-state vs. tube sound and you'll have some feel for what each tuner offers. I personally find the FM-3 to be almost too ripe and prefer the more analytical sound of the FM-5. The best of both worlds might be an FM-5 with film capacitors replacing or bypassing the signal-path electrolytics. If Detroit ever acquires a decent classical music station, I may go to the trouble of modifying one of the FM-5s just to see how it sounds with better caps.

 

[KentTeffeteller]

The Dynaco FM-3 is the best of their tuners for pure audio quality. It isn't selective or that sensistive. Not a good tuner for those who are urban or fringe listeners. The FM-5 is better suited for most real life FM conditions now. It is more sensitive and selective. It has nice sonics in it's own right.

 

[Punker X]

The Dynaco FM-3 is the best of their tuners for pure audio quality. It isn't selective or that sensistive. Not a good tuner for those who are urban or fringe listeners. The FM-5 is better suited for most real life FM conditions now. It is more sensitive and selective. It has nice sonics in it's own right.

Just wondering how many you have heard to have this opinion? I've had 6 or 7 come through here in the past few years. A few had average sensitivity. The rest had sensitivity on par with some of the better solid state tuners and better than most tube tuners. There is a selectivity mod also that puts a ceramic filter between the front end and the IF strip. From a fidelity stand point, its also a mixed bag. Really depends on how good a shape the PEC's in the de-emphasis circuit is. These really need to be replaced with the available component boards.

 

[Dr Tinear]

In addition to the PEC changes -- which I haven't yet done on my FM-3s -- there are four signal-path capacitors that should be changed on most of these old tuners. The two film caps at the output of the IF strip, between the discriminator and the multiplex board, tend to go high-ESR as they age. This will reduce the 19 kHz pilot level and roll off the highs. The results are reduced separation and a soft top end. These caps should be replaced with modern, low-ESR film caps of the same capacitance values. Be sure to recheck the multiplex integrator alignment after the cap change.

The output coupling caps on the PC-12 multiplex board should be increased in size if you plan to use the FM-3 with a solid-state preamp. The original caps provide adequate bass extension into the 250k input impedance of a Dynaco PAS tube preamp, but will roll off the low bass into the 50k-100k input impedance that most modern preamps present. Upsizing these caps by a factor of 10, from 0.1 to 1.0 uF, will restore the missing lows.

 

[KentTeffeteller]

Punker X,

My experience is with 8 different stock tuners. All of them save one kit built and aligned according to the kit manual. The factory wired unit performed better. With your selectivity mod, that aspect would improve. All 7 kits were carefully assembled by skilled kitbuilders. All of these were very new then. I would say that one restored and modded would be a performer. I love Dynacos myself. One of the best systems I ever owned was virtually all Dynakit (My first system I built at the tender age of 10). Would love to hear one again, one of yours preferred. I loved this tuner's musicality then and enjoyed mine back then. I listened to a lot of FM then.

 

[Punker X]

Weird. None I've seen have been completely stock and are usually in need of alignment. I don't follow the manual for the alignment. Just tweak them for best sensitivity, lowest distortion and best separation. Most have turn out to be pretty exceptional. If I didn't already have a number of Scott's and Fishers for tube tuners I would actively go out and find one.

 

[KentTeffeteller]

I am with you that the alignment procedure called for in the kit assembly manual is oversimplified. It doesn't yield lowest distortion or best separation performance out of this tuner. I agree they all by now need professional caliber attention on alignment and dealing with any other maintenance issues before serious judgment can be made on sonics or performance.