Topic: W.T.F. is an 'N-Box'?

[NOLAfishwater]

The electronics involved really aren't a mystery, or particuarly difficult, especially given that AKG has published the schematics.  This is a problem of machine work, not electronic design.  I don't do hardly any machine work, and I'm mainly only interested in my own microphones.

if someone can make the CAD drawings I can make it happen with a local state of the art machine shop.

[illconditioned]

Nah, you need a few more components in the capsule:  the bias resistor (AKG used 10G), a coupling cap for the FET, a few resistors to divide the FET bias supply, and another 10G to bias the FET.  Also, not too many FETs that you'd want to use as a capsule FET can tolerate 60V, so you need to divide that supply as well (or maybe bias the audio pins at a lower voltage, saves parts in the capsule).  AKG's scheme is even a bit more involved than that; check their schematic for details--they have another FET as a cascode, and an IC, and some feedback . . . then the question becomes are people just going to be happy with the simplified version?  I mean you can skip the FET bias, but that will degrade headroom.  Or you could build a simpler circuit to run off of 48V phantom (~41V to the capsule), that will drop sensitivity a tad and degrade SNR (as in the CMRs).  Then you have the question of whether people are gonna be happy with the epoxied capsules.

I can crank out a pre with a 60V bias supply, that is not a problem, it's the capsule end I'm not interested in tackling.  Although there has to be demand for the 60V pre; it's expensive to bring these products to market.  It's fairly cheap to do a circuit that fits in an XLR connector (as in my PFA) and does +41V, signal (biased if necessary), and ground.  It wouldn't be anywhere near the full AKG circuit, but it would work.

Oops, yeah you're right about the capsule.

Revised part list (at the capsule):
- 1MR and 100nF, circuit to take +polarize and smooth it out
- 1GR bias resitor (could be 10G, but 1G is enough I think)
- FET (from Transsound TSB-120A capsule)
- 4.7kR source resistor for FET
- 47pF ceramic between capsule and FET gate

I used the FET from the Transsound capsule because it is "self-biased" so I don't need a dividing circuit.

In my prototype I cut then end of a pair of Studio Projects C4.  This includes just the part to screw in to the capsule.  I built the above components.  The input is a standard (two-wire) battery box, plus +60V (polarization).

The prototype seemed to work (using a bunch of 9v batteries in series for the polarization), but I did not do any field testing yet.  If you could build me a battery box with polarization (eg., for parts plus a small charge), I would be willing to continue on the project, and share my results with anyone who is interested.  Oh yeah, running 40V polarization might be OK.  That is equivalent to running a mic with a 10 or 20dB pad on, right?  Ie., the noise floor increases, but it still handles loud signals, which is what *most* of us want.  Also, remember that we need +polarize, but it is very low current, so it is not like a phantom supply.

As far as epoxied capsules, I would start with something cheap, like Studio projects C4.  If this works well, go for AKG.  These are cheap anyway.  I wouldn't mess with Scheops, though.  Besides we have the new (CMR?) collettes now, these do *exactly* what the above does, and if you've got money for Scheops, you can afford the CMR!

The fact is, I'm trying to get out of taping projects, but if someone else jumped in, I would probably slip back in  .

  Richard

[it-goes-to-eleven]

someone should just send their JK setup to mshilarious (jon w/ naiant) and let him reverse engineer it. this is assuming there is a demand for the product.

Since when did ripping off someone else's design become acceptable?

I'm going to guess that Jon's morals wouldn't allow that.

if someone wants to invest their own time and money to improve on a design and bring products to the marketplace, I am all for it.

So you think you're entitled to steal someone else's design because you're "improving" it?   Ah yes, the entitlement attitude.   Is sloppy machine work and o-rings innovation?

There is a huge difference between going off and designing your own system and copying someone else's work.  There are a bunch of details and developement work required.  As MSH. mentions in a later post, it all takes time and money.   It is so much easier to copy someone else's work.   Just because the original designer isn't around doesn't make it okay.   What applies in this case is copyright, not a patent.  And morals... for those who have them.

The suggestion that the design isn't original or special.. Sorry, but if that was the case you wouldn't need to reverse engineer it.  Of course...  Some people will do anything to make a buck, and rationalize it any way they can.  Demand does not justify stealing a design, or anything else.  Ultimately, there's going to be profit involved and that makes it all about making a buck no matter how you try and spin it.

[illconditioned]

someone should just send their JK setup to mshilarious (jon w/ naiant) and let him reverse engineer it. this is assuming there is a demand for the product.

Since when did ripping off someone else's design become acceptable?

I'm going to guess that Jon's morals wouldn't allow that.

if someone wants to invest their own time and money to improve on a design and bring products to the marketplace, I am all for it.

So you think you're entitled to steal someone else's design because you're "improving" it?   Ah yes, the entitlement attitude.   Is sloppy machine work and o-rings innovation?

There is a huge difference between going off and designing your own system and copying someone else's work.  There are a bunch of details and developement work required.  As MSH. mentions in a later post, it all takes time and money.   It is so much easier to copy someone else's work.   Just because the original designer isn't around doesn't make it okay.   What applies in this case is copyright, not a patent.  And morals... for those who have them.

The suggestion that the design isn't original or special.. Sorry, but if that was the case you wouldn't need to reverse engineer it.  Of course...  Some people will do anything to make a buck, and rationalize it any way they can.  Demand does not justify stealing a design, or anything else.  Ultimately, there's going to be profit involved and that makes it all about making a buck no matter how you try and spin it.

Most electronics people will know the circuit.  I certainly do.  I don't have to reverse-engineer it.  All this stuff is pretty basic.  I'm not saying building it is easy.  There are mechanical (fittings) and electrical (noise) issues, but the ideas are pretty basic.  The only thing we are doing is copying Scheops original "collette" design, which is probably out of patent anyway.

  Richard

[NOLAfishwater]

someone should just send their JK setup to mshilarious (jon w/ naiant) and let him reverse engineer it. this is assuming there is a demand for the product.

Since when did ripping off someone else's design become acceptable?

I'm going to guess that Jon's morals wouldn't allow that.

if someone wants to invest their own time and money to improve on a design and bring products to the marketplace, I am all for it.

So you think you're entitled to steal someone else's design because you're "improving" it?   Ah yes, the entitlement attitude.   Is sloppy machine work and o-rings innovation?

There is a huge difference between going off and designing your own system and copying someone else's work.  There are a bunch of details and developement work required.  As MSH. mentions in a later post, it all takes time and money.   It is so much easier to copy someone else's work.   Just because the original designer isn't around doesn't make it okay.   What applies in this case is copyright, not a patent.  And morals... for those who have them.

The suggestion that the design isn't original or special.. Sorry, but if that was the case you wouldn't need to reverse engineer it.  Of course...  Some people will do anything to make a buck, and rationalize it any way they can.  Demand does not justify stealing a design, or anything else.  Ultimately, there's going to be profit involved and that makes it all about making a buck no matter how you try and spin it.

Most electronics people will know the circuit.  I certainly do.  I don't have to reverse-engineer it.  All this stuff is pretty basic.  I'm not saying building it is easy.  There are mechanical (fittings) and electrical (noise) issues, but the ideas are pretty basic.  The only thing we are doing is copying Scheops original "collette" design, which is probably out of patent anyway.

  Richard

I was thinking that a new unit could have a rechargeable battery, be smaller, have variable gain, one singe 5 pin cable instead of 2 cables. As far as my mounts are concerned, I was stepped up when nobody else would. Talk is cheap and action speaks louder than words. 

if someone wants to volunteer a 460/480 + CK6x capsule, I can get with a machinist here to figure out what it will take to make the housing. of course, Jon probably has a machine shop already. I am just saying that if people want to get this off the ground, I am willing to help even though I don't even use AKG microphones.

[Scooter123]

Since the thread was hijacked to an AKG NBox, I'll highjack it again--

What would be the advantage?  I know AKGs are a third of the price of Schoeps and the 61 cap is well regarded.  Is that it?

And yet another highjack diversion--I've not used AKGs, except a very long time ago for cards for miking drums.  How does the AKG compare to the Schoeps mk4's?  I don't want to start a mike war, but I'm wondering what the difference might be.  Certainly not better than mk4's although it might be different, eh?  Probably crisper and less warm? 

[NOLAfishwater]

Well the trick to the AKGs is they apparently have connections for diaphragm, backplate, and capsule case (I am not familiar with these at all).  So the capsule coupling has to be able to interface with that.  That's probably trickier than threading the piece of pipe.

Did a quick sketch, and the capsule components will fit on a circular PCB that is 1/2" diameter, all SMT except for 2x 1Gs and 1 TO-92 FET.  I would suggest including a 3-pin mini-XLR jack in the capsule coupling for convenience.

did you see the schematic here: http://taperssection.com/index.php?topic=93559.150

[illconditioned]

Since the thread was hijacked to an AKG NBox, I'll highjack it again--

What would be the advantage?  I know AKGs are a third of the price of Schoeps and the 61 cap is well regarded.  Is that it?

And yet another highjack diversion--I've not used AKGs, except a very long time ago for cards for miking drums.  How does the AKG compare to the Schoeps mk4's?  I don't want to start a mike war, but I'm wondering what the difference might be.  Certainly not better than mk4's although it might be different, eh?  Probably crisper and less warm?

Yes, you got it, AKG are way cheaper.  I would prefer the Schoeps if I had the money, but AKG are fine.

Why build an akg-box?  Well, it is *really* cheap.  Those capsules can go as low as $500 a pair, and you don't need bodies, so it is a great rig.

If I had the money I would just go for MK41/CMR rig like Dartrain has.  This setup is incredibly small, uses very little battery, and sounds great!

  Richard

[OFOTD]

Since the thread was hijacked to an AKG NBox, I'll highjack it again--

What would be the advantage?  I know AKGs are a third of the price of Schoeps and the 61 cap is well regarded.  Is that it?

And yet another highjack diversion--I've not used AKGs, except a very long time ago for cards for miking drums.  How does the AKG compare to the Schoeps mk4's?  I don't want to start a mike war, but I'm wondering what the difference might be.  Certainly not better than mk4's although it might be different, eh?  Probably crisper and less warm?

ck63 = BEST HYPER EVER!   

That's why.

[Todd R]

Um, having owned and used both, I'll have to disagree and correct you:  Gefell m210 -- best hyper ever! 

The AKG ck6x caps are all very nice sounding, and the ck63 is an excellent hyper cap.  I'd agree that the benefit over the schoeps is that the AKG line is much cheaper and sounds very good (and that AKG's aren't schoeps -- nice mics, but I don't really like them at all for amplified PA recording).

On the hypers, to me this is the biggest reason for the AKG active-capsule box.  If the box once designed plus the active cable/collette is going to be at least $500-700 or so (which seems quite possible), for the cost of that plus the ck6x caps, I'd opt for a set of milab vm44-links instead.  The milabs have omni and card caps, so the main difference in going to an AKG setup is the option for nice sounding, active-style hypercard mics.

[Todd R]

Question (probably for richard or jon):

Is it possible to design a box that provides a universal functionality of mic bodies plus the needed voltage/polarization to work with multiple mic brand capsules?  I realize each capsule might need slightly different polarization voltages or whatever, but if that can be fairly easily changed/customized within each box, could it be possible to have one basic design meet the needs of numerous brands of capsules?

I'm thinking that for AKGs and Gefells, someone or some homegrown startup company can make the specific machined collettes to fit the AKG ck6x caps and the Gefell m2x caps.  This theoretical company can outfit the collettes with a universal active circuit -- FETs, resistors, etc.  For MBHO and Milab, I'm hoping it would be possible to get the active cables (with FETs etc already in place as per usual) sold as individual parts.  Each of these different active cable lines could be outfitted with the same type of connector (4pin mini-XLR?) for use on the universal mic-body box. 

Probably could do the same with neumann, though they are really active capsules and not active cables, and I'm not sure a big company like this would like to supply parts so the market could bypass their existing product line (km100/km140/km150).  Ditto with schoeps, since they already have the CMR's and we have the n-box, the schoeps angle probably isn't worth it.

But if one company can make a universal box to act as the bodies for many different brands of mic capsules, and can even make this as a mic preamp as well (I'm thinking Naiant, since jon seems well established along this route), then the total market for these mic body/mic preamp boxes might be a large enough segment to address with a single product.

The homegrown collette/active cable company can act as a sister company to provide the needed gefell, akg, mbho, milab active cables for use with the universal box.

Pipe dream I'm sure, but Jon's tinybox got me wondering about this awhile ago.  If I could replace my milab mic bodies with a tinybox type box that acts as mic bodies and mic preamp, it would be great.  Even better if I could use the same box with my Gefell caps.

[page]

Question (probably for richard or jon):

Is it possible to design a box that provides a universal functionality of mic bodies plus the needed voltage/polarization to work with multiple mic brand capsules?  I realize each capsule might need slightly different polarization voltages or whatever, but if that can be fairly easily changed/customized within each box, could it be possible to have one basic design meet the needs of numerous brands of capsules?

I'm thinking that for AKGs and Gefells, someone or some homegrown startup company can make the specific machined collettes to fit the AKG ck6x caps and the Gefell m2x caps.  This theoretical company can outfit the collettes with a universal active circuit -- FETs, resistors, etc.  For MBHO and Milab, I'm hoping it would be possible to get the active cables (with FETs etc already in place as per usual) sold as individual parts.  Each of these different active cable lines could be outfitted with the same type of connector (4pin mini-XLR?) for use on the universal mic-body box. 

Don't the MBHO's contain all of their electronic pieces in the cap (which is one reason it's longer then a schoeps mk cap) so your cable is just a 4 or 5pin mini-xlr (like the beyers). I thought most of the changable cap systems were of that variety compared to schoeps.

Point stands though, effectively what differences are there in voltages required, and then second, what connector would need to be created. The connectors would be unit connecting to a normal multi-pin mini XLR and you select which option either at ordering similar to the jklabs equipment. You could do internal DIP switches and have it be field selectable so that the boxes are even more generic.

[Chuck]

Question (probably for richard or jon):

Is it possible to design a box that provides a universal functionality of mic bodies plus the needed voltage/polarization to work with multiple mic brand capsules?  I realize each capsule might need slightly different polarization voltages or whatever, but if that can be fairly easily changed/customized within each box, could it be possible to have one basic design meet the needs of numerous brands of capsules?

I'm thinking that for AKGs and Gefells, someone or some homegrown startup company can make the specific machined collettes to fit the AKG ck6x caps and the Gefell m2x caps.  This theoretical company can outfit the collettes with a universal active circuit -- FETs, resistors, etc.  For MBHO and Milab, I'm hoping it would be possible to get the active cables (with FETs etc already in place as per usual) sold as individual parts.  Each of these different active cable lines could be outfitted with the same type of connector (4pin mini-XLR?) for use on the universal mic-body box. 

Probably could do the same with neumann, though they are really active capsules and not active cables, and I'm not sure a big company like this would like to supply parts so the market could bypass their existing product line (km100/km140/km150).  Ditto with schoeps, since they already have the CMR's and we have the n-box, the schoeps angle probably isn't worth it.

But if one company can make a universal box to act as the bodies for many different brands of mic capsules, and can even make this as a mic preamp as well (I'm thinking Naiant, since jon seems well established along this route), then the total market for these mic body/mic preamp boxes might be a large enough segment to address with a single product.

The homegrown collette/active cable company can act as a sister company to provide the needed gefell, akg, mbho, milab active cables for use with the universal box.

Pipe dream I'm sure, but Jon's tinybox got me wondering about this awhile ago.  If I could replace my milab mic bodies with a tinybox type box that acts as mic bodies and mic preamp, it would be great.  Even better if I could use the same box with my Gefell caps.

Todd, this is exactly what I was thinking. If someone could do this, there would be huge market and a better motivation for someone to develop it.

[Todd R]

Don't the MBHO's contain all of their electronic pieces in the cap (which is one reason it's longer then a schoeps mk cap) so your cable is just a 4 or 5pin mini-xlr (like the beyers). I thought most of the changable cap systems were of that variety compared to schoeps.

Yeah, I was thinking that as I wrote it, but didn't know the answer so I just let it be.

My milabs do not have the active elements in the capsule, so I presume they are in the active cable heads.  DSatz makes it sound like for patent reasons, only schoeps the patent holder does this, but my milabs are the same design.  Clearly not like the active capsule design of the neumann ak40/ak50/etc. Isn't the Rode nt6 also the same design?

[illconditioned]

Don't the MBHO's contain all of their electronic pieces in the cap (which is one reason it's longer then a schoeps mk cap) so your cable is just a 4 or 5pin mini-xlr (like the beyers). I thought most of the changable cap systems were of that variety compared to schoeps.

Yeah, I was thinking that as I wrote it, but didn't know the answer so I just let it be.

My milabs do not have the active elements in the capsule, so I presume they are in the active cable heads.  DSatz makes it sound like for patent reasons, only schoeps the patent holder does this, but my milabs are the same design.  Clearly not like the active capsule design of the neumann ak40/ak50/etc. Isn't the Rode nt6 also the same design?

I think patent reasons prevented actives in the past, at least an active collette with a bare capsule.  Neumann put actives in the capsule to avoid this, probably.  But now we have at least three others: Milabs, Beyerdynamic, MBHO, and yes, you're right Rode, so patent is no longer an issue I'm guessing.

Now as to making a "general" box, I don't see the point.  All three actives above are priced right.  The only advantage I see is for AKG, since we can get a great hyper capsule for a cheap price.  As for Geffell, there might be some benefit, as this is a very good capsule, but it is pretty expensive, and not that common, so this need is less likely to be addressed by so-called "gear hackers".

As for making it financially worthwhile, I think this is dicey.  The box would have to be pretty cheap to compete with Milabs, Beyerdynamic, etc.  And the box is unlikely to be as well designed as those either.  One slight advantage of the box over bodies + active cables is reduced size and battery power.  It may be worthwhile to just get the mics + collettes from Beyerdynamic, etc and run a small battery box + polarization circuit.  Perhaps Jon could build one of those?  Even if it sold for the same price as the bodies, it would be smaller and lower power.

At this point I'm sitting on the fence.  If someone, Jon or otherwise, built a custom 3-wire battery box with an extra +60V polarization voltage in it, and price it at say $200, I would probably hardwire (FET + other parts behind) my CK63 caps and use it.

  Richard