Topic: jb3 external power II...

[F.O.Bean]

Would you mind running a test with 7.2 volts as the input source.

Thanks

sure. see above.

as you can see, the regulated voltage is stable across the Vin values EXCEPT for the 6v. there isn't enough of a V differential.

marc

+t thanks for the update.  If this works w/ a JB3 i can ditch my lead and hook into my UA5 powering solution

i ran my sony cd walkman (takes 4.5v) with the vr circuit and it worked fine. hopefully, i'll test out the jb3 soon.

marc

mark, so this works like a charm w/ a 9.6v rc battery too

if so, i have a 12v 12 amp for sale

[dnsacks]

To me, Marc's comments indicate that he hasn't yet had the opportunity to test the VR with a JB3 --

[F.O.Bean]

i bet it works just fine

i think im gonna do the rc battery thing myself, and put 4-pins on everything

[leegeddy]

i bet it works just fine

i think im gonna do the rc battery thing myself, and put 4-pins on everything

bean, as long as the jb3 is happy with 5.2volts, then it should be fine.  the voltage is regulated at 5.2v and can deliver up to 1.5A of current with ease.  you could probably run 2 jb3 simultaneously or 3 Sony DAT decks at a time.

marc

[F.O.Bean]

thanks marc, it works at 4.5 volt just fine, so hopefully it does fine w/ 5.2 also

[jdawg]

In the middle of a r/c 9.6v test running through this circuit delivering 5.19v (~5.15v while recording) - still recording after 1 hour. Although the LM317 gets mighty hot at ~190-200F

Resitor Values:  R2 = 470 ohm   R1 = 150 ohm

[leegeddy]

In the middle of a r/c 9.6v test running through this circuit delivering 5.19v (~5.15v while recording) - still recording after 1 hour. Although the LM317 gets mighty hot at ~190-200F

Resitor Values:  R2 = 470 ohm   R1 = 150 ohm

so the jb3 is fine with 5.2v...that's good to hear.  it's recommended that you install heat sinks for the LM317 since it can handle good amount of current.

marc

[ChrisV]

Is there anyway to get that value to fall between 4.5V and 5.0V?   I think that'd be ideal.  Or is 5.2V the only way to work it out?   Sounds like that still may work out though.


The 1.5A of current should be fine...the only part that it may cut it close is upon startup where it does exceed 1 amp(dunno if with or without internals batteries in makes a difference in that value).

[leegeddy]

Is there anyway to get that value to fall between 4.5V and 5.0V?   I think that'd be ideal.  Or is 5.2V the only way to work it out?   Sounds like that still may work out though.


The 1.5A of current should be fine...the only part that it may cut it close is upon startup where it does exceed 1 amp(dunno if with or without internals batteries in makes a difference in that value).

with R2=470, R1=150 Vout=1.25(1+R2/R1)=5.16667v, which is very close to 5.2v. one could use lower tolerance resistors and get the Vout closer to 5v.
if you wanted Vout=4.5v, then R2 would need to be: [(4.5/1.25)-1]*150=390ohms. personally, if jb3 work fine at 5.0 to 5.2v, then i would run it at those voltages.

marc

[mmmatt]

What is the advantage of building the resistor box over hacking a car adaptor???  I don't get it.

Matt

[fozzy]

What is the advantage of building the resistor box over hacking a car adaptor???  I don't get it.

Matt

I am going to test my car adapter on 7.2 volts and possibly other input voltages to see if it yields succcesfull results.  I am going to hack mine further if test are succesfull.  I am worried that the car adapter will have trouble taking a non 12v source and getting 4.5v. 

[leegeddy]

What is the advantage of building the resistor box over hacking a car adaptor???  I don't get it.

Matt

matt;
a VR power supply is much better that a "resistor box". a resistor box is not regulated. when your voltage drops, it simply drops. with a VR circuit, Vout is steady.

marc

[dnsacks]

I believe Matt was erroneously referring to lee's regulated supply as a resistor box.  To (try to) clarify, the box Lee's building would take a wide range of incoming voltages and convert the incoming voltage down to 5.2 volts for the jb3. It does this by using a voltage regulator on an integrated circuit chip.

The car adaptor is designed to only be fed 12 volts.  Thus, unless it uitilizes a voltage regulator similar to that Lee's using, it would not properly reduce an incoming voltage of other than 12 volts down to the 5.2 needed by the jb3.  Lee's adaptor would allow folks to use non-12-volt batteries such as the 9.6v and 7.2v rc car packs and the ubiquitous wallmart 9v lithium ion battery to directly power their jb3s

Very interested in hearing how long a single wallmart 9v would power both a ua5 (with phantom on) and a jb3

[bhtoque]

Creative's car adapter works with 9.6v rc batts. I can try the wally bat tonight and let you know, but I'm sure it will work too.

Rob C reports 10hours for a ua-5 w/ phantom off the wally bat. I've never let it go that long, but 4 hours only takes out the first led on the battery's meter.

JAson

[dnsacks]

NICE -- let me know what you find from your testing