Mikroport SK 2012

[cedd]

Hi all

I've just inherited a set of 4 x SK 2012's with EM 2003 recievers. I have googled and I know they are old kit, but I'm looking for a few more details on them.

From a helpful previous post in the BR archives I know what the controls do, and I also know that in their day, they were very good, and probably still are.

 

My issues are these;

 

They don't have mics at the minute. I'm told by the person I got them from that it's a reasonably easy mod to change them to a 3.5mm jack socket to take a modern mic. The existing socket looks like a smaller verson of an SMA RF connector (any ideas what this is and if anybody makes any adaptor leads?).

They also came with an antenna distribution unit, but no aerials (RX). I've been on the canford website and have looked at their offerings, but note that they say "specify frequency" on their sales page. Clearly there are going to be 4 frequencies in opration here - between 174.1 and 200.3 so I need a reasonably wide band VHF antenna. Any ideas?

 

Finally, the recievers are individual units of about a half rack unit width and 2 units high. Anybody know of any mounting hardware for these to make them rack mountable or do I need to buy rack shelves and fasten them to these?

 

Any help or details on these things very happily recieved.

 

Chris

[Paul TC]

Finally, the recievers are individual units of about a half rack unit width and 2 units high. Anybody know of any mounting hardware for these to make them rack mountable or do I need to buy rack shelves and fasten them to these?

 

Chris

 

CPC sell Penn Fabrication 2U ears which might be usable

 

Link

 

 

Or try this link to 10 out of 10

 

Another Link

[timtheenchanteruk]

Yep, its relatly easy to modify them use CPC part number CN05782. this will allow you to use locking jacks.

 

the existing sockets are microdot connectors.

 

the antennas are "tuned" the 175s are longer than the 200s they are interchangable, but not quite as efficient as they should be a perfect 1/4 wave.

 

they are still crackng bits of kit, and you can get the manuals from sennhesers website.

 

I hae a few to mod, that I intent on starting this week, I will take some pics for you.

[cedd]

Thanks for that,

 

I've been thinking about connectors and have had them open today to have a look. My other radio mics are 4 pin mini XLR, so I'm thinking of attaching a flying lead from the terminals inside, out to a 4 pin inline plug to connect with my existing mics. Saves having 2 different types that can't be interchanged. It also means less fiddling with the internls of the unit. I think I can even use the existing microdot body with the plastic inner removed and some heatshrink as a strain relief.

 

The great thing is, they strip down to just the casing with no plastic parts, so all 4 casings have just been through the dishwasher which has nicely removed all the old sticky identification labels, so I'm back to "as new" condition! Just don't tell mum!

[cedd]

well the deed has been done, I've exchanged the connectors.

 

It wasn't the easiest job I've ever undertaken. Main reason being that the 3.5mm jack sockets I was using didn't fit in the casing very well. Soldering to the board itself isn't too bad. In the end I pushed out the central core of the microdot connector and through the hole in the middle, pushed a 2 core audio cable. This is soldered to the board inside, then liberal amounts of heatshrink around the microdot to make a strain relief. This cable can then have any in-line connector soldered to it. In my case, I'd already bought 3.5mm jacks, expecting it to be an easy mod. Perhaps if I did it again, I'd fit 4pin mini XLR's as that's what my other mics are on.

 

All 4 now working and there's a yagi and dipole on the way from Canford. Just need to flight case the things now.

 

For reference, the casings of the receivers are 1.5U high, so a stack of 4, 2 wide by 2 high, plus aerial distribution unit (1u) is going to fit nicely into a 4u rack.

[ewanuno]

just recently we got the gift of three sk2012 radio mics and four em2003 recievers. from a big theater in town who were clearing out the warehouse. we also got a set of 10 cetec vega radio mics too,

 

but I thought I'd start with the sennheisers first.

 

like you I needed to get mics and ariels, the mics I got sorted out already, in the end I put 2.5m jacks and made an adapter cable.

I got some mediocre quality lightweight flesh coloured headset mics which look the part, but are definatly the weakest link

 

as for ariels I'm not quite sure what I need to get, how are you getting on with yours?

 

I'm thinking of getting simple whip antenna made localy, (I live in torino, italy which isn't as full of audio specialists as london.)

[cedd]

Are we talking receiver or transmitter aerials here? Transmitters could be interesting without the mikrodot connectors available. I'd be tempted to get some 90' SMA type connectors and try replacing them with these. I have a feeling it should be a reasonably straightforward modification, though don't have the need to try it for the time being. My aerials are then just a length of wire (single core I think) cut to the appropriate length for the wavelength. They appear to be sennheiser originals.

 

As for receiver aerials, I've now got some VHF Yagi's and Dipoles which are doing great service via the antenna distribution unit.

[timtheenchanteruk]

they are indeed single core, in an emergency on my trantecs I have just used a length of wire and some gaffa!!

 

I will be looking for some replacement bodypack antenna shortly, I`m down to my last couple of spares.

 

Oh and to get the 3.5mm jacks to fit, you need to cut the bit off the upright PCB (it only supported the original microdot), then file it as close to the on/off switch (or is it the limit switch) as you dare, it then just fits, then open out the hole in the case, and bingo, it takes the new sennheiser mics (or in my case the cheepo CPC headsets)

[ewanuno]

Are we talking receiver or transmitter aerials here? Transmitters could be interesting without the mikrodot connectors available. I'd be tempted to get some 90' SMA type connectors and try replacing them with these. I have a feeling it should be a reasonably straightforward modification, though don't have the need to try it for the time being. My aerials are then just a length of wire (single core I think) cut to the appropriate length for the wavelength. They appear to be sennheiser originals.

 

As for receiver aerials, I've now got some VHF Yagi's and Dipoles which are doing great service via the antenna distribution unit.

 

weve got all the transmitter ariels,

 

its the receiver aerials that I'm missing,

 

as far as I understand I can just got to a place that sells antennas, tell them what frequency its for and they'll give me something?

right?

 

I think I'll get antennas that fit directly onto the reciever since I don't have a distribution unit and I want to keep my setup simple.

[cedd]

Canford are your best bet, but be prepared to pay £60 each.

 

Don't be tempted t use TV aerials or domestic stuff, impedence mismatches cause more trouble it's worth for the saving!

[paulears]

Cut down VHF dipoles meant for radio 2 are very cheap and work pretty well. The ones I have have wingnuts at the centre, and a square section support arm, so they fold up nicely and can be clamped to upright or horizontal supports quite easily.

[ewanuno]

I'm not sure if I'm prapered to pay £60 each

 

Cut down VHF dipoles meant for radio 2 are very cheap and work pretty well. The ones I have have wingnuts at the centre, and a square section support arm, so they fold up nicely and can be clamped to upright or horizontal supports quite easily.

 

 

vhf ariels should be available just about everywhere right? like amatur radio stores.

how long should they be?

do you know of a good calculator to determine how long they need to be?

 

the more I read about antenas the more they seem like black magic.

it seems that although they are just bits of wire the right length and shape they need to have some kind of magical properties that I don't quite understand.

 

and also I've been searching online for a service manual for the em2003-90 receiver, and I'm not finding anything apart from paysites. do any of you guys have a pdf?

I found the sk2012 service manual though. and the owners manuals for both.

 

I've noticed that they em2003 recievers work from mains but not from 12v,which I prefer since sometimes we have to use a mobile setup. any ideas?

 

 

thanks.

[timtheenchanteruk]

for the manual, the user manual is on senheisers website, try e-mailing them for a service manual.

 

for the 12V running, a inverter seems the simplist solution

[johndenim]

the more I read about antenas the more they seem like black magic.

 

here is an interesting read on basic wireless principals, courtesy of

shurenotes.

 

 

John Denim.

 

A concurrent post has been automatically merged from this point on.

 

Sorry, front page.

[cedd]

If you open one of the EM2003's up you'll find a few components missing but labelled within the DC path. They were available with a lemo type 12v connector which used the same board but bypassed the transformer and rectifier. You could try and find out what these componnts were and replace them.

 

Alternatively I had one with a dodgy transformer on it (open circuit - was rattling round inside the casing wen I first got it). I just traced the path and attached a 12v dc power supply after the rectifier - worked fine.