# Adding a LED to a Godin Multiac



## JCJ (Jan 3, 2008)

I emailed the Godin people about adding an LED somewhere on my Godin Multiac Encore. It uses a 9 volt battery, and when the battery dies there is no warning and it makes a horrendous sound through the P.A.
They told me the problem couldn't be fixed, but I believe it can be done...

I'm going to try some DIY work on the guitar, including putting a small LED for the battery life, and looking for any ideas or thoughts about the process. I've taken this guitar out of live rotation for a while and will use it for repair/maintenance practice.

Ultimately what I'd like to do is build a similar model from scratch, with a neck radius I prefer and a shorter scale neck. I'm pretty sure we can find some better electronics for the instrument (although what Godin provides is functionally decent). A friend of mine is a guitar builder, but it would be 18 months before he'd have time to build one from scratch.

Anyway, I'm going to start with the LED. Feel free to make any (positive, constructive) comments.
TY
James


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## Steadfastly (Nov 14, 2008)

It would be easier, in my estimation to add a timer in the control box and hook it up to an LED. Then set the timer to light the LED when the timer reached 75% of the battery life. This will give you a safety margin of 25%. Personally, I wouldn't build a new guitar. I would have him do a new neck for me and use the existing body.


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## greco (Jul 15, 2007)

*I searched low battery indicator circuit...this was one example

LOW BATTERY INDICATOR CIRCUIT*

Posted on May 31, 2013 by shriram
The following post describes a simple low battery indicator circuit by using just two inexpensive NPN transistors. The main feature of this circuit is its very low stand by current consumption.

We can also make a low battery indicator circuit using a *741 IC* and a *555 IC*, which are no doubt outstanding with their abilities of detecting and indicating low battery voltage thresholds.
However the following post relates yet another similar circuit which is much cheaper and employs just a couple of NPN transistors for producing the required low battery indications.
The main advantage of the proposed two transistor low battery indicator circuit is its very low current consumption compared to the IC counterparts which consume relatively higher currents. A IC 555 would consume around 5mA, a IC741 around 3 mA, while the present circuit would just consume around 1.5mA current.
Thus the present circuit becomes more efficient especially in cases where stand by current consumption tend to become an issue, example suppose in units which depend on low current battery supplies such as a 9V PP3 battery.
Another advantage of this circuit is it’s ability to work even at voltages around 1.5V which gives it a clear edge over the IC based circuits.
As shown in the following circuit diagram, the two transistors are configured as voltage sensor and inverter.
The first transistor on the left senses the threshold voltage level as per the setting of the 47K preset. As long as this transistor conducts, the second transistor on the right is held switched OFF, which also keeps the LED switched OFF.
As soon as the battery voltage falls below the set threshold level, the left transistor is no longer able to conduct.
This situation instantly triggers the right hand side transistor, switching ON the LED.
The LED switches ON and provides the required indications of a low battery warning.


Cheers

Dave


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## JCJ (Jan 3, 2008)

Steadfastly said:


> It would be easier, in my estimation to add a timer in the control box and hook it up to an LED. Then set the timer to light the LED when the timer reached 75% of the battery life. This will give you a safety margin of 25%. Personally, I wouldn't build a new guitar. I would have him do a new neck for me and use the existing body.


Good suggestion on the neck-only idea. But, I figure if we're going that route, there are some things about the body I'd like to tweak as well.
But I will search out your idea on the timer in the control box...
TY

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greco said:


> *I searched low battery indicator circuit...this was one example
> 
> LOW BATTERY INDICATOR CIRCUIT*
> 
> ...


Thanks, Dave. I'll need to study this...been a long time since high-school shop class.


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## greco (Jul 15, 2007)

boomer said:


> Thanks, Dave. I'll need to study this...been a long time since high-school shop class.


There might be easier/better circuits to choose from...I just selected this one as a sample.

Good Luck with solving the problem.

Cheers

Dave


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## JCJ (Jan 3, 2008)

I'm back to DIY-ing the guitar, but this time I'm looking for a guitar tech who can do the job. Any recommendations for a good tech in the Oakville/GTA/Hamilton area please advise. I can travel a bit for the right guy!
James


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