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Alpha: Mic connector

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written by: MarkPowell

Hi John,
Thanks for the quick and honest reply. Although I'm not an absolute amateur with an iron I think I'll give it a miss and stick with a separate mic for now. If I change my mind it sounds like I'm better treating myself to DPA at some point.

Cheers,
Mark.

written by: Tenebrous

Sun, 27 Jun 2010 23:21:33 +0100 BST

Hey there :)

While I'm quite away off from even thinking of connecting a mic to the Alpha, I was wondering why do Eigenlabs need to do some custom electrical work on the mic to get it to work on the Alpha?

Also... wouldn't it make more sense to put the 'custom electrical work' into a little converter plug? Like a "3-pin xlrm" TO "4-pin LEMO" type thing?

Perhaps for us cheapskates, a 3.5mm stereo jack to 4-pin LEMO ;)

Obviously I'm only thinking of the connector differences here, and totally ignoring the electrical differences, since I have *no idea* about those :)


written by: geert

Mon, 28 Jun 2010 04:34:03 +0100 BST

Or even better, just some schematics that explain what's going on, we can then solder our own stuff and experiment.


written by: Tenebrous

Mon, 28 Jun 2010 12:51:16 +0100 BST

Generally speaking I agree with you Geert... but that has some really horrible implications with regards to the warranty though :)


written by: geert

Mon, 28 Jun 2010 13:09:30 +0100 BST

Why's that? I don't intend to open up the Alpha and solder stuff inside, it's to know the purpose of the pins and be able to solder my own cables with a Lemo connector that goes into the Alpha.


written by: john

Mon, 28 Jun 2010 13:10:39 +0100 BST

I'd dearly love to publish a little schematic and let everyone wire their own up, but the warranty and legal issues are too difficult for now. We wouldn't be able to warrant the instrument if you wired your own mic.

The Mic input supports three levels of phantom power, 48V, 20V and 8V, to suit different types of condenser microphone. This is partly software switchable but does require a wiring change between them as well, and its important to get that wiring right. Also, if you've ever tried to wire one of those tiny LEMO connectors up you'll appreciate how nice it is to have someone else do it for you, they are really difficult to get right, and really expensive to buy.

We may change this policy at some point in the future, but we'll need to review all the possible wiring errors that could be made and test them to make sure you can't blow anything up in the input and power circuitry first, a task we have yet to do. I'll ask Phil about it at some point to see what kind of ETA he might have for this, but it won't be in the next couple of months as he's working on the Basestation Pro MIDI right now.

John


written by: geert

Mon, 28 Jun 2010 13:41:39 +0100 BST

thanks John ... another todo! ;-)


written by: Tenebrous

Mon, 28 Jun 2010 14:24:08 +0100 BST

@geert - I think John answered the "why" there - I totally wouldn't want to plug something home-made onto the Alpha and risk killing something inside it!

Although of course my other question still stands - how feasible is it for Eigenlabs to (eventually) provide converter/adapter connectors?


written by: john

Mon, 28 Jun 2010 14:44:09 +0100 BST

Quite feasible if you don't want phantom power. If there is demand we could make some accessory available on this front. What did you have in mind? Say a 1.5M trailing lead, LEMO to female XLR? If it is going to be general, it would need to be a normal XLR, which is a huge connector, so I think the wire would need to be long enough so that you could loop it through a belt...

Sugestions welcome...

John


written by: Tenebrous

Mon, 28 Jun 2010 14:58:52 +0100 BST

@John - I don't have a use for it (yet, I'm afraid!) but my question was prompted by something in Geert's video regarding the mic supplier having his mic on backorder. I'm assuming any mic he'd use would need phantom power though.

I'm not at all a mic expert or anything... I'd probably just need a 3.5mm stereo -> LEMO.

You'd definitely need a small amount of wire between the LEMO and the other end though, as you say.


written by: geert

Mon, 28 Jun 2010 15:11:22 +0100 BST

@John, the LEMO to female XLR would be very handy indeed, no need for phantom power


written by: Tenebrous

Mon, 28 Jun 2010 15:32:33 +0100 BST

@Geert, sorry, I should not have spoken for you with regards to the mic connector you'd need ;)


written by: keywolf

Tue, 24 Apr 2012 04:21:11 +0100 BST

Low-Cost Lemo Connectors available here:
http://keywolf.com/


written by: MarkPowell

Tue, 24 Apr 2012 21:42:52 +0100 BST

Out of interest, did anything happen with this? I've already got mic's that I could use, but I'd buy a LEMO to XLR connector if it had support for phantom power and the price was sensible.


written by: john

Tue, 24 Apr 2012 22:08:58 +0100 BST

Hi Mark

We aren't going to make a converter lead (the quantities are just too vanishingly small to warrant it), but it's pretty easy to make your own, or just rewire a mic with a Lemo connector directly. Phil wrote a technical document on the interface which you can find here. There are quite a few different options in terms of mic power and type, you will need to wire to suit the kind you have. You will also need to make sure that you have some shock absorption built in to the mount - the DPA we supply has a clever little rubber mounting and we found that handling noise on the instrument bleeds into the mic very badly without it. We tried a number of mic's before settling on the DPA. Which, inevitably, was the most expensive of the lot, but also clearly way better than everything else.

Be careful doing your own wiring here - the mic input is designed to be tough but it's not indestructible and frying it probably means a new motherboard, which is an expensive mistake to make. We don't warrant self made connections, so if you do wire something up yourself and do damage then I'm afraid you're on your own. Having said that, there's no reason that you can't do it if you have some technical chops, or know someone who does - Phil's paper is pretty comprehensive.

You can find the Lemo connectors here if you're in the UK and want to buy one. They're best described as 'really fiddly' to solder, a steady hand and fine iron are needed.


John


written by: MarkPowell

Tue, 24 Apr 2012 23:42:28 +0100 BST

Hi John,
Thanks for the quick and honest reply. Although I'm not an absolute amateur with an iron I think I'll give it a miss and stick with a separate mic for now. If I change my mind it sounds like I'm better treating myself to DPA at some point.

Cheers,
Mark.



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