Topic: jb3 external power II...

[tms]

How about a panel volt meter? 

http://www.mpja.com/productview.asp?product=8718+ME

No affiliation, just a customer,

I've got everything coming to do a mock up and will be testing without any air flow initally, just heat sinks.  If all goes well, then I will explore getting the PCBs made up.  I'll let everyone know how it goes.  I know a few people have made boxes based on the same circuit, but have not heard anything related to thermal issues, especially with multiple circuits.  The LM317 stuff I have seen indicates the chip does have overheat protection so it would shutdown before damaging the chip, but you would loose power suddeny if the overheat protection kicks in.  Anyone know how to make a circuit that would indicate input voltage through some LEDs?  We could build that in so you can monitor input voltage level and know when you are getting low.  I wouldn't think it would be too hard, but I'm not a electronics wiz.

[dgodwin]

I went to radio shack yesterday and they didn't have any heatsinks (apparently they're being discontinued)  What did y'all use for heatsinks on the LM317T, and did any folks add a fan to make sure it stays cool?   Thanks!

[jdawg]

I think I got mine from this old scanner I took apart. Trust me, it's nothing fancy and looks nothing like a heatsink you may have seen at RS, inside a PC, or elsewhere. If you have some scrap metal/alluminum, cut a peice off of that, drill a hole in it and screw it to the 317. Also, check RS online. I'm sure they have some out there.

I went to radio shack yesterday and they didn't have any heatsinks (apparently they're being discontinued)  What did y'all use for heatsinks on the LM317T, and did any folks add a fan to make sure it stays cool?   Thanks!

[wbaldwin]

Tested external power for the JB3 and UA5 last night, running off of one of the batteryspace 9.6v 3300maH RC batteries and got a bit over five hours....  I've got two of the 3300 and two of the 3000, so I'm guessing about 18 hours from the 4 reliably.

Does anyone know if there is an advantage to running one at a time and switching them out over time, or can you just hook two up and reliably expect to get double the time?  I'm going to try to test that this evening..... 

Also, I had the test set up in my living room, recording a playing CD at first, and then TV, with the gain on the UA5 cranked up pretty good, (~ 90%).  Do you think this is a pretty accurate test, or would they drain faster when you have the higher SPL coming from a loud PA in a live situation?

Trying to get all of this figured out before heading up to Suwanee next weekend.  I'm also planning on borrowing a 12v 7.2Ah SLA from work to bring along.  Between the two, I'm figuring that I won't have to recharge over the two days.

Thanks for any all insights

[jdawg]

The main thing it to make sure it's writing to the drive (recording), not just in playback mode. Which it sounds like your already doing. That should be all you need to do for your test.

[tms]

I'm thinking of getting some custom made PCB boards made that would support this circuit.  One place I checked out would make a board that is about 3.5 x 2 and would be able to support up to 3 of the LM317 based circuits so you could have 3 outputs each with a different voltage off a single input and be able to change the output voltage just by swapping out 2 resistors.  My only real concern in heat.  While there would be room for heat sinks in the box, there would not be any airflow.  Just how hot do these things get?  Obviously as the quantity goes up the price goes down so I'm also curious how many people would be intreseted in buying a PCB board if I had them made.  I've attached a quick CAD drawing of the circuit I'm looking at.  Any comments?

FYI it is a 2 layer board the green is on the bottom layer the red is on the top layer and where the components go through the board it makes the electrical connections

Very cool board !

I ended up just taking a 7805, soldered +12VDC, ground, and +5VDC out to the 3 pins and ran it to the JB3 to feed it 5VDC.   Mounted the chip to a piece of scrap aluminum.  The only heat I felt was when it was charging the internal battery from the SLA battery.

Running this, or a RadioShack car adapter (4.5V), or a Walmart car adapter (4.5V) or even the stock AC power supply results in beeps and clicks while recording line-in, 44.1 wav, and +12dB gain.  I'm pretty sure it's the internal circuit charging the battery.  The AC power supply from Creative also adds a 60 hz hum.

To avoid the noise I just pull the battery and run off the external 5V alone.  There is still some very low hard drive noise but it's unavoidable unless I go to external A/D and feed it digital.

My electronics geek friend tells me the 7805 chip supplies very low noise power, like battery level. No need for caps to smooth it.

What do others do about JB3 festival power?  I need about 20 hours worth.  I think it's finally all set.

Todd in Buffalo

[fozzy]

just ran 4 days @ OSMF w/o recharging.  Taped
Coopers Uncle
New Monsoon
Railroad Earth
Austin Loung Lizards
Bela Fleck Trio
Sarah Jaroz
two high string band
plus 4gigs (dunno time duration on 16/44.1) of campsite jam sessions

Gear was left powered on w/o recoding during setbreaks.

4x 3200 Mah 7.2v nimh > custom LDO/boost regulator box(9v, 6v & 5v) > JB3 & modSBM1.  9v was not used but is always on.

[tms]

just ran 4 days @ OSMF w/o recharging.  Taped
Coopers Uncle
New Monsoon
Railroad Earth
Austin Loung Lizards
Bela Fleck Trio
Sarah Jaroz
two high string band
plus 4gigs (dunno time duration on 16/44.1) of campsite jam sessions

Gear was left powered on w/o recoding during setbreaks.

4x 3200 Mah 7.2v nimh > custom LDO/boost regulator box(9v, 6v & 5v) > JB3 & modSBM1.  9v was not used but is always on.

Excellent, what's the 9V for?

Anyone actually measure the mA of the 5V going into the JB3 while recording?

[fozzy]

9v is for my Hosa box incase anyone needs an optical patch or i want to run my second JB3 as a backup.  This was also the solution prior to the DIY 7-pin optical cable.  I have also used the Hosa for patching of another Rig

[tms]

Hey leegeddy, I've got a question about your Bumblebee VR-JBOX.  Can the circut regulate down somewhere between 3.2v and 4.1v?  I've converted and internal jb3 battery to accept external power.  I made a 3v battery and it works great, the problem is recharging it.  As I have a ua-5 on the way a vr-box seems more useful than trying to make a single "altoids tin" circut to regulate the battery.

How's this working out?  I considered something similar, was going to hack the 3.6V Li-ion battery and add a big external pack of batteries so that the internal battery circuitry was still in the loop.  Those 4 connectors actually do go somewhere, it's not just + and -. 

What happens when you feed it 3.6 V battery power to those 2 terminals?  Does the battery gauge on the display still work properly?  Does the JB3 shut down safely when the battery finally does die?

I ended up just feeding the 5V input on the JB3 with a 7805 chip from RadioShack because I use 12V for my preamp anyway.  It was like $1, soldered wires to the 3 pins on the chip, screwed it to a hunk of aluminum and it works fine.  Just pull the battery out and plug in the external power and it works as normal.

[leegeddy]

just ran 4 days @ OSMF w/o recharging.  Taped
Coopers Uncle
New Monsoon
Railroad Earth
Austin Loung Lizards
Bela Fleck Trio
Sarah Jaroz
two high string band
plus 4gigs (dunno time duration on 16/44.1) of campsite jam sessions

Gear was left powered on w/o recoding during setbreaks.

4x 3200 Mah 7.2v nimh > custom LDO/boost regulator box(9v, 6v & 5v) > JB3 & modSBM1.  9v was not used but is always on.

[keanu]whoa[/keanu]

almost 13AH capacity!! 

marc

[F.O.Bean]

just ran 4 days @ OSMF w/o recharging.  Taped
Coopers Uncle
New Monsoon
Railroad Earth
Austin Loung Lizards
Bela Fleck Trio
Sarah Jaroz
two high string band
plus 4gigs (dunno time duration on 16/44.1) of campsite jam sessions

Gear was left powered on w/o recoding during setbreaks.

4x 3200 Mah 7.2v nimh > custom LDO/boost regulator box(9v, 6v & 5v) > JB3 & modSBM1.  9v was not used but is always on.

[keanu]whoa[/keanu]

almost 13AH capacity!!

marc

thats nothing marc, i will have at least 6x 3300mah NIMH batts for the festies this summer ;Dso thats about 25mah battery power, plus the 6v's i'll have strictly for my v3

[fozzy]

just ran 4 days @ OSMF w/o recharging.  Taped
Coopers Uncle
New Monsoon
Railroad Earth
Austin Loung Lizards
Bela Fleck Trio
Sarah Jaroz
two high string band
plus 4gigs (dunno time duration on 16/44.1) of campsite jam sessions

Gear was left powered on w/o recoding during setbreaks.

4x 3200 Mah 7.2v nimh > custom LDO/boost regulator box(9v, 6v & 5v) > JB3 & modSBM1.  9v was not used but is always on.

[keanu]whoa[/keanu]

almost 13AH capacity!! 

marc

weighs less than my 7.5ah SLA too.  My next battery solution should be 22ah @ 14.8v or 44ah @ 7.4v and about 2/3 the width of a 722 w/ about the same height and depth.  The coolest thing about batteries from the RC/EV market is that they charge at an incredible rate.  the nimh's i have now i can do 2 packs at a time @ 2.5amps.  the next-gen will be able to handle 1C or ~22amp charge rate. 

[fozzy]

just ran 4 days @ OSMF w/o recharging.  Taped
Coopers Uncle
New Monsoon
Railroad Earth
Austin Loung Lizards
Bela Fleck Trio
Sarah Jaroz
two high string band
plus 4gigs (dunno time duration on 16/44.1) of campsite jam sessions

Gear was left powered on w/o recoding during setbreaks.

4x 3200 Mah 7.2v nimh > custom LDO/boost regulator box(9v, 6v & 5v) > JB3 & modSBM1.  9v was not used but is always on.

[keanu]whoa[/keanu]

almost 13AH capacity!!

marc

thats nothing marc, i will have at least 6x 3300mah NIMH batts for the festies this summer ;Dso thats about 25mah battery power, plus the 6v's i'll have strictly for my v3

why not ditch the 6v entirely.  The V3 has such a flexible operating range.

[momule]

I have a ? about splitting the 5v feed from a Walmart adapter box.

Could one simply Snip the End of the cable that has the adapter plug end on it and wire in another plug to make it feed (2) 5v feeds at the same time . (Simply a "Y" connector if ya will)

Would sniping this cause it to drop the amperage or the voltage , or Both.

TIA
Nick