Using an Outdoor Volume-Control as a Guitar-Speaker Attenuator
To get better control over the volume of a guitar-amp that’s too loud, instead of spending hundreds on a speaker attenuator, use an outdoor volume-control instead, at a fraction of the cost. Just make sure the control has the same wattage rating as the amplifier. This example is for a 100-watt amp.
Volume Control: Audtek VC-100RO Impedance-Matching Outdoor Stereo Volume Control, 100-Watt, in rain-tight wall-mount enclosure. Available from Parts Express. Part # 300-569. www.parts-express.com $25.98 each.
You will also need some male and female connectors. I used the quick-disconnect type; I call them “push-on” types; the female typically used as a speaker-terminal connector. However, note the size on your speaker. They come in different sizes. Or you can use male and female 1/4-inch phone connectors instead, if preferred. You will also need a few feet of ordinary 2-conductor speaker wire, with one conductor having a black or white stripe, and basic electronics tools, including a crimp tool if you use the push-on connectors. I have tools and plenty of speaker wire but obtained the connectors at Home Depot. They label them “Disconnect F” and “Disconnect M” types of connectors. See examples at Parts Express; part numbers 095-302 and 095-312, but you have to buy in bulk (50 per pack) to order them there.
I have an open-back combo amp, which made it easy to attach the control to an inner side once I had the jumper-wires ready to go (explained below). For a closed-backed combo or amp-head, you may want to use male and female 1/4-inch phone connectors anyway, to be able to patch the control in externally using ordinary speaker cables. But I must leave this for the reader to figure out, since I did not do it that way.
Here are the steps to take to install the control in an open-backed combo-amp.
Step 1. With the amp off and unplugged, pull off the Disconnect F connectors from the speaker terminals and inspect them. Sometimes speaker vibrations will cause them to suffer wiggle damage, weakening the wire at the crimp. If necessary, clip them off and put new ones on, but leave as much wire coming from the amp as possible. You may also need to do that anyway if the connectors you have are a different size (both things are what happened to me).
Step 2. Make two jumpers using new 2-conductor speaker wire as follows. Measure how much wire you need to go from the speaker to where the control will be mounted and cut two pieces of wire; each a few inches over that length, or more. You want plenty of slack, which should be wound up and zip-tied later anyway. [I made my jumpers 2 feet long.] On both jumpers, remove about 1/4-inch of insulation from one end of each conductor and twist the exposed wire strands on each end to make the ends stiff enough to insert into the terminal inside the control (assuming you have stranded speaker wire). On the other end of one of the jumpers remove 1/4 to 1/2 inch of insulation and attach a female connector to that end of each conductor. Then do the same to the other jumper but using male connectors instead. Thus, you will have one jumper with male ends and another with female ends, but with all other ends bare.
Step 3. Disassemble the volume control. There are four screws holding the cover on and four screws holding the circuit assembly to the backplate of the box. Be careful removing the knob; it pulls straight off but is difficult to remove. It can be pried, but don’t damage it. [In my case, I loosened the cover first and used it to pull the knob off.] Hold the circuit assembly by the transformers, not the circuit board, as you work. [Caution! Don’t drop it on a hard floor. And don’t misplace the screws!!!] Also, if you want to keep the box rain-tight, there is a small o-ring under the knob. Save it, to reinstall later.
Step 4. Using the jumper with Disconnect M ends, connect the bare ends to the + and – terminals of either the Left or the Right channel on the Input side of the control circuit assembly (I used the Right channel), keeping track of the terminal you chose for the striped conductor. You will need small screwdrivers, like jeweler’s screwdrivers (Phillips and flat-blade), since the terminals are very small. And you must back the set-screws out quite a bit to get the wires in. I used a Phillips head screwdriver for this, then did the final tightening with a flat-blade screwdriver. That done, tug on the wires to make sure they are being held securely by the terminal. Now you have the jumper with male ends connected to the Input side of the control.
Step 5. Using the jumper with Disconnect F ends, connect the bare ends to the + and – terminals of the same channel on the Output side of the control circuit assembly, making sure to connect the striped conductor to the same + or – terminal you used on the Input side. And here too, once done, tug on the wires to ensure a tight connection. Then you will have the jumper wires with female ends connected to the Output side of the control. Here, I used only one channel, the R channel, which is only rated at 50-watts, because I do not intend to use my amp any louder than that. However, if you need all 100-watts capability from the control, for cranking the amp’s master volume most or all the way up to get an overdriven tone, then you can use small single-conductor jumpers to connect the separate + and – terminals of the circuit assembly; + jumped to +, and – jumped to – as shown in the sketch below. Caution! Continue to keep track of which terminal goes with the striped conductors on each main jumper.
Step 6. Run the two main jumpers from inside-out through the hole in the bottom of the control’s box and then reassemble the control. Temporarily use the knob to orient the circuit assembly how you want it; with the dial’s OFF position (fully counterclockwise) pointing up or pointing down. [I installed the hole and the OFF pointing up, since I do not expect it to rain inside my amp, and I wanted position 5 to point down.] You now have a reassembled control with protruding jumper wires.
Step 7. Fasten the control to the inner wall on one side in the back of the amplifier cabinet, with the jumpers hanging loose. [Do not connect them to the amp or speaker just yet.] I used the left side, and set the control very near the outer edge, to easily reach the knob with my right hand. The control box has flanges with screw-holes for mounting to a wall. Caution! Use wood screws that are no longer than the thickness of the cabinet’s side, so the screw-tips will not stick out from that side’s outer surface.
Step 8. Connect the Disconnect M jumper to the wires from the amplifier, making sure to keep track of which one you chose for the striped conductor. Then connect the other jumper to the speaker, sticking with the same polarity. Turn the control’s knob all the way OFF, then plug the amplifier in, connect your guitar, and turn the amplifier on. After warmup, turn the amp’s master volume control to a desired position, then the speaker control to any position from 25% to 75% and start playing. You should notice quite a difference in the loudness of the amp compared to how loud it was before. Experiment with different settings of both the master volume and the new speaker control to learn how they are going to interact. You may also notice a difference in tonality (such as an increase in treble response) as the speaker control is turned down. For a solid-state amp, you should not hear much of an increase in distortion as the master volume is turned up and the speaker control is turned down. But with a tube-amp, you will be able to get a cranked-up sound at a much lower volume than would otherwise be the case.
Personal Note: Speaker attenuators gained popularity with tube-amp users who wanted to get overdriven tones but without the ear-damaging loudness. OK, but I have a solid-state amp with a built-in processor that gives me any sound I want, including tube-amp sounds. However, it’s way too loud. And the master volume control has dead spots at low settings. But since I installed the new control, I can turn the master up past the dead spots without getting too loud. And I am very pleased.
EOF
To get better control over the volume of a guitar-amp that’s too loud, instead of spending hundreds on a speaker attenuator, use an outdoor volume-control instead, at a fraction of the cost. Just make sure the control has the same wattage rating as the amplifier. This example is for a 100-watt amp.
Volume Control: Audtek VC-100RO Impedance-Matching Outdoor Stereo Volume Control, 100-Watt, in rain-tight wall-mount enclosure. Available from Parts Express. Part # 300-569. www.parts-express.com $25.98 each.
You will also need some male and female connectors. I used the quick-disconnect type; I call them “push-on” types; the female typically used as a speaker-terminal connector. However, note the size on your speaker. They come in different sizes. Or you can use male and female 1/4-inch phone connectors instead, if preferred. You will also need a few feet of ordinary 2-conductor speaker wire, with one conductor having a black or white stripe, and basic electronics tools, including a crimp tool if you use the push-on connectors. I have tools and plenty of speaker wire but obtained the connectors at Home Depot. They label them “Disconnect F” and “Disconnect M” types of connectors. See examples at Parts Express; part numbers 095-302 and 095-312, but you have to buy in bulk (50 per pack) to order them there.
I have an open-back combo amp, which made it easy to attach the control to an inner side once I had the jumper-wires ready to go (explained below). For a closed-backed combo or amp-head, you may want to use male and female 1/4-inch phone connectors anyway, to be able to patch the control in externally using ordinary speaker cables. But I must leave this for the reader to figure out, since I did not do it that way.
Here are the steps to take to install the control in an open-backed combo-amp.
Step 1. With the amp off and unplugged, pull off the Disconnect F connectors from the speaker terminals and inspect them. Sometimes speaker vibrations will cause them to suffer wiggle damage, weakening the wire at the crimp. If necessary, clip them off and put new ones on, but leave as much wire coming from the amp as possible. You may also need to do that anyway if the connectors you have are a different size (both things are what happened to me).
Step 2. Make two jumpers using new 2-conductor speaker wire as follows. Measure how much wire you need to go from the speaker to where the control will be mounted and cut two pieces of wire; each a few inches over that length, or more. You want plenty of slack, which should be wound up and zip-tied later anyway. [I made my jumpers 2 feet long.] On both jumpers, remove about 1/4-inch of insulation from one end of each conductor and twist the exposed wire strands on each end to make the ends stiff enough to insert into the terminal inside the control (assuming you have stranded speaker wire). On the other end of one of the jumpers remove 1/4 to 1/2 inch of insulation and attach a female connector to that end of each conductor. Then do the same to the other jumper but using male connectors instead. Thus, you will have one jumper with male ends and another with female ends, but with all other ends bare.
Step 3. Disassemble the volume control. There are four screws holding the cover on and four screws holding the circuit assembly to the backplate of the box. Be careful removing the knob; it pulls straight off but is difficult to remove. It can be pried, but don’t damage it. [In my case, I loosened the cover first and used it to pull the knob off.] Hold the circuit assembly by the transformers, not the circuit board, as you work. [Caution! Don’t drop it on a hard floor. And don’t misplace the screws!!!] Also, if you want to keep the box rain-tight, there is a small o-ring under the knob. Save it, to reinstall later.
Step 4. Using the jumper with Disconnect M ends, connect the bare ends to the + and – terminals of either the Left or the Right channel on the Input side of the control circuit assembly (I used the Right channel), keeping track of the terminal you chose for the striped conductor. You will need small screwdrivers, like jeweler’s screwdrivers (Phillips and flat-blade), since the terminals are very small. And you must back the set-screws out quite a bit to get the wires in. I used a Phillips head screwdriver for this, then did the final tightening with a flat-blade screwdriver. That done, tug on the wires to make sure they are being held securely by the terminal. Now you have the jumper with male ends connected to the Input side of the control.
Step 5. Using the jumper with Disconnect F ends, connect the bare ends to the + and – terminals of the same channel on the Output side of the control circuit assembly, making sure to connect the striped conductor to the same + or – terminal you used on the Input side. And here too, once done, tug on the wires to ensure a tight connection. Then you will have the jumper wires with female ends connected to the Output side of the control. Here, I used only one channel, the R channel, which is only rated at 50-watts, because I do not intend to use my amp any louder than that. However, if you need all 100-watts capability from the control, for cranking the amp’s master volume most or all the way up to get an overdriven tone, then you can use small single-conductor jumpers to connect the separate + and – terminals of the circuit assembly; + jumped to +, and – jumped to – as shown in the sketch below. Caution! Continue to keep track of which terminal goes with the striped conductors on each main jumper.
Step 6. Run the two main jumpers from inside-out through the hole in the bottom of the control’s box and then reassemble the control. Temporarily use the knob to orient the circuit assembly how you want it; with the dial’s OFF position (fully counterclockwise) pointing up or pointing down. [I installed the hole and the OFF pointing up, since I do not expect it to rain inside my amp, and I wanted position 5 to point down.] You now have a reassembled control with protruding jumper wires.
Step 7. Fasten the control to the inner wall on one side in the back of the amplifier cabinet, with the jumpers hanging loose. [Do not connect them to the amp or speaker just yet.] I used the left side, and set the control very near the outer edge, to easily reach the knob with my right hand. The control box has flanges with screw-holes for mounting to a wall. Caution! Use wood screws that are no longer than the thickness of the cabinet’s side, so the screw-tips will not stick out from that side’s outer surface.
Step 8. Connect the Disconnect M jumper to the wires from the amplifier, making sure to keep track of which one you chose for the striped conductor. Then connect the other jumper to the speaker, sticking with the same polarity. Turn the control’s knob all the way OFF, then plug the amplifier in, connect your guitar, and turn the amplifier on. After warmup, turn the amp’s master volume control to a desired position, then the speaker control to any position from 25% to 75% and start playing. You should notice quite a difference in the loudness of the amp compared to how loud it was before. Experiment with different settings of both the master volume and the new speaker control to learn how they are going to interact. You may also notice a difference in tonality (such as an increase in treble response) as the speaker control is turned down. For a solid-state amp, you should not hear much of an increase in distortion as the master volume is turned up and the speaker control is turned down. But with a tube-amp, you will be able to get a cranked-up sound at a much lower volume than would otherwise be the case.
Personal Note: Speaker attenuators gained popularity with tube-amp users who wanted to get overdriven tones but without the ear-damaging loudness. OK, but I have a solid-state amp with a built-in processor that gives me any sound I want, including tube-amp sounds. However, it’s way too loud. And the master volume control has dead spots at low settings. But since I installed the new control, I can turn the master up past the dead spots without getting too loud. And I am very pleased.
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