Ashdown ABM owners club

[dagrev]

I was able to use a car trim removal tool to carefully get the plugs out. Changed valves and that was not is source. 

[dagrev]

Clip of the bizz. Will have to turn it up a little. It's more quite in the clip than live. 

 

[BassAdder60]

Have you tried it in a different electrical socket ? 
Mains hum perhaps ? 
Presumably it makes that noise with no input ? 

Edited Monday at 18:41 by BassAdder60

[dagrev]

Yes, same noise.

But no noise if nothing connected in the input. 

Does get louder if output is raised. Never goes away even is output is all the way off.

Edited Monday at 19:33 by dagrev

[DGBass]

The easiest way to prove if you have a noisy tube is to make sure the valve drive plus button is switched off, ie all the way out. Plug your bass in and you will be bypassing the tube function with the valve drive button out. If you still hear a buzz/hum then its not the tube that's causing it. FYI, ABM's like the EVO IV will be quiet with no instrument plugged. The input jack has a switched signal contact to ground with nothing plugged in. In general most ABM's should be quiet at idle with an instrument connected, and not buzz or hum if they are in good condition. If you have only just bought the amp, and the noise persists and it doesnt appear to be the tube, might be worth returning it or taking a chance and asking a Tech to look at it for you. It could be something simple, like a loose ground screw or ribbon cable plug if its been jiggled about in a courier truck at some point in time. But then again it might be something else that is causing the noises. My own EVO IV is dead silent at idle with a bass plugged in and any ABM I've owned in the past has always been quiet at idle with a bass connected.

Edited Monday at 22:21 by DGBass

[dagrev]

I just heard back from a bass player friend who has a PhD is electronic engineering, also happens to know Mark Gooday a little.  He said to return it. Should not be that way and could be simple or expensive to fix. I emailed the big online seller and they said they would send a free return label. So my great deal kind of went out the window. Bummed about that. Might ask if they have a tech in the area as I would really like to keep it. Such is life. 

 

I appreciate all the help and advice. If something changes, I'll update. 

Edited Tuesday at 02:02 by dagrev

[ClusterOne]

9 hours ago, dagrev said:

Yes, same noise.

But no noise if nothing connected in the input. 

Does get louder if output is raised. Never goes away even is output is all the way off.

I may be well drifting into the BS territory but my way of thinking is as follows:
Dodgy input socket? Is its ground connection ok? By that i mean ground connection on PCB at the input socket terminal up to the end of the lead/cable once that is plugged in..Eventually the continuity of the ground all through the preamp..

Input lead/cable acting like an antenna - picking up some stupid signal - here i would take whole thing (amp) to a friend’s house to see if the same issue persists.

But then i believe you must have been using different amp in the same room at some point so it would be pretty obvious if the other amp was doing the same.

 

And obviously I would try different lead/cable ..
 

However, if you can send it back for a refund then I would do that given that any further investigation may render the guarantee invalid..

[dagrev]

Thanks. You may be on to something. It does sound very similar to what one might get from a single coil and if you move something it would change or go a way. This just doesn't go away. I may try it in another room or location before sending it back just to make sure as a last ditch effort to keep my good deal. 

[dagrev]

I tried the head upstairs with with different cab. Not as buzzy, but still there. Oddly enough when I would move the Pbass around the sound would change. @ClusterOne may be on to something as it or the cords seemed to be acting like an antenna (maybe). 

I tried my 500 iii and did notice some of the same thing when in front of the cab downstairs. I never noticed it before because the two fans cover it up, unless right in front of the cab. Not as loud, but something there nonetheless. I think Wed night I will take it to where it will get the most use and see what happens. 

 

[ClusterOne]

@dagrev btw that sound sample you posted sounds to me like 50HZ from mains…

If you plug the cable in but do not plug guitar, what does it do? Does the buzz go away?

 

Because it may be that the pickups are picking up some noise from poorly filtered dc adapter or something.

 

Funny enough, yesterday i got myself some cheap cab and had to place it somewhere so as a result my bass is now picking up (pickups more precisely) some electromagnetic interference from the Warwick gnome i have sat on the top of it because it is practically right in front of me about a meter & half from pickups. Not as noisy as in your sample but i also noticed when i moved around with the bass the noise disappeared or faded away. I mean I should have known better but it didn’t click 🤦‍♂️😁

So that’s normal, in sense you can use the bass to track where the interference is coming from by following the signal..

 

By any chance do you have any power adapters (dc power supplies) plug in while using the amp? 

The other day i had cheapo dc supply that feeds my pedals transmitting an interference much worse than the one in your example. And I accidentally found out when unplugged it from mains..

 

 

 

[dagrev]

@ClusterOne Thanks for the info. Same buzz with cable but no bass. 

Briefly this morning when I had some time I connected both the 500 iii and the 300 iv and left an instrument cable unconnected to a bass. Both make the same noise/sound, with the 300 being a little louder. Touching the tip, same sound. And, kind of "shorting" the cable trick by touching the sleeve and then the tip, both make noise when this is done (louder hum). I had input/output low as it was early. At lunch will try again, but I'm beginning to wonder if it's not something in the house since neither one was quite when I "short" out the cable. (Said the person who knows nearly nothing!) Wed night I will try another location entirely and see what happens. 

Edited 15 hours ago by dagrev

[ClusterOne]

Electrical interference in live line or electromagnetic interference are invisible so we can’t know what/where the source is unless trouble shooting it like this..

Unplugging everything but amp may help to see.. Applies for the rest of the house.Never know.

 

I love to overthink you know. 🤦‍♂️

 

Back in the good old days of CRT TVs and two stroke mopeds riding by your house, sometimes you could tell before it could be heard 😁 due to f*cked capacitor in moped’s ignition 🤦‍♂️😁
 

And to be honest sometime it may depend on the time of the day as the source of this (interference) may be even outside your premises.. Entirely possible that less buzz is generated at e.g midnight..

 

Let’s see what happens when trying it somewhere else..

[0175westwood29]

Hey guys so is it ok to post about the Little Giant amps here? 
 

im looking to see if anyone has a set of the rack ears? 

[ClusterOne]

@dagrev by any coincidence - you don’t have any pedals in chain, even if turned off/disengaged but still fed by power supply?

 

I noticed just today that my few pedals somehow cause this sort of interference resulting in such buzz very similar to yours.

I normally have my bass plugged directly into amp but it was just tonight i poked around my pedals and all of sudden got this buzz but it died as soon as i unplugged the pedal’s power supply from mains..(the power supply is a proper one, brand new, some Harley Benton for about £65 with hundreds of great reviews so i f*ck wonder now)..

 

Will have a look at how to trace the culprit as i have few ideas why that might be..

 

Btw, apologies to everyone else, we should have been posting this in some ,, troubleshooting,, section.. 

[dagrev]

Update: Took the 300 to rehearsal to check for buzz. I noticed it. Hard to tell how loud with people talking, etc.  Not loud, but still there, so I think it will be gong back. But, I will take the 500 over there tomorrow to compare before sending it back. The fans on those covers a little buzz and with the 300 having no fan noise, buzz is more apparent. Also a little louder on the 300 as well. Nice sounding amp otherwise. Not a big in the lows or all around heft, but it's got knobs and sliders to fix that.

 

Sorry about the incorrect place to post this. At another forum where I'm a regular in the States, this is where such discussion would go, so my apologies.