weird amp problem - power supply /wiring??
Hi guys was wondering if I could get your opinion on an issue.
I've just emigrated to Australia from Ireland and have recently just got my furniture shipment from home.
I've been pretty busy and only recently unpacked my music gear. I plugged in my trace Elliott combo for a quick play and noticed that that there was a slight buzzing/hissing coming from the amp. I also noticed that when i put my hands on the bass it went away. I had bought a second hand fender jazz in oz when I arrived to keep me busy so I kind of assumed (stupidly with hindsight) that this was the problem. Naturally enough I assumed it was a grounding issue and cracked open the bass and did the usual shielding, soldering etc.
This did help somewhat but the noise was still there and was still annoying me. I then tried my p-bass the hiss was still there!
I then assumed it was the amp or cables. I checked all my cables and they seem fine though the noise was less on my more expensive ones.
Assuming it was the amp I then set up my Hartke rig only to discover the noise is still there!!!
Out of annoyance and frustration I then went through my other basses. When I got to my stingray (my only active bass) the noise was completely gone. Experimenting I put my passive basses through the active input - no noise at all!!!
I've no idea what the problem could be. It occurred to me that it could be a discrepancy in the amps power usage - though my hartke rig was bought in australia (i lived here before for a year whilst my wife was training) so that would seem to rule that out.
The only thing that occurs to me is that the house wiring. We are renting until we can sell our house in ireland and the landlord had some problems with dodgy builders apparently. Is this even possible??
it probably seems stupid - as the solution is just to plug into the active input and the loss of volume won't be an issue on a 500w rig- but this sort of thing just annoys me!
Plus I had to leave my band to come here so its not like anybody else is going to notice!!
Any advice/insight would be very much appreciated.
If you've checked the grounding and shielding properly, it seems that there is some EMI radiation in your house wiring that is getting into the bass wiring and pickups. Can you check it somewhere else for comparison?
Your old house may have had all the wiring in a metal conduit providing good shielding while the new house uses the unshielded type of wiring.
I just noticed that you said "hiss" rather than "hum" or "buzz". Hiss can ONLY come from the amp.
The guitar can only pick up the 50-60 Hz AC hum or buzz. Active guitars have a much lower impedance in the pickups and wiring making them more resistant to hum pickup as well as a stronger output level to decrease the effect of hum pickup in the cable.
Any other strong EMI/RFI sources nearby? I used to do customer service for a wireless speaker company and one customer had a large radio station antenna close to his house causing all kinds of problems.
Try it somewhere else first.
Good luck with this.
As Bassamatic said, hiss comes from the amp.
The hiss also seems to be there with a high impedance input condition (passive input,
passive bass), and absent with a low impedance input condition (active input, active
bass). So it certainly sounds like amp input noise.
I can't offer any explanation as to why it is only occuring now though.
Have you always used pedals before, or something that gave you low impedance, maybe?
I was being a bit generic describing the noise. Its more of a buzz really. I would have suspected the input too but the fact that its happening on both my combo and my stack suddenly suggests that its an external problem and the fact that its varies in strength significantly across all my basses from really bad (vintage p-bass) to bearable (jazzes) to non-existent (active sting-ray) probably bears that out.
There is a television station with a massive dish - less than a km away - could that be it?
thanks again guys
Now for the real bad news;
If the station engineer is a musician he/she could be a resource of assistance in mitigating it, but the best solution, if indeed it is the transmitter site, would be to relocate to a 'cooler' location (less RF).
I live in Australia and recently moved house and in this new place I'm getting a lot more 50hz hum on single coil passive basses... My three actives are dead silent too... The worst is the SCPB which although it is well shielded, picks up hum that changes in intensity depending on the direction you are holding it... If I hold it up towards the ceiling I can almost work out the path of the wiring to the lights, and as they are down-lights with a transformer for each, there are four spots in the ceiling that are effectively hum generators... Very annoying. The pbass I have with barts is also quiet.
I think you are suffering a similar issue, any down-lights in your place or dimmers ?
thanks again guys - you lot are awesome!
I'd say conservatively there are 50 down lighters in this house (its brand new, big and kind of fancy) could that be the issue?
I plugged in my pedal board and that lowered the buzz again. Though its still slightly there especially on my P.
I may just be being picky - I am used to my gear only giving off the slightest of hums.
I'm almost convinced its the wiring at this stage. I'm going to take the combo out of the house tomorrow and see what happens.
Thanks again guys
weird amp problem - power supply /wiring??
Edit: after I moved, I also thought something was wrong with my gear until I thought about it, and did some testing, it was my active basses that also got me thinking...
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