#1
Basically I was at my bands lockup with a friend, and with little knowledge of guitars/amplifiers we decided to use our guitar player's equipment - A Laney 120 head and a Peavey Valveking 412 cab. Now i knew these two were compatible because our guitarist always uses them together, but it was just a case of connecting the two together.

The head had two jack outputs labelled loudspeakers (no labels indicating ohms) and the cab had two jack inputs. We stupidly used instrument cable (I now know this is wrong) to connect one of the outputs on the head to one of the inputs in the cab, and tried all different combinations between these four connections with no sound. We also (again I now know this is wrong) connecting the preamp and power jack outputs on the head to the cab inputs, which resulted in a loud buzz coming from the cab. There was no 'Pop' or burning smell coming from the cab either, which leads me to believe that it hasn't blown. Also the head was gigged the day before and was working fine.

Basically I just need to know what the problem is, thanks!
#3
not sure what the problem is but if I had to guess I'd say you busted your lamps (tubes or whatever you want to call them) but definetly not blown. How loud was it?
I like shotguns. thats all you need to know
#4
Well i've tried it with a short cable that was lying round the lockup which I assume is speaker wire and still no luck, although when i turn the head on i hear the initial 'click' out of the cab, and when i had my ear right up against it i could hear a very faint hum.

And fairly loud, but not so loud that it would blow the amp, the sound didnt suddenly cut out either.
#5
then its not blown but I have no idea what happened
I like shotguns. thats all you need to know
#6
Turn the amp off. Leave the room. Stop messing with the amp. You're only doing more damage.

Hopefully you just didn't know how to work it, but if you keep doing the things you're doing you are going to blow out the power transformer. You may have already done it.

Call the guy who knows what he's doing and have him figure it out. You're taking shots in the dark and you're going to make it worse if you keep messing with it.
#7
I know I was stupid to mess around with it but I shit myself when i wasn't working, i just wanted to try everything to get it working again to reassure myself I hadn't ****ed it - I didn't know the risks

What exactly is the power transformer
#8
I meant to say the output transformer. The power transformer is the second most expensive part in the amp. The output is the most expensive part. They're the two big metal boxes next to the tubes. The power transformer supplies high voltage AC to the amp, and the output transformer is the interface between the power tubes and the speaker.
#9
Ok cheers, so you think that is most likely the problem? If so
then I'm completely screwed as I'm completely skint!
#10
Hopefully not. It's possible it's just a fuse or something but there are a lot of possibilities given the situation.

Reading over again - is this a tube amp? I assumed it was but you didn't indicate either way. A solid state amp may have survived being unplugged a bit more readily, but if it blew, it's completely shot.
#11
I think it is a solid state. Laney haven't made a 120 watt tube head to my knowledge but they have had solid states at 120 watts.
#14
Quote by wragg
We stupidly used instrument cable (I now know this is wrong) to connect one of the outputs on the head to one of the inputs in the cab, and tried all different combinations between these four connections with no sound. We also (again I now know this is wrong) connecting the preamp and power jack outputs on the head to the cab inputs
What in the world prompted you to do this?
#15
Quote by al112987
What in the world prompted you to do this?


Me being a drummer prompted me to do this
#16
Does anyone else have an idea of what might have gone wrong?
#17
http://www.furtadosonline.com/images/laney_lx120h.jpg

i think this is the head if it helps> i'd heard about having to match the ohms with the cab before, but the two jack inputs labelled 'loudspeaker' on the back of the head didn't have any ohm labelling. Perhaps I used the wrong one?

Please guys I need to sort this out pretty soon
#18
I'd kick your a$$ if it were my amp.hope fully your just stupid and cant hook it up properly. Learn your lesson don't mess with other peoples gear. My drummer had to replace my practice amp one time a $700 "accident"
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#19
Finger's crossed you're right. The weird thing was, the first thing i tried was just connecting the head to the amp with a short speaker cable (which I now know is the correct way to hook them up) and it didn't even work then.
#20
with out seeing it I can't realy say, but I know using instument cables for speaker cables don't work too well.
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
#22
Hmm...try taking it to a repair shop. You would probably have to resort to GC if there is no other place near you. They should (if its GC, the most likely won't) know what happened.

When I first read it, I didn't expect something to go wrong with the amp. The only thing that SHOULD be damaged is the instrument cable. Tell your guitarist about this, he might have a solution after he kills you

Also, try attaching the head to another cab if you can. The problem probably isn't the cab but you can always try.....

Worst case scenario: You have to buy him the same head which will be very hard to find. Its very cheap for a 120w head but they are rare.

EDIT:http://www.guitarcenter.com/In-Store-Used-USED-LANEY-LX120H-120W-GUITAR-HEAD-106465372-i1889111.gc
You're welcome
Quote by FEngHLyan

She will join the prom.

She insists to wear this lights.

I don't think so.

How can I persuade her?
#23
ok so please tell me you didnt plug the cab into the effects loop instead of the speaker out section.

if you plugged into the effects loop and had nothing connected to the output jack, you probably blew the output transformer.

if you used an instrument cable, from amp to cab, you have blown the output transformer.

you may have also simply plugged the guitar into the wrong jack on the front. the guitar input is the one on the far right (which is weird as hell to me.)

so try this...

connect the left loudspeaker jack to the left input jack on the cab using a speaker cable.
connect the guitar to input jack on the far right ride of the amp.
turn on the amp

If it works, hooray. However, f no proper guitar sound comes out, then you have blown the output transformer and you will have to buy him a new amp.
Last edited by kolonelkadat at May 30, 2011,
#24
I'm pretty sure I tried that yesterday with every combination of loudspeaker to
cab and still no sound would that output transformer be
in the head or the cab. Please forgive my ignorance, as I said, I have
little to no guitar knowledge whatsoever
#25
Quote by wragg
I'm pretty sure I tried that yesterday with every combination of loudspeaker to
cab and still no sound would that output transformer be
in the head or the cab. Please forgive my ignorance, as I said, I have
little to no guitar knowledge whatsoever
Well, if it's a solid state amp, as some people have mentioned, it probably doesn't have an output transformer... So you're probably okay in that regard.
Quote by MightyAl
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#26
Thank god, what else do you reckon the problem
could be then. Is it possible I was just hooking it all
up wrong?
#27
Would the fact that I plugged the preamp output of the head into the cab be a really bad thing also? When I did this a really loud buzz came from the amp
#28
Quote by wragg
Would the fact that I plugged the preamp output of the head into the cab be a really bad thing also? When I did this a really loud buzz came from the amp



I don't think doing that would be the problem.
Quote by FEngHLyan

She will join the prom.

She insists to wear this lights.

I don't think so.

How can I persuade her?