Topic: JB3 power use

[tms]

Sorry if this topic has been covered already, but I've been looking at this topic for a few weeks now and never saw this info, so here it is. 

Yesterday I measured the current consumed by my JB3 while recording line-in using an external power source.  My external power source is a $2 7805 5 volt regulator from RS.  To use it I pull the internal battery so that the JB3 doesn't try to charge it with the external power.  That would be a big waste of the external battery, plus it adds a whole bunch of hiss, clicks and beeps to the line-in recording. 

Here are the results:

Boot-up and harddrive 'punches' : 750 mA spikes
Toggling thru the menus (back light on): 120 mA
At rest, no back light on: 70 mA
Here's the important one, Recording: 230 mA with an occasional spike to 750 mA when the HD punches, I'm calling it 300mA.

The 7805 chip (and Leegeddy's variable volt box) consumes the exact same amperage as is sent to the powered devices.  The excess wattage (Vin - 5 V)*amps goes to heat.  In my case, it's a 12V supply, so (12-5 V)*0.3A = 2.1 watts of waste heat.  The chip is mounted to a scrap piece of aluminum and doesn't even seem warm to the touch.

I also use a pre-amp which uses 30mA at 12V.   Based on this, my 12 Ahr 12V SLA battery should last (12,000 mAhr)/(330 mA) = 36 hours.

Hopefully this will be useful for someone planning to use or build an external power supply for festivals, etc.

Cheers!
Todd in Buffalo


BTW, even with the internal charging circuit taken 'out of the loop' by removing the internal battery, I still do get faint 'beeps' in my line in recordings at the highest gain settings as the hard drive punches and records the data.  At +12dB gain the beeps are obvious when there are no other sounds being recorded.  For me (not an audiophile) these don't matter as long as the gain is <8 or so because they are so faint even at +12dB. 

I stealthed Natalie MacMaster 4/27/05 using SP mini mics, a battery box and the JB3 on +12dB.  I only hear faint beeps during the quietest parts of the show. Not ideal, but better than no recording at all.

[Bdifr78]

Sorry if this topic has been covered already, but I've been looking at this topic for a few weeks now and never saw this info, so here it is. 

Yesterday I measured the current consumed by my JB3 while recording line-in using an external power source.  My external power source is a $2 7805 5 volt regulator from RS.  To use it I pull the internal battery so that the JB3 doesn't try to charge it with the external power.  That would be a big waste of the external battery, plus it adds a whole bunch of hiss, clicks and beeps to the line-in recording. 

Here are the results:

Boot-up and harddrive 'punches' : 750 mA spikes
Toggling thru the menus (back light on): 120 mA
At rest, no back light on: 70 mA
Here's the important one, Recording: 230 mA with an occasional spike to 750 mA when the HD punches, I'm calling it 300mA.

The 7805 chip (and Leegeddy's variable volt box) consumes the exact same amperage as is sent to the powered devices.  The excess wattage (Vin - 5 V)*amps goes to heat.  In my case, it's a 12V supply, so (12-5 V)*0.3A = 2.1 watts of waste heat.  The chip is mounted to a scrap piece of aluminum and doesn't even seem warm to the touch.

I also use a pre-amp which uses 30mA at 12V.   Based on this, my 12 Ahr 12V SLA battery should last (12,000 mAhr)/(330 mA) = 36 hours.

Hopefully this will be useful for someone planning to use or build an external power supply for festivals, etc.

Cheers!
Todd in Buffalo


BTW, even with the internal charging circuit taken 'out of the loop' by removing the internal battery, I still do get faint 'beeps' in my line in recordings at the highest gain settings as the hard drive punches and records the data.  At +12dB gain the beeps are obvious when there are no other sounds being recorded.  For me (not an audiophile) these don't matter as long as the gain is <8 or so because they are so faint even at +12dB. 

I stealthed Natalie MacMaster 4/27/05 using SP mini mics, a battery box and the JB3 on +12dB.  I only hear faint beeps during the quietest parts of the show. Not ideal, but better than no recording at all.

Nice work!  Where can I find out how much power the UA-5 uses?

[tms]

Nice work!  Where can I find out how much power the UA-5 uses?

Thanks.  If the UA-5 power use isn't on here somewhere I would just measure it with a multimeter, that way you know for sure.

[Brian Skalinder]

Nice work! Where can I find out how much power the UA-5 uses?

Why, in the UA-5 FAQ, of course.  Check the Archive | Pres, A/Ds and Processors forum.

[tms]

Nice work! Where can I find out how much power the UA-5 uses?

Why, in the UA-5 FAQ, of course.  Check the Archive | Pres, A/Ds and Processors forum.

Thanks Brian,
Wow, 450mA! That thing is a power-pig!  With the JB3 recording you'll be drawing 750 mA.

[Brian Skalinder]

Wow, 450mA! That thing is a power-pig!

On the contrary, that's fairly low for a pre/ADC combo.  Check out some other gear current draw.

[Bdifr78]

Thanks Brian!

[tms]

Wow, 450mA! That thing is a power-pig!

On the contrary, that's fairly low for a pre/ADC combo.  Check out some other gear current draw.

True, it's just that as a newbie I'm used to my little MD player recording about 7 hours on a AA battery.  No wonder the need for toting 10 Ahr RC batteries.  (the light goes on... briefly)