How to use headphones from line out or speaker out jack?

[GatorDogDoc]

I have an Acoustic (brand) B200 combo amp which is perfect for all my uses, except it has no headphone jack--only an XLR line out connection and a 1/4 inch speaker jack (wired in series).

When I play with my church band, the XLR line out is used to run sound to the PA sound board, and I use the amp as a monitor.

I would rather use skullcandy earbuds as a low-cost in-ear monitor, but not sure what I need to make that work.

I was assuming I would need some sort of direct box hook up, but then I was thinking there might be a way to use the speaker out jack? I'm no electronics expert, but I think I remember reading about impedance differences between a typical headphone jack and an amp's speaker jack.

Suggestions on how to use my earbuds?

Can the speaker out jack (in series) be used to drive headphones without damaging the amp (or headphones)?

Specifics:
Acoustic B200 combo: 200 watts, 4 ohm minimum; internal speaker = 4 ohms
skullcandy "smokin bud" model: impedance = 16 ohms

Thanks!

[bongomania]

NO. You cannot use either the line out OR the speaker out for headphones. The first will get you nothing but a quiet, distorted sound in your phones, and the second will get you a destroyed pair of phones.

You need a headphone preamp. End of story. Cheap examples include the EHX headphone amp "pedal", the Vox Amplug line, a used Scholz Rockman, and various inexpensive digital multifx pedals.

[GatorDogDoc]

Originally Posted by bongomania

NO. You cannot use either the line out OR the speaker out for headphones. The first will get you nothing but a quiet, distorted sound in your phones, and the second will get you a destroyed pair of phones.

You need a headphone preamp. End of story. Cheap examples include the EHX headphone amp "pedal", the Vox Amplug line, a used Scholz Rockman, and various inexpensive digital multifx pedals.

Well, the problem is that I want to be using earbuds as monitors while I'm playing and using the floor amp, not instead of an amp (like the Vox).

Thanks for the warning!

But because the church I play at doesn't yet have subs, I need my amp to pump out the low bass frequencies...AND I need to use the line out jack to supply the PA house mix for the rest of the bass frequencies... so I want something that I can run a cable from the speaker out jack to a box which in turn I can plug headphones into to use as in-ear monitors.

Most of the headphone amps are made to plug into the guitar jack (not what I need).

I found this Behringer MicroAmp HA400 Headphone Amp (which supplies 4 headphones if I wanted), but not sure if the impedance rating is what I need for my application:

Behringer MICROAMP HA400 Headphone Amp and more Headphone Amplifiers at GuitarCenter.com.

Would this work from the speaker out jack using a standard 1/4 inch speaker cable?

[jkramer5]

no

[steveksux]

The problem isn't impedence so much as power. Speakers might be getting hundreds of watts, and headphones need fractions of watts.

If you knew what you were doing, theoretically you could probably make a resistor network to connect the speaker outputs to headphones while dropping the power the phones would see to an appropriate level, and add a little volume control at the same time. Not recommended if you don't know what you're doing. You could damage the phones, the amp, or both. Put it in a little box with appropriate jacks.

Randy

[bongomania]

Originally Posted by GatorDogDoc

...because the church I play at doesn't yet have subs, I need my amp to pump out the low bass frequencies...AND I need to use the line out jack to supply the PA house mix for the rest of the bass frequencies... so I want something that I can run a cable from the speaker out jack to a box which in turn I can plug headphones into to use as in-ear monitors.

Actually what you need is a box that would go between the bass and the amp, NOT between the amp and the speakers. You could DIY a box that would go in the speaker out like stevek suggested, but only if you are comfortable with basic circuit design and assembly. For a more practical choice, look into pedal-format preamps and multifx, because some of them have both a headphone output and an output that would go to the amp input.

[GatorDogDoc]

Originally Posted by bongomania

Actually what you need is a box that would go between the bass and the amp, NOT between the amp and the speakers.... For a more practical choice, look into pedal-format preamps and multifx, because some of them have both a headphone output and an output that would go to the amp input.

Ahh, that makes sense.

Just don't know any to start with... looks like off to GC online for a look around.

Sure wish my Boss TU-3 pedal had a headphone out jack... that would solve it all!

I like the idea of a simple pedal... any (low cost) suggestions?

[BassBob1]

what every you get to go between your bass and amp make sure use of the headphone out does not mute the other outputs. For example, my svt 7 pro has a headphone jack, once in use it mutes all other outputs on the amp. (except maybe the tuner out). just something to keep in mind.

[GatorDogDoc]

I think I've found a better solution:

Here is a headphone amp that has a monitor input and headphone output. Since my amp signal is run to the PA sound board, I could have the sound man run a monitor line to me, but instead of using a floor speaker monitor like the others, I'm thinking I could use this box instead with my earbuds.... then I can have him dial up whatever mix of me and the rest of the band I want in my ear.

Behringer Micromon MA400 Headphone Amplifier

Thoughts on if this would work like I'm thinking?

[Munjibunga]

If the two outputs are wired in series, neither would work unless both were plugged in.

Anyway, get a headphone amp and run the line out to that.

[bongomania]

If you are fine with running a line from the desk to where you're playing, then yes: the Behringer will do what you want.

[GatorDogDoc]

Originally Posted by Munjibunga

If the two outputs are wired in series, neither would work unless both were plugged in.

Anyway, get a headphone amp and run the line out to that.

Originally Posted by bongomania

If you are fine with running a line from the desk to where you're playing, then yes: the Behringer will do what you want.

My soundman thinks this will do what I want, so we are gonna try it when I get the gear, especially since it isn't a big investment.

I may post an update in a few weeks when that happens.

Thanks for the feedback and suggestions!

[BassmanPaul]

Make yourself a headphone adapter box. You'll need a mono phone socket, a stereo phone socket to match your headphones, a pair of 1KΩ 5W resistors and a small plastic box to hold everything. Mount the two sockets to the box. Wire the sleeve connection of each socket together (ground). Wire each resistor to the tip (left) and ring (right) connections of the stereo socket. Wire both of the resistors opposite ends to the tip of the mono jack. Make sure all wiring is insulated with sleeving or heat shrink tubing.

Connect the mono jack to the amp with a speaker cable and your headphones into the stereo jack. Bring up the volume on the amp to a comfortable level and play away.

[vin*tone]

Interesting. What impedance does the amp see with this little contraption?

[okcrum]

Originally Posted by BassmanPaul

Make yourself a headphone adapter box. You'll need a mono phone socket, a stereo phone socket to match your headphones, a pair of 1KΩ 5W resistors and a small plastic box to hold everything. Mount the two sockets to the box. Wire the sleeve connection of each socket together (ground). Wire each resistor to the tip (left) and ring (right) connections of the stereo socket. Wire both of the resistors opposite ends to the tip of the mono jack. Make sure all wiring is insulated with sleeving or heat shrink tubing.

Connect the mono jack to the amp with a speaker cable and your headphones into the stereo jack. Bring up the volume on the amp to a comfortable level and play away.

+1. Cost at RS: maybe $10 plus an hour to assemble. Vin, this device bridges, so the amp sees essentially just the original speaker load.

[GatorDogDoc]

Originally Posted by BassmanPaul

Make yourself a headphone adapter box. You'll need a mono phone socket, a stereo phone socket to match your headphones, a pair of 1KΩ 5W resistors and a small plastic box to hold everything. Mount the two sockets to the box. Wire the sleeve connection of each socket together (ground). Wire each resistor to the tip (left) and ring (right) connections of the stereo socket. Wire both of the resistors opposite ends to the tip of the mono jack. Make sure all wiring is insulated with sleeving or heat shrink tubing.

Connect the mono jack to the amp with a speaker cable and your headphones into the stereo jack. Bring up the volume on the amp to a comfortable level and play away.

Happen to have a photo of what the inside of one looks like? Would help me on the wiring/connections.

[bongomania]

Look at the letters "I V". At the bottom of the letters there are two points, and at the top there are three. Imagine there is a jack above the "I V" and a jack below it. The mono jack has two contacts, the stereo jack has three. The "sleeve" (outer part) of one jack connects to the sleeve of the other--that's the "I". The "tip" (middle part) of the mono jack connects to both of the remaining tabs on the stereo jack, and that makes a "V". The "I" is made with just a piece of wire, while the "V" is made with two resistors.

[GatorDogDoc]

Originally Posted by bongomania

Look at the letters "I V". At the bottom of the letters there are two points, and at the top there are three. Imagine there is a jack above the "I V" and a jack below it. The mono jack has two contacts, the stereo jack has three. The "sleeve" (outer part) of one jack connects to the sleeve of the other--that's the "I". The "tip" (middle part) of the mono jack connects to both of the remaining tabs on the stereo jack, and that makes a "V". The "I" is made with just a piece of wire, while the "V" is made with two resistors.

Great and simple visual "graphic"... are you teacher?
Thanks for the tips, I'll have to definitely look into this.

okcrum mentioned RS... assuming that is Radio Shack.

Two more questions:
(a) Does the brand of resistor matter?

(b) What gauge wire is appropriate for this?

I have the soldering iron and solder from wiring leads on guitars, so should be set there.

[bongomania]

Brand of resistor does not matter, and wire gauge doesn't matter a lot in this particular case either (it does matter in some other applications). 22 or 20 would be fine for the ground. Although I guess if you use wire to extend the length of the resistors, it might be best to have a fatter gauge (like 18 or 16) for the end that connects to the speaker output.

[MNAirHead]

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