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 yesterday 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.