Dead Amp

InFlame00 · June 09, 2006, 06:22:52 AM

Don't know if this is the right place on the forum to ask this question but anyway...
I blew up my cambo trying out the bazz fuss, I opened it today to see if something is wrong, I can't find any errors..
My thought is that it can have somthing to do with some groundcircuit because there are noise coming from the speaker when I'm not touching the strings, it has nothing to do with my guitar because the noise is there with every guitar I've tested.
everything seems to work in the amp (effect,volume,gain etc) except that I can't get any tone from the guitar out of the speaker.

Any ideas what could be wrong?

theblueark · June 09, 2006, 07:51:37 AM

I never knew any 9V effect could blow up an amp. Is this really possible?

InFlame00 · June 09, 2006, 07:54:49 AM

Quote from: theblueark on June 09, 2006, 07:51:37 AM
I never knew any 9V effect could blow up an amp. Is this really possible?

Trust me, pigs might fly.

DuncanM · June 09, 2006, 08:01:39 AM

The only responsible reply to this question is:

"take it to a reputable technician"

Don't mess with your amp if you don't know what you're doing - you could do yourself serious harm.

That said, have you first checked your leads?
How do you know "everything seems to work in the amp (effect, volume, gain etc.)" ?
How have you tested this and what do you mean by it?

Does the noise stop when you tough the strings?

InFlame00 · June 09, 2006, 08:05:28 AM

Nha, I won't do myself serious harm. Only 10V power in.
What do you mean with checking the leads? (swedish and don't undertand what you mean by that)

I know that everything works because I can use effects etc on the noise-signal that apears when not touching the strings.

DuncanM · June 09, 2006, 08:37:06 AM

So either you've destroyed the input stage or your guitar lead is faulty...? (never overlook the obvious).
No sound from the guitar (apart from noise) ?

What amp is it?
OK, 10v is pretty safe to tinker with

InFlame00 · June 09, 2006, 08:51:56 AM

No, there are no sounds from the guitar apart from the noise and the noise wont be affected no matter what I do with the guitar except from touching the strings.

It's a Roland Microcube, (just use it for goofing around at home)

trevize · June 09, 2006, 09:37:46 AM

i usually make smoke the frontend (the first tl072) of my bedroom m80 fender amp trying 386 based effects

now it's socketed

btw usually means that i already happened three times.... now with a ne5532 everything works fine!

syndromet · June 09, 2006, 10:29:35 AM

If you are able to see the pcb-lines, it might be a good point to probe that thing. I would also suspect the input IC. Just probe around to see where the signal stops. This might be a handy tin to have.

InFlame00 · June 09, 2006, 10:58:27 AM

I've tried using the beeper of my multimeter but with no sucess. I find it strange because I can still control the noise that comes from the guitar, it's not like the signal is dead but there are no reaction when I hit the strings at all. And also, there are no" popping" sound when I put the cable fram the guitar in to the amp (you know that pooping sound when you plug somthing in and the amp is on)

gez · June 09, 2006, 11:55:12 AM

Is there a schematic on-line for your amp? If not, did you get one with a service manual when you bought it? Without a schematic, or unless you're willing to trace at least part of it, or can give a little more technical info...it's a bit pointless asking.

Chances are it's just the input stage, but it could also be coincidence (something else might have gone wrong while you were plugged in and it seemed like you'd fried it with a pedal).

InFlame00 · June 09, 2006, 12:51:12 PM

Can't find any schematics online, and no schematic in the manual either...but aren't there any other in here that have gotten the same problem as I have described?
Or anyone that got some sugestions about what could be wrong?

gez · June 09, 2006, 02:10:06 PM

Try one of the amp forums. Chances are someone there will have worked on/has a schematic for your amp and can walk you through things.

christobean · June 09, 2006, 04:45:47 PM

Quote from: theblueark on June 09, 2006, 07:51:37 AM
I never knew any 9V effect could blow up an amp. Is this really possible?

its not the voltage or anything, but the extreme amount of volume boost with it. i built one and have to dial the amp volume knob to teh lowest with sound still coming thru, otherwise the speaker cant handle it.

syndromet · June 09, 2006, 06:50:47 PM

have you tried it with another speaker?

Peter Snowberg · June 10, 2006, 12:39:58 AM

It's almost impossible to hurt 99.9% of amps with 9V so I would suspect something else. It could still be the amp but I can't tell much without a schematic.

Most amps will have a resistor in series with the input so that if does get connected to a voltage source there isn't any problem. It is possible that the input circuit contains "crowbar" style protection using a pair of zener diodes which could fail in way that would kill the sound.

Can you take pictures of the insides and post them?

InFlame00 · June 10, 2006, 03:25:08 AM

Ok!
Could'nt take closer pics...bad cam.

MetalUpYerEye · June 10, 2006, 04:13:40 AM

Although i'm sure you already have, plug your guitar into another amp and make sure that the guit and cable aren't the problem. I had a crap cable that made me rip up my fish-food Ruby amp trying to figure out what was wrong...

InFlame00 · June 10, 2006, 05:31:22 AM

@#$%ing piece of shit. Bought a new cable and now It works...
Thread can be closed

syndromet · June 10, 2006, 05:54:42 AM

Good stuff!!! Now it's time to get that bazz fuss up and running!

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Dead Amp