Hiss when L1 Compact is turned on

Hi, I just purchased the L1 Compact 1 month ago and am really enjoying the new system. However, I've been noticing a faint hiss when whenever the L1 is turned on. I normally have the volume dial at the 12 o'clock and the hiss is noticeble when close to the speaker. When I really push the volume, to say 3 o'clock, the hissing gets even louder. The hiss occurs even when nothing is plugged in to the speaker. This is not usually a problem for loud music, but for quiet passages its not so good.

Has anyone else encountered this before? It this 'floor' noise normal for the L1 Compact?



Hi Drew,

Thanks for joining the Community. I'm glad that you are here.

Normally, if you are not using a channel, you would turn its volume all the way off. There should be no hiss.

If you are playing music through channel two and don't have a microphone plugged into channel one, then you should turn channel one all the way off.

When you play music through channel two and you have channel one turned off you shouldn't be able to hear hiss above the sound of the music. If you do:

Try another source for the music. Perhaps run a CD/MP3 player or phone into channel two through the RCA or 1/8" jack.  Turn the volume up to around 2/3 of the full volume on the source device. Then bring up the volume on the Compact.

Do you hear the hiss above the music?


Hi ST,

Thanks for your reply. The hiss occurs even when the volume trim on both channels are turned to 0. The hiss is noticeable if no music is playing and I'm standing / sitting close to the speaker ~4 feet. it is also noticeable if the music is played very quietly and I'm close enough to the speaker.

it sounds like a faint continuous static noise. It would be interesting to see if any other L1 owners are experiencing this issue. 


Perhaps I have the answer to your problem. The hiss or ground noice is coming from the wallplug. If you change, and only have 2 prongs, instead of 3, you can hear a difference. I play keyboard with my L1 Compact, and when I push the button on my keyboard, there is only silence. I have an old Yamaha Electone D65 and there are only 2 prongs on the wallplug.

Hope this helps. From Jan - Eve.

Hal lo again! Well there must be a reason why Bose have 3 prongs in the cable. Perhaps someone know whats best. From Jan - Eve.

Jan-Eve posted:

Hal lo again! Well there must be a reason why Bose have 3 prongs in the cable. Perhaps someone know whats best. From Jan - Eve.

Hi Jan,

thanks for the tip! I did some research on the 2 prong cable and read tha it can be dangerous using the 2 prong cable as it could put you at risk of being electrocuted. Don't want to take the risk of damaging the PA system or killing myself 🙂 looks like I'm the only one who is experiencing this hiss issue? 

Hal lo! I have the original cable with 3 prongs from the wall. You don´t  hear so much of the hiss noice, when you are playing your keyboard and singing. Best to be at the safe side... Best Regards Jan - Eve

Hi drew-t,

Did you ever get a good solution for this? I have just got a new L1 Compact - tested it at my parents (gift from them) and it worked beautifully, but at home am getting a horrible hiss audible from many feet away even with both channels to minimum volume.  We have made sure keyboard and speaker both plugged into same socket in case of a ground loop but no joy... the hiss persists. Open to any safe ideas for what to try next! Thank you.

Hi Lizziwizzy,


Sometimes a damaged connecting cable can cause hiss.


Start with no mic or instrument connected and the volume turned down on both channels. 


Connect one cable/instrument at a time to see at what point the hiss begins. Try to determine if the Compact is hissing on its own or if the hiss is being introduced by something you are connecting to it.


Let us know what you discover from your trouble shooting.





As I understand it:


When the mains plug has 3 "prongs/connectors", 2 of them are the ones providing the current/voltage needed for powering the unit and the third is the earth/ground wire which is there to basically protect the people using the unit in case of the user through some failure or other comes into contact with the live voltage (e.g. if the unit has a metal housing, or in the case of musicians who are plugged directly into the unit as with microphones or guitar cables). Under no circumstances whatsoever should such a unit be used without the earth connection. 


Units which only have 2 "prongs/connectors" generally have insulated housing so that the user can't directly be connected to the live power. To date I've never personally come across an amplifier which doesn't have 3 prongs/connectors for the wall socket. Maybe someone can correct me here if I'm wrong.


Regarding a slight amount of hiss being audible when a unit is only switched on an not being run or if at all only very quietly: I would accept this as being normal, especially in equipment which isn't absolutely Hi-End, where each component is chosen for its sonic quality. These components come at a considerably high price, which is one reason why audiophile equipment is so expensive. Normal PA's don't come into this category as they would be much too expensive for most users. Also, sitting right next to PA speakers isn't the norm. Yes, I know that people using the L1 family of systems stand or sit near to the units, but the amplified signal is loud enough to drown out the basic hiss of the amplifier itself. If I'm playing so quietly that I can hear the hiss, I don't need to amplify myself.


This is just my view on the subject. I hope that it's of some help.