Topic: AKG Active Project part 3

[datbrad]

I have been reading this thread, along with every other one on TS over the years about the idea of a remote capsule option using the CK6x>460/480 akin to the Schoeps/Neumann products. I must have missed the part in the most recent chapter of this thread where there is a mention of the active circuit that must be added to allow such a capsule separation with the AKGs, and if so please exuse me.

Now, I may be wrong, but my understanding is that the Schoeps active circuit is in the end of the KC5/KCY that the capsule mounts to, and with Neumann, the active circuit is included in the capsule, allowing for the use of the LC3 cable.

The CKx>MK46>460 remote capsule works because the CKx series have permanently polarized elements (electret) and since the CK61/62/63 capsules require polarization voltage, does this not require an active circuit, not just the cable and threaded connectors to hook everything together? My thought here is that all the listed parts another poster gave have been available for over 20 years, so why has this not been already done if it is a simple as just adding a wire with connectors at each end that match the threads?

Not trying to squash anyone's efforts, as I would be all over a genuine active cable solution that would sound identical to having the capsules mounted directly to the preamp bodies. Even if it was close to the same price as the Schoeps cable, it would be fine because it would be getting AKG sound with the Schoeps/Neumann active setup ergonmics which would be awesome.

Hope this really goes somewhere this time...............

[Chuck]

I have been reading this thread, along with every other one on TS over the years about the idea of a remote capsule option using the CK6x>460/480 akin to the Schoeps/Neumann products. I must have missed the part in the most recent chapter of this thread where there is a mention of the active circuit that must be added to allow such a capsule separation with the AKGs, and if so please exuse me.

Now, I may be wrong, but my understanding is that the Schoeps active circuit is in the end of the KC5/KCY that the capsule mounts to, and with Neumann, the active circuit is included in the capsule, allowing for the use of the LC3 cable.

The CKx>MK46>460 remote capsule works because the CKx series have permanently polarized elements (electret) and since the CK61/62/63 capsules require polarization voltage, does this not require an active circuit, not just the cable and threaded connectors to hook everything together? My thought here is that all the listed parts another poster gave have been available for over 20 years, so why has this not been already done if it is a simple as just adding a wire with connectors at each end that match the threads?

Not trying to squash anyone's efforts, as I would be all over a genuine active cable solution that would sound identical to having the capsules mounted directly to the preamp bodies. Even if it was close to the same price as the Schoeps cable, it would be fine because it would be getting AKG sound with the Schoeps/Neumann active setup ergonmics which would be awesome.

Hope this really goes somewhere this time...............

I can start to answer some questions for you.
Not everone agrees on what they want out of this project. Some will only be happy with an "active" cable that gioes between the pre-amp bodies and the caps. Some want to reverse engineer the JKLabs box. Then, still some want to make a minimal circuit housed near the capsule that allows the caps to be used without the pre-amp bodies and or the JKlabs type box. I'm in the later camp. I know there are circuits out there already that will allow the CK-6x caps to work without the pre-amp bodies. That's the quick and dirty way, like the Schoeps group has done with the Naiant tinybox.

I keep hearing that the reason this isn't moving is because of the machining needed to make the proper connection between the caps and the "active part of the circuit.


edit to add:

I am trying to collect all the info needed to have ready when we find a machinist that can make the collettes.

[Chuck]

The way I see it, every group needs this one thing, the machined collettes regardless of what electronics they need to achieve their goal. . If we can get plans drawn up for those, everybody would benefit...

edit to add:

It would be nice if the finished cap/collette combination had the same dimensions that some of the other available active options have, so we could use existing stereo type bars (think Kwon bar or NOLA bar) to mount them.

[datbrad]

The way I see it, every group needs this one thing, the machined collettes regardless of what electronics they need to achieve their goal. . If we can get plans drawn up for those, everybody would benefit...

Thanks for the explanation, and based on your breakdown of potential user demand, I fall in the camp that is looking to keep the 460/480 bodies in the path, with an active cable like the one Schoeps has with their collette series separating the capsule.

I say this because I have yet to hear any of the DYI solutions that remove the preamp bodies, the JK Labs or the various Nbox/Naiant solutions with Schoeps, that don't audibly alter the tone of the mics. The only "no bodies" solution I have ever heard that sounded basically the same as with the bodies is the Schoeps VMS boxes using the KCY cable.

[illconditioned]

This is not rocket science, folks.

It will come about when:
- Jon makes a littlebox that gives 40-60v polarization voltage.  This seems to be in the works (to power Beyerdynamic CK930 caps)
- someone gets a pair of collettes and gives them to someone, a hacker.  Not me, but someone like Jon or Chris Church maybe

Once we see a prototype with CK6x capsules dangling off a littlebox, I think things will start moving...

  Richard

[Todd R]

Brad -- there've been a lot of threads on this, but here's one that Chuck is probably thinking of you may have missed:

http://taperssection.com/index.php?topic=136687.msg1780455#msg1780455

Short version, it seems that jon/mshilarious is considering making something to fit the bill using a version of his PFA circuit.  So from what I understand, it would be the needed active electronics in the collette head (ie., FET) and a separate PFA-like circuit to convert 48v phantom from the preamp to the necessary voltages for the capsule (ie, take the place of the mic bodies).

On the sound, I think this will indeed change the current sound, but I also think no matter what is done, including keeping the 460/480 bodies in the equation will change the sound.  My jklabs ECMS box for the ck6x caps changed the sound (not much, but some) and for that matter when I did a controlled comp of neumann km184's to km140s, there was a difference in the sound, though neumann claims they share the same capsule and electronics.  Send the signal through one additional FET which is necessary for the de-coupled capsules and bodies and you can/will change the sound some.  Likely very very little, but purists seeking the 460/480 sound with active-cables might never achieve the exactly-the-same sound, no matter if the new active cables keep the bodies in the equation or not.

Chuck -- on the connectors, if the new active capsule "heads" were made to accept a detachable mini-XLR cable (so no integrated cable, just the active head), there are kwonbars for the MBHO line of "active" mics that would fit this new AKG project.  This does make the whole setup longer and bigger for those really doing true stealth with them, but by keeping the cables separate, it allows you to have longer or shorter cables as needed and allows you to just cheaply replace the cable should it go bad, rather than replacing or fixing a combined collette head and cable.

[Dkrogh]

2 things that I have discovered since I ordered the parts from AKG I posted on the previous page.

If this project is to use the parts you order from AKG (their PCB & plastic PCB holder, I don't know if the ring will need to be used), you can not insert them through the front of the threads on the mic body tubes so I assume this would be the same with any brass colette that was to be machined.  Second, about the only way to use the AKG parts would be to have some kind of design where they enter the colette like the AKG body circuitry enters, from the back.

If the AKG parts were to be used there always is a chance the parts are discontinued, if AKG comes out with another style of condenser mics.

I have thought about the retaining ring that was talked about but I aborted that thought since AKG parts couldn't enter the front of the colette (based on previous assumptions stated above).  I think that if a custom PCB is made, though, there is a chance that the original colette's may work from a design standpoint.  If a retaining ring is to be used I thought it would need to be plastic because I have not been able to find brass rings online (I searched through a few pages of google is all) and I figured that any other type of metal would cause corrosion either on the brass, or the retaining ring itself and leaving a residue on the electronics of the colette causing problems with the longevity of the head/box.  I have found however a website/company that will make custom ring's online (http://www.arconring.com/design). I don't know prices or any info along those lines. 

http://www.arconring.com/eaton/internal-notched-retaining-ring-in < website page is an example of the type of ring I think would need to be used, not necessarily the metal or finish.

I also do not know if AKG parts are discounted for larger orders, if they do it may be something to take into consideration.

Again, link to pictures of 460 bodies, caps, pins, electronics that I took as well as AKG parts I ordered.

AKG bodies etc http://www.flickr.com/photos/davidkrogh/sets/72157624728953731/
AKG parts (PCB, plastic holder, ring) http://www.flickr.com/photos/davidkrogh/sets/72157624977412924/

If people would like to see some other angle with parts/bodies I will take the pictures and put in the appropriate album.

[willndmb]

i thought people where having trouble getting the center pin figured out - guess i was lost
shouldn't any machine shop be able tp measure and make the end cap?

[datbrad]

Brad -- there've been a lot of threads on this, but here's one that Chuck is probably thinking of you may have missed:

http://taperssection.com/index.php?topic=136687.msg1780455#msg1780455

Short version, it seems that jon/mshilarious is considering making something to fit the bill using a version of his PFA circuit.  So from what I understand, it would be the needed active electronics in the collette head (ie., FET) and a separate PFA-like circuit to convert 48v phantom from the preamp to the necessary voltages for the capsule (ie, take the place of the mic bodies).

On the sound, I think this will indeed change the current sound, but I also think no matter what is done, including keeping the 460/480 bodies in the equation will change the sound.  My jklabs ECMS box for the ck6x caps changed the sound (not much, but some) and for that matter when I did a controlled comp of neumann km184's to km140s, there was a difference in the sound, though neumann claims they share the same capsule and electronics.  Send the signal through one additional FET which is necessary for the de-coupled capsules and bodies and you can/will change the sound some.  Likely very very little, but purists seeking the 460/480 sound with active-cables might never achieve the exactly-the-same sound, no matter if the new active cables keep the bodies in the equation or not.

Todd, Thanks for this explanation. I agree on the difference between the 184 and 140, but I have heard tons of recordings with the KM100s using the AK40s both mounted on the bodies and separated by the LC3 cable, and I can't hear a difference between them. Same with the CMC64 combo versus the CMC6>KC5>MK4, I can't hear a difference. I expect that was the point for both systems.

If AKG was going to make an active cable, I also expect they would seek to make it audibly invisible compared to caps on the bodies.

Thinking about the form factor of the KM184s, I wonder if it would be possible to take the 460 bodies and chop them short like 184s, which can then be mounted in a holder smaller than 460/480s can currently, but not quite as small as a collette would be. It's a compromise that may work. If the XLR connector was eliminated, for example, and the bodies hard wired like the Schoeps CCMs.


Just thinking out loud........................

[Todd R]

Brad -- the lack of any audible difference with the schoeps body vs active system is probably a result of good engineering and testing.  On the km100+ak40 caps vs km100+lc3ka cables+ak40 caps -- DSatz has had a number of threads on this, but the lc3ka cables aren't actually active cables like the schoeps.  The active circuitry (FET presumably) is not found in the lc3ka cables but instead is found in the ak40 capsule head.  You can see this in the length of the "capsule" head, and can see that this ak40 capsule is a different size and configuration than the unscrewable (but not user replaceable theoretically) capsule on the km184.

So for the km100+ak40 combo, the signal path goes through the same electronics, including FET, whether it is just bodies + caps or bodies + caps + cables (since that FET is actually in the capsule head, not the cable).  This would explain why they sound the same (and possibly why the combo sounds different than the km184) -- it really is exactly the same circuit with or without the "active" cables, since the "active" lc3ka cables are in fact passive.  This was done to not infringe on the schoeps active cable patent, that puts the active electronics (FET) in the cables, not the capsule head. 

[datbrad]

Brad -- the lack of any audible difference with the schoeps body vs active system is probably a result of good engineering and testing.  On the km100+ak40 caps vs km100+lc3ka cables+ak40 caps -- DSatz has had a number of threads on this, but the lc3ka cables aren't actually active cables like the schoeps.  The active circuitry (FET presumably) is not found in the lc3ka cables but instead is found in the ak40 capsule head.  You can see this in the length of the "capsule" head, and can see that this ak40 capsule is a different size and configuration than the unscrewable (but not user replaceable theoretically) capsule on the km184.

So for the km100+ak40 combo, the signal path goes through the same electronics, including FET, whether it is just bodies + caps or bodies + caps + cables (since that FET is actually in the capsule head, not the cable).  This would explain why they sound the same (and possibly why the combo sounds different than the km184) -- it really is exactly the same circuit with or without the "active" cables, since the "active" lc3ka cables are in fact passive.  This was done to not infringe on the schoeps active cable patent, that puts the active electronics (FET) in the cables, not the capsule head.

Todd, Thanks again, but I think you may have missed where I stated a few posts back where I get the distinction between the two.

Now, I may be wrong, but my understanding is that the Schoeps active circuit is in the end of the KC5/KCY that the capsule mounts to, and with Neumann, the active circuit is included in the capsule, allowing for the use of the LC3 cable.

I know that the solution will require the active electronics to be within the cable system, and I agree that to get one that has no audible difference than caps mounted to bodies will require "good engineering and testing". I guess I am a pipe dreamer in saying that for me, having an active cable to separate the caps from the bodies without compromising the quality and character of the sound is the only option I would personally invest in. I hope one day someone pulls it off, I really do.

[Todd R]

Oops, you're right Brad, I did miss that -- sorry!

[datbrad]

Oops, you're right Brad, I did miss that -- sorry!

No problem.

[Chuck]

I stumbled on this recently:

http://www.prodigy-pro.com/diy/index.php?action=printpage;topic=26226.0

Marik made some adapters that allows him to mount CK-61 and CK-62 capsules on another mic body.

[Chuck]