Topic: What are active cables and why do so many people use them?

[ycoop]

Second half of the question might be redundant.

I often see people using active cables as part of their rig. I searched the forums and couldn’t find anything explaining what active cables are. My google searching came up mostly blank, at least when it comes to active cables used for mics.

I come before you as a humble padawan, teach me the ways of the active cables.

[Gutbucket]

Makes for a more-compact, smaller and lighter rig at the microphone end of things.  "Active cables" are special high-impedance cables and connectors which allow one to separate the microphone capsule from the microphone amplifier body to which it is normally attached.  The microphone amplifier bodies can then be be placed remotely along with the recorder, or sometimes eliminated entirely if a special preamplifier is used in their place.

[rigpimp]

What Gutbucket said. 

An active cable is a small thin cable that allows one to separate a modular microphone capsule to be mounted away from the microphone body.  The result is a tiny, lightweight and compact rig on the stand and everything else tucked into your padded gear bag.

For MANY years only very high end mics had "active" options.  Schoeps, DPA, Neumann, etc.  Everyone else had to run full body mics and full size XLR cabling.  Fast forward to just a couple of years ago where a few very clever folks here reverse engineered the required active cable circuitry and capsule mounting for a lot of the more common microphone manufacturers like AKG, MBHO, etc.  You will often see these referred to as Nbob cables but they serve the same purpose, however for mics that might not normally have an active cabling option it makes them highly desirable.

Great question!  Keep 'em coming ycoop.

[ycoop]

Thanks for the responses!

If I’m understanding correctly with active cables you’d have something like mic capsules on rig > active cables > preamp > recorder as opposed to mic capsule connected to (pre?)amp body > regular ol’ cable > recorder?

Plenty more questions where that came from

[adrianf74]

Thanks for the responses!

If I’m understanding correctly with active cables you’d have something like mic capsules on rig > active cables > preamp > recorder as opposed to mic capsule connected to (pre?)amp body > regular ol’ cable > recorder?

Plenty more questions where that came from

Pretty much spot on. The "preamp" could be anything from a true preamp to PFA's (which allow the active cable to be powered by Phantom Power) to an nBox or baby nBox.  The latter two run on 9V power and have either RCA or 1/8" output allowing you to run direct to small deck like an M10, R05, etc. 

[thespacefish]

Was curious of this myself - thank you everyone who posted such thorough answers!

[rigpimp]

A good read if you have a spare hour or two:

http://taperssection.com/index.php?topic=160212.0
http://taperssection.com/index.php?topic=168809.0

It doesn't necessarily start at the beginning as that was the AKG actives thread.  I'm sure that can be found with some digging.  It was the genesis of the reverse engineering that created an active cable solution for the AKG CK capsule series...and a legend was born

[heathen]

The "preamp" could be anything from a true preamp to PFA's (which allow the active cable to be powered by Phantom Power) to an nBox or baby nBox.  The latter two run on 9V power and have either RCA or 1/8" output allowing you to run direct to small deck like an M10, R05, etc.

Is there an option that allows for either powering via phantom (like PFAs in your description) or powering via battery like the nBox?  Kind of a swiss army knife option?

[adrianf74]

The "preamp" could be anything from a true preamp to PFA's (which allow the active cable to be powered by Phantom Power) to an nBox or baby nBox.  The latter two run on 9V power and have either RCA or 1/8" output allowing you to run direct to small deck like an M10, R05, etc.

Is there an option that allows for either powering via phantom (like PFAs in your description) or powering via battery like the nBox?  Kind of a swiss army knife option?

Easy, get the active cables terminated in some form of small connection (there's a connection that is used for the nbob cables that escapes me right now) and then get PFA and preamp to accept that.  That's what I did previously.

[heathen]

I meant one box that could connect to the cables and either allow for phantom power or provide battery power.

[adrianf74]

I meant one box that could connect to the cables and either allow for phantom power or provide battery power.

I'm sure it could be done by why have one box that could be the point of breakdown?  Better to have different options available depending on what recorder/conditions you're recording in.

[H₂O]

Active cables - any cable that has active components (components that need power to be provided to operate) as part of the cable, connectors, etc.
Passive cables - any cable that does not have active components as part of the cable, connector, etc


Active components could include Transistors (i.e. FETs), opamps, vacuum tubes, etc


Examples of active cables for microphones: - Schoeps KC5, KCY, nBob's, DPA d:dictate series, New Neumann KM A/D series LC4 cable

Examples of non-active extension cables for microphones: Neuman KM100 series cables, MBHO 603 cables, Schoeps vintage CMMT cables,  Sennhieser MKH 8000 series extension cables

[larrysellers]

I guess the new nbob MBHO cables built as kcy or nbox style would qualify as active then.

[Hypnocracy]

The Epic AKG Active...started in 2006
http://taperssection.com/index.php/topic,59577.0.html

Naiant made three runs of 12 pairs starting in 2013...but, no more...Chuck with the first set...

I made a comparison recording of a moe. show: C-481 vs CK-61 > Naiant Active cable

http://taperssection.com/index.php?topic=159568.0

As noted above now SchoepsNBox is the only supplier of those and other makes.

[rigpimp]

The Epic AKG Active...started in 2006
http://taperssection.com/index.php/topic,59577.0.html

Naiant made three runs of 12 pairs starting in 2013...but, no more...Chuck with the first set...

I made a comparison recording of a moe. show: C-481 vs CK-61 > Naiant Active cable

http://taperssection.com/index.php?topic=159568.0

As noted above now SchoepsNBox is the only supplier of those and other makes.

I'm showing my ts.com age here but JK Labs made them before Nick did.  Not many but they worked.  There may even still be a set in the hands of someone here.

[H₂O]

nbox is around 2003?
rbox rumored to be in early 1990's (1993 - is this true?) - OK so 1991 per below
JK Labs (DVC and other product - can't remember both names - one was had the pre-amp and one didin't and simply replaced the bodies)  2001-2002 (possibly back to 1999) - 1998 or slightly before

nbox is an rbox (Reutelhuber box) built by Nick


Original nbox and rbox used some schoeps parts to build the capsule connectors (housing and contacts) - now nick uses nbob parts


Anybody know the timeframes around these?

[jefflester]

JK Labs (DVC and other product - can't remember both names - one was had the pre-amp and one didin't and simply replaced the bodies)  2001-2002 (possibly back to 1999)

Definitely earlier than 2001-2002. I borrowed a DVC and CK61 setup from Dan Schar in May 2000 for a few shows. His DAT trade list had some recordings made in 1998 with that setup:
Sam Butera and the Wildest
11-13-98   All   AKG CK61->DVC->HHB1Pro, 9ftstand, fob
MMW
6-20-98      ALL   AKG ck-61>DVC>SBM-1>D100   stage
Marc Ribot Y Los Cubanos Postizos
6-20-98      ALL    AKG ck-61>DVC>SBM-1>d100   Stage

DVC was the one with preamp, ECMS was the one without.

[daspyknows]

nbox is around 2003?
rbox rumored to be in early 1990's (1993 - is this true?)  April 18 1991 was the first show recorded with the first RBox.  Bill and I recorded Edie Brickel and the New Bohemians at Zellerbach Hall in Berkeley.  I had spent considerable time working to convince Bill to attempt the first Schoeps RBox rig and purchased the MK4 capsules on spec.  Those are the same MK4 capsules I still use today.

nbox is an rbox (Reutelhuber box) built by Nick The original NBox was a more professionally built RBox.  We used to refer to the original RBozes as the bomb which wasn't good in the post 9/11 world.  The design has evolved through the collaboration between Nick and Bill and today's version is an upgrade over the original design.  I still have my original RBox and use it as a backup rig.


Original nbox and rbox used some schoeps parts to build the capsule connectors (housing and contacts) - now nick uses nbob parts


Anybody know the timeframes around these?

[DSatz]

Active accessories (cables, goosenecks, rigid extension tubes that go between the capsule and amplifier of a condenser microphone) were invented and patented by Schoeps in 1973 as part of the Colette series. They were called "active" because the capsule end of the cable (etc.) contains active circuity--equivalent to the first FET stage of the microphone's amplifier.

The second manufacturer to offer a variety of remote capsule extensions was Neumann, for the KM 100 series (their first interchangeable capsule series after they introduced a cardioid-only microphone, the KMF 4, that had a permanently-attached extension cable--it could ONLY be used with that extension cable in place). In order to honor Schoeps' patent, they put the active circuitry into the capsule heads rather than the extension cables / goosenecks / tubes. Thus their capsules were "active capsules" rather than the cables (etc.) being "active cables" (etc.).

After the Schoeps patent expired, Neumann discontinued the KM 100 series and replaced it with the KM-A and KM-D series, which use passive capsules and active extensions. It's a better system for people who work with interchangeable capsules, since you don't have to pay for the FET circuitry again and again in each capsule that you buy.

In the past, Neumann and AKG had both offered capsule extensions with no active circuitry in them. But those were quite limited in length and were an RFI and distortion hazard, since the connections were unbalanced and at VERY high impedance.

--On this board, the term "active" has come to mean any extension cable for a condenser microphone capsule, whether it is truly active or not. Of course that's a misnomer in some cases.

--best regards

[justink]

I learned some stuff in here.

are the dpa402x series considered actives, or no?  i know all the guts are in the XLR connector.  i always considered my dpa4023/4028's as "actives".

[Charlie Miller]

Is there any difference in sound when using actives? I used to have KC5's for my Schoeps but got rid of them since they were more of a hassle when doing hundreds of shows a year (recording on stage). I honestly don't remember if I ever did a comparison to see if there was any difference,

[noahbickart]

Is there any difference in sound when using actives? I used to have KC5's for my Schoeps but got rid of them since they were more of a hassle when doing hundreds of shows a year (recording on stage). I honestly don't remember if I ever did a comparison to see if there was any difference,

Schoeps states that there is no sonic difference. However, some tapers claim to hear one.

[Charlie Miller]

Is there any difference in sound when using actives? I used to have KC5's for my Schoeps but got rid of them since they were more of a hassle when doing hundreds of shows a year (recording on stage). I honestly don't remember if I ever did a comparison to see if there was any difference,

Schoeps states that there is no sonic difference. However, some tapers claim to hear one.

 I would think that the full-bodied mic would have a better sound.

[noahbickart]

Is there any difference in sound when using actives? I used to have KC5's for my Schoeps but got rid of them since they were more of a hassle when doing hundreds of shows a year (recording on stage). I honestly don't remember if I ever did a comparison to see if there was any difference,

Schoeps states that there is no sonic difference. However, some tapers claim to hear one.

 I would think that the full-bodied mic would have a better sound.

Why? and "better" how?

I believe that the kc5 is an unbalanced cable, which limits the usable length and perhaps provides less RF rejection, but assuming the kinds of lengths tapers tend to use, I can't imagine how the kc5 might influence the sound in any way- that's what the people who designed them say, anyway.

I can understand why, if you didn't need to be "low profile," or weren't worried about weight on the stand, that you'd prefer to just mount the capsules on the bodies. Fewer parts = fewer potential points of failure.

On the other hand, the advantages of a smaller lighter mounting system, especially given the dedicated mounting options for active cable, are fairly obvious. I suspect nobody could successfully discern which rig was which in a mk4> cmc6 vs. mk4> kc5> cmc6 ABX comp.

There's another reason not to run the bodies these days: Cost. A nbob KCY> Niant PFA system is about half the price of a pair of cmc6 bodies. That's why I run actives all the time.

[ts]

So what exactly does a PFA do? I have 2 sets of active cables, both configured with Naiant PFA’s. I always assumed the PFA operates in a similar manner as the old Audio Technica phantom power modules, allowing 48V to be supplied to the mic cap. But as usual I’m probably wrong. 

[noahbickart]

So what exactly does a PFA do? I have 2 sets of active cables, both configured with Naiant PFA’s. I always assumed the PFA operates in a similar manner as the old Audio Technica phantom power modules, allowing 48V to be supplied to the mic cap. But as usual I’m probably wrong. 

Yes. The PFA takes the 48v Phanton Power and converts it to the 60v which the capsule needs.

Which, by the way, is exactly what a CMC6 does.

[Gutbucket]

A PFA does a few other things besides simply converting phantom power to whatever juice the microphone needs. 

When used with externally polarized condenser capsules such as this, it provides the polarization voltage as mentioned (commonly 60V but varies by manufacturer and sometimes mic-line), converts high microphone capsule output impedance to a lower impedance suitable for a cable run and driving the preamp or recorder inputs correctly, provides some amount of signal amplification (the first stage of amplification is the most important), and provides a balanced output.  All that is also the same functionality of the equivalent microphone amplifier body which the PFA replaces.

Some PFAs provide a much lower voltage for powering pre-polarized electrets (PIP mics) and varying degrees of amplification (some with unity gain). This is the same functionality as the AT PPAs.

Not all PFAs are alike, being made to suit specific microphone types and brands, but all serve the same basic roll in providing an appropriate interface between the microphone (capsule) and recorder input.

[yug du nord]

I have no evidence or examples or comps or anything scientific to prove anything...  but as great as PFA'a are, I don't/can't believe that they equivalent to mike bodies/amplifiers.
If so, then all mike bodies/amplifiers would be nothing but "snake oil".
Is the only reason that Schoeps (or any other brand) doesn't make their own PFA because it would eliminate the need for consumers to purchase their mike bodies/amplifiers??
I can't buy into that theory.

I do think that PFA's are fantastic..  they allow for lower profile rigs and they allow many more people the ability to run higher end capsules at a more affordable price. 

But I think that the electronics in high end microphone bodies/amplifiers help achieve the sonic character of the capsule that the manufacturer intended. 
Just my two cents and defense in running mike bodies/amplifiers. 

I've never run capsules with PFA's, but I've ran a few different variations of "active" mikes...  and have been strictly running bodies/amplifiers for a number of years now and am absolutely in favor of running bodies/amplifiers.  Although different preamps have also made a difference in the overall sound IMO.

[Gutbucket]

I have no evidence or examples or comps or anything scientific to prove anything...  but as great as PFA'a are, I don't/can't believe that they equivalent to mike bodies/amplifiers.
If so, then all mike bodies/amplifiers would be nothing but "snake oil".

No snake oil. They both perform a number of vital rolls in the recording chain as outlined above.  That they may or may not perform those rolls to the same specification shouldn't be an overly contentious thing to assert on a recording forum.  Obviously each microphone manufacturer uses a somewhat different implementation, and Schoeps has an outstanding reputation for quality.  Each implementation should be expected to measure somewhat better or worse in each category.  Whether those physical implementation differences and measurable specification differences are audible or not is another question - and a more difficult one to answer.  Some may not hear any audible difference, some may, and that difference might actually be significant or it may be imagined, and in either case some other unconsidered variable may be having a larger influence.

Is the only reason that Schoeps (or any other brand) doesn't make their own PFA because it would eliminate the need for consumers to purchase their mike bodies/amplifiers??
I can't buy into that theory.

 

A PFA is an amplifier body.  Its a replacement amplifier body from a different manufacturer.  Schopes actives are their "PFA" solution by a different name.

I do think that PFA's are fantastic..  they allow for lower profile rigs and they allow many more people the ability to run higher end capsules at a more affordable price. 

But I think that the electronics in high end microphone bodies/amplifiers help achieve the sonic character of the capsule that the manufacturer intended. 
Just my two cents and defense in running mike bodies/amplifiers. 

Of course, yet I don't see any one arguing against that.  Substitute the word preamp for PFA. Schoeps offers various preamps and their microphones work well with them.  Their microphones also work well with other manufacturers preamps.  They should be expected to measure somewhat differently.  Some will also sound different, others won't sound significantly different. 

[jcable77]

Is there any difference in sound when using actives? I used to have KC5's for my Schoeps but got rid of them since they were more of a hassle when doing hundreds of shows a year (recording on stage). I honestly don't remember if I ever did a comparison to see if there was any difference,

Schoeps states that there is no sonic difference. However, some tapers claim to hear one.

 I would think that the full-bodied mic would have a better sound.

I can only speak from the experience ive had with the akg naiant actives, but to my ear, theres a slight less “balls” on the lower end with the actives than the full body 460/480’s. Im guessing this isnt quite the case with shoeps actives or neumanns. The convenience factor is substantial though.

[noahbickart]

I have no evidence or examples or comps or anything scientific to prove anything...  but as great as PFA'a are, I don't/can't believe that they equivalent to mike bodies/amplifiers.IMO.

Respectfully, I don't think you get to have it both ways. If you think one piece of gear sounds better than another, you must think that on the basis of some evidence. 

I can think of loads of reasons that one might prefer the mic body to a PFA even if their sound is identical. Durability and ease of interfacing with studio gear come immediately to mind. The sexy nextel grey is another. We've already noted the ability to drive much longer cable runs.

But in terms of sonics? The only way to answer this question is with a double blind test. I’m skeptical that anyone would be able to identify a difference let alone a preference. But I’m willing to be convinced by evidence.

[wforwumbo]

I don't know the innards of the PFA circuit topology, but if the circuits are identical and the components are made to the same spec/tolerance, there should be no discernable difference. Electrons are electrons, and filters are filters; short of heat causing component drift, I don't see why they will sound any different.

Re: longer cable runs and reduced noise... that could be a function of running balanced vs. unbalanced. I thought the 5-pin binder KCY was balanced, but I can't say that I know whether or not the KCY/PFA implementation is fully balanced; if it were, then there should be no discernable difference on that front.

For what it's worth, I have zero issues running my KCYs and don't see a need or desire to run full bodies. If there is a significant difference, I'll take the convenience of active cables any day of the week, it's not like they don't make absolutely phenomenal tapes. I hear very little-to-no noise running my KCYs + PFA into my sound devices converters/preamps.

[jbell]

KCY cables aren't balanced!

I don't know the innards of the PFA circuit topology, but if the circuits are identical and the components are made to the same spec/tolerance, there should be no discernable difference. Electrons are electrons, and filters are filters; short of heat causing component drift, I don't see why they will sound any different.

Re: longer cable runs and reduced noise... that could be a function of running balanced vs. unbalanced. I thought the 5-pin binder KCY was balanced, but I can't say that I know whether or not the KCY/PFA implementation is fully balanced; if it were, then there should be no discernable difference on that front.

For what it's worth, I have zero issues running my KCYs and don't see a need or desire to run full bodies. If there is a significant difference, I'll take the convenience of active cables any day of the week, it's not like they don't make absolutely phenomenal tapes. I hear very little-to-no noise running my KCYs + PFA into my sound devices converters/preamps.

[wforwumbo]

KCY cables aren't balanced!

This is good to know, thanks! That does change things a little bit, though not in the way many are probably thinking it will.

The major benefit of running the full-bodied capsules, then, is in running balanced outputs. For the better, this allows for better noise rejection in noisy setups (though if you're running a battery-powered unit and have noise issues with unbalanced and any cable run less than 75 feet, there are bigger problems in your setup that should be addressed first). For the worse, balanced outs require additional circuitry at the output stage of the mic and the input stage of a mic pre. This additional circuitry usually means less linearity in the overall signal chain. So preferring balanced outs/bodies discredits the theory that signals should remain as pure as possible between the microphone and playback.

I can understand that there's a difference in sound between the two; as to whether or not the difference is significant or even noticeable, and if it's possible to identify why - I can't really say.

[Charlie Miller]

Is there any difference in sound when using actives? I used to have KC5's for my Schoeps but got rid of them since they were more of a hassle when doing hundreds of shows a year (recording on stage). I honestly don't remember if I ever did a comparison to see if there was any difference,

I also noticed that the AKG 460's sounded better than the actives. Fuller sound. I ran a bunch of tests with obaaron using both of our mics.

Schoeps states that there is no sonic difference. However, some tapers claim to hear one.

 I would think that the full-bodied mic would have a better sound.

I can only speak from the experience ive had with the akg naiant actives, but to my ear, theres a slight less “balls” on the lower end with the actives than the full body 460/480’s. Im guessing this isnt quite the case with shoeps actives or neumanns. The convenience factor is substantial though.

[rippleish20]

Is there any difference in sound when using actives? I used to have KC5's for my Schoeps but got rid of them since they were more of a hassle when doing hundreds of shows a year (recording on stage). I honestly don't remember if I ever did a comparison to see if there was any difference,

Schoeps states that there is no sonic difference. However, some tapers claim to hear one.

 I would think that the full-bodied mic would have a better sound.

I can only speak from the experience ive had with the akg naiant actives, but to my ear, theres a slight less “balls” on the lower end with the actives than the full body 460/480’s. Im guessing this isnt quite the case with shoeps actives or neumanns. The convenience factor is substantial though.

And even if if there is a sound difference, it could be attributable to the Naiant amplifier/power supply, not the active cable.


I'm with Noah, unless someone does real sound tests everything is just speculation.

[Charlie Miller]

I’m traveling but will post the samples when I get back. There’s a clear difference with the AKG’s

[bobwiely]

The Epic AKG Active...started in 2006
http://taperssection.com/index.php/topic,59577.0.html


I'm showing my ts.com age here but JK Labs made them before Nick did.  Not many but they worked.  There may even still be a set in the hands of someone here.

You are correct sir. I have had Dan Schar’s Jon Kajol Labs DVC (#6) for a decade or so, lol.
I have actives for both akg ck (61) and schoeps mk (4 & 41) caps.

[jefflester]

The Epic AKG Active...started in 2006
http://taperssection.com/index.php/topic,59577.0.html

I'm showing my ts.com age here but JK Labs made them before Nick did.  Not many but they worked.  There may even still be a set in the hands of someone here.

You are correct sir. I have had Dan Schar’s Jon Kajol Labs DVC (#6) for a decade or so, lol.
I have actives for both akg ck (61) and schoeps mk (4 & 41) caps.

Cool! I borrowed that JKLabs rig a few times from Dan when he was at UCLA, back around 2000.

[bobwiely]

MMW
6-20-98      ALL   AKG ck-61>DVC>SBM-1>D100   stage
Marc Ribot Y Los Cubanos Postizos
6-20-98      ALL    AKG ck-61>DVC>SBM-1>d100   Stage[/i]

I was there for these We ran the 414s upstairs.

[rippleish20]

I meant one box that could connect to the cables and either allow for phantom power or provide battery power.

Tha Naiant IPA (Not PFA) can be powered via internal 12v battery, external battery, or phantom power...

[jerryfreak]

Active cables - any cable that has active components (components that need power to be provided to operate) as part of the cable, connectors, etc.
Passive cables - any cable that does not have active components as part of the cable, connector, etc


Active components could include Transistors (i.e. FETs), opamps, vacuum tubes, etc


Examples of active cables for microphones: - Schoeps KC5, KCY, nBob's, DPA d:dictate series, New Neumann KM A/D series LC4 cable

Examples of non-active extension cables for microphones: Neuman KM100 series cables, MBHO 603 cables, Schoeps vintage CMMT cables,  Sennhieser MKH 8000 series extension cables

so were the neumann km100 series "actives" as ive always seen them called more subject to noise than say a true active solution?

[Gordon]

^^^

I think technically but I ran them for 12 years and never once had any noise or cell phone interference.  my set was made prior to 2007 but no idea how long before.