Ashdown After Eight - escessive white noise/hiss

[RPaul]

I've got an After Eight, about 5 years old, owned form new. Got it from PMT or whatever it was called at the time, in Leeds.
The problem is that there's a noticeable amount of white noise from it - with or without instrument or anything else plugged in, through the speaker or headphones. So it's basically something in the amp itself, isn't it?
I can't get rid of it whatever the knobs combination - obviously, goes down with treble, but never disappears completely. Half an hour of it in the headphones, and I start hissing myself

Searched the Web, couldn't find anything of the kind. Got in touch with Ashdown, they wrote the following:

[i]"There is nothing wrong with your amp.. It is designed as a practice amp and as such does indeed have a little bit of background noise from the circuitry..[/i]

[i]Regards,[/i]
[i]Guy[/i]

[i]Service Engineer" [/i]

How little is a little bit, is obviously a matter of opinion, but I've never had so much hiss from any other bass combos.

Any thoughts?

Thanks.

[RandomBass]

You know, I'd expect a practice amp to be designed without a certain level of hiss and background noise. Surely Ashdown should have considered this?

Edited October 16, 2013 by RandomBass

[RPaul]

Yep, I can't find much logic in the answer either. I, in my naivety, thought that a practice amp would have comparatively lower power and simpler functionality - and after eight has both. But to have background noise built into it? What, to practice playing in noisy pubs or something?
Unless he meant that practice amps are cheaper not only because they're smaller and have limited functions, but also because their sound quality is just about acceptable and not good enough for gigging. Meh, I don't know. At a hundred quid a pop I'm certainly getting more hiss than I've paid for. Bargain Sort of.

But the main question remains: apart from taking it to the nearest specialist to take a look at and opening up the wallet, is there anything I could do? I probably know the answer, but...

[Bill Fitzmaurice]

[quote name='RPaul' timestamp='1381907708' post='2245120']
apart from taking it to the nearest specialist to take a look at and opening up the wallet, is there anything I could do?
[/quote]Even a specialist won't be able to do anything, A poor signal to noise ratio is a common charateristic of an inexpensive design. The cure is a better/more expensive amp.

[6v6]

[quote name='RPaul' timestamp='1381879403' post='2245053']
[i]"There is nothing wrong with your amp.. It is designed as a practice amp and as such does indeed have a little bit of background noise from the circuitry..[/i]
[/quote]

Translated that means "the amp was designed to use the cheapest components we could possibly find, as such does indeed have a very significant amount of background noise"

There might be something a decent amp tech could do to quieten it down a bit, but it's very likely to be uneconomical on such a cheap amp and may be impossible if it's due to poor PCB layout or other non-tweakable issues.

FWIW I tried to fix a very expensive Mesa-Boogie guitar amp a while back which had the same issue, and in the end I had to conclude that it was just poor design, not an actual fault which could be fixed. I swapped out some tubes in the preamp which reduced it a bit, but sometimes it's just layout, component choice and gain combined and there's nothing much you can do. I told the owner (a mate) to turn it up louder and get some earplugs!

[RPaul]

Yeah, well, shame, really. I was quietly hoping it's because of a blown de-hiss-inator or something equally hi-tech, and that they are a quid a dozen on eBay.