PDA

View Full Version : Camac/Fischer Connectors. (Was Mark Levinson mad?)



The Grand Wazoo
06-05-2009, 23:45
I've got a couple of Mark Levinson power amps. They're old, but don't hold that against them - they're very very good bits of kit.

They use these funny connectors called Camacs, made by Fischer, on the inputs.

Camac stands for: Computer Automated Measurement And Control. It's an IEEE-standard (583), modular, high-performance, real-time data acquisition and control system concept. Born in 1969, CAMAC now appears in many thousands of scientific, industrial, aerospace, and defense test systems in more than 40 countries. (ref: http://www.kscorp.com/Products/camac/cables_and_connectors/index.htm)


http://img4.imageshack.us/img4/4513/camac.gif

In audio at least, Camacs have a reputation for being awkward. I suspect this is as a result of dealers and reviewers not living in the real world - they have to switch components a lot, unlike us civilians - the people who the kit was made for.

Camacs are pretty expensive & many people use Camac:RCA adaptors, which kind of short circuits the reasons that they were specified in the first place - they are incredibly reliable, they're a uniquely sensible solution to an engineering problem and they sound better.

They allow the cable to rotate through 360 degrees in relation to the plug body.

Contact areas are heavily gold plated.

They allow for earth connection to be made before live connection.

They have a self-locking mechanism.

The strain relief system doesn't pinch or distort the signal conductor/s.

The sockets are flush mounted

As long as you can use a soldering iron you can make up cables with Camacs.

Do some of these things sound familiar? - Don't forget, I just said the standard was defined in 1969

To my ears, they're streets ahead of any RCA connector or any other for that matter - and, yes, I have done meaningful comparisons. Does anyone else have any experience of these and why are they not used by anyone else in audio?

Barry
07-05-2009, 14:04
I've got a couple of Mark Levinson power amps. They're old, but don't hold that against them - they're very very good bits of kit.

They use these funny connectors called Camacs, made by Fischer, on the inputs.

Camac stands for: Computer Automated Measurement And Control. It's an IEEE-standard (583), modular, high-performance, real-time data acquisition and control system concept. Born in 1969, CAMAC now appears in many thousands of scientific, industrial, aerospace, and defense test systems in more than 40 countries. (ref: http://www.kscorp.com/Products/camac/cables_and_connectors/index.htm)


http://img4.imageshack.us/img4/4513/camac.gif

In audio at least, Camacs have a reputation for being awkward. I suspect this is as a result of dealers and reviewers not living in the real world - they have to switch components a lot, unlike us civilians - the people who the kit was made for.

Camacs are pretty expensive & many people use Camac:RCA adaptors, which kind of short circuits the reasons that they were specified in the first place - they are incredibly reliable, they're a uniquely sensible solution to an engineering problem and they sound better.

They allow the cable to rotate through 360 degrees in relation to the plug body.

Contact areas are heavily gold plated.

They allow for earth connection to be made before live connection.

They have a self-locking mechanism.

The strain relief system doesn't pinch or distort the signal conductor/s.

The sockets are flush mounted

As long as you can use a soldering iron you can make up cables with Camacs.

Do some of these things sound familiar? - Don't forget, I just said the standard was defined in 1969

To my ears, they're streets ahead of any RCA connector or any other for that matter - and, yes, I have done meaningful comparisons. Does anyone else have any experience of these and why are they not used by anyone else in audio?

Yes, I would certainly agree with everything you have said.

RCA phono plugs are probably the poorest design for a connector I have ever seen. Designed in the 1940's by RCA to be a cheap connector to allow phonograms (hence their name) to be connected to amplifiers, they rapidly replaced the much superior (but more expensive) 1/4" jack plug current at that time. It is unfortunate that the RCA phono connector was adopted as the industry standard, but suspect that low cost and small size had a lot to do with it. All the alternative audio conectors available: XLR; DIN (yes DIN); 1/4" jack and even the humble Belling and Lee TV aerial connectors, are superior, despite relative shortcomings of size, cost, or ease of wiring.

No amount of gold, silver, rhodium, tin or nickel plating is going to transform the inherently poor design of the RCA plug, and the development of the 'bullet plug' takes a poor design and makes it worse.

Yes CAMAC connectors are expensive (Lemo 00 conectors, which are compatable with the Fischer connectors, are about £6 each), but are not that much more expensive than the best RCA connectors (made by Neutrix; the type that have a sliding outer connection which connects first on mating and last on demating, and when mated grips like there's no tomorrow). Considering that people will quite happily pay a similar amount of money for a bulk foil resistor or a special capacitor, I can't understand why a compromise is made in the choice of connector.

In times past I have made a number of moving coil amplifiers and have used Lemo 00 conectors with them. The problem is that I have to live in the real world and replacing the RCA connectors on my cassette decks and CD player would be tedious. Fortunately the rest of my system uses XLR, 1/4" jack or DIN connectors.

Barry

DSJR
07-05-2009, 22:02
Speaking as an ex-Naim dealer, I'd say that alternatives to phono plugs are a PITA to be honest, but it does maintain brand loyalty I suppose..

I hate DIN connectors with a vengeance, as only small gauge cables can be used. I don't know why phono's are so bad, as when using screened connectors, the only failing is the +ve connecting first in most plugs.

I suspect Levinson had the same "problem" as Naim had with using BNC's, only the Naim lot are far more vociferous and possibly loyal too, despite Levinson gear of the eighties and early nineties being in a different and far better realm to Naim and Linn IMO... I think it was the ML28 preamp that was fully balanced throughout from input to output and was the first preamp that a dealer friend regarded as a sensible next step from the Croft Mega Micro of the early nineties. You see these 28's for around £750 these days. Got to be better than a Naim 82.....

Spectral Morn
07-05-2009, 22:20
Dartzeel products use a 50ohm connector as an alternative to rca/xlr...is it the same ? If not what sort are they using. Must admit I like XLR's but have never had any issue with RCA's...that I know of.


Regards D S D L

Barry
08-05-2009, 14:45
Dartzeel products use a 50ohm connector as an alternative to rca/xlr...is it the same ? If not what sort are they using. Must admit I like XLR's but have never had any issue with RCA's...that I know of.


Regards D S D L

I can't tell you off-hand, I would need to see a photo to identify the connector.

I can't say that I have heard any audible superiority of CAMAC connectors over RCA phonos. This is not to say that I question Chris's opinion here; I have read of people who can hear the difference between various makes of phono connector. I don't, and I can't think of reasons why there should be, but that doesn't mean to say that differences might not exist. (I was using CAMACS made by Lemo, rather than Fisher; perhaps an audible difference lies between these two makes?)

No - my diatribe against RCA phonos was based on that unfortunate fact that a cheap and modestly designed connector was adopted and having been adopted, has been tarted up such that now, versions are sold for rediculous amounts. As I said, no amount of gold, platinum-iridium plating or cryo-treatment is going to transform a mediocre design. What was adequate in the 1940's is no longer so today. The CAMAC connector is a much superior connector for all the reasons listed by Chris, and they are similar in size to the phono and competitive in cost (compared to the OTT prices asked by Furukawa, they are a positive bargain!) They are available with collets that can accept cable up to 5mm OD (or whatever the OD of RG58 cable is). If you want to use thicker cable than you will have to go elsewhere.

Yes, DIN connectors are a pain in the ass to wire, especially if you want to wire up all 5 pins. You can't do it in a hurry, but then you should not wire up any connector in a hurry. With a bit of time, patience, and admittedly, a certain skill with a fine-tipped soldering iron, you can do a neat job.

I think Quad was the first British manufacturer to employ DIN connectors (on their series 3 electronics). They did so, citing the electrical superiority of DIN connectors over RCA phonos. They were heavily criticised over this at the time, probably because everyone else (Leak, Radford, etc.) had stuck to phonos. Even SME had to offer a special lead fitted with a DIN plug to use with the Quad 33 pre-amp. Surprisingly when NAIM introduced their electronics fitted with nothing but DIN connectors, they received no complaint at all over this. I suspect that Naim adopted DIN connectors as it readily allows the star (?) earthing system they employed.

I forgot to mention BNC connectors. I think Naim were first to use them for pickup arm connections on their 52(?) preamp. I would like to think that they were chosen for their superior build quality rather that the nonsense that Naim quoted in their literature (the fact that BNC connectrors are a constant impedance design; the concept of characteristic impedance of cables and connectors does not apply at audio frequencies for cable lengths less than 1.5km). They are a superior connector to RCA phonos and I am glad to see that they are starting to become adopted for the digital coaxial output of CD players (the 75Ohm BNC version is used, though even at 192KHz sampling rates, the adherence to this characteristic impedance is only important for cable lengths greater than 150m).

Finally to XLR connectors. These are my favourite and I wish that they had been adopted. They are rugged, not too expensive, easy to wire and can be used for either balanced of unbalanced systems. I think that balanced systems are the way forward and I notice that manufacturers are fitting them to equipment that has balanced I/Os, now that this arrangement is becoming more prevalent.

So, Was Mark Levinson mad? No, I think he was just ahead of the game, but was unfortunately not followed by others.

Regards

Barry

The Grand Wazoo
08-05-2009, 15:37
Dartzeel products use a 50ohm connector as an alternative to rca/xlr...is it the same ? If not what sort are they using. Must admit I like XLR's but have never had any issue with RCA's...that I know of.


Regards D S D L

I think they're BNC's Neil - although they somewhat elusively are referred to as Zeel Connectors

The Grand Wazoo
08-05-2009, 15:45
No - my diatribe against RCA phonos was based on that unfortunate fact that a cheap and modestly designed connector was adopted and having been adopted, has been tarted up such that now, versions are sold for rediculous amounts. As I said, no amount of gold, platinum-iridium plating or cryo-treatment is going to transform a mediocre design. What was adequate in the 1940's is no longer so today. The CAMAC connector is a much superior connector for all the reasons listed by Chris, and they are similar in size to the phono and competitive in cost (compared to the OTT prices asked by Furukawa, they are a positive bargain!) They are available with collets that can accept cable up to 5mm OD (or whatever the OD of RG58 cable is). If you want to use thicker cable than you will have to go elsewhere.

So, Was Mark Levinson mad? No, I think he was just ahead of the game, but was unfortunately not followed by others.

Regards

Barry

The cable diameter issue seems to be a problem to some folks, though the girth of a cable has never yet impressed me, except the ones I once saw feeding power to a dragline machine on an open-cast coal mine - perhaps 7 inches in diameter!. There are plenty of good quality 5mm cables about to choose from.

The sub-text of my original post was, I guess, that rather than spending alleged fortunes on 'research' into polishing the turd that is the RCA phono connector, the audio industry has ignored a perfect solution - and in fact, as you say, Barry, several others.

..........ho hum.

hifi_dave
08-05-2009, 18:41
As ML dealers (back in the day) we used Camac connectors on ML incon cable and it made a good, reliable, not too expensive incon whenever we demonstrated the kit. I can't say I ever noticed an improvment using Camac over good quality Phono's though.

The Camac connectors, like BNC aren't the easiest to make up and you do require the correct construction and dimensioned cable for best results.

DSJR
08-05-2009, 19:21
Naim didn't use star earthing until the early to mid eighties when the .5 versions of their preamps came out and the earthing of the amp "system" is still cack-handed according to Avondale's Les, who puts his reasoning quite intelligently I think...

There were complaints about the DIN's Naim used, back in the late seventies, especially as Quad were starting to move away from this connector. It was regarded as "B&O" Lo-Fi I seem to recall.

BNC's seem to make excellent sense and large diameter entry versions are available for 10mm style coax cables like the Ecolflex 10's I made up (they sound damn good too and I found some phono's from Maplin which work ok). Naim went over to these in the mid eighties while the 32.5 was still available IIRC, but bearing in mind the vicious HF limiting in their designs, I doubt that clean and wide bandwidth had anything to do with it.

markf
09-05-2009, 03:07
"they rapidly replaced the much superior (but more expensive) 1/4" jack plug current at that time."

the 1/4 jack is good up to 100Khz , the RCA phono is good to
10Mhz ,if you need higher (ie for your Shure cart) go for BNC at 2Ghz