Remote Volume Adjustment

barrysfarm

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I'm working on a Donkey Kong (with original wiring) and I'd like to put an additional volume adjustment in a place where I can adjust it easily. Somewhere in easy reach of opening the coin door. I just don't want to wake up my girlfriend when I play in the early mornings.

I tried attaching a Rheostat (http://www.radioshack.com/product/index.jsp?productId=2062299) in line with the speaker. I couldn't get it to do much. I put inline with the white wire going to the speaker. When all the way down, the volume is at about 30% and all the way up is 50%. I'd like it go go the full range.

I'd prefer not to mess with the wiring on the audio board itself.
 
First off a 25Ohm pot is a pretty small range. A typical volume pot is 5K (5000 Ohm)
And keep in mind your max volume will only be as loud as what the main board is set to. (so turn it up)
The input an douput in the diagram being the ONE speaker line you cut and tie the pot into. Leave the other speaker line alone.
 

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Right. I'll give a bigger pot a try. I thought that I read that for inline speaker wiring the pot should be much lower, as apposed to a pot on the pcb. I guess not.

I believe that's how i have it wired. Though the input/output may be backwards.
 
remote speaker volume

BARRYSFARM,

You should be using a low OHM pot, if you are inline with the speaker from the output of the amplifier. If your speaker is, for example 4 Ohms, and you add a 4 Ohm resistor in series, it will be more or less, half as loud. So, basically you want a variable resistance that you can put in series with your speaker. If your series resistance is 10X - 20X your speaker impedance it will be very, very quiet. Q-Bert use a 100 Ohm pot in series for a remote volume, see pic.

Also, you can either use it as a rheostat and tie on end of the pot to the wiper and use the open end and the wiper/other end as your 2 wires or use it as a voltage divider like in the Q-Bert schematic. Be sure to use audio ground and not a cabinet ground, twist your wires together, or you could pick up unwanted background noise.

Kenneth

Forgot to mention that this schematic chunk and my suggestion is for you to put the pot in series with the Audio "+" line.
 

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Last edited:
First off a 25Ohm pot is a pretty small range. A typical volume pot is 5K (5000 Ohm)
And keep in mind your max volume will only be as loud as what the main board is set to. (so turn it up)
The input an douput in the diagram being the ONE speaker line you cut and tie the pot into. Leave the other speaker line alone.

He's putting the POT in series with a 4 ohm speaker.. assuming no additional connection resistance, that pot (if wired correctly) should give full volume down to ~14% volume. (4 / (4+25)) = .138).

Typical volume pots go on the INPUT of the amp, not the OUTPUT.

You might be better off just bypassing the amp on the monitor and putting your own amp in and mounting it right next to the speaker.
 
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