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Author Topic: How do you wire the Denecke PS-2 to a single mini plug?  (Read 9213 times)

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Offline ScoobieKW

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Re: How do you wire the Denecke PS-2 to a single mini plug?
« Reply #15 on: September 13, 2011, 05:01:57 PM »
I've considered leaving my ps-2 intact. In my case, with my shop and techs I have, I feel like I can make the mod in a clean reversible way.  Desoldering the whole cable assembly and replacing with a 3 wire solution. This way I haven't chopped the original cable and can restore it to standard config.

I'm currently using a shorted adapter, which is why in my case I'm confident that shorting pin 3 to ground will work.

As to equipment that doesn't like shorted unbalanced, do you have models to watch for? Types of gear? I'm not being facetious, it's just that as a company we've been using the shorted technique for years. Well over the 7 that I've worked here.
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Offline hi and lo

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Re: How do you wire the Denecke PS-2 to a single mini plug?
« Reply #16 on: September 13, 2011, 05:47:10 PM »
DSatz explains it best, so I will quote him! Personally, I've never used equipment where shorting pin 3 was potentially hazardous, but there are certainly situations where it would be.

Quote from: DSatz
This is a recurrent question, and perhaps it ought to be handled in a "frequently asked questions" list.

Unfortunately the various methods of unbalancing a signal are all needed in various situations. There is no one general approach to unbalancing a signal that always works regardless of the output circuit that is generating the signal. The manufacturer of that equipment must always be asked. In some cases you'll need to leave one lead or the other unconnected entirely; in other cases you'll need to connect one lead or the other directly to ground; in yet other cases you'll need to connect one lead to ground via a capacitor. So that's six different adapter or wiring schemes right there--and in some cases, using the wrong approach (particularly grounding one of the leads directly) can damage the equipment from which the signal is coming, interfere with the powering scheme for a microphone, and/or cause gross distortion to occur.

An input transformer is probably the "most nearly general solution," but good audio transformers are far from cheap (as you may have noticed on the Jensen site--I use and recommend their gear), but a transformer suitable for microphone-level signals and impedances isn't usually suitable for line-level signals and impedances or vice versa, so again it always comes down to specific cases.

If you want to build or buy an adapter or adapter cable, you MUST find out the specific recommended connection scheme from the manufacturer of the equipment that is producing the signal (e.g. the microphone), and use ONLY that connection scheme with that equipment. You can't infer from "similar" equipment of another brand, or even from another model made by the same manufacturer. For example, if you connect a Neumann KM 140F to an unbalanced input the same way Neumann recommends doing it for the KM 140, you'll get nothing but crosstalk and noise--no useful signal at all. Similarly, if you connect a Schoeps CMC 5-- or 6-- microphone the way that was recommended for the CMT 5-- series, you'll very likely damage the microphone.

I have seen postings here that have recommended connection schemes that would work OK at low-to-moderate sound pressure levels, but would reduce the headroom of the microphone substantially; this is not something to determine by casual experiment or hearsay. Ultimately the information has to come from the equipment manufacturer to be reliable. Enough said, I hope?

Offline yousef

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Re: How do you wire the Denecke PS-2 to a single mini plug?
« Reply #17 on: September 14, 2011, 02:28:14 AM »
I'm getting more confused now...

DSatz, as quoted, seems to be referring to plugging a mic into an unbalanced input - but do the issues he mentions also apply to what we're doing (unbalancing the output of a power supply)?

Or do they amount to the same thing in practice?
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Offline DSatz

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Re: How do you wire the Denecke PS-2 to a single mini plug?
« Reply #18 on: September 15, 2011, 10:52:21 PM »
yousef, yes, they amount to the same thing in practice as far as the audio signal is concerned.

But remember, too, that some phantom power supplies leave the DC on their outputs along with the audio signals. If you unbalance those connections by grounding one signal lead, you can draw more current (ca. 7 mA per shorted lead) than the supply is designed to put out. I have actually had equipment burn out and put out a puff of smoke because too much current was being drawn from its phantom power supply by a pair of microphones.

--best regards
music > microphones > a recorder of some sort

Offline yousef

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Re: How do you wire the Denecke PS-2 to a single mini plug?
« Reply #19 on: September 17, 2011, 04:30:04 AM »
Oh, there's nothing simple is there...

Thanks for all the replies.
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Offline Nick's Picks

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Re: How do you wire the Denecke PS-2 to a single mini plug?
« Reply #20 on: December 14, 2011, 07:35:58 AM »
I think a real pimp way to do this would be to jump new wires onto the PCB, and drill a hole in the aluminum case for a 1/8th jack (no wire).

Offline F.O.Bean

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Re: How do you wire the Denecke PS-2 to a single mini plug?
« Reply #21 on: December 28, 2011, 04:15:43 AM »

While there is debate as to whether shorting one half of the balanced signal to ground is a good idea, it works with my setup. Your mileage may vary.

I know the Denecke PS-2 modification is quite common, but have you considered simply making a breakout xlr > 1/8" cable? This solution, while not as streamlined, keeps the unit unmodified for resale value and better yet, you definitely won't damage it attempting the modification.

This is what I do out of my Sonosax>M10 setup, and it works like a frickin charm ;D 8) I just had Darktrain make me an XLR>1/8" cable and its a solid connection now. Its much more rugged/robust than running 1/8" Line-Out of my Sonosax, which just isnt as snug as I'd like it to be :(
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Offline yoclay

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Re: How do you wire the Denecke PS-2 to a single mini plug?
« Reply #22 on: January 22, 2012, 05:38:18 AM »
I had posted in the Yard sale section that I am looking for Denecke PS-2 and Dsatz touched on a point which probably needs to be resolved here, instead of there.

From the looks of it two competing points of views of the feasability of this in the field.

Quote
Quote from: DSatz on Yesterday at 10:01:22 PM

    Just please be aware that any "minijack mod" can only work with certain types of microphones. It will damage other types and/or give you almost no signal at all. Finally, with still other types of microphones you will get a good signal but the microphones will go into distortion at lower sound pressure levels than they normally would.

    I've posted statements like this many times on this board, and I'm sorry if some people have to read this again and again, but there seems to be a naive expectation that signals from balanced microphones can be unbalanced simply by shorting one audio lead per channel to ground at the output of the power supply. Sometimes it can, but that depends entirely on how the output circuit of the microphone is designed. And the design varies from manufacturer to manufacturer, and even from model to model within the same manufacturer's product line.

    The two things that matter most are whether XLR pins 2 and 3 of the microphone are both "actively driven"--or if only one pin is, then which pin is actively driven and which one isn't. If both pins are actively driven and you short one of them to ground (as the "mini-mod" does), you risk damage to the microphone and/or the microphone may distort prematurely when the sound levels increase, unless the microphone uses an output transformer.

    If only one pin is actively driven and it happens to be the one that you short to ground, you will get only a tiny whisper of a signal. Some microphones have only pin 2 driven actively while others have only pin 3 driven actively!

    So no universal solution is possible short of using input transformers--but good input transformers are rather expensive, and they add one more box and a pair of cables to what you have to bring with you to a recording.

    Always check with the manufacturer of your microphones to find out how to use them with unbalanced inputs, and follow the instructions carefully. Don't expect the phantom power supply to solve this problem for you, because it can't, unless it has audio transformers built in at its outputs (a rather rare situation, and not the case with the Denecke supplies).

    All in all, if a recorder has unbalanced inputs, it's often better to use a preamp that has balanced inputs and phantom powering built in. Then either the preamp will have unbalanced outputs that you can connect directly to the recorder, or else you can generally work out a simple way to unbalance its outputs--and then you'll be ready to use any and all types of microphones with it.

    --best regards


Thank you for your informative reply DSatz.  Appreciative of the fact that you have repeated yourself.

I am working with a Sennheiser MKH-60 and occasionally an Oktava MK012 (hypercardioid).  No idea how those pins terminate.
I see a potential issue with one of these mics though.  This thread refers to specifically this question related to the Oktava:
http://taperssection.com/index.php?topic=141868.msg1831066#msg1831066

However, Nick's Picks wrote this a while back in your forum:
Quote
Quote

    on the PCB of the PS2, the wiring output is as follows:

    RIGHT CHANNEL
    red wire +
    clear wire -
    shield is the ground

    LEFT CHAN
    blue wire +
    black wire -
    ground.

    they are laid out across the edge of the PCB, and are very easy to get at for de-soldering off of the board.
    the stock cable they use is a bit too thick for 3.5mm plugs, only the switchcraft fatty will really fit it well. I've just removed the cable entirely and replaced it w/a run of millspec. two hot conductors for L/R and the shield for ground.

    the output, as we know is balanced. this re-wireing is a ghetto-unbalanced version, but it works just fine and has absolutely no issues or interference with whatever mics you are using. the input scheme remains unchanged. It allows you to run condensers into a small deck like an r9 or the new sony...


Two competing point of views.

So, I understand what you are saying, for instance the reason the Sony XLR-1 accessory is so expensive ($450) is because it incorporates balancing transformers.

Many people simply use a Hosa dual female XLR to 1/8" mini jack from the Denecke to their recorders.

Would this be what you mean by "...or else you can generally work out a simple way to unbalance its outputs..."?  The Hosa cable becomes a "safe" termination?  For myself this starts to be extremely unwieldy as a portable device.

So the key question here is:
Quote
but it works just fine and has absolutely no issues or interference with whatever mics you are using. the input scheme remains unchanged. It allows you to run condensers into a small deck like an r9 or the new sony...

Is this true or not?
« Last Edit: January 22, 2012, 08:49:00 AM by yoclay »

Offline Nick's Picks

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Re: How do you wire the Denecke PS-2 to a single mini plug?
« Reply #23 on: January 23, 2012, 07:29:56 AM »
its true about 85% of the time.  Depends on the mics, but I dont understand how any damage could occur by altering the output of a phantom module.  I dont ground any of the wires, I leave them floating.
« Last Edit: January 23, 2012, 08:08:27 AM by Nick's Picks »

Offline yoclay

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Re: How do you wire the Denecke PS-2 to a single mini plug?
« Reply #24 on: February 28, 2012, 03:30:36 AM »
UPDATE:
Richard Crowley from over at DVXuser did a great mod finally on my PS-2. It is now the perfect compliment to my Sony PCM-D50. He put in a minijack to go 1/8" out and use any cable length you want, as well as a transient diode to prevent voltage surges. 
Photos and wiring scheme here:
http://www.rcrowley.com/Denecke/PS2mod.html

 

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