UNLEASH your KaBoOM with this Bass/Treble/Surround Hack

Prime

Member (SA)
May 6, 2009
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Michigan, USA
This hack is for the JVC RV-NB1 Kaboom and similar models with BH3852S audio IC.
This hack will give you Full Control of Bass and Treble. Enable the HIDDEN Surround feature. Force ACS on all the time. Your Kaboom will finally have treble with balls!

The BH3852S is a signal processing IC for volume and tone control. Its driven directly by the micro-controller. There are separate current driven control lines for bass and treble along with a surround mode feature.

Normally, the micro-controller handles the BH3852S with respect to the EQ profiles.
The highest treble setting in the EQ profile is well below what the chip can do.
The treble/bass boost capability is significantly higher with this hack.

The hack essentially overrides the control lines coming from the micro-controller and offers the user full control of bass and treble, switchable surround and ASC force mode.

The BHH3852S has a surround feature that is normally disabled on the Kaboom.
Grounding pin 11 turns it ON.

Also, the ACS (Active Clear Sound) normally comes on and off to augment the highs.
Forward biasing the base of Q8353 will force ACS on all the time.

Enjoy!
Brett











 

Ken

Member (SA)
Aug 30, 2009
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Bremerton, WA, USA
Very nice. This should work in my RV-B55BU. Same chip. :rock: Just need a new CD player. And there's three flashed-over accessory holes not used (optical, mix. mic, & mix. level) Would Q8353 take being constantly forward-biased? Maybe skip the switch & leave it on all the time when the Kaboom's on? You could then put the other switch and the pots on the back. :hmmm:

Thanks, Brett. :bow: I second the motion. This is very cool. :cool:
 

Prime

Member (SA)
May 6, 2009
94
0
6
Michigan, USA
Yes, Q8353 can be held on indefinitely. When ACS is off, the high end is slightly attenuated before it enters the BH3852S. When the ACS is on, the attenuation is removed by a pair of FETs. Q8353 turns on Q8352 which turns on both FETs which shunt out the attenuation network.
 

gsbadbmr

Member (SA)
Apr 2, 2010
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Boombox Museum
Superduper said:
Cool. Now to figure out a way to interface those controls onto the weird kaboom cabinet in an aesthetically pleasing way.....
:agree:


I would hide the controls in the battery compartment...i don't think many use the Kaboom with batteries...the batteries die out in under 20 minutes :lol: