Hissing from headphones

So Now that we’re at chords and arpeggios lesson, I finally decided to use headphones for the first time with my new Fender LT25 Rumble 25. Unless I’m not supposed to, I plug my bass (Squire Fender) directly into the headphone jack on the amp. EVERY headphone set I try, creates a hiss, even if not plugged into the bass. And because I’m a beginner, it makes my mistakes even more painful to listen to, lol.

I tried adjusting gain and volume, but amp and bass would have to be at almost zero settings to eliminate the hissing. Tried new cables, different outlets, you name it. Headphones work decent on my LYZ PRO 20 amp, but I wanted to use the new amp. What am I doing wrong? I’m sure it’s beginner user error. So am I supposed to connect the cable to something else, THEN CONNECT TO THE AMP?

Headphones tried: ISK HP-960B, OneOdio and a new pair of Ath-M30x.

I’m ready to progress. Love my classes, but need some help with this one.

Hmm. You said above you plug your bass directly into the headphone Jack? I’m assuming this isn’t correct as your bass goes in the normal input and your headphones plug into the headphone Jack. I’m guessing this is just a typo.

I had a rumble 40 and don’t recall this issue.
I would say it’s either an issue with the amp and you should return it OR it’s just the quality of the amp.
You could see if you can try another LT25 at a store with your headphones etc to see if it’s all LT25s or if yours is just “special”.


I’m with @John_E on this. I have a rumble 40 and there is nothing like that. If you’ve tried it on your other amplifier and it doesn’t do that, that says to me your issue is with the amplifier.

I agree, it may be the issue with the amp, especially if you don’t hear that hiss through the combo internal speaker.

Pretty sure it’s not the quality of the amp. It’s over 200 euros in Europe and I got preamps that cost only 25 euros and don’t give a hiss either. It sounds like a grounding issue, maybe try the amp in a different house? If it still has the same problem I would contact the dealer.

You are definitely not supposed to. You might even cause damage doing this, as you are connecting an output (bass) to an output (headphone). Your bass is likely a passive bass, though, so you probably didn’t hurt anything.

So. Plug bass into Rumble’s input. Plug headphones into the headphone output. Is it still hissing?

Edit I just peeped at the Rumble 25, and there’s little chance you plugged the bass directly into the headphone out. Two different-sized cables, so unless you used a 1/4" to 1/8" cable, you did not plug the bass directly into the headphone jack :slight_smile:

I have a Rumble 100 - bass gets plugged into the Input on top of the unit, Headphones get plugged in to the headphone jack and the back of the unit. No hissing on mine.

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Yes. Sorry. correction. I plug the bass into the Input outlet on the amp, and the headphones into the headphone output. Hiss.

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the only time I had a problem like this was when I had low impedance (ie consumer or prosumer) headphones with my OP-1’s output that was actually a line out. I fixed it using a $25 Fiio E5 or A1 headphone amp, but you shouldn’t have to do that here; Fender very likely would not design a 40W combo amp expecting people to be using 250 or 600ohm headphones, especially on a 3.5mm headphone jack.

TL;DR - I would try to exchange the amp if you can. It could be a bad/sketchy opamp or some other component in the headphone amplifier portion that is bad.

Hiss can be caused by a poor noise floor so the headphone volume is amplifying the noise to perceptible levels and it shouldn’t. This is why say, magnetic tape, especially cassette tapes, were known to “hiss” w/ out noise reduction tricks.

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