Music Man HD-130 and Ampeg cab review

[drbassman]

If it is indeed the cone that is misaligned, there is no other way than to re-recone it I´m afraid.
It is possible though, to check  - you can remove the dust cap and measure or look if it´s OK.

Beware, doing so may very well damage the speaker!

If the sound does not bother you at playing volume, just leave it as-is.

Thanks.  At volume, I can't hear it so that's good!  I think I will just leave it and if it should bite the dust, I'll have it reconed again.

[Psycho Bass Guy]

To be sure that it is indeed a coil alignment problem, all you have to do is take off the speaker grille and gently push the cone back and let it rebound. If you hear scratching, the recone was done wrong and will fail in the near-term anyway.

[drbassman]

thanks guys, I'll check it out today!

[drbassman]

To be sure that it is indeed a coil alignment problem, all you have to do is take off the speaker grille and gently push the cone back and let it rebound. If you hear scratching, the recone was done wrong and will fail in the near-term anyway.

Well, I did gently move the cone in and out and I can hear a faint scratching sound.  If I press a little more on one side vs. the other it's louder.  Oh well, back to the shop!

[Psycho Bass Guy]

That should have been caught before it was returned to you. There is no way (that I can think of off the top of my head) you could cause that to happen yourself without taking the speaker completely apart. Even if it was just a bad recone kit, the speaker should have had a motion test. What you're hearing is the voice coil scratching the sides of the coil gap.

[drbassman]

Makes sense to me, too.  At least the speaker guy is taking it back and fixing it at no extra charge.  Nice guy!

[jumbodbassman]

happened to an old EV speaker after about 15 years or so of use.....

[Psycho Bass Guy]

happened to an old EV speaker after about 15 years or so of use.....

That's a different story. Repeated use had heated up the coil enough to make it deform and catch in the gap. A recent recone doing that wouldn't have time to deform. It would either blow or lock up if it was hit with too much power. Out of curiosity, what cab was it in? In theory, ported cabs should be much more prone to this than sealed.

[jumbodbassman]

It was in that standard  ported EV designed (theil or something like that)  with the ports on the bottom that have removable blocks of wood.   i can actually feel it rubbing as i move the cone.   Have to get iot rebuilt as soon as I find A JOB and  have some money moving in the opposite direction of what it has for most of the current year.     

[Psycho Bass Guy]

I figured it was a ported cab. When you get it reconed, add a large capacitor (you'll have to know what the cab's tuning frequency is and amount of power being fed to it to calculate its value) to the crossover to act as a high-pass filter and that should keep it from happening any more. People who use eq filters ahead of the power section don't realize that amplfier operation can produce sub and infrasonic power on its own. When you put the cap in there, anything below the r/c curve never gets to hit the speaker and is safely shunted to ground. The end result is that your speakers will last longer, be louder and more efficent (sub-tuning power dramatically affects resonant frequency response) and tighter sounding.

[Granny Gremlin]

That's going to be a big/expensive cap.

[Psycho Bass Guy]

That's going to be a big/expensive cap.

There are lots of surplus doorknob and oil caps on eBay for next to nothing all the time. When they were new, they cost almost as much as the RF tubes they fed, but since transmitters are mostly s/s now, good quality NOS caps, even made the USA, have flooded the market. Old Russian and Eastern European stock is tough as nails and costs less than pennies on the dollar to what went into making it.