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Topic: Will my Evans survive? |
Doug Jones
From:
Oregon & Florida
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Posted 16 Jul 2005 11:46 pm |
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| I have a small cabinet FET-500 Darrell made for me in the mid 80's. This sucker has been my workhorse ever since. Tonight, at an outdoor gig (generator powered), the amp sounded like it was ready to die! There was a buzzing sound from the generator. Then it started making a loud distorted buzz when the light rig was set up and the tech switched between lights. After checking all my cords and backup volume pedal the problem was still there; lack of gain with a distortion in the low end. I had to up the gain almost twice the usual amount and periodically it would pop and momentarily be incredibly loud. First set was a real bummer. I ended up using my acoustic guitar amp for the rest of the night (that's a whole other story). I have yet to try it again since returning home. Any ideas before I take the chassis out and send to Ed or Scott at Evans ? |
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Eric West
From:
Portland, Oregon, USA, R.I.P.
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Posted 17 Jul 2005 1:12 pm
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So...
What happened?
EJL |
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Jim Sliff
From:
Lawndale California, USA
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Posted 17 Jul 2005 1:59 pm
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This is why for 20 years I've always kept a voltage regulator with me at gigs.
Anything outside at a fair or in a club with questionable electrical supply, and I hook everything through it. It maintains voltage, protects againt surges and ripple currents and has probably saved my equipment many times when I didn't even know it. |
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Dave Mudgett
From:
Central Pennsylvania and Gallatin, Tennessee
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Posted 17 Jul 2005 2:15 pm
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It's possible (even probable?) that the generator power was bad - voltage too low or high, bad waveform, etc. On an outdoor gig like that, be it a generator or even a long power cable run, I use a Furman AR15 voltage regulator - it keeps the voltage much closer to spec, and also cleans up a bad waveform. A bad waveform can make an amp sound distorted. I've played generator-powered gigs with old Fender amps - they're pretty fault-tolerant, but they sounded so bad that I got the Furman. The most common symptom was a very gravely, distorted sound.
You also mention switching a light system in and out. For me, that's almost a guarantee of power problems, even on non-generator house power. Lights take a lot of juice - light and audio should be on separate circuits, IMO.
If bad power is what caused the problem, and if that problem didn't do damage to your amp, it may be that everything is just fine. I would normally open up the chassis and look for anything abnormal - burnt traces, burnt components, etc. If I see anything unusual, I won't power it up, but get it to service.
Perhaps the best thing to do is ship the amp for service immediately regardless of what I find. Nonetheless, I sometimes fire up an amp at home that's given me problems at a gig if I don't see any obvious problems. If you do that, make sure you use the correct fuse value, and if you hear, see, or smell anything funny, shut if off immediately and get it to service. In testing like this, I always turn volume down all the way, and very gradually bring the volume up, listening carefully for problems. If there's anything unusual, I'm quick to shut it down and either work on it or get it to service.
The real bad thing about bad power is that it can do damage to an amp. The Furman doesn't eliminate that possibility, but it cuts the power fluctuations a lot. |
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Dave Grafe
From:
Hudson River Valley NY
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Posted 18 Jul 2005 11:05 am
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Doug, where was this gig and who was responsible for the power?
Several things are wrong with this picture, the comments about insufficient and fluctuating voltage and noise from the lights lead me to believe that (1) the electrical system was not properly balanced, (2) there was no ground rod sunk as is required by the NEC (most fly-by-night operators don't know beans about the laws governing their activities), (3) the generator was obviously not adequate for the task at hand and (4) the technicians were obviously not adequate either.
I want to know who and where because I will follow up and see exactly what was going on.
When the voltage sags the current rises, at 90 volts your gear will draw 30% more current, which can damage power transformers, load resistors and occasionally output devices. Still, if your amp was not smoking and was still passing sound when you turned if off it should be OK. As always, you're welcome to bring it by for a check-up before you go shipping it somewhere that will cost you a bundle for who knows what.
------------------
 Dave Grafe - email: dg@pdxaudio.com
Production
Pickin', etc.
1978 ShoBud Pro I E9, Randall Steel Man 500, 1963 Precision Bass, 1954 Gibson LGO, 1897 Washburn Hawaiian Steel Conversion
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billy tam R.I.P.
From:
baton rouge, louisiana
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Posted 18 Jul 2005 11:35 am
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Doug, I've had this happen before with Evans, as well as other amps. More than likely there are some fried output transistors. Will probably need to go to Ed. I use an Evans rack pre-amp but have always used a Furman regulator with it(no problems). I have found voltages from 95 - 130 in various venues.
thanks
Billy Tam |
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Dave Grafe
From:
Hudson River Valley NY
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Posted 18 Jul 2005 2:32 pm
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Oh yeah,
| Quote: |
| periodically it would pop and momentarily be incredibly loud |
that's most likely because they also had the food vendors on the same generator circuit - most likely what was drawing the voltage down so low - you are hearing the result of the deep fryers, microwaves, ovens and refrigerators whatever turning on and off. |
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Danny Bentley
From:
Hendersonville Tn
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Posted 23 Jul 2005 6:24 am
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Check out the Furman Power Factor
It works for me!
Dan Bentley |
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Doug Jones
From:
Oregon & Florida
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Posted 6 Aug 2005 9:44 pm
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| Good news! I finally had the chance to play it again on an outdoor festival stage. To be safe, I had a back=up in case it was still screwed up. Fortunately, it sounded great. The problem must have indeed been because of the generator. Thanks so much to Scott at Evans and those who e-mailed me and the input on the forum. OK to close. |
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