Dual 1073 style micpre & EQ in 1u

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onlymeeee

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Feb 27, 2007
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436
Location
London
Hi all..
A while ago now I was having a conversation about the lack of a dual 1073 in 1u form with the same style as the original..  I was saying it was a shame that the original was a little bit wider than 1u or else it would fit great..  This lead to a "well why don't you build me one!" from my friend, and so I did!  This was almost a year ago now (wow how time flies)..  Anyway, I've recently took up the project again as my friend wants me to build a couple more and rather than do the metalwork by hand again, I'm going to get a batch made.  If there's any interest I can get a larger batch made up and make it a DIY project on my site www.thedonclassics.com too.

Anyway here's some pics! (I never got round to screen printing the unit I built, but the batch I get made will of course have screen printing on)
2nv73-front.jpg

2nv73-insides1.jpg

I also wanted to make a couple of extra features that aren't on other clones out there:
Powering system:
It can be powered either with a 24VAC transformer/adapter plug..  I normally chop the cheap 2.1mm connector off and use a good screw in Switchcraft connector..

Or it can also be powered by 51X.  Either the +24V rail or the -24V rail.  I realised I wasn't utilising the -24V rail on my 51X rack that much so decided to make use of it!

Almost no wiring:
It uses PCB mount Grayhill with hollow shafts.  So there's hardly any wiring to do.  The big annoyance of making a 1073 style unit in the original style is the immense amount of wiring, so with the PCB mount switches all that is avoided.. It's all connected with simple IDC ribbon connectors..
The only wiring is the 51X connector.
2nv73-pot-shafts.jpg


Easy to build/troubleshoot:
It uses all individual amp cards like the original did.  I've used pins and sockets like discrete opamps.. This is useful in troubleshooting..  if you have a problem with the unit, you can just lift out the card.. swap it with another etc.. fix it..  and put it back in without having to remove everything from the unit.
2nv73-ba-card.jpg


Full 80dB gain:
The problem with the 12 position switches normally is you can't have all the positions that a 1073 had..  so what I've one, is add a little 3 way toggle switch on the back so that when you're on 70dB gain on the front rotary switch, you can click to the side to get 75dB, and the other side to get 80dB.  Obviously not something you'll use often, but nice to have the option.

DI input:
As it's also a pin and socket card, there's the option of diying any design you like and slotting it in. Personally I've designed a "Rupert Neve-ish" DI based on what I think would suit best an old 1073..  ie. transistors.. BC caps..  mustard caps..
2nv73-insides-rear.jpg


2nv73-sim-front.jpg

2nv73-sim-back.jpg


The main PCB has footprints so that it can be built as a 1073, or a 1084.  I'm also planning on designing some other units that can slot in too for future projects.. 
 

okgb

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Joined
Oct 18, 2004
Messages
5,808
Location
Winnipeg Mb Canada
Looks Great!
although I'm in the process of downsizing
any rough idea of cost for critical components ?  or things you would supply ?
 

morganzgz

New member
Joined
Sep 4, 2017
Messages
1
This is one of the finest projects i've ever seen! Could you make a DIY project? I'm really interested in trying to do it.

Again, congrats!

 

onlymeeee

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Joined
Feb 27, 2007
Messages
436
Location
London
Thanks for the kind words everyone!  In that case, I'll definitely order a batch and do a DIY kit option, no problem.
I guess it'll be similar to my other kits.. ie. Metalwork.. PCBs.. and any important hard to get parts.. eg. The hollow shaft Grayhills.. then a Mouser cart for the other parts..
 

kante1603

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Dec 2, 2009
Messages
1,942
Location
Munich,Germany
This will be a great project,no doubt.
Though I can not see a switch for phantom.Will the inputs be fed externally (I have Neumann Phantom PSUs here,so no biggie for me)?


Just curious,


best regards,


Ido.
 

onlymeeee

Well-known member
Joined
Feb 27, 2007
Messages
436
Location
London
kante1603 said:
This will be a great project,no doubt.
Though I can not see a switch for phantom.Will the inputs be fed externally (I have Neumann Phantom PSUs here,so no biggie for me)?


Just curious,


best regards,


Ido.

Individual phantom switches are near the output gain pots, each with an LED to indicate phantom on
 

burdoto

Well-known member
Joined
Apr 13, 2015
Messages
85
Location
St Paul, MN
Sweet schnibets, I thought I was the only one to ever tried this. I built a rougher looking project similar to this with all the tedious wiring. Mine took so long I can't imagine making another one.

Yours looks much trustable.
 

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