F connectors often use the coax inner as the centre pin, so oxidation could be a problem.
Also, in my experience, F connectors can get confused between the screw thread for attaching to the socket and the screw thread which attaches to the coax outer. When you try to remove the plug you end up accidentally dismantling it too.
Stick to RCA or BNC.
Also, in my experience, F connectors can get confused between the screw thread for attaching to the socket and the screw thread which attaches to the coax outer. When you try to remove the plug you end up accidentally dismantling it too.
Stick to RCA or BNC.
there are a few positive things to say about the F-type--- the dielectric is low loss and low capacitance and often can be had with triple shielding all for very low cost. And, if you do not plan to be frequently unplugging/plugging, it makes a good ground connection and wont loosen or fall out. The center pin is gripped by a hard enough contact pressure to break thru oxidation and makes a good contact. At least it isnt worse than an RCA. It is reliable and can be had in air/water tight for outdoor use for years if not decades.
As with all cable/connectors, the quality of the construction method used is important for reliable use.
-Thx-RNMarsh
As with all cable/connectors, the quality of the construction method used is important for reliable use.
-Thx-RNMarsh
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Hey there was somebody a while back who tested a bunch of balanced cables and concluded that one copper and one constatine conductor sounded best.
But you are right the all copper silver plated stuff is not very common. Cable tv rg cables usually have a steel core as they need the strength. Ordinary cable expects supports every ten feet or less.
A good Type F connector and coax (good to 1 GHz) is far superior to any RCA-type that I've ever seen. BNC-type is probably 3X better than type F (and is good to 3 GHz). But neither of those is available in a metrology-grade version.
Of course, I'm talking about RF usage. But maybe what's good for RF is good for everything. (Bloody unlikely... but still far better than RCA.)
The very best commonly-available connector type would probably be 3.5 mm (NOT SMA-type), in metrology grade (good to 33 GHz). But those might be a couple hundred dollars per connector, if from a reputable manufacturer. (But don't EVER mate them with anything SMA, even though they appear to be compatible.) Or instrument-grade or production-grade could be used, for a much lower cost.
TNC type is OK. It looks like a BNC diameter, but with threads. They're good to 11 GHz but are not available in metrology grade or instrument grade; only production grade.
I really like the Type N metrology-grade connectors (good to 18 GHz); maybe with some nice LMR-600 cable.
But beware! Even the very best RF connectors are usually rated for only up to about 100 mating/un-mating cycles. After that, the high end of their frequency response starts to measurably degrade. (Little-known fact: Until relatively recently, SMA-type connectors were only available in "crap" grade, and were only rated for up to ONE mating/un-mating cycle!)
But I doubt that we're worried about what's happening up at 18 GHz, for audio connections!
Still, if you have an expensive piece of RF gear with built-in connectors, it would be a good idea to install M-F adapters (which don't change the original sex), so that you can replace them after every 100 mating/un-mating cycles. That way you can get 10,000 mating/un-mating cycles, instead of 100, before the built-in connectors would need to be replaced.
http://www.home.agilent.com/upload/cmc_upload/All/EPSG085963.html?&cc=US&lc=eng
Of course, I'm talking about RF usage. But maybe what's good for RF is good for everything. (Bloody unlikely... but still far better than RCA.)
The very best commonly-available connector type would probably be 3.5 mm (NOT SMA-type), in metrology grade (good to 33 GHz). But those might be a couple hundred dollars per connector, if from a reputable manufacturer. (But don't EVER mate them with anything SMA, even though they appear to be compatible.) Or instrument-grade or production-grade could be used, for a much lower cost.
TNC type is OK. It looks like a BNC diameter, but with threads. They're good to 11 GHz but are not available in metrology grade or instrument grade; only production grade.
I really like the Type N metrology-grade connectors (good to 18 GHz); maybe with some nice LMR-600 cable.
But beware! Even the very best RF connectors are usually rated for only up to about 100 mating/un-mating cycles. After that, the high end of their frequency response starts to measurably degrade. (Little-known fact: Until relatively recently, SMA-type connectors were only available in "crap" grade, and were only rated for up to ONE mating/un-mating cycle!)
But I doubt that we're worried about what's happening up at 18 GHz, for audio connections!
Still, if you have an expensive piece of RF gear with built-in connectors, it would be a good idea to install M-F adapters (which don't change the original sex), so that you can replace them after every 100 mating/un-mating cycles. That way you can get 10,000 mating/un-mating cycles, instead of 100, before the built-in connectors would need to be replaced.
http://www.home.agilent.com/upload/cmc_upload/All/EPSG085963.html?&cc=US&lc=eng
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The F connectors kit I have from Agilent (Suhner) are way more expensive ($5K) and are calibrated to 3 GHz. 85039B Economy Mechanical Calibration Kit, DC to 3 GHz, Type-F, 75 ohm | Agilent (And they call this economy). But I would never use them for audio. If you are departing from current connector options there are better than F but nothing as convenient.
For analog audio I don't see a need for controlled impedance. In some circles there is a fetish for minimum contact area. I have not reconciled that with getting good shielding, but what do I know?
For analog audio I don't see a need for controlled impedance. In some circles there is a fetish for minimum contact area. I have not reconciled that with getting good shielding, but what do I know?
Ok, thanks guys, some interesting snippets there.
Of course I agree BNC is a better connector for repeated insertion/removal, but at the downside of more tedious fitting of connectors to cables.
For permanent/semi-permanent connection F connectors ought to be close to electrically ideal.
I will try some SPDIF connection experiments in the near future and see (hear) what I get.
Dan.
Of course I agree BNC is a better connector for repeated insertion/removal, but at the downside of more tedious fitting of connectors to cables.
For permanent/semi-permanent connection F connectors ought to be close to electrically ideal.
I will try some SPDIF connection experiments in the near future and see (hear) what I get.
Dan.
As we speak, someone somewhere is writing an audio white paper which proves that for good sound you need at least 12GHz even for an analogue interconnect. This is best achieved by using hook-up wire carefully plaited (get your sister to do it if she knows how to plait a pigtail) - of course it must use teflon insulation.gootee said:
In my early days developing instrumentation there was an assistant professor who specialized in radio astronomy. He had the brilliant idea of making a radio interferometer using a couple of TV tuners. This would somehow save a lot of time. However, he knew very little about electronics. The worst idea was that the antennas would be dipole arrays. Well, OK, if done with great care and cleverness, and on a large-enough scale, perhaps not utterly hopeless. But when it came time to connect the dipoles he felt one could simply string them together, with no regard for impedances. When I protested he insisted that we simply try it.
He got very impatient with me on the electronics, as I made them out of copper-clad circuit board material and soldered the seams together. He thought this must be the reason they took so much time to fabricate. The notion that any design was involved for the front ends and the distribution of a 1/8 center frequency mixer LO and upconversion local to each preamp seemed to elude him. A complete idiot, and he was denied tenure, appropriately I think, although I doubt it had much to do with the 405MHz telescope project. In any event I learned a lot about RF design.
Much later a very sharp guy joined the department and got a ~7' dish on a mount that went on the roof and could be aimed at the galactic center. With a decent LNA it did work, looking at mostly neutral hydrogen emission at 1.420 GHz, but the preamp was prone to break because where the thing had to aim was almost line-of-sight for high-powered radar from San Pedro.
At least it gives us something to laugh at.1audio said:
To make real money from audio it helps if you are either very ignorant or very dishonest. Normal people with a bit of knowledge and a bit of integrity either couldn't make it up or would never try to get away with it. Thus they are condemned to designing and selling competent gear at a reasonable price, merely inflated by 'management' and marketing costs.
Sadly, this is not my experience. It is difficult to make a good living in audio, because the 'mark-up' at the manufacturing stage is very low.
Calling a significant number of people in the audio business, either ignorant or dishonest, just shows your prejudice against audio designers, but how do you make a reasonable living? Are you well paid for what YOU do? Is it really commensurate with the skill and 'added value' that you add to whatever you do? Or is it like military/industrial, somewhat overpriced because the market can bear it?
Calling a significant number of people in the audio business, either ignorant or dishonest, just shows your prejudice against audio designers, but how do you make a reasonable living? Are you well paid for what YOU do? Is it really commensurate with the skill and 'added value' that you add to whatever you do? Or is it like military/industrial, somewhat overpriced because the market can bear it?
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