https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/ Guitar Noise Discussion Board en-US Fri, 05 Jun 2026 00:56:38 +0000 wpForo 60 https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237864 Thu, 12 Apr 2007 03:00:33 +0000
It does not have to be the power being dirty. You can get interference from a variety of sources. I've still got an eye out for that, but I did try to work my way through those possibilities fairly early on in the hunt. Not easy to turn everything off in a house though. Even if you get all the obvious things like freezers, TVs and such, there can still be a VCR on standby that you've forgotten, or an alarm system or something. But I think I pretty much ruled most things out.

We're a fair way from any other houses (at least a couple of hundred metres) and I've tested the power at several different spots on the property. For instance, I can do things like turn the whole household system completely off and test the amp in the shed or at the first fuse box at the power pole. Or even switch the house over to our own generator.

So far it still looks like cheap circuitry not coping well with a mediocre power supply. Especially as the Vox amps work fine. But who knows? Electricity is voodoo stuff.... maybe it's just my magnetic personality coming out when I pick up that bass... :shock: :wink:

Cheers,

Chris]]> Bass Players Discussion Chris C https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237864 https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237828 Wed, 11 Apr 2007 20:48:39 +0000
It does not have to be the power being dirty. You can get interference from a variety of sources. Flouroscent lighing can often create a hum, as can motors operating in the area. It is also possible to get RFI from other devices, like cell phones, cellular antenas.. For example, I recently got a new PDA type cell phone, which also gets email. If I have it near any amp (or even a regular phone), periodically it sends a nasty burst of noise...]]> Bass Players Discussion vink https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237828 https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237799 Wed, 11 Apr 2007 11:42:49 +0000
Interesting trip. Of course, the amp performed just fine in the shop! Virtually no hum at all. :? :wink:

But they were able to relate tales of other amp owners who had different results from the same amp, depending on where they were at the time. So this threw suspicion back onto the power at our house.

Now, it could have been the earthing system , except that I tested that and it seemed fine. I also took the amp and guitar about 100ft from the house to the pole where the power arrives on the property. This pole has a separate power point and its own copper earth spike (grounding). Same result - lots of hum.

So it appears to be the power signal itself. Our power grid is notoriously crummy in the area where I live. The feeder lines are much longer than they should be, and the transformers are not always well balanced. Power cuts and sags are not uncommon. So "dirty power signal" sounds like a reasonable theory. I found plenty of articles on the net about the need to design studio recording systems (and even home audio systems) with considerable care, in order to avoid 'noisy' lines, induced hum, etc.

A 'power conditioner' might fix the problem, but may not be worth the cost. My Vox amps seem way better designed to filter out unwanted noise. So unless I learn anything different I'm going to put it down to just one reason why the Johnson amps are as cheap as they are. Still perfectly usable once the hum is tuned out.

Cheers,

Chris]]> Bass Players Discussion Chris C https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237799 https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237649 Tue, 10 Apr 2007 02:53:24 +0000
It could be that they just cut a lot of corners on the cheap stuff. I have another Johnson amp (same make as the Bass one) which is a 15watt. So cheap it was the equivalent of free with the guitar in a 'starter pack'. That also hums loudly with just a cable in, but goes quiet once any guitar is connected, so not a problem. The Vox (like yours) behaves well all the time.

I can live live with the peculiarities of the Cheapo bass amp, but it will be interesting to see if its mate in the shop is just as bad.

Cheers,

Chris.]]> Bass Players Discussion Chris C https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237649 https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237646 Tue, 10 Apr 2007 02:45:52 +0000
Did you check that your power outlet was grounded (3-prong)? Also, some basses forget to ground the strings, which can cause the hum/crackle that goes away when you touch the strings. Plus your 6-string into the bass amp and see if it's better. Plug your bass into the Vox and see what happens. Thanks for the suggestions Laz. :)

All our outlets here are 3 pronged and properly grounded. Sometimes by this time of year (past the end of our summer in Australia, and it's still very dry) the earthing systems in houses get a bit inefficient because the soil is so dry. The usual remedy is the give the soil a good soaking around the earth (grounding) spike. But I did all that a few days ago, and according to my multimeter it's all working OK.

I also tried making up a separate grounding cable and touching it to the strings. That didn't work - it had to be a hand touching them. :? When I checked the way the input socket is mounted in the amp, it's fitted using a plastic spacer ring that appears to be designed specifically so that the outside of the socket doesn't touch the grounded chassis of the amp where it passes through the metalwork. Not sure how all that works, but circuitry can pick up "noise" in all sorts of ways, so I assume that's intentional.

I already did try your other suggestions - I swapped cables, amps and guitars around. The problem does seem to be with that particular amp. The same hum continues with a 6 string unless the tone is turned right down. And everything works fine on the Vox, no matter what's plugged in.

A trip to the shop today should clarify things. They had another of the same amps, so we can compare them. I'll try mine in their wall sockets too.

Cheers,

Chris]]> Bass Players Discussion Chris C https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237646 https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237640 Tue, 10 Apr 2007 00:51:59 +0000 Bass Players Discussion vink https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237640 https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237625 Mon, 09 Apr 2007 20:44:54 +0000
Did you check that your power outlet was grounded (3-prong)? Also, some basses forget to ground the strings, which can cause the hum/crackle that goes away when you touch the strings. Plus your 6-string into the bass amp and see if it's better. Plug your bass into the Vox and see what happens.]]> Bass Players Discussion Dan Lasley https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237625 https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237588 Mon, 09 Apr 2007 08:06:49 +0000
It looks like a case of 'you get what you pay for', and that model amp has a very limited tone range, or possibly that particular one is slightly faulty.

Once the guitar is connected you can removed or reduce the hum by turning the tone knob back to 0 or touching the strings. I've tried different cables (4) and other non-bass guitars, and the story is much the same - only OK with the tone backed right down.

Put the same cables and guitars in my Vox amp and there's no hum either with or without a guitar, at any settings.

I wonder if that hum just an inevitable by product of the cheapo design and manufacture of that amp, or might it be improvable in some way? They had 2 at the shop, so if it's still there tomorrow I'll see if the other one is the same.

Cheers,

Chris]]> Bass Players Discussion Chris C https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-237588 https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-25097 Mon, 09 Apr 2007 05:59:42 +0000

Hi all,

Well, I cracked on Saturday and added a bass to the list of instruments that I own but can't play very well.... :oops: :oops: :D

It's just a cheapie but it will do to learn the basics on, and to see if I make enough progress to deserve something better.

It came with a cheapo 30va practice amp. So here's the first newbie question:

What is the deal with all the buzz and hum from the amp?


The amp hums. Not super loud, but certainly noticeably. I don't know what the right terms are, but if I try and get a really 'sharp' 'crunchy' sort of sound by cranking 'Presence' (what exactly is that??) on the amp, and Tone on the bass, both round to 10 it hums like hell.

I've set the Treble, Middle, Bass and Presence knobs at halfway, and the volume way down at 1, which seems plenty loud enough. On the bass I set the two pickup volumes to full.

If I turn down Treble and Presence on the amp and Tone on the bass then the hum disappears, but the sound is muddier and more muffled. Two questions.

1. Why does the hum greatly reduce or disappear when you put your hand on the strings? The strings don't seem to be directly connected, so is it 'earthing' in some way? And how? Some other electrics seem to do this to a smaller degree, but it seems to show up a lot more on this setup.

2. Is this humming basically just what you get with a cheap amp? I.e. only able to handle a narrow range of tones?

It's perfectly usable at the 'compromise' settings, and sounds fine. Just interested to learn more. If anybody can please help it would be appreciated. Thanks. :)

Cheers,

Chris]]> Bass Players Discussion Chris C https://guitarnoise.forum/bass-players-discussion/dumb-noob-bass-amp-question/#post-25097