Schertler PUB 280 - does yours buzz (50Hz hum)?

douglas81 · #1 09-09-2009, 11:11 AM

Hi,

I was using my Pub 280 as a hi-fi speaker today (just to see how it stacks up against a good pro audio monitor) and I noticed it has a bit of a ground buzz. It's noticeable in a quiet room even from a few feet back. It doesn't change even if I lift the earth, and I've tried it on several different sockets in the house, but no difference. Always the same level of buzz. Also, it doesn't matter what I have plugged in to the speaker, always this same buzz.

Has anyone else noticed this? It's not too loud as to be noticeable in a gig, but definitely too loud for critical monitoring.

Thanks,

Douglas.

steve_n_his_urb · #2 09-09-2009, 08:56 PM

One suggestion - does it come only from the speaker, or from the unit itself? Sometimes, poor mains power can make the transformer hum - usually if there is some DC present.

Trying the amp at another address could help you eliminate this possibility.

Steve

douglas81 · #3 09-10-2009, 07:22 AM

Thanks for you reply. Yes, there is a bit of transformer hum too, but as far as I'm concerned, a well designed power supply should eliminate this buzz from the output signal. Especially on a unit of this cost.

tornadobass · #4 09-10-2009, 08:40 AM

Were you running a laptop's output into it? My MacBook will add hum to some sound gear unless I use the grounded plug rather than the two-pronger from the power block.

douglas81 · #5 09-10-2009, 08:45 AM

Quote:

Originally Posted by tornadobass

Were you running a laptop's output into it? My MacBook will add hum to some sound gear unless I use the grounded plug rather than the two-pronger from the power block.

Nope, no laptop. It does it no matter what I plug in. Or even if I have nothing plugged in.

Aleph5 · #6 09-10-2009, 09:50 AM

I've never noticed any hum from mine, though I've not connected it similarly for critical listening or in a really dead room.