Hi from Denmark (NP Elektroakustik, 1983).

[SiBo]

Hi there

I am a studio rec/mix technician/ producer. Also PA sound. I do my best to service my equipment myself, still learning! So I am not an engineer, fx building my own clones. But it would be nice to find time for such projects one day.

Some Danish broadcasting history...

I own a 1983 previous Danish Broadcast corporation (DR) OB truck/ "Radio wagon" (Mercedes 613D) with a integrated NP Elektroakustik mixer. The power supplies are sitting behind the passenger seat in the cab.

Back in those days they custom build those mixers, so it seems like all of them are more or less different. Here is one of them...

https://da.m.wikipedia.org/wiki/Fil:U42_radiohuset.gif

I have attached a few fotos from my project here. My NP Elektroakustik, 26/8/2. 6 sends. Ch 25 and 26 were dedicated the one Lexicon reverb they had in the truck. They also had 8 x mono NTP (or was it 4 x stereo?) compressors for the 8 subgroups. Unfortunately the Lexicon and the NTPs were gone when I bought the rest .
No multitracking in that truck in 83. They mixed direct L/R for transmission, and one Studer stereo reel to reel tape machine + one more Studer for backup. The stereo recordings just for registration i believe.

The same year, 1983, DR also got their first OB "Music bus". For both direct transmissions and for multitracking, up to 48 tracks.

The electrolyte caps in my NP seems to be exactly as old as the rest! Some are leaking and some seems to have an out-of-body experience! None of them seems to have exploded though. So it is time to recap the whole mixer. Prepare yourself for questions about "the right caps"...

I signed in because Google showed me the way to some recent NP talk in here, and this other Danish guy, Erik. I will try to get in touch with him.

Oh, by the way, it must be time to replace both my mobile - and desktop phone

Cheers, Simon

 

[micolas]

@SiBo
Welcome to groupdiy!

 

[SiBo]

Thanks. Interesting forum

 

[erik_DK]

Hello Simon.

Welcome to groupDIY.
Good to meet other people interested in those old NP consoles.
The channel strip in your photos looks very much like the IK31 - am I right? Unfortunately I have only the block diagram and the component overlay for this one. It is in the technical documents section.
Hope you have all or some of the manuals and schematics for your desk. I would be glad to help you making scans and publish them here.
It is correct that most NP-consoles were custom built, but many of them share electronic design details. Eg. the mic pre amps are often the same basic topology just with some minor differences. The custom part often was about where to have the functions placed on the desk. Your modules have the gain controls at the bottom right over the fader, which is a bit unusual.
Feel free to contact me. I live in Århus, where are you? PM me for telephone number.

Kind regards Erik

 

[gyraf]

Velkommen, Simon!

I see that you already met Erik - he's probably the best resource for everything NP around here..

/Jakob E.

 

[Charlie]

I have a pair of preamp do sell! ik42b

 

[erik_DK]

I have a pair of preamp do sell! ik42b

Nice! IK42B. This is the IK42 with line-in only. No mic amp. Very good eq and filters.

 

[Charlie]

Hello Erik! Thanks for replying. I did see the reply a little late though... sorry
I am looking for the schematics of the IK42B because I do not find them anymore!!! I had them!!! disappeared!!!! Can you help?
Also, what are the main voltages I need to turn them on? My memory (which is usually wrong) tells me +15 -15 +24 0. Can you help with this too?

Thank you very much

 

[erik_DK]

Sorry for the late answer!

I think the schematics for the IK42B are the same as for the IK42, just that there is no mic module. I have made a post with all the schematics I have for the IK42 in the Technical documents section. Just look at page 6 of this document.

And you are right: +/- 15V and 24V should work - pinout is the same as for the "normal" IK42.

/Erik