Joebethell Posted March 5, 2018 Share Posted March 5, 2018 So I have recently got a nice new amp and cab with the plan to get out gigging again in the near future. My issue is I get a quiet hiss/hum with no instrument plugged in but when plugging a bass into the amp the hum/hiss becomes extreme. I have tried differing rooms so I know it' not the plug socket, two speaker leads, basses,cables etc. The only thing I can think is it' s cab issue as the head and cab are new. The company are happy to have it shipped back but I was wondering if I can try anything else before having to go through the hassle of shipping? (I only have one cab/amp at home) Quote Link to comment Share on other sites More sharing options...
CameronJ Posted March 5, 2018 Share Posted March 5, 2018 What amp are you using and what are your settings? Also, what bass? Most amps will have an audible “noise floor” which means a little bit of hiss is inevitable, depending on how high you have the amp turned up. Boosting treble on an active preamp (on the amp itself or on a bass) will often add to the hiss. If using a traditional Jazz bass, soloing either the neck pickup or the bridge pickup on their own will introduce hum. Noise cancelling jazz pickups avoid this issue. If your bass is poorly shielded then it can be susceptible to picking up electrical noise from dimmer switches etc. Using an overdriven sound (whether from a pedal or the amp itself) that can contribute massively to the overall noise/hiss level of the amp, even when nothing is being played. If you have a pedalboard the number of potential causes of noise can multiply very quickly! Quote Link to comment Share on other sites More sharing options...
Pea Turgh Posted March 5, 2018 Share Posted March 5, 2018 If the amp doesn’t make the bad noises with nothing plugged in, I’d hazard a guess it’s what you are plugging in to it. Active bass needs new batteries? Bass needs earthing/shielding? Quote Link to comment Share on other sites More sharing options...
Joebethell Posted March 5, 2018 Author Share Posted March 5, 2018 Hi no pedals in the chain just straight in. As I said there is a noticeble hum when nothing plugged in, (wasn't noticeble in the shop where I purchased the head ABM 600) the cab is a zilla 2x12 600w also purchase new. I did try another head an old swr which had even more noise and my old mesa setup which I recently sold never hummed in this way with any bass etc. If you plug a bass in regardless of volume a large increase in the hum doesn't matter which bass I have tried 3 a guild starfire, fretless ESP and a yamaha BB. It' got me a bit stumped the only thing I think is to get someone to bring another head and cab to me and see if we can isolate the problem or take them to a retailer to do the same. Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted March 5, 2018 Share Posted March 5, 2018 4 hours ago, Joebethell said: The only thing I can think is it' s cab issue as the head and cab are new. Cabs only reproduce the signal sent to them, they don't create their own. If you're using the same bass and didn't have a problem with your previous amp it's the amp. Quote Link to comment Share on other sites More sharing options...
Joebethell Posted March 5, 2018 Author Share Posted March 5, 2018 I don't suppose anyone has a free hour in the Leicestershire area over the next couple of days for a second set of ears at the issue. Quote Link to comment Share on other sites More sharing options...
Joebethell Posted March 5, 2018 Author Share Posted March 5, 2018 I have had another play this evening after work and the hum is quiet without a bass plugged in. It is noticeablyworse with a bass plugged in and as you increase volume and is worse with certain pickups. So it looks like earthing as mentioned. The only confusion I have is when I tried the amp on purchase sounded perfectly normal with no buzz/hum even with the same bass. So that accounts for part of the sound but not all of It. Would a speakon connection alter anything as I only have jack speaker cables and the head was connected to the cabs in the shop via speakon? Is there anything else I can try? Quote Link to comment Share on other sites More sharing options...
BassBunny Posted March 5, 2018 Share Posted March 5, 2018 If it is quiet with nothing plugged in then I would assume the Amp/Cab/Speaker cable are OK, although that said Speakons are considered the "norm" now.. Could it be the instrument lead? They can be notorious for introducing all sorts of noises when they start to fail. 1 Quote Link to comment Share on other sites More sharing options...
Bill Fitzmaurice Posted March 6, 2018 Share Posted March 6, 2018 Speakons don't cause noise. Single coil pickups do. Quote Link to comment Share on other sites More sharing options...
Dan Dare Posted March 7, 2018 Share Posted March 7, 2018 Bill's correct. Try different leads, instruments, etc before blaming the amp/cab. Also try the amp with a different cab. You have to isolate the cause of the issue by testing each link in the chain individually. Quote Link to comment Share on other sites More sharing options...
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