Amp Buzz, and Heat

Discussion in 'Audio Hardware' started by Kyhl, Oct 12, 2002.

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  1. Kyhl

    Kyhl On break Thread Starter

    Location:
    Savage
    SamS's question about amp buzz made me seek more advice. Having a similar amp, I was very interested in all of the comments on the amp buzz thread. I have two, probably unrelated questions, and not wanting to hijack the buzz thread.....

    The transformer in my PVA-5 creates an audible buzz. I've only had it for about a month and it has concerned me since I noticed it a couple of weeks ago. It does not make noise through the speakers. The amp itself makes a buzzing sound audible from a few feet away. It sounds like it is coming from the transformer.
    My first reaction was to go back to the store and check out the sound from their demo. It has the same buzz, but not as loud. I do not use a line conditioner. Is this normal, well it get worse over time, and is there something/someway to reduce it?

    Also, the amp gets Hot (really hot to me). After about 4 hours of use stereo or MC, the fins that are exposed on the top get so hot that you can barely touch them. Living in MN it makes for a nice radiator, but how hot should I expect it to be?
    I'm using it to drive a couple of Klipsch forteII's. I checked the speakers after about 15 minutes of listening to 80dbs and they read 4.5 ohms (everything off and disconnected). Should I be concerned, any suggestions?
    Thanks in advance.


    P.S. You can add Klipsch to the spell checker.:love:
     
  2. SamS

    SamS Forum Legend

    Location:
    Texas
    Kyhl,

    From my experience most SS amps have some sort of transformer-generated hum/buzz. My Anthem has this (unrelated to my speaker buzz problem), but only if you listen very closely.

    I don't know enough about transformers to properly explain, but I'm sure someone here can :)

    McIntosh solves this problem by dipping their power transformers in a hot tar and sealing them in a "can" which then eliminates the hum.
     
  3. Sckott

    Sckott Hand Tighten Only.

    Location:
    South Plymouth, Ma
    Humm and buzz and similar vibration and disturbances can also be caused by a faulty or a moderate inefficiant capacitor in the power supply.

    My Dynaco ST70 amps, just about every one, has a very slight buzz. You have to put your head in the cone of the speakers, but a whisper at 5" from the midrange makes it invisible.

    One of the 3 I had used to MMMMMM just idling, but didn't make a noisy experience in the playback, just in the physical world. It ate weak tubes also. I replaced a few caps in it, and it doesn't make a peep now. Solid as a rock, performs better.

    With some SS amps, the capacitors are usually quite large and are sometimes hard to replace at a user level.

    Yes you should be concerned, and FYI, that amp shouldn't get that hot. Maybe warm, like the feeling of a warm sandwich, but not "hot car in august" hot.

    I'd watch it's ass! Although the fuse or cap would be the first to go, and most likely in the power supply. I would seriously think of having it taken to a qualified repair center, something with good experience with some SS amps.

    If a cap lets go, there have been times where more serious damage could be avoided if it's caught on time, much like some cancer....

    How old is this unit?
     
  4. JohnG

    JohnG PROG now in Dolby ATMOS!

    Location:
    Long Island NY
    I never has buzz problems til I added an AudioSource mono amp to my system to power a SVS subwoofer. I used a cheater plug to stop the buzz but that amp has a loud fan.
    The loud fan is not a problem really cause I only turn on the SVS sub for movies anyway and the movies can be so loud, you'd never hear that fan:D

    BTW, it is a wonder to behold when my SVS sub and my Velodyne sub are both on during a rockin' sockin' movie. The house trembles.
     
  5. cwon

    cwon Active Member

    The power transformer of one of my (tube) monoamps buzzed when I first got it. I don't know the mechanics of transformer operation, but I was told by almost everyone that some buzz is common - just the loudness varies. I tried damping the chassis internally with adhesive anti-vibration materials from a car audio shop to at least make the buzz quieter, but it never went away completely.

    The designer/manufacturer (George Wright) suggested that it might be too close to a power source and the interaction could cause the hum - moving the amp around didn't help, and anyway, only one amp buzzed, and they were next to each other. The sound of the amps were so good that I was able to accept the buzz.

    After a short time, George spec'd and received upgraded power transformers for that model and swapped mine out. Both amps are now dead silent.

    This probably doesn't help you except to suggest that you ask your amp store about the buzz and see if they can exchange the amp for you or check it out. And then ask the manufacturer if they have a fix for it.
     
  6. Kyhl

    Kyhl On break Thread Starter

    Location:
    Savage
    Thanks for the suggestions

    My computer died within minutes of starting this thread. I got the ok from the wife:eek: to get a new computer rather than piece it back together again.

    Thanks for the suggestions. I will keep an eye on it until I can talk to one of the techs associated with my dealer.

    Oh, The amp is about a month old.

    P.S. Ever get the feeling you are isolated from the world when your computer is broken? Yikes.
     
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