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Understanding Krone Blocks

By Damien Tyson
Posted 2 September 2016, 5.24am edt
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I'm trying to get my head around how Krone blocks for audio work in an analogue studio environment.

Can anyone provide a link to any documentation online that I can read to find out more? Having read a few articles, the information I've been able to find seems a bit vague.

The part I'm struggling to understand is how the inputs and outputs work. I'm sure in my head I'm making it more complicated than it is!

Comments

1 year ago

Very simple really: top row is for equipment or sources, bottom row is to link between blocks with jumper wire.

1 year ago

Thanks for the reply, Andrew.

So, for example, say I wanted to connect a CD player to a mixing desk. The audio out of the CD player would go into the top row, but how does the audio then get from the Krone to the fader on the desk?

1 year ago

Bring all your channel inputs to the top row of another block(s) and the connect the CD player to the channel by 'jumpering' between the corresponding bottom row contacts.

1 year ago

Here's an example Krone layout for you.

BLOCK A
1a - CD Output Left hot - Jumper on bottom row to Block B, tag 1a
1b - CD Output Left cold - Jumper on bottom row to Block B, tag 1b
2a - CD Output Right hot - Jumper on bottom row to Block B, tag 2a
2b - CD Output Right cold - Jumper on bottom row to Block B, tag 2b
3a - not connected
3b - not connected
4a - not connected
4b - not connected
5a - not connected
5b - not connected
6a - not connected
6b - not connected
7a - not connected
7b - not connected
8a - not connected
8b - not connected
9a - not connected
9b - not connected
0a - not connected
0b - not connected

BLOCK B
1a - Mixer Input Left hot - Jumper on bottom row to Block A, tag 1a
1b - Mixer Input Left cold - Jumper on bottom row to Block A, tag 1b
2a - Mixer Input Right hot - Jumper on bottom row to Block A, tag 2a
2b - Mixer Input Right cold - Jumper on bottom row to Block A, tag 2b
3a - not connected
3b - not connected
4a - not connected
4b - not connected
5a - not connected
5b - not connected
6a - not connected
6b - not connected
7a - not connected
7b - not connected
8a - not connected
8b - not connected
9a - not connected
9b - not connected
0a - not connected
0b - not connected

You would need a krone tool:

http://www.canford.co.uk/Products/20137/46-201_KRONE-Inserter-tool-2A

And some jumper wire:

http://www.canford.co.uk/JWH-SERIES-UNSCREENED-TWISTED-PAIR-SOLID-CONDUCTOR-JUMPER-WIRE

This book might be helpful: http://amzn.to/2pb6FIT

1 year ago

There are cheaper places to by a Krone tool and jumper wire (and indeed everything!) than Canford! For a tool try cpc, for the jumper wire go to Bryant Broadcast.

1 year ago

Depends on how good a trade discount you get ;)

But yes, CPC and Bryant are both excellent value.

1 year ago

Blimey, you must get one hell of a discount to get Canford's criminally over-priced stock down to a level that's value-for-money!

1 year ago

Depends on what you're ordering, but Canford do often work out the cheapest if you have a good discount. I'd imagine the discount is only available to their largest customers (i.e. spending 10k-100k a year, i.e. BBC, Sky etc).

1 year ago

Again, thanks for the replies...some really helpful information there!

I'll be installing a new studio at a hospital radio station soon. While I'm fine with everything else, I don't have much experience with Krone so I'm trying to get on top of it before I start the work.

1 year ago

Damien, if you need any advice of assistance just email me on info@station-z.co.uk

Andy

1 year ago

Cheers Andy :-)

I guess in general, I'm struggling to see the point in Krone. Why can't you just connect a CD player or other equipment straight to the mixer, why Krone it?

Our installation is pretty permanent. We have no need to be able to patch stuff or move bits around, so I wonder if Krone is pointless in our environment.

1 year ago

If everything is in one room and is predominantly 'equipment-to-mixer' configuration then I would agree: Krone is probably overkill. If, on the other hand, you have a separate racks room and lots of incoming and outgoing lines then it's very useful.

In the wacky world of TV (at least in the old days) EVERY bit of audio equipment in the entire station would be fed to a massive centralised Krone frame and thence back to each studio mixer input!

1 year ago

It's a shame you're so far away Andy (we're up in West Yorkshire)!

1 year ago

Coming up to Hull in the not too distant future!

1 year ago

In the modern world of 'Audio over IP', Krone is not needed as much as it used to be, but if you have lots of analogue equipment then wiring everything direct to the mixer can be inflexible. Having everything wired into the krone frame makes re-arranging your connections (relatively) trivial (you just move the jumpers rather than spend hours soldering new cables).

Krone is also very useful in larger multi-studio facilities. All your studios have multicore cables from their small krone frames back to the one large krone frame in a central location. This makes it easy to wire any signal from anywhere in the building to anywhere else in the building.

In a busy facility with multiple radio stations and constantly changing technical requirements (e.g. radio stations launching, closing down, moving onto different platforms and different transmitters) you would be regularly moving jumpers around.

A single studio in a small hospital station? Krone probably wouldn't provide a huge benefit, but I would say as soon as you have more than one room with equipment in then it becomes worthwhile.

As I mentioned, if you were building a 'state-of-the-art' facility you would probably go down an 'audio over ip' route. This replaces krone frames and large analogue multi-core cables with standard networking hardware (i.e. switches, routers, cat-5/6 cable and fibre optics) and all 'connections' are actually just re-directing IP packets to different devices... no jumpering or patching necessary.

1 year ago

I think because we already have Krone, it'd be easier to keep them in-situ when I install the new desk and woodwork. Plus we have audio coming from a few different places which I think probably requires Krone (feeds from studio 2 and our production room).

While I'm here, I don't suppose anyone has an electronic copy of a manual for an Alice Air 2000? I've tried contacting the people at Alice but I'm struggling to get in touch.

1 year ago

Alice are effectively closed down now. Annoyingly their website is still live and their telephone has an answering machine on it. According to Companies House it was dissolved in 2014, https://beta.companieshouse.gov.uk/company/07233311

As I said before, let me know if you need any advice.

1 year ago

Ah I didn't realise. Hopefully I'll be able to get a manual from somewhere!

Regarding Krone cable...we currently use CAT5, is there any benefit at all in putting shielded CAT5 in? The cable runs aren't massive but there is a lot of electrical equipment nearby and power cables.

1 year ago

Cat 5 is more than adequate for analogue (and digital) audio going to Krone, as long as you keep the twisted pairs together. If you're using properly balanced audio throughout, screening shouldn't be necessary, especially if the cable runs aren't particularly long. The balanced connection should reject all pick-up from nearby power cables and equipment.

Shielded cat-5 may make a difference for unbalanced connections or very long runs, and if the price isn't too much more might be worth just going for that for peace of mind, but if you're on a budget shielding is optional.

1 year ago

Thanks again for the information!

We're going with CAT5 shielded cable for the balanced connections between the desk and the Krone.

I understand that the drain cable goes to pin one on the XLR end, but where does it go on the Krone block?

These are the blocks we're using - http://www.theonlineengineer.org/TheOLEBLOG/wp-content/uploads/2013/05/KRONE.jpg

1 year ago

If everything is balanced then you don't need to ground it although it's good practice to ground one end if you can.

1 year ago

Great...thanks, Andrew. So just soldering the drain to pin one on the XLR should be adequate? I always assumed it should be connected at both ends.

1 year ago

Balanced and floating is the description. OK for line level sources but not for mics that need the earth to enable phantom power.

We don't tend to run mics through Krone though.

1 year ago

Final question (I promise!) - our Alice Air 2000 has a few 25-pin D-type connectors for various inputs and outputs. Should there be any problems with crosstalk, or not because they're balanced?

1 year ago

Because they are balanced, no.

1 year ago

Regarding the drain cable, it is good practise to ground it on one end, but NOT both ends. Grounding on both ends can lead to 'ground loops', which can cause humming noises to be introduced to the signal.

You can either ground the drain on the equipment end (i.e. Pin 1 of the XLR) or at the Krone frame end (by soldering the drain wire onto a longer wire and connecting it to a ground bus block or bar on the frame itself). The latter can be useful for multicore cables where there is no obvious 'pin' to ground to (e.g. inter-studio ties), but generally it is simpler to just connect it to pin 1 of the XLR connector.

As Andrew said, general practise is to run microphones directly into the back of equipment, rather than via krone, to avoid trouble with grounds, phantom power etc.

1 year ago

Thank you, David!

I'm being really cautious over the wiring as at the minute we get an awful lot of crosstalk and mains hum on certain channels. Sadly the person who did it didn't use twisted pairs or ground anything. The current install has been in for 26 years though so I guess it hasn't done bad!

1 year ago

You're asking all the right questions. If you stick with balanced connections on twisted pairs, that will solve 90% of hum/noise problems.

5 months, 2 weeks ago

Does anyone have any advice on how to test a Krone patch? I'm getting a patch lead made that will allow me to use headphones to hook into a given point in a block, but how would I ensure that it's in phase and free of cross-talk?

5 months, 2 weeks ago

In the industry people tend to use test equipment from Lindos (http://www.lindos.co.uk/), which can check for phase, crosstalk, distortion, frequency response etc. etc. However, this gear ain't cheap.

You would make cables to hook it up to your krone frame with these kind of cords: http://www.canford.co.uk/KRONE-PATCHCORDS

If you want a cheaper alternative, you could look at the products from here: http://www.canford.co.uk/Test-and-measurement

or even get a cheap Behringer tester for basic tests: http://www.music-group.com/Categories/Behringer/Accessories/Cable-Testers/c/1234011?group=Cable%20Testers&colExpFlag=,Cable%20Testers

5 months, 2 weeks ago

It's a little pricey as a specialist book - but can recommend Dave Walters' "How to build a radio station" book, there's lots of good advice on designing and wiring Krone frames.

5 months, 2 weeks ago

Just seen this topic. I have a handy free 16 page guide entitled "Using Krone Blocks In a Studio Installation" that I would be happy to pass on. Email me at info@avresilience.co.uk with Krone Guide in the subject line and I will send it on. Re test kit: Lindos is great but they have never had an AES solution I like so try this as alternative http://www.ctpsystems.co.uk/dbbox2.html - about £300 x VAT IIRC.

5 months, 2 weeks ago

Nice tip on the dbbox2 Iain, I've never sen that before and I've been looking for a cost effective AES meter.

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