New Speaker Advice: Pro Reverb

Discussion in 'Amps and Cabs' started by Rumble5, Feb 3, 2015.

  1. Rumble5

    Rumble5 Member

    Messages:
    1,477
    Joined:
    Jan 11, 2015
    Hi. Tonight I installed two new Alnico speakers in my '66 Pro Reverb (see the link). http://avatarspeakers.com/home/product/hellatone-sa40/

    When I powered the amp up they sounded awesome, just what I was looking for- a raunchy Neil Young grind. At 96db they were much quieter than my previous speakers which is what I wanted, to be able to get old school tube breakup at reasonable volume levels.

    However, within 5 minutes I could tell that something wasn't quite right. There was a nasty vibration coming through them similar to when the old Utahs blew and the cones began rubbing on the voice coils (from what my amp tech said), but more noticeable and worse sounding.

    I was able to figure out that it's just coming from one of the speakers, so the other one is good. I was running the amp loud, but the Pro Reverb is a 40-watt amp, and with a switch to a 5U4GB rectifier tube it should only have been putting out about 35 watts, so two 40-watt speakers for a total of 80-watts of power handling should not have a problem with the power of the amp. So there's no way I could have blown the speaker right off the bat.

    The only thing I could think of was maybe my soldering job wasn't clean enough and the connection isn't as strong as it should be. If that was the case, would it cause it to sound like a blown speaker?

    If not, are there any other possibilities for why it would sound like that, besides it being a defective speaker?

    Any advice is appreciated.
     
  2. Red House

    Red House Silver Supporting Member

    Messages:
    1,295
    Joined:
    Mar 7, 2010
    Location:
    Woodshed
    How much did you tighten the nuts when installing the speakers?

    If you over-tightened them, the frame will distort, and can cause problems with voice-coil alignment.
     
  3. Rumble5

    Rumble5 Member

    Messages:
    1,477
    Joined:
    Jan 11, 2015
    I hand tightened them. They're in there firmly, but I didn't put a bunch of pressure on them. If I tried hard I could probably tighten them more (which of course I wouldn't do). I'll go down and loosen them a bit, but if the frame has distorted it would be bent for good, correct?
     
  4. Rumble5

    Rumble5 Member

    Messages:
    1,477
    Joined:
    Jan 11, 2015
    I loosened the nuts and then re-tightened them with my fingers. They were fastened pretty firmly, but I couldn't tell if it was so tight that they would have distorted the frame. With them re-tightened by hand there's no difference in the sound. It still sounds like a blown speaker. Any other ideas out there?
     
  5. 46346

    46346 Member

    Messages:
    5
    Joined:
    Nov 12, 2011
    sounds like you're ok with the mounting nuts. did you check your solder on the speaker leads like you suspected? it can make a staticy-popping sound at certain frequencies if it's not a solid joint.

    if that checks out, sometimes speakers just fail. if there was a problem in the build of the speaker, it usually becomes apparent very quickly.
     
  6. DaveKS

    DaveKS Member

    Messages:
    15,854
    Joined:
    Feb 26, 2013
    Location:
    KS
    If they were shipped to you it possible that your speakers have been UPS'd (ie dropped hard enough to throw the voice coils out, it happens).

    Try this, turn speaker cabs 180° upside down or on side 90°, see if voice coil rub wanes, sometimes it does work. If so you got damaged speakers from a hard jolt.
     

Share This Page