Plug headphones directly into active bass?

I just got my first bass and started playing a little bit. I also got an amplug2 to play with headphones, but it has a very noticeable hiss. It’s also a bit clunky and when I play sitting on my sofa (hey, gotta practice where inspiration strikes!), the volume control rubs against the fabric and gets turned down fairly frequently.

So I figured I’d just plug my headphones (Grado Sr225i, 30Ω I believe) straight into the bass (Yamaha TRBX304). At max volume, I can hear it reasonably well in the Flat setting, and fairly well at the Solo setting. It’s all rather quiet, but good enough in a quiet room. Best of all, no more hiss!

Are there any concerns with doing that? I know it’s technically just a preamp in the bass, but I don’t think these headphones can draw a lot of power. And I figure any recent opamp should easily be able to drive these mid-impedance headphones without bursting into flames.


It won’t hurt anything but is your preamp even turning on? Most headphones have a stereo male connector but most (all?) built-in preamps need a mono male jack plugged into them to complete the power circuit to turn them on.


It definitely turns on, there would be no sound in the headphones otherwise. I’m also getting sound in both ears, which is surprising now that I think about it.

So I just took off the back plate. The jack has five or six solder pads, though only three are in use. I wonder if there’s a mechanical switch in there rather than running power across the plug (I can’t tell without unscrewing the plug, which I want to avoid for now). Or is the power running through my headphones? That would be bad… it would explain the very loud clicking when I plug them in, though. I’ll have to measure that with a multimeter.


Basically what is going to happen is that this will work but it will sound terrible compared to what the bass should sound like.

While the voltage ranges are similar for line, instrument, and headphone level signals, you are really underdriving the headphones on current when you do this. And so what you are doing is exactly the same as when you have a normal audio system underdriving a pair of high-impedance headphones that normally require a headphone amplifier.

The symptoms will likely be a lack of full volume, some distortion/fuzziness at full volume, and a loss of both low and high end harmonics, making the signal lack distinction and depth and sound lifeless and dull.

Additionally, even though the TRBX304 has an active EQ preamp, it still has passive pickups. It’s outputting an instrument level signal, not even line level. This is a common source of confusion. At least it confused me :slight_smile:


Welcome aboard @eagereyes,
Enjoy the ride.
Cheers Brian


Yeah, that makes a lot of sense. And the level is pretty low. I was more worried about damaging my electronics, but this isn’t a permanent solution anyway. Browsing around a bit here I found some mentions of the NUX Mighty Plug, which looks mighty interesting.

My amp is actually just an integrated amp for listening to music though, which has worked pretty well so far. I have to crank the volume a bit, but given the high impedance of the input, it should be alright sound-wise. I’m sure it’s not the “correct” sound for a guitar/bass, but it sounds pretty good to me so far :wink:


Amplug hiss is common, I improved mine some. The nux mighty plug isnt stellar but it’s generally a better product imo. If I were to buy just one it would be the nux.


The only issues I have with Amplug is when Tone in on. If I turn it off all the way, at least my unit is dead silent.


Welcome to the community @eagereyes!


Turning down the tone helps, but mine is still far from silent. I also have it on the lowest gain setting and I can still hear the hiss. So overall I’m not super impressed with the quality of this thing, but I guess it’s in line with what it costs. I might get a NUX sooner or later to see if it it’s better.

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Just a quick note since I got my NUX Mighty Plug today: much better than the Amplug2! I turned the volume on the bass up and the gain on the MP down, and it’s almost completely silent. Its hiss is also less annoying for some reason, it might be the way it interacts with my rather bright headphones. And I feel it sounds better, but I haven’t done any direct comparisons.

I do like the different modes and all the options you have in the app as well. The Funk setting is a bit silly but it’s also fun. And the drums sound good to me too, and there are a lot more than in the amplug. I mean, give me reverb or give me death! :wink:

So IMHO the NUX is the much better choice, and for $75 still a good deal. Though I may also have a NanoBattalion on its way to me, because I do prefer playing with speakers. But the NUX is a really great option for playing on the sofa with headphones.

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