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Ground Problem

B

borgward

Sep 28, 2006
378
140
#1
I have ground problem w/Peavey Bass 400 Mark III. The noise is diminished when I am touching the strings. I thought the problem was w/my Ripper Bass, but the problem repeats with any instrument I plug in, and with a number of cords .

The power cord was replaced a few years ago. Could it be connected improperly? There is a 2 way power switch on the back. It makes no difference which way it is positioned.

I used a GK amp a few weeks ago and had Zero noise/ground problems w/my Ripper.
 
#4
It has a 3 core power cable. It has a 3 position power switch, on off on. How would I check if the third (ground) prong is operating? I ran a jumper w/alligator clips from the heatsink on the back of the amp to ground in my house wiring w/no change.
 
#8
billfitzmaurice said:
It could just be a noisy amp. All amps hum, especially with passives when you're not touching the bridge or strings. Some are worse than others, though.
Click to expand...

Could be to a certain extent. Peavey amps used Motorola transistors which made a slight high frequency hiss like shhhhhhhh..... This amp is making a lot more noise than it used to.

My Gibson Ripper does not use any passive stuff. I do not use any effects, etc. I just plug directly into the amp.

As for all amps humming, the GK I used a while ago was completely silent. They are a little out of my price range and I really like the tonal qualities and amount of control the Peavey Bass provides. More than enough power too.
 
#10
borgward said:
Could be to a certain extent. Peavey amps used Motorola transistors which made a slight high frequency hiss like shhhhhhhh..... This amp is making a lot more noise than it used to.

My Gibson Ripper does not use any passive stuff. I do not use any effects, etc. I just plug directly into the amp.

As for all amps humming, the GK I used a while ago was completely silent. They are a little out of my price range and I really like the tonal qualities and amount of control the Peavey Bass provides. More than enough power too.
Click to expand...

does the hum get louder as you turn the amp up?

a passive bass is one that doesn't have any active electronics in it, i.e. just a vol and tone control like your ripper.
 
#11
First make sure the amp is wired correctly when they changed it to a three wire cord.

The ON off ON power switch should no longer be changing the polarity of the power cord.

Ground goes to the chassis and the power transformer should no longer be grounded on one side. The wide blade on the plug, or the silver blade or the white wire on the cord now is the neutral (the old grounded wire)

Next it might be time to recap the old amp.

BOB
 
#12
Get a $10 plug-in circuit tester at Home Depot. It plugs in and shows you if your outlet is wired with the proper polarity and grounded correctly. Often they are not, and then the amp is not properly earth grounded.

You should also carry this with you for gigs. If the outlet for your amp is wired differently than the outlet for your PA, this can increase the chances if getting a shock when you touch the mic.
 
#14
rbonner said:
First make sure the amp is wired correctly when they changed it to a three wire cord.

It was always a 3 wire cord. They replaced the whole cord instead of putting on a new plug.

The ON off ON power switch should no longer be changing the polarity of the power cord.

Why not?

What is the purpose of the on off on switch??

Ground goes to the chassis and the power transformer should no longer be grounded on one side. The wide blade on the plug, or the silver blade or the white wire on the cord now is the neutral (the old grounded wire)

Next it might be time to recap the old amp.

BOB
Click to expand...

Been recapped
 
#15
billfitzmaurice said:
It could just be a noisy amp. All amps hum, especially with passives when you're not touching the bridge or strings. Some are worse than others, though.
Click to expand...

Ha-ha...I love it! My Fender Bassman 150 combo has a slight buzz but the intensity increases when I switch to certain channels on my TV. Channel 3 is pretty forgiving and the weather girl is pretty sharp so its a win / win situation.

Riis
 
#16
I used a Carvin bass amp last night. No terribly offending noise. Taking my Peavey to the shop today. The guy there suspects that the new power cord was improperly connected (as I do).

There are a world of crummy venues where I live. The wiring in a lot of them is suspect. Not much I can do about that. I have heard of people using power conditioners between their equipment and the power supply. I am wondering if a UPS (uninterrupted Power supply) for computers would clean up suspect electricity.
 
#17
There was a mouse nest inside and a few chewed wires.Would have liked to have seen the look on the mouses face the first time I cranked that amp up. I noticed that part of the plastic grill on top was missing. Will replace w/metal screen.
 

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