Great new low tones....while they lasted, that is....

So last night, I got to throw my new Carvin 15's into my 2x15 cabinet, and I also installed my new Hartke LH500 into my rack. Fired it up, and voila'! Awesome low end and tone! Jammed with the boys for three hours, everything is going great, working on a new tune, almost to the end of the song....then....silence.

My low channel cut out entirely. No hiss, no pop, nada. It just quit.

So I swapped my guitar cable, thinking maybe it had died. Eureka! Sound back on! Jam another tune....then right at the end of the song....silence.



Another guitar cable swap. Same thing. Sound comes back for a bit....then....nothing.

Now, the band did notice what they termed a "burnt Band-Aid smell", so I started thinking that maybe the Hartke is defective. I'm also wondering if maybe the battery in my EMG is dying, although I think Andy used a brand-new one, and they are supposed to last for 3,000 hours.

So here is what is running through my head about this, and I am hoping you Guys can offer some insight here.

1) If a battery in an EMG is dying, will the sound cut off entirely, then come back sporadically after swapping the cable? Or isn't it supposed to become more distorted and lower in volume as the battery dies?

2) If it's the amp, what could cause it to cut out with no warning, then come back on every time I swapped the cable?

3) If it's in one of my new speakers, wouldn't there be some warning like distorted sound? And since the speakers are in parallel, if one dies, then the other one should still produce sound. I'm really not thinking this is the problem, though.

I'm so lost!

Burnt band- aid smell is the smell of Carvin voice coil cooking.

#1 double chek your wiring. Make sure your ohm load is correct. Make sure your pumpin the right wattage in and that the speakers can handle it. Voice coils cook because they are getting hot from being overworked.

#2 chek your purchase order with the serial numbers on what you got from carvin and that they are what you ordered and what you think you are running. Perhaps there was a mix up with the order. That speaker you posted a picture of looked like a neo to me.

#3 Carvin will replace bad voice coils (it happens ... happened to me) no questions asked, with new replacement speakers in 90 days I think ... so don't worry about killing them experimenting.

#4 perhaps you are overworking the voice coils because the speakers are working against the pressure they building in the cabinet. They can't "breathe". The motion of the voice coil is limited by the pressure on the cone. Make sense? Start small ... put a 2.5 or 3" port hole in the cab ( you were thinking of doing it anway ) and see what you get.

My money would be on 3 or 4. The amp probably has an overload cut out ... mine does. If there is a bad voice coil and its parallel, its overloading at 4 ohms dummy load or all those dummy watts@ 8 ohms ... it works untill the amp decides it doesn't want to do it anymore. Cutting the gain by turning it off, turning it down all the way or flipping to standby when you switched the cable probably reset the amps overload switch. Then you go overloading it again. Overworking voice coils isn't speakers" blowing" .. but it will. Read up, double chek the wiring and ohm loads and relieve some pressure on your cones with a port.

Its a speaker amp issue ... and it sounds like its doing what its supposed to do when somethings not right( not letting you continue to do it). Its not a battery, pickup, bass or shorting cable problem. You gotta relieve whatever is making your speakers emit that burnt band aid smell.

I hear what you saying MadMike, but the only thing is that the smell seems to be coming from the amplifier.

1) The wiring is perfect. I did the work myself, and double-checked it afterwards. The Carvins are rated at 400 watts and 8 ohms each, so two of them in parallel makes the cabinet 800 watts at 4 ohms. The Hartke puts out 500 watts into 4 ohms, so there is 300 watts of headroom in the cabinet.

2) Double-checked. Definitely not the Neo's, but are the PS15-8's.

3) If I can confirm it to be the voice coils, then that's good to know that Carvin will replace them.

4) Hmmm....this is an interesting point. But since the cabinet was designed closed, would putting the Carvin's into it really make that much of a difference in the air pressure? At any rate, this would be the simplest thing to try.

Also, I ripped out the voice coil from the SA speaker I fried, and it was absolutely cooked. But I don't remember smelling anything when the speaker blew. I'll post a picture of it here in the next day or so.

In the features overview, the manual does indicate some sort of protection, and I quote:

*Protection relay circuitry that protects connected speakers from dangerous overloading and also prevents "thumps" when powering on or off. I am guessing this is what you meant by overload cut-out, correct?

How can I be certain it isn't the amp? And are you absolutely certain the burnt Band-Aid smell would be a voice coil, and not some part of the amp?

Run the amp thru your high end speakers and put it thru the motions.

I think that's a good idea, Bro. I'll give it a whirl next weekend.

i still dont think its your amp. i think your overworking your amp (and voice coils in your new carvins) because the speakers cant move because of the +- pressure inside that SA cabinet.

In that case, I think I'll go ahead and drill out a 3" hole in the cabinet to allow the air to flow out. Hopefully this will take care of it.

now that's a great analogy "Bandaid smell"

I like that,l or like mike said the lacquer they spray the coils with has a distinct electrical smell when burning like what I smelled at our hardrock gig coming from my cabinet.

I have no gigs and my cab is at our practice place for the past couple weeks, but I REALLY need to pull the speakers and check each one's ohms to see if there is a 1/2dead one in that thing.

Its crazy! That's what it is ... the overheating of a laquer covered part ... and that's exactly what it smells like ... burnt bandaids.

Indeed. I just got off the phone with Carvins Tech Support, and the guy told me that he feels really strongly that the cabinet, while on the smaller size while being un-ported, should still work. I emailed him the dimensions of the Seismic Audio cabinet, and he is going to have his engineers compute the numbers for me. He also said that he has witnessed firsthand the burnt Band-Aid smell coming from the voice coils going whacko. He also thinks that it's more than likely that one of the speakers is defective, so it looks like I can get them replaced for free if need be.

This has happened to me as well. Carvin is good about replacing them.

Cool deal. But I still want to be sure about the cabinet volume with the Carvins.

OK....went to Andy's last night, pulled the Carvins....sniff, sniff....yep....faint trace of burnt Band-Aid smell coming from the voice coil vents on both speakers. It wasn't the amplifier.

Carvin says to check the DC resistance, and look for a range of 5.5 to 8.5 ohms....both speakers....6.5 ohms. No shorts, and not blown. Whew!

Next is to port the Seismic Audio cabinet....no problemo....Andy brings in his drill and 3" hole cutting bit, and whoosh! New port hole in the back! Then I threw the speakers back into the cabinet, and buttoned it all up.

I didn't have my bass, but I grabbed one of Andy's seven stringers just to make sure I had re-soldered the speakers correctly, and to get some idea of what the new port hole would do. I used my distortion channel through the cabinet just to get as much volume as I could, and WOW!!!! The amount of air blasting out of that port hole was unreal! It actually sounded really good! TONS of low-end! Even Andy had to admit that it would make a killer guitar rig!

I'll try it with my bass next week, as we aren't jamming this weekend. But for now, things appear good. I hope they stay that way!

Remember ... the numbers I came up with were for (2), 4" port holes. I told you 3" as to start small and go bigger if you need to.

The frequencies you got from a guitar aren't as low. Im sure it did sound better .... but with the lower bass frequencies, you will be more than likely to hit your vent mach (that anoying whistling). Lower frenquency, wider the waveform, more speaker movement, more air being moved.

If you hit your vent mach or feel like your speakers are still restricted, sounded easy enough ... cut the other 3" hole.

I should have clarified a bit. When I plugged in Andy's guitar, I specifically dropped the bar to make the notes as low as possible. Since we tune down half a step, and since hie guitar is a seven stringer with a low B, I was able to get some really ultra low notes happening. Granted, it isn't the same as my bass, but it was still enough to make the windows and walls rattle!

MadMike, I will keep an ear open for that whistling sound, and if need be, I can have Andy cut out another 3" hole. Obviously, I want to see if I can get through an entire evening of practice so then I'll know if the port solved the problem. The other thing is how the bass cabinet will respond in terms of frequency with the port in there now.

Gotchya ... and may the force be with you.




That always sounded like a church thing to me.

Eric!

We haddent heard back from you on this.

How's your carvins holding up after a few weeks with the new port in the cab?

Shoot! Sorry, Bro!

Honestly, the port made all of the difference. Not only has my amp stayed on for an entire night, but it made the cabinet deeper and LOUDER! Just one 3" port on the back to the right was all it took!

So, my hat is off to you yet again MadMike! It was you that made the suggestion, and it worked perfectly. Thanks, Bro!

Awesome!

Im waiting for a cat to get back to me from CL. He's got 2 old fender 215 unloaded cabs ... I want em.