Guitar + Ipod into heaphones

res07njc · 11th May 2005, 03:14 PM

There's a new? product out...the Jampod. It mixes your guitar with your Ipod so you can jam with your mp3's.

So as an experiment, I took one of my OPA2132 headphone amps, and I paralleled my guitar signal(2ch mono) with the Ipod input. The result? I get Ipod, but no guitar. If I unplug the Ipod, I get guitar.

All I want is Ipod stereo, guitar 2 ch mono, coming through the same headphones. What is the proper way to mix these signals?

leadbelly · 11th May 2005, 04:35 PM

Why are you referring to your guitar as 2 ch mono? Does it have a standard 1/4" phono plug output?

This is what I found:

Quote:

JamPod works with any electric guitar, electric bass, or other instrument that sends a guitar-level output signal through a 1/4-inch instrument jack. Just plug the included cable into the 1/4-inch jack on your guitar, bass, acoustic-electric guitar, or other instrument that produces a standard instrument level output signal to a 1/4-inch jack.

Is this what you are doing?

res07njc · 11th May 2005, 08:36 PM

I wired my single wire guitar signal to both left and right channels on the headphone amp. I don't know what else to called that than 2ch mono. I'm using a mono 1/4" jack.....typical guitar...

The text you found is exactly what I'm trying to do. I saw a review on this product and they said it was a great idea that was poorly executed. IOW, a POS. I'd like to build a good unit with decent componts.....but something that works unlike my previous experiements. The amp that I'm using at the moment has a .1uF and 100K on the input.

pinkmouse · 11th May 2005, 10:10 PM

The best thing to do is just add a "virtual earth" mixer to the input of your headphone amp. You just need a dual opamp running inverted, with each input having it's own 10K resistor.

BobEllis · 11th May 2005, 10:41 PM

try mixing the signals by putting a 10K resitor in series with the guitar inputs and the ipod input. join the other end of the 10K resistors and connect this to your headphone amp input. Without the resistors, thelow output impedance of your ipod effectivelyshorts out the guitar. Thinking about it, if it is a passive guitar, you might want to bump up to 100K in series.

You may find that you want a little more gain on the guitar - an easy op-amp stage will work here, and serve as a buffer for the guitar output. (so you can use 10K mixing resistors and lower the noise)

res07njc · 12th May 2005, 06:41 AM

Hey Bob, I did just that...except I used a couple 100k on the ipod, and a 22k on the guitar. WORKS! I'll have to play around with different values though; I could tell that the guitar signal needs some frequency tweaking. It sounds too hifi-ish...doesn't sound quite right with the Ipod mix. I have the feeling that I want to roll the tone off a little (besides the tone control on my Telecaster) Maybe that will help it cut through a little better without having to crank up the guitar's volume. Suppose I'll just parallel a cap (.022?) with the 22K. Thanks

BobEllis · 12th May 2005, 10:15 AM

The frequency response of guitar speakers is nowhere near as flat as your ipod headphones, which contributes a great deal to the sound you are looking for. Rolling off the highs on the guitar input is a good start. You may want a buffer stage to keep from affecting the ipod sound too much. There are lots of tone stacks out there in the diy guitar world.

Better yet, turn away from the dark side and play bass. Our instruments generally sound good in a hi-fi type system.

11th May 2005, 03:14 PM	#1
res07njc diyAudio Member Join Date: May 2005 Location: Tampa Fla	Guitar + Ipod into heaphones There's a new? product out...the Jampod. It mixes your guitar with your Ipod so you can jam with your mp3's. So as an experiment, I took one of my OPA2132 headphone amps, and I paralleled my guitar signal(2ch mono) with the Ipod input. The result? I get Ipod, but no guitar. If I unplug the Ipod, I get guitar. All I want is Ipod stereo, guitar 2 ch mono, coming through the same headphones. What is the proper way to mix these signals?

11th May 2005, 10:10 PM	#4
pinkmouse diyAudio Moderator Join Date: Apr 2002 Location: Chatham, England	The best thing to do is just add a "virtual earth" mixer to the input of your headphone amp. You just need a dual opamp running inverted, with each input having it's own 10K resistor. __________________ Al I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while. Charles Fort

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11th May 2005, 08:36 PM	#3
res07njc diyAudio Member Join Date: May 2005 Location: Tampa Fla	I wired my single wire guitar signal to both left and right channels on the headphone amp. I don't know what else to called that than 2ch mono. I'm using a mono 1/4" jack.....typical guitar... The text you found is exactly what I'm trying to do. I saw a review on this product and they said it was a great idea that was poorly executed. IOW, a POS. I'd like to build a good unit with decent componts.....but something that works unlike my previous experiements. The amp that I'm using at the moment has a .1uF and 100K on the input.

11th May 2005, 10:41 PM	#5
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	try mixing the signals by putting a 10K resitor in series with the guitar inputs and the ipod input. join the other end of the 10K resistors and connect this to your headphone amp input. Without the resistors, thelow output impedance of your ipod effectivelyshorts out the guitar. Thinking about it, if it is a passive guitar, you might want to bump up to 100K in series. You may find that you want a little more gain on the guitar - an easy op-amp stage will work here, and serve as a buffer for the guitar output. (so you can use 10K mixing resistors and lower the noise)

12th May 2005, 06:41 AM	#6
res07njc diyAudio Member Join Date: May 2005 Location: Tampa Fla	Hey Bob, I did just that...except I used a couple 100k on the ipod, and a 22k on the guitar. WORKS! I'll have to play around with different values though; I could tell that the guitar signal needs some frequency tweaking. It sounds too hifi-ish...doesn't sound quite right with the Ipod mix. I have the feeling that I want to roll the tone off a little (besides the tone control on my Telecaster) Maybe that will help it cut through a little better without having to crank up the guitar's volume. Suppose I'll just parallel a cap (.022?) with the 22K. Thanks

12th May 2005, 10:15 AM	#7
BobEllis diyAudio Member Join Date: Sep 2003 Location: Upstate NY	The frequency response of guitar speakers is nowhere near as flat as your ipod headphones, which contributes a great deal to the sound you are looking for. Rolling off the highs on the guitar input is a good start. You may want a buffer stage to keep from affecting the ipod sound too much. There are lots of tone stacks out there in the diy guitar world. Better yet, turn away from the dark side and play bass. Our instruments generally sound good in a hi-fi type system.

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