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Matt Martin

Battery Eliminator for G3

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I am thinking about building my own battery eliminator for my Sennheiser G3's. Of course there is always the option of buying their DC-2, but at $65 (without a connector) I am sure I could build one for about a third of the price. So I would like to get all of your thoughts on my design and components.

Basic design is put one of theses 3.3v 1A voltage regulators:

(specs here: http://www.dimension...oducts/de-sw033)

DE-SW033big.jpg

inside two of these AA adapter shells ( somehow glued together and the inside sides notched out to fit the regulator)

B2Vm.jpg

Attach my wires, terminate with my connector and call it a day? Can it be that simple? About $20 including shipping.

A few questions for you fine folks.

- The only voltage regulator I could find steps down to 3.3v (The G3 states it needs 3 volts.) Will this .3v harm anything?

- To which of the 4 "battery" contacts do I connect my leads? + to both + contacts and - to both -'s? Or just one of each? I tried looking closely at the DC-2 pics online (attached below). I can only see one side and it looks like just the bottom left has a hole for the G3's negative spring contact to go into. I am assuming the other side has the top right (+) contact available. The other two battery contacts seem to be covered over for no connection. The seems to make sense to me, but does anyone know for sure?

dc_2.jpg

Thoughts on this plan? Thanks!

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How much do you make an hour?

How much time do you spend researching and designing the damn thing?

$65 is a fare deal.

Lectro charges $165 for theirs.

Maybe you enjoy DIY projects.

I personally only make my own cables because they are very expensive and easy to make.

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I'm a great believer in DIY because that's the only way to learn, but you need to start out on some simple projects that don't involve destroying relatively expensive gear. After you blow up your G3, the $65 will look real good.

Best Regards,

Larry Fisher

Lectrosonics

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I'm a great believer in DIY because that's the only way to learn, but you need to start out on some simple projects that don't involve destroying relatively expensive gear. After you blow up your G3, the $65 will look real good.

Best Regards,

Larry Fisher

Lectrosonics

+1.

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How long do AAs last in a G3 series? I don't have G3s, but I own G2s and they go over 8 hours on alkalines and well over 12 on Powerex NIMH. :)

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- To which of the 4 "battery" contacts do I connect my leads? + to both + contacts and - to both -'s? Or just one of each? I tried looking closely at the DC-2 pics online (attached below). I can only see one side and it looks like just the bottom left has a hole for the G3's negative spring contact to go into. I am assuming the other side has the top right (+) contact available. The other two battery contacts seem to be covered over for no connection. The seems to make sense to me, but does anyone know for sure?
You have to put it in serial config. Like on this site:

http://batteryuniver..._configurations

And you probably can use a meter to find out how the batteries are 'wired' inside the G3.

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Fun project!

I tried the same voltage regulator with an Edirol R09 but it caused some weird interference to get into the audio, especially when the oled screen was manipulated.

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I'm a great believer in DIY because that's the only way to learn, but you need to start out on some simple projects that don't involve destroying relatively expensive gear. After you blow up your G3, the $65 will look real good.

Best Regards,

Larry Fisher

Lectrosonics

I have done quite a few simple projects: BDS for my bag, direct box for instrument impedance matching, custom patch panels, momentary push to talk switch for balanced talkback mic to boom op, countless cables and adapters, etc.... I assumed (possibly incorrectly?) that this project was fairly simple.

How long do AAs last in a G3 series? I don't have G3s, but I own G2s and they go over 8 hours on alkalines and well over 12 on Powerex NIMH. :)

Yea, my rechargeables last about 8 hours, so on an average day with moderate setup time (power downs) I can usually get away without swapping out. But the reason for the battery eliminator is more so for charging convenience rather than run time. It would be great to just throw two NP-1's on my 4 bay charger for 6 hours overnight and have my bag powered on one switch all day. I also am considering modifying my DIY BDS (or the cables) to run through a switch so I can easily power down the receivers separately and keep the mixer running.

You have to put it in serial config. Like on this site:

http://batteryuniver..._configurations

And you probably can use a meter to find out how the batteries are 'wired' inside the G3.

Thanks for the link!

Fun project!

I tried the same voltage regulator with an Edirol R09 but it caused some weird interference to get into the audio, especially when the oled screen was manipulated.

hmm.. I'll have to investigate that further. I think someone else had a thread about a DIY BDS with this regulator installed in the BDS itself. Wonder if they had any issues.

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I have experience using both the regulator you mentioned and the Sennheiser eliminator. I'd recommend buying the Sennheiser unit. I found a slightly better price, I couldn't tell you where at the moment because I'm not at the studio. Do your Google research and you should be able to shave a few dollars (compare including shipping).

With the switching supply, you could run into the induced noise issues mentioned above. The Sennheiser unit is purpose-designed for what you want and includes a new door with a pass-through hole for the cable.

If you still wish to follow the DIY route, I can take a look at mine this evening to tell you which contacts.

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Yeap. Sorry. I missed that.

Thank you Larry.

(when I'm studying mathematics today too much my head is blow up)

;D

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How long do AAs last in a G3 series? I don't have G3s,

with 2500mA NiMh batteries, far more than 8 hours. A good point for G3s even if they are not my first choice.

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hmm.. I'll have to investigate that further. I think someone else had a thread about a DIY BDS with this regulator installed in the BDS itself. Wonder if they had any issues.

That was me. Jason and I appeared to have the same set-up. He had a hum, I didn't. We exchanged emails, but never got to the root of the problem.

I'm on the 'fun project' side.

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I'm looking into something like this, not for a G3, but for my 9v-powered butt-plugs. Has anyone thought about using just a 9v Zener diode?

I might be completely wrong about this, but it is my understanding that the Zener is specifically designed as a voltage gate, that when wired in reverse, breaks down in an acceptable fashion (i.e. not permanently) at a rated voltage, and only passes that voltage through itself - 12v+ becomes 9v, etc.

Or am I completely off here?

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I'm looking into something like this, not for a G3, but for my 9v-powered butt-plugs. Has anyone thought about using just a 9v Zener diode?

I might be completely wrong about this, but it is my understanding that the Zener is specifically designed as a voltage gate, that when wired in reverse, breaks down in an acceptable fashion (i.e. not permanently) at a rated voltage, and only passes that voltage through itself - 12v+ becomes 9v, etc.

Or am I completely off here?

You're off<g>. The Zener conducts (breaks down) when the voltage across it gets above a certain point. Generally they are used in shunt with some series resistance to limit current. If you apply 15 Volts directly to a 12 Volt Zener, you would have 3 Volts of excess voltage that would drive many Amps through the Zener, vaporizing it or at least melting the internal junction, causing a short on your supply. If the supply can provide big currents, that is what will flow through your now shorted Zener. At some point something explodes or melts big time. With series resistance, the Zener conducts enough current so the excess voltage is dropped across the series resistance. For instance, assume the 15 Volt supply goes to a 100 Ohm resistor in series with a 12 Volt Zener to ground. The Zener will conduct 30 mA since that will develop 3 Volts (the excess voltage) across the 100 Ohm resistor (30 mA times 100 Ohms= 3 Volts). Everything is now balanced; you started out with 15 Volts and lost 3 Volts in the 100 Ohm resistor and have 12 Volts across the Zener which you can use as a regulated voltage, within limits.

What if you used a 10 Ohm resistor? Then you would pull 300 mA to get the same 3 Volts across the resistor and the fixed 12 Volts across the 12 Volt Zener for the original 15 Volts. Note that 300 mA times 12 Volts is 3.6 Watts which is going to heat up the Zener pretty well. The resistor will also get warm but that is only 0.9 Watts. Again things are balanced because 300 mA from a 15 Volt supply is 4.5 Watts, the sum of the power in the resistor and Zener.

What if you use a 1 Ohm resistor? Now the 3 Volts excess will draw 3 Amps and obviously smoke will be involved as the Zener will dissipate 36 Watts for a few seconds.

Zeners are typically used as voltage references at currents of a few mA's since their voltage is pretty constant over a wide range of currents. If you want to use them as a voltage regulator, you must send more current to the shunt Zener than your device or circuit after the Zener will use. For instance, if you have a device that uses 15 mA at 12 Volts then you could feed a 12 Volt Zener with 20 mA, bleed off the 15 mA you need for your device and have 5 mA left to keep the Zener operating at a fixed 12 Volts. This would require a 150 Ohm series resistor if you used the 15 Volt supply above. If your supply voltage fell to 14 Volts or below, the circuit would go out of regulation because there would be no current for the Zener. At 14 Volts from the supply, there would only be 2 Volts across the 150 Ohm resistor for a current of 12 mA but your device needed 15 mA. The voltage would fall to 11.75 Volts, seriously out of regulation. If the input supply voltage goes to 18 Volts, the current draw would now go to 40 mA even though your device still only requires 15 mA with the remaining 25 mA going through the Zener producing 0.3 Watts of wasted power. All this to say, Zeners make reasonable but wasteful voltage regulators which is why 99.99% of power regulation is done in other ways not involving Zeners. Most usually, the device is an IC that is efficient, simple to use, works over a wide supply range and is 40 cents to a few dollars.

Best,

Larry F

Lectro

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I have three Sony UWP-V1 wireless mic kits, which use AA batteries. On a typical shoot, I'll go through 6-10 AA batteries a day, and I'm looking for an option, because I hate going through so many batteries. I have a set of NiMH rechargable batteries, but they take an eternity to recharge, and I can't really trust them on a busy set.

I know there are better ($$) wireless systems out there, but these have served me extremely well and I don't see a reason to get rid of them - though I might be buying a couple of Lectros when the time comes to upgrade.

My kit has a BDS ( with an NP-1 brick) powering a 552 and a Tascam DR680, which leaves room to power the three receivers. The Sonys have sliders which house two AA batteries. I'm not experienced in this type of adaptation, but it seems to me that I buy get a few of those sliders as spare parts and turn them into battery eliminators, with a cable going into the BDS.

If any of "youse" has any suggestions or pointers, I'd be extremely grateful for your help.

Cheers,

BK

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You're off<g>.

Best,

Larry F

Lectro

That was extremely informative, and I thank you for the education. I hadn't really understood how a Zener functioned based on my project experience with them, and now I do. Awesome.

Most usually, the device is an IC that is efficient, simple to use, works over a wide supply range and is 40 cents to a few dollars.

Best,

Larry F

Lectro

Oookaaayyy... So if the IC is so cheap, where is the gold-plated unobtanium component in your Lectro Battery Eliminators? <g> :D

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Oookaaayyy... So if the IC is so cheap, where is the gold-plated unobtanium component in your Lectro Battery Eliminators? <g> :D

Hi Jim,

"Pay no attention to that IC behind the curtain".

The sound mixer analogy would be: S(h)e only needs 3 Subway Tunas a day to stay alive. Why are the rates so high?

Here's the complete, secret pricing algorithm for accessories:

Take the parts $ plus assembly labor $ plus overhead $ plus electrical engineering design time $ plus mechanical engineering design time $ plus Part 15 FCC certification $ plus Bill of Material documentation $ plus torture testing $ plus recent hamburger price increases at our favorite lunchtime haunt $$ plus a lot of little things $ and add that all together. Now divide it by the huge (100) projected sales and you have the price. Submit that to sales who ROTFLTAO, say you won't sell 10 and strongly recommend that you double your psychotropic medication. Reduce the price to something that your suffering customers will grudgingly pay and hope that you'll make the losses up in increased transmitter and system sales. That's the unobtanium tango.

Be$t Regard$,

Larry Fi$her

Lectro$onic$

p.s. With a capital <G>

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Oookaaayyy... So if the IC is so cheap, where is the gold-plated unobtanium component in your Lectro Battery Eliminators? <g> :D

One day a big tanker truck got itself wedged under a bridge and was blocking a major interstate. Cops and firetrucks arrived but couldn't do anything. A guy six cars back walks up to the truck driver and says, "If your company will give me $1000 I can get you out of this mess and on your way in less than an hour." So the driver calls the head office and gets the okay for the $1000. The guy from six cars back walks up to the truck and lets most of the air out of all the truck's tires, lowering the truck enough so that it can easily roll under the bridge and over to the side of the road. The guy tells the driver, "Okay, now pump up your tires and be on your way."

It isn't really what you do or how you do it, it's KNOWING what to do and how to do it that counts.

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Hi Jim,

"Pay no attention to that IC behind the curtain".

The sound mixer analogy would be: S(h)e only needs 3 Subway Tunas a day to stay alive. Why are the rates so high?

Here's the complete, secret pricing algorithm for accessories:

Take the parts $ plus assembly labor $ plus overhead $ plus electrical engineering design time $ plus mechanical engineering design time $ plus Part 15 FCC certification $ plus Bill of Material documentation $ plus torture testing $ plus recent hamburger price increases at our favorite lunchtime haunt $$ plus a lot of little things $ and add that all together. Now divide it by the huge (100) projected sales and you have the price. Submit that to sales who ROTFLTAO, say you won't sell 10 and strongly recommend that you double your psychotropic medication. Reduce the price to something that your suffering customers will grudgingly pay and hope that you'll make the losses up in increased transmitter and system sales. That's the unobtanium tango.

Be$t Regard$,

Larry Fi$her

Lectro$onic$

p.s. With a capital <G>

LOL - a lot!

I suspected it was something like that, the prices at the local hamburger joint must be really rough on you guys - Thanks for the dance anyway! :D

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Whoever wants to buy DC2s:

Be aware that the cable senny uses is... politely spoken: poor. I had the coating rubbed off on both ends on 4 ov my 6 DC2s after half a year of occasional bag usage. On the connector's end it is quite easy to shorten and resolder, but on the eliminators end, you'd need to rely on Senny's warranty mercy. So, before you solder some connector on the DC2, make shure you put some shrinking rubber hose over all parts of tha cable that could be stressed.

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