Ashdown ABM Neo 210 with sub issue

[Mick Bailey]

I've played plenty of Ashdowns+Sub with guitar and found it to work fine on single notes - like any other sub-octave generator. In this case though the effect only works on the lower notes due to the LPF and gets trashy on chords.

When troubleshooting the sub circuit I always use a variable sine wave to see what's happening. Scope the input and output and sweep the frequency to make sure the sub output tracks the input. There are at least two different circuits that Ashdown uses - the earlier ones are on a separate sub board and different topology, but either way the sub output is a real speaker killer when the amp is cranked.

[MarkusBass]

Aw, man I think you're being a bit hard on the poor Ashdown designer guys
You may be overlooking what happens with that square wave. It is used to switch an invert/ non-invert of the original signal at the /2 rare so retaining it's essential character whilst halving the frequency. I think that was pretty smart of them.
I don't have a bass so I just test these using the low E string. I think it sounds nice with those sorts of frequencies.

You're right - I overlooked some details. But I still claim that the resulting sound is very poor. You can hear it on the youtube test. I play bass and I would never use such a bad effect. The method is clever but I would call it "cheap" and the results are veeeeeery far from perfect .

Mark

[blindboybenton]

Would like to thank you all for your input

It looks like there maybe nothing wrong and ive been "barking up the wrong tree " But i am yet to reassemble at test

The customer told me that the amp has been back to ashdown 3 times and every time it works for about a month then back to being faulty
apparently the amp tech at the retail shop said it failed in front of him and it was sent back .
I spoke to ashdown and ashdown confirmed 100% that its been back once!!!..
and also ashdown or somebody apparently has changed all the speakers in the combo and the 18" extension cab !!!! i have my doubts

When i tested it with a bass it didnt sound right there seemed to be some distortion aswell when you pressed the sub s/w. I didnt touch it for 5 days as the workshop was moving from home to a room out the back of a guitarshop.
when i got in the guitarshop i stripped out the board for inspection could see some soldering had been down. so i was convinced that their was a problem

so it looks like there wasnt. thanks again.. I'm really annoyed at myself for getting caught up with. Maybe it wouldnt of happened if i had my bass in the workshop, but as i don't play live anyone ive sold all of them and just left with one, my Fender jazz bass. So i must get a cheap bass for workshop now
But hay hoe nobody is perfect
Off now to put back together and give a full test. Need to use a bass too.. time to look though the racks of them here

ALL DONE and WORKING.......... CASE NOW CLOSED


BBB