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Old 11th Apr 2021, 7:39 am   #21
mark_in_manc
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

Quote:
Originally Posted by Jez1234 View Post
Nagras are of course cheap nasty crap that needs disposing of properly and if you have any laying around you should send them to me so I can take them to the skip for you
Would Nicolet Scientific be foul language I wonder? Mini-Ubiquitous FFT Analyser... a story for another day I think... if this was the Mini one then I hate to think how big the normal one was!
I like it I never nicked anything that wasn't already in the skip (and also that depended on how much space I had at the time and who I knew to move things on to - I wasn't on this forum when all that B&K gear got dumped in 2005!), and although my employers were indiscriminate, they never threw a Nagra away so I never ended up with one! So David, we are safe from that kind of oneupmanship.

Nicolet - never seen one of them; I'd like to. Talking of weird FFT this is my favourite skip find of all time - the video is at the end:

https://www.vintage-radio.net/forum/...t=81707&page=2
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Old 11th Apr 2021, 12:01 pm   #22
m0cemdave
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

I have, and still use, various bits of B&K gear. Some of it acquired from radio rallies (remember them?) and internet sales, and a few items intercepted on their way to skips. Like all used test equipment, it normally requires servicing before putting back to use.

Remember that much of this kit was used in situations where it would be stacked on a shelf with other equipment, with little in the way of ventilation. The whole lot would probably be turned on with a master switch first thing in the morning, and off by the last person to leave the lab ten hours (or more) later. Some will have been used 24 hours a day for long periods, logging measurements. The service life of an electrolytic capacitor depends on temperature, and many of them - B&K used a lot of Frako's, which don't seem to fare as well as Philips - will now be long past their best.

But the first thing to do is re-seat any plug-in boards, preferably after cleaning the edge connections, and clean the switches. This usually results in signs of life if there were none before.

There used to be official sets of extender cards available for servicing the plug-in boards in various instruments, and it is possible to make up substitutes if you can find some suitable stripboard and edge connector sockets.

The B&K JP0101 connector is effectively a screened banana plug and there is usually a 4mm earth terminal adjacent, so a test lead with a pair of standard 4mm plugs can be used.

The worst thing about older B&K equipment is the obsolete mains connector. It's possible to modify the mains input panel and convert to a "protruding" type IEC connector as fitted to later B&K equipment, but these are are also extremely hard to obtain. Does anyone know of a source, in small quantities?

Oh, and there are two varieties of the 7-pin condenser mic connector - an older one with a long shell and a new one with a short shell. Adaptors (both ways) were available, but like the odd connectors and cable sets they usually get binned when the equipment is disposed of because the "disposers" don't know what they are...

Some of the larger instruments are combinations of other items and use many common circuit boards - for example a 2120 contains a 2607 measuring amplifier, as does a 2010.

My fondness for B&K is due to having used it extensively in the 1980s when I worked for a loudspeaker company. It was always very well made and a delight to use.

Some manuals and service notes are beginning to turn up in obscure places online, so it's always worth a careful search.

--------

On a related note:
Who remembers the old GPO type 46A measuring set (made by Wayne-Kerr) and its impossible-to-replace Suppressed Zero Meter?

Last edited by m0cemdave; 11th Apr 2021 at 12:07 pm.
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Old 11th Apr 2021, 5:05 pm   #23
mark_in_manc
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

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Originally Posted by m0cemdave View Post
Oh, and there are two varieties of the 7-pin condenser mic connector - an older one with a long shell and a new one with a short shell. Adaptors (both ways) were available, but like the odd connectors and cable sets they usually get binned when the equipment is disposed of because the "disposers" don't know what they are...
Make that 3 - some of the 'long' ones have a ring around the end which protrudes as far as the pins do, to try to stop the pins getting bent and snapped. And some (with snapped and bent pins) don't

One of the Norsonic 830s I already re-housed might have had the 'long-to-short' 7-pin adpators installed, but I wasn't that fussed as 2639 preamps are much too 'new' to appear in my pile of old s***e (I only have a couple of 2615s, which have valves in and therefore won't work with battery PSUs - hence not required by the former owner).

Dave - I'll try to find the scale plates and respond to your PM
cheers
Mark
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Old 11th Apr 2021, 5:47 pm   #24
wireman
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

Quote:
Originally Posted by Jez1234 View Post
Nagras are of course cheap nasty crap that needs disposing of properly and if you have any laying around you should send them to me so I can take them to the skip for you

I lost my way in how this thread developed but are you talking about the company Nagra that is well known for field recording products.
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Old 11th Apr 2021, 7:09 pm   #25
mark_in_manc
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

Yes - the mind-bogglingly expensive ones, hence this joke! We used them with B&K gear to get site recordings (B&K SLM, ac out into a tape recorder, 94dB 1kHz cal tone on tape to set a level) back to the lab for analysis using various other bits of B&K, and other, gear we have been discussing. It's my fault for shanghai-ing this thread on a specific bit of acoustics gear into a more general trip down B&K lane...but the topic is unusual on this forum so I don't feel too bad.
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Old 11th Apr 2021, 10:46 pm   #26
m0cemdave
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

1/ Long Socket
2/ Short Socket
3/ The Plugs
4/ Gold Dust!
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Old 11th Apr 2021, 10:50 pm   #27
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

Long plug with protective ring (detachable)::
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Old 13th Apr 2021, 12:17 pm   #28
duncanlowe
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

One of my first jobs I was the first to use some newly acquired B&K gear. A sound pressure level meter with a programmable filter set, plus a chart recorder. All of these battery powered. Used with a pink noise source (either a B&K generator or a CD) to do frequency response plots. Always struck me as incredibly robustly made equipment, and I'm sure it cost them a fortune to buy it!
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Old 13th Apr 2021, 12:48 pm   #29
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

When I was working in acoustics half a century or so ago, B&K had by then managed to achieve the enviable position of adding credibility to any acoustic measurement, whether for a client report or for journal publication. If your lab had serious pretensions in the discipline, B&K equipment was mandatory.

In the field of sound level meters, there were other brands such as Dawe (British) and GenRad (American), but none achieved the B&K credibility.

And once brilliant Polish Engineer Stefan Kudelski launched his Nagra III portable recorder, it quickly achieved a similar crediblity in recording the output of a B&K sound level meter. I guess that its flat response and speed consistency were important, but its straightforward and clearly visible tape path helped to ensure a reliable field recording. Its line input also happened to match the signal output level of a B&K 2203 series sound level meter rather well.

Reputation is important!

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Old 13th Apr 2021, 4:03 pm   #30
mark_in_manc
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

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Reputation is important!

Martin
Yes, especially when (as was often impressed upon me) you might end up defending your measurements in court!
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Old 13th Apr 2021, 4:36 pm   #31
Jez1234
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

Quote:
Originally Posted by mark_in_manc View Post
Quote:
Originally Posted by Jez1234 View Post
Nagras are of course cheap nasty crap that needs disposing of properly and if you have any laying around you should send them to me so I can take them to the skip for you
Would Nicolet Scientific be foul language I wonder? Mini-Ubiquitous FFT Analyser... a story for another day I think... if this was the Mini one then I hate to think how big the normal one was!
I like it I never nicked anything that wasn't already in the skip (and also that depended on how much space I had at the time and who I knew to move things on to - I wasn't on this forum when all that B&K gear got dumped in 2005!), and although my employers were indiscriminate, they never threw a Nagra away so I never ended up with one! So David, we are safe from that kind of oneupmanship.

Nicolet - never seen one of them; I'd like to. Talking of weird FFT this is my favourite skip find of all time - the video is at the end:

https://www.vintage-radio.net/forum/...t=81707&page=2
There's a tenuous link to that thread in that IIRC the Nicolet FFT analyser was developed for analysis of vibration etc in the wings of fighter planes, IIRC the Phantom. probably apocryphal or i just got my facts wrong but I recall reading something about this instrument being $250,000 then and only a very small number being built. I got it non working and one look inside told me it is going to stay that way... loads of huge hand built boards with hundreds of TTL IC's on each one, all wire wrapped construction for the logic sections! There's big fully encapsulated hybrid DAC's etc made by Burr Brown and possibly AD as well.
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Old 13th Apr 2021, 4:53 pm   #32
Jez1234
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Default Re: Bruel and Kjaer 2610 Measuring Amplifier

Quote:
Originally Posted by m0cemdave View Post
I have, and still use, various bits of B&K gear. Some of it acquired from radio rallies (remember them?) and internet sales, and a few items intercepted on their way to skips. Like all used test equipment, it normally requires servicing before putting back to use.

Remember that much of this kit was used in situations where it would be stacked on a shelf with other equipment, with little in the way of ventilation. The whole lot would probably be turned on with a master switch first thing in the morning, and off by the last person to leave the lab ten hours (or more) later. Some will have been used 24 hours a day for long periods, logging measurements. The service life of an electrolytic capacitor depends on temperature, and many of them - B&K used a lot of Frako's, which don't seem to fare as well as Philips - will now be long past their best.

But the first thing to do is re-seat any plug-in boards, preferably after cleaning the edge connections, and clean the switches. This usually results in signs of life if there were none before.

There used to be official sets of extender cards available for servicing the plug-in boards in various instruments, and it is possible to make up substitutes if you can find some suitable stripboard and edge connector sockets.

The B&K JP0101 connector is effectively a screened banana plug and there is usually a 4mm earth terminal adjacent, so a test lead with a pair of standard 4mm plugs can be used.

The worst thing about older B&K equipment is the obsolete mains connector. It's possible to modify the mains input panel and convert to a "protruding" type IEC connector as fitted to later B&K equipment, but these are are also extremely hard to obtain. Does anyone know of a source, in small quantities?

Oh, and there are two varieties of the 7-pin condenser mic connector - an older one with a long shell and a new one with a short shell. Adaptors (both ways) were available, but like the odd connectors and cable sets they usually get binned when the equipment is disposed of because the "disposers" don't know what they are...

Some of the larger instruments are combinations of other items and use many common circuit boards - for example a 2120 contains a 2607 measuring amplifier, as does a 2010.

My fondness for B&K is due to having used it extensively in the 1980s when I worked for a loudspeaker company. It was always very well made and a delight to use.

Some manuals and service notes are beginning to turn up in obscure places online, so it's always worth a careful search.

--------

On a related note:
Who remembers the old GPO type 46A measuring set (made by Wayne-Kerr) and its impossible-to-replace Suppressed Zero Meter?
Indeed it was a short circuit Frako electrolytic in the 2610... and yes an odd two pin mains connector so I erm bodged that by soldering the mains lead to the pins and then filling it with hot melt glue to insulate it.

I already tried cleaning edge connectors and switches in the 2607 to no avail.
Even the Ref oscillator seems to be non functioning. It has some signs of life in as much as touching a screwdriver to the input can peg the meter and on some ranges cause the overload neons to light but the meter is randomly flickering about other than that and its position seems to change randomly according to which switch is pushed or control turned... it's not even repeatable in that pushing certain switches can give different results each time, even after applying contact cleaner to them.

I can't justify the time in fixing it ATM and even more so now that I have the 2610 up and running anyway (and already had 2609). It would be a shame though for an instrument of this pedigree and huge new price to not someday be restored to operation though.. a rainy day round tuit maybe

I must look into getting some of those B&K input and output plugs though... quite what was the problem with using BNC's like everyone else one can only guess at!
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