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Ampeg SVT-3 Pro making Siren noise

Discussion in 'Amps and Cabs [BG]' started by christopantz, Dec 21, 2017.


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  1. christopantz

    christopantz

    Sep 16, 2015
    Hi everyone,
    I just got a SVR-3 Pro I ordered off ebay. I plugged it into my 410HLF to test it. When I turned it on, it started making this weird whining noise (coming from the amp itself, not the speaker cabinet). I originally thought there was a police siren outside my house, because that’s what it sounded like. I turned it off to see if it would stop. The sound rose in pitch as it turned off before cutting out completely.

    I can still play bass through the amp when it is on.

    Is this a normal issue? Should I return it? I’ve attached a video with the sound. It starts at around 0:10. thanks.
     
  2. Sorry but I failed to hear a siren like sound. I did hear the cooling fan but that was it.
     
  3. christopantz

    christopantz

    Sep 16, 2015
    UPDATE: After doing some more research, it seems that the siren sound while turning off is the capacitors discharging. The amp also does not make a droning sound while it is on anymore, which is weird that it disappeared. Should I be worried?

    Also, I cannot hear a fan on this amp. After playing for maybe 10 minutes, the top of it started feeling warm. is this normal? Thanks.
     
  4. SteveBass5

    SteveBass5 It all sounds the same, It's all one song! Supporting Member

    Aug 11, 2009
    Massachusetts
    Fan might be gone. I can hear mine. It has 5 tubes so it does get hot but not really hot.
    Where the tubes removed when it was shipped?
    Did you open it up and check it out?
     
  5. Ben B

    Ben B

    Jul 13, 2006
    San Diego, CA
    As SteveBass5 mentioned, the amp getting warm is normal due to the tubes. I heard the noise on your video. It could be a fan bearing/bushing, but it didn't really sound like it. You could take off the amp's top, unplug the fan and turn on the amp. If the noise goes away, then it is the fan. If the noise remains, take it to a tech.
     
  6. christopantz

    christopantz

    Sep 16, 2015
    Tubes were not removed during shipping, but the amp was packed really well so I wouldn’t suspect the tubes to be broken. I’ll open it up and look more when I’m home tonight.
     
  7. dagrev

    dagrev Supporting Member

    Jun 21, 2006
    Kentucky
    As mentioned the fan doesn’t seem to be working. You can’t miss the fan on a 3PRO. The noise does sound electrical not mechanical to me.
     
  8. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Checking if the fan is on is easy...however, there are fans that only come on when it's needed. Not sure if the 3 Pro has one of those fans but it wouldn't surprise me.

    The whining noise, as you said, is the caps discharging when they power down. It is fine, a lot of amps do it, and all you have to do to stop it is to turn the volume down when you power down.
     
  9. agedhorse

    agedhorse SUSPENDED Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    No, this is not normal. Most amps (certainly quality amps) have output muting circuits that mute the amp during power up and power down periods. This should be checked out, unless the OP feels lucky.
     
    Killed_by_Death likes this.
  10. SteveBass5

    SteveBass5 It all sounds the same, It's all one song! Supporting Member

    Aug 11, 2009
    Massachusetts
    The siren must if been the fan dying.
    Send into a pro to get fixed.
     
  11. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Well you're the amp designer in the room so I'll defer to you, but I've used plenty of backlined amps that have done it. My SWR SM-500 always did it through the PA if I powered down while the PA was still on and the XLR was plugged in. People who heard it were a little shocked, but other than that, it never hurt the amp and it ran fine for quite a good while problem free until I sold it. I guess there's a chance you can blow a speaker, but other than that, what can happen?
     
  12. agedhorse

    agedhorse SUSPENDED Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    Ouch, I'm sure the sound guy appreciated that.

    Most DI outputs do not have power up/down muting. Generally the sound guys would want to know when you shut down do they can mute the channel first.

    I'm talking about the power amp output, most amps have mute circuits at this point, though there are some legacy amps (and low quality modern amps) that do not. The reason is that as power levels have increased, these noises become more irritating and potentially damaging.
     
    JimmyM likes this.
  13. Bim1959

    Bim1959

    Apr 15, 2009
    Naples Florida
    Sales and electronic tech/piano tech: England Music Center - Clinton IA - now closed
    My 3 Pro never made noise like that but it did get warm to the touch mainly where the tubes were. It did have its flaws (muting circuit took up to 30 seconds to kick out so I could play it and I had to rebias the output transistors at least once a year) and I loved it right up until the day the transformer decided to go up in smoke.

    Christopantz. Did you get the amp new or used off ebay? Did you get ahold of the person/company you bought it from and let them know of your problems and questions about the amp?
     
  14. christopantz

    christopantz

    Sep 16, 2015
    Thanks for all your advice guys. Since I got it off ebay I think i’m gonna try to get my money back.
     
    Killed_by_Death likes this.
  15. I own two 4 pros and both make the same noise. They have been doing it ever since I bought them several years ago
     
  16. abracadunphy

    abracadunphy

    May 22, 2015
    I had an ampeg svt-4 that did the same, I used it for a long time and never had a problem.
     
  17. This doesn't sound right.

    Big, broad guess on my part so take it with a grain of salt.
    Some kind of mechanical oscillation of an electrical component as in a part that is loose mechanically and whatever oscillation it normally incurs is being transferred to another part of the amp, acting like a transducer??

    I's suggest either return it or plan to have it serviced.
     
  18. JimmyM

    JimmyM Supporting Member

    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    That 30 second delay was because it has tubes and it's not good for tubes to play an amp while the tubes are warming up. You will find similar delays on most amps that have tubes, and if they don't have them, you should wait at least that long before playing into one.
     
    SirMjac28 likes this.
  19. mpdd

    mpdd neoconceptualist

    Mar 24, 2010
    LA
    great, now i need to get an svt-3pro for the intros and bridges in the noise band ;)
     
    agedhorse likes this.
  20. christopantz

    christopantz

    Sep 16, 2015
    The amp was bought used, but the seller described it as “perfect working order”. I’m gonna message them
    today to see what they say.
     

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