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nch

questions about power for my little sound bag.

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I’m trying to put together a power supply for my little sound bag. I have a Mix Pre and a Marantz and mostly have a MKH 416P 48 running out of it. Electricity is not my strong suite but this is what I’ve got so far.

The Marantz is 5V at 1.4A so 7W but the Mix Pre I can find nothing on except that the DC is 5-18V. Someone on the Handyman forum calculated that it was about 3.75W from the batteries making a total of about 10W required. So for the whole day I need 90-100Wh battery.

But there is the phantom power, dose this change the picture a lot? I presumed it was such a small amount it was negligible but I really don’t know. And though SoundDevices states 5-18V I’ve read in forums that it’s best to stay over 10V, is this correct? And what’s the amp draw from the Mix Pre, anyone know?

At present I’m looking at one of these power banks with a step up cable to 12V for the Mix Pre, great convenient shape for the bag and cheap but will need to make something to lock the USBs in the sockets.

That or using one of the battery plates I have knocking about for the Sony NP-F Batteries, solid connection, good charger and not too expensive. They go up to 60 Wh.

Or a 95W V-mount, reliable but an expensive option.

Any help or advice on what solution you guys have come up with would be most appreciated.

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2 hours ago, nch said:

I’m trying to put together a power supply for my little sound bag. I have a Mix Pre and a Marantz and mostly have a MKH 416P 48 running out of it. Electricity is not my strong suite but this is what I’ve got so far.

The Marantz is 5V at 1.4A so 7W but the Mix Pre I can find nothing on except that the DC is 5-18V. Someone on the Handyman forum calculated that it was about 3.75W from the batteries making a total of about 10W required. So for the whole day I need 90-100Wh battery.

hiya, luckily you are way off here.... : )

The number on the Maranz sounds high to me, which Marantz you have? and try putting some AAs of known capacity in (like envelop) and see how long it runs off those with your typical setup, then it's easy to calculate the draw.

 

2 hours ago, nch said:

But there is the phantom power, dose this change the picture a lot? I presumed it was such a small amount it was negligible but I really don’t know.

generally you can calculate with 0.1W per phantom powered mic. here's a good link for more precise info:

https://www.sounddevices.com/tech-notes/phantom-powering-basics

 

2 hours ago, nch said:

And though SoundDevices states 5-18V I’ve read in forums that it’s best to stay over 10V, is this correct? And what’s the amp draw from the Mix Pre, anyone know?

there are two versions of the MixPre: 

the older one can run off 5-18V and the newer MixPre-D 10-17V. If they say it will run off 5V it will most likely perform ok on that voltage (I mean, it can run just fine off 2V internally, so no reason why it wouldn't work well off 5V externally). (it might be slightly more efficient with higher voltages, but that's probably more academic). 

here are the two manuals:

http://cdn.sounddevices.com/download/guides/mixpre_en.pdf

http://cdn.sounddevices.com/download/guides/mixpre-d_en.pdf

the first one says:

Internal: 2 AA alkaline batteries, 6 hours life typical with +4 dBu signal into 600 ohms, no phantom External: Isolated external DC input jack, 5–18 V on locking 4-pin Hirose connector, pin-4 = (+), pin-1 = (–), Use gold Hirose #HR10A-7P-4P or silver Hirose #HR10-7P-4P for locking mating DC connector, voltages above 18 VDC cause no damage to unit, but will open an internal poly fuse. Poly fuse will reset when voltage is removed.

and the MixPre-D:

The MixPre-D can be powered from either internal batteries or from external DC. The power-efficient MixPre-D can operate from two AA alkaline batteries for nearly a production day (less with phan- tom powering). While many users prefer external DC sources to power both their mixer and wireless receivers, the use of internal batteries is perfectly feasible for both primary and backup powering of the MixPre-D. 

if we assume about 2Wh per AA battery under this load,  that would mean that the MixPre draws about 0.7W and the MixPre-D about 0.4W (give or take). add the 0.1W for your phantom mic.

 

2 hours ago, nch said:

At present I’m looking at one of these power banks with a step up cable to 12V for the Mix Pre, great convenient shape for the bag and cheap but will need to make something to lock the USBs in the sockets.

That or using one of the battery plates I have knocking about for the Sony NP-F Batteries, solid connection, good charger and not too expensive. They go up to 60 Wh.

Or a 95W V-mount, reliable but an expensive option.

A power bank with step up is ok if you make sure that your power converter doesn't introduce audio problems from the switching, and you'd loose a bit of energy in the conversion.

NP-F you could run it into the MixPre directly (if you have the non-D model) and use a step down converter for the Marantz. 

or personally I'd likely use a separate power bank for the maranz and a NP-F on the MixPre (with internal envelop as backup), that way you avoid the power converters altogether and could use two smaller batteries instead of one big one. 

V-mount are way too heavy and expensive for your purpose

my guess is for a 12 hour production day you'd need about 10Wh for the MixPre and maybe twice that on the Marantz. If you go for a power bank, keep in mind that most state the capacity based on cell voltage (i.e. 3.3V) and not 5V output voltage, and they usually overrate even that. so a 10000mAh power bank would be about 30Wh.

hope that gives you a starting point for some testing

chris

 

 

 

 

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The Marantz is the PMD661 MK2 and the number are strait off the back of the device. However in the documentation it says 5 hours operation time for the 4 internal AA batteries.

I didn’t think the phantom would be a too much, thanks for clearing that up and giving me some numbers to work with.

It’s the Mix Pre, the older one. So line out into the Marantz for recording, not a digital out. I’ve a couple of Sony plates with little boards in to step up to 12V I was going to use but I’ll get them out if it’ll run fine on 7.5V, especially if there is a risk of introducing noise. I could sew a pocket with two Sony plates at the bottom, one for each device with separate cables into the mixer pocket and the recorder pocket.

I’m unclear on the “audio problems for the switching” point. Would a step down converter for the Marantz also introduce noise?

Thanks for taking the time Chris, it appreciated.

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1 hour ago, nch said:

The Marantz is the PMD661 MK2 and the number are strait off the back of the device. However in the documentation it says 5 hours operation time for the 4 internal AA batteries.

are the numbers on the back of the recorder or the power supply? Sounds like a max value to me in either case.

But if we assume the same 2Wh AA batteries, that be total of 8Wh for 5hours runtime, so about 1.6W or 0.3A at 5V.

so 20Wh for a 12h production day (which would mean my guess above was not too bad, ha!). for more precise numbers you'd have to run a test with your configuration and a known power source (as mentioned, 4 eneloop would give solid numbers)

 

1 hour ago, nch said:

I’m unclear on the “audio problems for the switching” point. Would a step down converter for the Marantz also introduce noise?

well, most cheap step-up/step-down converters use a high frequency switching circuit to change the voltage. depending on a lot of factors in all the components (including the mixer/recorder) that might or might not cause problems. my guess is in most cases there's enough voltage filtering so that it's not a problem, but as soon as you have many devices it gets problematic to trouble shoot, and unless it's a no-budget production people usually like to play it safe.

chris

 

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I messaged Sound devices and they got back to me with this:

"Thank you for contacting Sound Devices.  The newer MixPre-D requires 10-17 volts.  The original MixPre definitely requires less voltage (5 to 14 volts).  Your MixPre should work fine with the 7.5-volt batteries.  However, if the batteries are starting at just 7.5-volts, they may quickly get into the minimum voltage requirement of the MixPre (around 5 volts).  You would get a longer running time and have less stress if you were to supply 10+ volts to the MixPre from an external source, as you would not already be at the lower limit for operating voltage.  I would recommend a slightly higher-voltage battery so that you will have reserve voltage when you encounter extreme cold, humidity, heat or other factors that may reduce battery life."

I'm not a fan of using USB connection for my power in the bag. Seems like something that could come unplugged too easily. The Sony's are going to be too week according to SD. I could use the battery plates for the Sony's that put out 12V but then I guess I'm going to be back into the problems with the step up on the Mix Pre and a dumb plate and a Step down on the Marantz.

Without using something to change the voltage the only things I can think of is the V-mount which as you say seems like over kill.

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2 hours ago, nch said:

The Sony's are going to be too week according to SD.

no, what they said is that if your battery *starts* at 7.5V they *might* be too weak.

I guess that you asked them about 7.5V batteries, which would indicate that you plan to pack 5 AA Alkaline together, they will start at 7.5V , but end around 4.5V, meaning you'll loose the last 20-30% of the capacity.

But NP-F type batteries are labeled 7.2V or 7.4V and will start around 8.4V and end up around 7V discharged. So if you asked them, about 7.2V Li-Ion batteries I'm pretty sure that they would say no problem at all.

2 hours ago, nch said:

Without using something to change the voltage the only things I can think of is the V-mount which as you say seems like over kill.

well, there's the old trusty NP-1 type (nominal 14.4V) which were the standard for years or the audio root type batteries that everybody seems very happy here (search this site if you're interested in more info about those). They would both be more robust solutions, but then you'd need a power distro for your recorder and with chargers etc it would be probably about three to 4 times the money as a USB power bank and an NP-F.

If you're worried about USB connections, why not put some AA inside the marantz as a backup so if things get loose the recording continues? doesn't get much better for a UPS then that.

chris

 

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Ah, I see. NP-F back on the menu then. 

I have a V-mount system for the camera and I found a 73W from IDX at a respectable 0.6Kg and £130 on line.

The more expensive options you mention look great but I have to prioritise my money elsewhere and for my little set up it's probably over kill. The V- mount is a stretch.

I'm going to do some tests with the NP-F batteries and the power-bank, see if it brings me round. The shape of it makes for easy storage in the bag, it's got that in it's favour I suppose.

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hi,

i had to look for a powering solution for my bag.

at the end i decided to go with a smart batterie.

i bought one from rrc batteries

http://www.rrc-ps.com/en/products/battery-packs/standard-smart-battery-packs.html

they got battery packs with different voltages, for your purpose RRC2057 / 7.5V / 6.40Ah / 48.0Wh or RRC2040 / 11.25V / 2.95Ah / 33.2Wh/

RRC2040-2 / 11.25V / 6.40Ah / 72.0Wh could fit.

http://www.texim-europe.com/products/rrc

Prices here in europe at texim are from 50€ to 90€, so the price for a small one is like a NP-F970 from a good brand.

in the states you should find even more smart battery choices from other brands.

You need a charger (ca 100€)  and a cable (15€), some connectors and a voltage regulator/step down converter.

did you ask marantz for the voltage specs for external powering when not using their psu?

at the marantz site i could find no specs for external powering.

if i find the time tommorow i gonna post some pics of my DIY solution

karsten

 

 

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Something happened to Marantz. The specifications and other links stopped working on the PDM661 MK2 page. I message them and got a reply saying something about a shuffle in departments of something. They did provide a rather strange forwarding address for question about this recorder and I shall get back onto them if needs be.

I did find the AC power supply and on the back it says the same as on the back of the device: "OUTPUT : 5V DC 1.5A." Is this not enough? Could the DC power requirements from a battery pack be different?

Perfect power bank territory as is. I'm just making up a cable now and will run a test tomorrow to see how long the 10000 mAh one I got for Christmas lasts to get a real idea of running times.

I came across those Smart Batteries in another post on here, it was yourself I believe. Anyhow I kind of skipped over them. I've got soldering irons and multimeters and bits of wire all over my desk as I'm trying my best to learn this stuff but your DIYing sounded a bit advanced to me with break out boxes and battery data displays as I recall. I think you threatened to put up a thread or video showing how you went about it, did you ever find the time to do so? I for one would be interested to see.

  The V-mount would cost the same as the Smart Battery with the charger but the Smart Batteries are much lighter. The IDX 73W is 600g and the RRC2040-2 72W is 355g!

What are the connections like on the RRC batteries? Or is it just wires and you make up your own cabling and sockets for them?

Someone else on a DIY forum has pointed out these:

http://www.ebay.co.uk/itm/Lithium-Thionyl-Chloride-D-Cell-Battery-ER34615H-/172556116637?hash=item282d25629d:g:HLYAAOSwuxFYtuXb

2 in series in a little holder like this:

http://www.batteryholders.com/part.php?pn=BH2DW&original=D&override=D

I'm not even sure what kind of battery these are?

I'm in the UK by the way.

 

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41 minutes ago, nch said:

I did find the AC power supply and on the back it says the same as on the back of the device: "OUTPUT : 5V DC 1.5A." Is this not enough? Could the DC power requirements from a battery pack be different?

well, the question is how much variance on voltage the input can take. From what we know so far I'd guess it's rather tight, something like 4-6V, so you most likely will need a constant regulated power source (which most batteries aren't, with the power bank being a lucky exception).

41 minutes ago, nch said:

The V-mount would cost the same as the Smart Battery with the charger but the Smart Batteries are much lighter. The IDX 73W is 600g and the RRC2040-2 72W is 355g!

well, an NP-F with 20Wh is about 100g, costs 20quid and probably gets you through the day if you use a power bank for the marantz (even more so if you load AA eneloop as backup).

frankly I don't see the point in getting expensive heavy batteries for your setup, better keep things light and save up for a better recorder, add a nicer boom or wind protection or wireless etc. 

chris

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I'll email "inmusicbrands" about the recorder and see exactly what the requirements are.

Yes but the charger and cabling will mean it's not going to be the cheapest of the solutions and I feel if I'm going to invest in a system like this it'd be nice to make it a single battery for the whole bag. I'm unsure about this Step up/step down noise problem thought.

The 600g V-mount is something I would like to avoid really, it's just been a point of reference.

What work comes with these batteries? The charger is a docking plate and there seems to be a connection similar to that on a laptop battery from looking at the pictures. Do I need to buy plates to fit into the sound bag to mount them on? I'm struggling with their web site too learn more and can find nothing elsewhere about these batteries.

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