Guitar Amp Problems
 

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[Closed] Guitar Amp Problems

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I have an Orange Dual Terror valve amp. Its about 4 years old but has sat pretty much unused since covid started (i've been playing acoustic instead).

I've now discovered the amp isnt working. Ive given it a bit of a clean (it wasnt that dusty as was left under a cover) and a few squirts of contact cleaner but to no avail. Every now and then i get a bust of sound for a second then silence again. If i turn everything up i can hear it working but as if on mute.

Any suggestions before i have to take it in for what i expect will be an expensive service??


 
Posted : 29/07/2021 10:39 am
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fuses ok ? my marshall has 2 at the back of the case.


 
Posted : 29/07/2021 11:00 am
 ji
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Just checking the basics. Have you tried it with a different lead, different guitar?


 
Posted : 29/07/2021 12:03 pm
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what happens if you twiddle the knobs while making sound not cracking or anything?


 
Posted : 29/07/2021 12:10 pm
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If i turn everything up i can hear it working but as if on mute.

I'd guess part of the power section has gone pop - I.e. a tube. Or maybe as above a fuse has gone.

I don't think that amp has a separate pre-amp output (like for 4 cable method) so you can't test that separately.

I'm not sure how much home diagnostics is feasible / sensible with these. I'd just take it to get fixed by someone who knows what they are doing!


 
Posted : 29/07/2021 12:55 pm
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I’d just take it to get fixed by someone who knows what they are doing!

Yep, think thats what will happen, i'm just trying to rule out the obvious first.


 
Posted : 29/07/2021 1:10 pm
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If it has an effects loop, trying going in the effects return. Depending on how it's laid out, this might bypass the preamp and could indicate where the problems lie.


 
Posted : 29/07/2021 2:14 pm
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The factory for their UK-made stuff is in Borehamwood, I imagine that's where it'll have to go, at least it won't have to be posted to the back of beyond and incur import/export nonsense.


 
Posted : 29/07/2021 2:14 pm
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like this from the manual


 
Posted : 29/07/2021 2:26 pm
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If they're like a Marshall JCM anyone who can read a multimeter can set the bias. I'd buy one each of the tube types and swap them out one by one before taking it to a specialist.


 
Posted : 29/07/2021 4:15 pm
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Thanks everyone. I've managed to fix it. It was corrosion in the speaker cab input. A bit of sandpaper and contact cleaner got it sorted in a way that wiggling / swapping cables didn't.

Its the obvious things that evade me most often :-/


 
Posted : 29/07/2021 4:25 pm
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Nice one. At least you found the problem without spending a fortune, unlike me who sent his bass amp head away to the approved repairer who, after charging £££ couldn’t find anything wrong with it…


 
Posted : 29/07/2021 10:27 pm
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Ouch!


 
Posted : 30/07/2021 9:49 am
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Yup! They decided it was a problem with the pots so replaced them all at cost of £125 parts and labour, plus the diagnostic fee, plus the labour for testing, plus the insured shipping back, I didn't seem much change from £270.

I could have bought a second-hand replacement head for less than that!


 
Posted : 30/07/2021 10:31 am