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Gear / Technical Help => Battery Boxes, Preamps, Mixers, ADCs, and Processors => Topic started by: Walstib62 on February 26, 2020, 10:30:06 PM

Title: Tinybox 9 volt Mod
Post by: Walstib62 on February 26, 2020, 10:30:06 PM
I decided to change the internal 7.2 volt internal cell to a 9 volt rechargeable. It just fits inside. I can now power from the internal, or also connect an external 9 volt pack simultaneously, which extends the run time significantly.
Title: Re: Tinybox 9 volt Mod
Post by: jerryfreak on February 26, 2020, 11:23:21 PM
cool move. those li-ion 9Vs arent 9V but thats good, as they run at the same voltage as the packs.

does it charge ok with the default setup? Out of the box the TBs couldnt charge and operate at the same time, so what you describe is def. different
Title: Re: Tinybox 9 volt Mod
Post by: Walstib62 on February 27, 2020, 07:10:21 AM
The internal battery and external DC input are in parallel, so yes the tinybox is powered by both at the same time.  With the 7.2 volt pack, you could do the same thing, but you would have to limit the external input to 8.4 volts max. With this mod it is much easier because you can use 9 volt cells.
The internal cell has to be rechargeable.

9 volt operation has the added advantage of keeping the amplifier circuits at proper DC supply levels. There have been performance issues noted with the 7.2 volt battery discharging during use and causing distortion due to low DC levels. 
Title: Re: Tinybox 9 volt Mod
Post by: jerryfreak on February 27, 2020, 08:02:43 AM
yes but again it’s not a ‘9V’

it’s the exact same configuration as the original li-ion (if so equipped)... 2 3.6V (aka 4.2V) cells in series

if the previous battery didn’t operate the unit correctly, it shouldn’t have been because of the battery type, it was likely because the battery was defective (same for the 5*nimh cells batteries, which are slightly lower voltage but still operate the unit to full spec, afaik.) they run about 6v until they start to tail off

more importantly, putting 9v in parallel with that battery sounds dangerous. they can take higher voltages as long as cell voltage isn’t above 8.4, but once they hit 8.4 the voltage needs to be controlled. with an external 9v you can be well past 1C charge rate and hit 8.4 sooner than you think. practically speaking those 9V alkalines wont be above 8.4v for long with any significant load on them. in any case if you didn’t alter the circuit inside there’s a charge controller onboard, as tiny boxes charged from any unregulated wall wart of adequate voltage.
Title: Re: Tinybox 9 volt Mod
Post by: TheMetalist on February 27, 2020, 10:57:33 AM
Thank you for the pictures and clarification.

I still don't understand how it's possible to fit a 9V battery inside of the unit? I have tried in mine but no... The 9V battery is too long. Looking at your pictures, your TB seems to have a different circuit board than mine. Perhaps yours is smaller so you have more space inside.

What kind of connector do you use for the external power? I have tried various connectors but none really stick nicely in the 9-15V input plug. I'm afraid it would come loose when in stealth mode and stuffed away in my bag.
Title: Re: Tinybox 9 volt Mod
Post by: Walstib62 on February 27, 2020, 11:14:13 AM
I think it's the "M" plug. I'm not absolutely sure.  I had one that fit properly
Title: Re: Tinybox 9 volt Mod
Post by: TheMetalist on February 27, 2020, 11:42:28 AM
I think it's the "M" plug. I'm not absolutely sure.  I had one the fit properly
Thanks. I'll check that out.
Title: Re: Tinybox 9 volt Mod
Post by: youngsbest on March 04, 2020, 01:39:40 PM
I did something similar for my pipsqueak.  The internal battery failed, so I got a new one from Naiant, but it's expensive as I'm in the UK.  I got a four AAA battery holder and wired that up to fit the pipsqueak and removed the internal battery. I cut a notch in the case for the cable & attached it with some elastic webbing. I can charge the batteries in an ordinary charger before putting in the holder. It adds about 12mm in height to the pipsqueak, but that's not a problem for me.  So no more battery worries.  The four AAAs give 4.8v, the same as the internal battery.  If I used non rechargeable batteries, that would be 6v.  Would that damage the pipsqueak?
Title: Re: Tinybox 9 volt Mod
Post by: perks on March 04, 2020, 02:05:06 PM
I love reading about alternative powering solutions for the Naiant preamps especially the Tinybox as I stopped using mine once the battery I got when I purchased the device became unreliable. I tip my hat to all the pioneers willing to test out new options. I guess my question is why wouldn't Jon have offered an option like this during the build? It just seems like such a simple solution or at least no more complicated than Jon's offer and remedy to replace the internal rechargeables when their life finally expires.
Title: Re: Tinybox 9 volt Mod
Post by: Walstib62 on March 05, 2020, 10:25:49 PM
UPDATE:  I performed the first "run time" test today. I have a pair of AT 933 mics powered, and currently at 13 hours the power LED is still green. Battery voltage is at 7.7 volts, down from 8.4 at full charge. The really cool thing here is that the Talentcell battery can charge from USB. I enlarged the hole in the rear panel to allow access to the USB connector. Before I started the test, the battery was discharged to the point that tinybox would not power up. As soon as I plugged in the USB, tinybox powered up and LED was green, fully functional and passing signal just fine. This tells me that the USB can be used to charge the battery and power the unit simultaneously. Picture of rear panel below.
Title: Re: Tinybox 9 volt Mod
Post by: jerryfreak on March 05, 2020, 10:32:17 PM
oh i see! so the tbox doesnt see that as 'charging' from the usual charging circuit, just dc power from the bat itself

clever!
Title: Re: Tinybox 9 volt Mod
Post by: TheMetalist on March 06, 2020, 02:47:46 AM
I still don't get how you can fit the battery inside the tinybox. Is the Talentcell smaller
(in lenght) than a regular 9v alkaline?
Title: Re: Tinybox 9 volt Mod
Post by: Walstib62 on March 06, 2020, 07:54:06 AM
I still don't get how you can fit the battery inside the tinybox. Is the Talentcell smaller
(in lenght) than a regular 9v alkaline?


you may need to put short spacers behind the rear panel to extend it out about 3mm but it should fit
Title: Re: Tinybox 9 volt Mod
Post by: spyder9 on March 06, 2020, 08:03:53 AM
+T on this Mod!   :smash:
Title: Re: Tinybox 9 volt Mod
Post by: jerryfreak on March 06, 2020, 08:25:24 AM
you may need to put short spacers behind the rear panel to extend it out about 3mm but it should fit

alternatively you could dremel out the backplate to the same cross section of the battery itself and let it stick out 1/8" or whatever, and hot glue it to the plate so you have a positive female socket to plug the usb charger into
Title: Re: Tinybox 9 volt Mod
Post by: johnmuge on March 06, 2020, 03:38:43 PM
Great job on this. I need to open mine up and see if I have the same board as you. Mine has dual output with and without transformers so we'll see.
Title: Re: Tinybox 9 volt Mod
Post by: Walstib62 on March 06, 2020, 11:30:42 PM
Great job on this. I need to open mine up and see if I have the same board as you. Mine has dual output with and without transformers so we'll see.

the xformers probably occupy some of the space where the battery would be but I'm not sure