Quad Fm3 question
- Thread starter The Captain
- Start date
seyles
Retired Child
FM3 is shown as having 5 pin 180 degrees DIN on the schematics
Pin 1 Mono
Pin 2 Ground
Pin 3 Left
Pin 4 Not Used
Pin 5 Right
See this link for lots of FM3 info on the wonderful Quad Hifi Info website
Pin 1 Mono
Pin 2 Ground
Pin 3 Left
Pin 4 Not Used
Pin 5 Right
See this link for lots of FM3 info on the wonderful Quad Hifi Info website
John Phillips
pfm Member
Yes I also think the OP will be OK.
However, looking at the FM3 schematics via the link in post #22 I see that for later serial numbered FM3s there's just a 0.1 µF output coupling capacitor. To stop the bass rolling off too early, the 47 kΩ input impedance (I think) of the Naim 32.5 the OP mentions looks just about good enough. Earlier serial numbers do not look like they are impacted like this, but later ones probably need 47 kΩ minimum and 100 kΩ might be a little better in this particular way.
This effect happens with the FM4 as well. See https://www.audiomisc.co.uk/QuadFM4/FM4.html.
The Captain
~~~~~~~~~~
B b but the picture of your aerial shows it up tethered to a chimney. I'm a bit confused by this!
Anyway it won't be be here until prolly mid next week, then the cable to figure out. Capt
The Captain
~~~~~~~~~~
Hi there John, thanks for your input.
Re-thinking things: it's gonna be used with my Arcam alpha 3, 2nd system up in bedroom/ as pic.
Sorry I revised my thinking whilst doing the thread yesterday.
Thx Capt
The Captain
~~~~~~~~~~
@Jim Audiomisc thanks also for your contribution. Welsh small valley here, although I'm perched twds top of my village, I have two valley sides close by. One side kinda interrupting a clear line to my (160m high) TX on the coast.
Btw is your avatar from J. Carpenter's The Thing?
Capt
Btw is your avatar from J. Carpenter's The Thing?
Capt
miktec
retired
The 4 pin din plugs are only used for the output link twixt 33 and power amp (such as 303)
miktec
retired
I use one of these in the rafters of my garage:
www.screwfix.com
A stellar performer …… originally paired to an aging Creek tuner and now a Cambridge Audio 640. Strong signals and reasonably wide coverage.
Positioned to point at nearest station but also (fortunately) close enough to the tuner to fine tune by ear.
Labgear Omni-Directional FM Radio Aerial Kit - Screwfix
Order online at Screwfix.com. Receives all available FM radio station signals through 360°. Mount externally or install in a loft. Complete with 10m cable and fixing kit. FREE next day delivery available, free collection in 1 minute.
Positioned to point at nearest station but also (fortunately) close enough to the tuner to fine tune by ear.
John Phillips
pfm Member
I think that's OK - it will certainly work but perhaps you might perceive radio stations as a bit bass-light from that particular combination. It's just a theoretical observation based on looking at the FM3 schematic and @martin clark may disagree with me.
martin clark
pinko bodger
@John Phillips - No it's a good point; I have an FM3 and since my DPA preamp is about 8K input impedance (!), I just tacked compact 3.3uF film type out of the bits box (wima mks2,irrc) in parallel with the original output caps. and removing them again, does not miss much I count impotant, at all.
...iirc, FM only really goes down to c 30Hz, so 0.1uF/ into 47K is def not losing much low-end that matters /isn't there anyway (-6dB at most)
...iirc, FM only really goes down to c 30Hz, so 0.1uF/ into 47K is def not losing much low-end that matters /isn't there anyway (-6dB at most)
Tony L
Administrator
This is significant when using it in a full Quad system as IIRC selecting ‘mono’ on the 33 selects the mono out and results in lower noise on hard to pull-in stations. It is a very long time since I had mine running (I still have the FM3 from my very first system), but I remember it working like that. I also remember it never sounding as good through other preamps as it did through the 33, which is likely the capacitance thing mentioned above. It is also low output compared to modern sources. When working well it can sound exceptionally good, I remember Peel sessions and live Radio 3 sounding stunning through it. The BBC have jumped the shark since those days though. Lovely tuner though. 3-series Quad is a design classic for sure. Especially in the wood case!
martin clark
pinko bodger
I have otherwise left my FM3 alone. and yes, mono-to-stereo on FM exacts a 20dB SNR reduction, which is why - mono mix (or not using stereo decoders on insensitive tuners in the first place) was always a huge win.
Quad FM4 is same for 'low level' output, c 300mV pk. And inherently 'quieter'.
But while not changing that output level - with the FM4 there are a couple of simple parts substitutions, that can really let it free; drop-ins , not cut tracks. I really need to write this up, at some point.
Quad FM4 is same for 'low level' output, c 300mV pk. And inherently 'quieter'.
But while not changing that output level - with the FM4 there are a couple of simple parts substitutions, that can really let it free; drop-ins , not cut tracks. I really need to write this up, at some point.
Mike Reed
pfm Member
Not mine Captain. Someone else's aerial maybe, as I've not posted pic's. Advantageous to have an antenna as high as poss, which is usually a chimney. A mast further increases height. For coax, CT whatever (100?) (so-called computer cable?) is the stuff to use. There was a thread with handy suggestions on here not so long ago.
Operajulian
Julian
My Quad FM # is connected to a Magnum ST2 Aerial.
www.magnumdynalab.com
Not outside but just leaning up against the bookcase that the Quad sits on. Works just fine here in Toronto and even did when I lived 4500 feet up from sea level in the mountains of Banff, Canada.
Happy listening. My only beef with them is replacing the "bloody" indicator lamps when they fail.
ST2 - Omnidirectional FM Antenna | FM Antenna for FM Tuners
ST2 FM Antenna. A more powerful FM Antenna than any single element dipole antenna, the ST-2 vertical antenna is probably one of the best things ever to happen to FM listeners in urban and fringe reception areas alike.
www.magnumdynalab.com
Not outside but just leaning up against the bookcase that the Quad sits on. Works just fine here in Toronto and even did when I lived 4500 feet up from sea level in the mountains of Banff, Canada.
Happy listening. My only beef with them is replacing the "bloody" indicator lamps when they fail.
The Captain
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Ah sorry, it was another Mike earlier.. who kindly linked me to his 1/2 wave diapole whatnot type for £21-£41, whose website picture showed it on a chimney. Which I guess is effectively a wall behind it? ( that being my point).
Can anyone recall what the "CT whatever computer cable" was? A bit of diy = good
Thanks y'all, Capt
seyles
Retired Child
CT100 is one of many 75 ohm coaxial cables that can be used as an antenna cable.
The computer cable was 10 base 2 or thinnet, but that was 50 ohm.
WF100, WF125 and WF165 are the foam insulated coaxial cable types we used at the BBC for RF distribution, the type chosen purely on the required length.
The computer cable was 10 base 2 or thinnet, but that was 50 ohm.
WF100, WF125 and WF165 are the foam insulated coaxial cable types we used at the BBC for RF distribution, the type chosen purely on the required length.
Hi All, Its great to see lots of love for the QUAD FM3. It’s a brilliant little tuner in both looks and performance. For a text book circuit that uses an off the shelf stereo decoder from Motorola the FM3 puts in a fine performance. I had one for a while, sold it only to realise how good it was then had to buy another to fill the gap.
As has already been mentioned before, the 5 pin DIN outputs on the QUAD are all industry standard so there is no need for special cables. If you are in doubt, the PIN-OUTS are clearly marked on the back of the FM3 tuner then again on the 33’s input sockets. The mono output on pin 1 is to feed the QUAD 33 control unit as this has a peculiar Mono L / Mono R / Stereo switching that used the extra output from the FM3. On non-QUAD gear the Pin is not connected. 4 pin DIN plugs are typically only used between preamps and power amplifiers, not line level source components.
As has also been mentioned, the output coupling capacitors are only 0.1 uf which is fine for 50k ohm and above inputs but if you use it into more modern 20 or 10k ohm RCA inputs you will get an audible bass roll-off. The good news is that there is plenty of room underneath the FM3’s circuit board for a low voltage 2.2 uf film capacitor. If you shunt C124 & C125 with a 2.2 uf capacitor you should be good to feed a 10k ohm input. You can mount the capacitors on the underside of the PCB without disturbing C124 & C125, the rest of the FM3’s output circuit will comfortably cope with a 10k ohm load. Earlier FM3’s (below serial No. 5885) did use a .64 uf Capacitor but this is still a bit on the low side for loads below 50k ohm.
As for an antenna, the FM3 is happy to work with whatever would work for any normal tuner. The FM3 has an average sensitivity with no special antenna requirements, if you are close enough to the transmitter tower you may get away with an indoor 300-ohm ribbon into a 300 – 75-ohm Balun Adaptor, cheap as chips and easy to set up. When I was living in a major capitol City this is how I ran mine and I was about 30 Km away from the transmitter tower with a 50 Kw signal.
Happy listening and enjoy.
As has already been mentioned before, the 5 pin DIN outputs on the QUAD are all industry standard so there is no need for special cables. If you are in doubt, the PIN-OUTS are clearly marked on the back of the FM3 tuner then again on the 33’s input sockets. The mono output on pin 1 is to feed the QUAD 33 control unit as this has a peculiar Mono L / Mono R / Stereo switching that used the extra output from the FM3. On non-QUAD gear the Pin is not connected. 4 pin DIN plugs are typically only used between preamps and power amplifiers, not line level source components.
As has also been mentioned, the output coupling capacitors are only 0.1 uf which is fine for 50k ohm and above inputs but if you use it into more modern 20 or 10k ohm RCA inputs you will get an audible bass roll-off. The good news is that there is plenty of room underneath the FM3’s circuit board for a low voltage 2.2 uf film capacitor. If you shunt C124 & C125 with a 2.2 uf capacitor you should be good to feed a 10k ohm input. You can mount the capacitors on the underside of the PCB without disturbing C124 & C125, the rest of the FM3’s output circuit will comfortably cope with a 10k ohm load. Earlier FM3’s (below serial No. 5885) did use a .64 uf Capacitor but this is still a bit on the low side for loads below 50k ohm.
As for an antenna, the FM3 is happy to work with whatever would work for any normal tuner. The FM3 has an average sensitivity with no special antenna requirements, if you are close enough to the transmitter tower you may get away with an indoor 300-ohm ribbon into a 300 – 75-ohm Balun Adaptor, cheap as chips and easy to set up. When I was living in a major capitol City this is how I ran mine and I was about 30 Km away from the transmitter tower with a 50 Kw signal.
Happy listening and enjoy.
Mike Reed
pfm Member
Any array on a chimney will be affixed to a mast (which is strapped to the chimney) which takes it well above chimney pot level, hence free space. Solid surfaces behind aerials are a no-no.
Mike Reed
pfm Member
Yuk! If you want max. performance, you don't try to get away with anything. Think the Captain is some way away from the TX (can't find mention here) so a proper 75 ohm (exterior preferably) aerial would be required, I'd think.
Having said that, if you simply listen to speech, signal input is not so important, but music, o.t.o.h., and esp. with R3's low output, a 4 or 6 element array is recommended.
Captain, it would be useful, now that you have the info., of stating the direct distance to the TX and its output and as you mentioned it, if you thin you have reasonable line of sight. According to Ron Smith's aerial guide of 30 years ago, you have Wenvoe,Carmel and Presely in the S & SW plus Blaenplwyf mid-west plus 2 more on the north coast. Think these are TV stations but also prob. radio too.
I couldn't get R3 in Saundersfoot from my (indoor facing beach 3 storeys up) flat facing Swansea way. Tricky in Wales!
Jim Audiomisc
pfm Member
No. 8-] Its a pic of me at the top of Mauna Kea, Big Island, Hawai'i. 8-]
cf https://jcgl.orpheusweb.co.uk/history/qmc3/hawaii1.html
When I was working on receiving radio radation at over 1,000x times the frequency of Band II FM. Also usually a tad weaker to pick it up.