question about amp

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question about amp

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Miguel de Maria

Posts: 3532
Joined: Oct. 20 2003
From: Phoenix, AZ

question about amp

For all you giggers, here is a question:

last night, I was playing at a resort for dinner for about 80 people, in a large rectangular room. I had a stage and my set up was as follows:

Guitar with Fishman Matrix
1/4" cord
Zoom 504II effects
1/4" cord
Samson Expedition Express Powered Speaker with Battery

I arrived very early because I had never been to this resort (the very nice Wigwam resort in Avondale, AZ), and set up about an hour and a half before the gig was to start. Anyway, everything looked good, so I checked out the grounds and arrived twenty minutes before my start. Now...a few minutes before downbeat, a strange sound came out of my amp, to my horror...it was like rpppppppp pppfffff... it sounded sort of like if you took a playing card and put it in the spokes of a bicycle.

Anyway, in a mad panic I got an extension cord and luckily the outlet near me worked (I distrusted the battery), and got a mic set up in case the pickup was somehow to blame (I didn't have a mic stand, unfortunately). I also changed channels, thinking maybe the channel was faulty. Luckily the gig went off without a hitch and the sound did not recur.

This morning I changed the 9 volt in my guitar in case that was to blame. I am in the process of attempting to duplicate the problem in my studio, but of course, nothing is happening.

Anyone have any ideas what could have been the culprit?

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 19 2005 17:16:26

Ron.M

Posts: 7051
Joined: Jul. 7 2003
From: Scotland

RE: question about amp (in reply to Miguel de Maria)

Mike,
Electronic equipment does break down, although the human experience these days accepts that washing machines, dishwashers etc do break down, but things like TV's and HiFis don't.
I get phone calls from folk saying that they can't believe it but their Widescreen TV set has just broke down and they totally can't understand it, 'cos it was working yesterday.
(They never stop to consider that the TV has usually had more operating hours than the light bulb in their room.

)

The worst thing is an intermittent fault, ie the one that goes away by itself only to come back at the most inconvenient time.
I have a sneaking suspicion that you could have one of those faults and it could be anywhere between the pickup and the loudspeaker frankly.
Unlike software problems, you will not be able to get a simple answer to it or Google it.
Thats the diff beween computers and analogue (real) electronics.

Good luck anyway,

Ron

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 19 2005 20:20:50

Miguel de Maria

Posts: 3532
Joined: Oct. 20 2003
From: Phoenix, AZ

RE: question about amp (in reply to Ron.M)

Ron,
hmmm, well I have had this amp for a couple of years and I suppose it does have a few miles on it. A wild guess is maybe 50 gigs with an average of 3 hrs use per gig = 150 hrs. That would be pretty bad for it to break down this early, wouldn't it?

If this was your main rig and you depended on it for about half of your gigs, what would you do?

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 19 2005 20:44:45

Ron.M

Posts: 7051
Joined: Jul. 7 2003
From: Scotland

RE: question about amp (in reply to Miguel de Maria)

Mike,
Being scientific and professional about it, you should replace everything, or at least take 100% backup with you to gigs.
But we are all human and therefore risk-takers.

cheers

Ron

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 19 2005 20:50:47

Ron.M

Posts: 7051
Joined: Jul. 7 2003
From: Scotland

RE: question about amp (in reply to Miguel de Maria)

quote:

A wild guess is maybe 50 gigs with an average of 3 hrs use per gig = 150 hrs. That would be pretty bad for it to break down this early, wouldn't it?

Mike,
Electronics is not like car engines. In theory the semiconductors should work for over 100 years.
But that's the theory.
In practice, minor flaws in the manufacture lead to problems later.

I've had about six Toshiba "all singing, dancing" Widescreen TV's in this year, all with 3D surround sound and costing over $1500.

Most of them were between 15 to 18 months old and the CRT (Cathode Ray Tube) had a fault in all of them, costing maybe $800 to replace?

Time and use is not a factor in Electronics.

cheers

Ron

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 19 2005 20:58:55

Miguel de Maria

Posts: 3532
Joined: Oct. 20 2003
From: Phoenix, AZ

RE: question about amp (in reply to Miguel de Maria)

Ron,
so basically, I'm SOL and should try to sell it to someone else and get something else for myself! ?:)

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 19 2005 22:00:25

ToddK

Posts: 2961
Joined: Dec. 6 2004

RE: question about amp (in reply to Miguel de Maria)

Im not sure i understand you.

This battery that powers your speaker, its supposed to last indefinatly?

with no recharging?

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REPORT THIS POST AS INAPPROPRIATE | Date Oct. 19 2005 23:19:09

Florian

Posts: 9282
Joined: Jul. 14 2003
From: Adelaide/Australia

RE: question about amp (in reply to ToddK)

Miguel your amp is broken fukin

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 19 2005 23:41:58

Miguel de Maria

Posts: 3532
Joined: Oct. 20 2003
From: Phoenix, AZ

RE: question about amp (in reply to Miguel de Maria)

Todd,
the battery charge lasts 4-8 hrs. I recharge it before each gig. I know those batteries are supposed to gradually fade and last less and less, but they're definitely not supposed to make strange noises like that. Plus, I've only had the battery for maybe 8 months.

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 20 2005 2:59:32

Florian

Posts: 9282
Joined: Jul. 14 2003
From: Adelaide/Australia

RE: question about amp (in reply to Miguel de Maria)

sorry about my post, it seemed funny at time

I imagined the line in my head with a broken estern european accent.

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 20 2005 3:52:03

Jon Boyes

Posts: 1377
Joined: Jul. 10 2003

RE: question about amp (in reply to Miguel de Maria)

Can't help you I'm afraid, though I can sympathise lots

I've had an intermittent fault with one of my rigs as well.

Did my first proper gig with Mark the other day and after setting up I could get no sound at all from guitar. Eventually traced it to a connection in the preamp case that houses the 9v battery. Yikes. Got me thinking about getting a back-up guitar, but then what if my PA breaks as your amp did? I don't want to lug two systems around..

Yeah, these things are a worry for sure, especially if you've just travelled a few hundred miles to play at someone's wedding or something.

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Spanish Guitarist in Devon, Cornwall and Somerset

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 20 2005 8:15:51

Ron.M

Posts: 7051
Joined: Jul. 7 2003
From: Scotland

RE: question about amp (in reply to Miguel de Maria)

quote:

Ron,
so basically, I'm SOL and should try to sell it to someone else and get something else for myself! ?:)

Mike...Now you see why it's always a bit risky buying used electronic equipment unless you can get some kind of written guarantee for at least 3 months.
Stuff can appear to work OK, but every now and then has some quirky problem.

Anyway...on to the positive side.
I have to deal with intermittent problems all the time when fixing stuff.
First you've got to provoke the fault by tapping, shaking or banging the chassis or PCB.
This will show up any bad solder joints or connections.
(Other methods include heating/freezing...but let's leave that out in the meantime).
You've got the added problem that you don't know if it's the pickup, preamp or main amp, but try everything. Don't be too gentle with it...PCBs etc are pretty tough!
Once you can provoke the fault, you're halfway there to fixing it.

cheers

Ron

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 20 2005 8:42:00

Mark2

Posts: 1882
Joined: Jul. 12 2004
From: San Francisco

RE: question about amp (in reply to Miguel de Maria)

Go to Guitar Center and trade it in

That's why I like rock gigs-that stuff becomes part of the show! Seriously, in the old days I'd have all these stomp boxes and if one didn't work, I'd just stomp on it again. Sometimes strange stuff would happen that sounded good. Anyone remember those electro harmonix things?
Solo gig with 80 people-I'd go with an amp and a mike. The more gear, the more problems, but that does seem like a simple rig. Do you like the sound of that pickup more than a mike? I've got a rig that I use with my group which consists of a bunch of old junk, McLish pickup, pre-amp, old cords

etc. which on many occasions just doesn't work right. Since I'm just doing casuals with it, I live with it. Other choice is to buy new stuff regularly, or really learn how to fix all this stuff. And those damn 9 volts-they always go out when you don't have a spare ten minutes before the downbeat! Go to costco and buy 10 of them for 8 bucks and stick them in your bag. Or at least tongue test them when setting up! Yeoow.

REPORT THIS POST AS INAPPROPRIATE | Date Oct. 20 2005 18:34:54

Escribano

Posts: 6418
Joined: Jul. 6 2003
From: England, living in Italy

RE: question about amp (in reply to Mark2)

quote:

That's why I like rock gigs-that stuff becomes part of the show!

Agreed, they are part of the band - we gigged with a converted 150-pound/20W PA amp out of a 50's submarine and a marine ply speaker cabinet that I made when I was 12 years old because the dinghy it was meant to be didn't float (it would have been at home on the sub).

We were gigging with this stuff into my 30s and it never broke once

Of course, this "stack" clearly had to be miked up but we supported many better equipped bands with it. Nico of Velvet Underground thought it "a statement".

You can hear the set-up on the lead guitar in this 80's clip:

http://www.shearston.com/SHP.mp3

Technical Note: I'm on bass with an old Washburn, a Fender Bassman (that someone peed in at a Notting Hill carnival) and a 60's WEM lead top.

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REPORT THIS POST AS INAPPROPRIATE | Date Oct. 20 2005 19:00:29