Problems with Ampeg SVT412HE Cab

Derick Joel · #1 09-10-2011, 01:00 AM

Hello, I'm having a few problems with my rig, hope you guys can help out. First, Im using a Italia Bass with a dimarzio super distortion pick up, my band is a bass drums duo and I like my bass with distortion, so I'm using a Big Muff Pi to my Ampeg B1RE + Ampeg SVT412HE Cab. Recently i changed a speaker to a Eminence 4 ohm 500 watts. It was working fine, but the other day the amp started to make a weird loud ground noises and feedback like never before, is starting to loose volume and sucks really, because i love to play loud. any suggestions will be appreciated, thanks!

rodl2005 · #2 09-10-2011, 01:48 AM

Ummmmmmm, could be a lot wrong here. You shouldn't just put a speaker in there that isn't matched to the others-sonically & mechanically!
Amp COULD'VE blown! Try amp into another cab, one that is matched to the amp's impedance-see ' sticky ' @ top of amp forum

RickenBoogie · #3 09-10-2011, 07:31 AM

+1 you can't just drop another spkr into a cab like that. All 4 need to be the same, and all 4 need to be matched to the box. I think your problem lies there.

Derick Joel · #4 09-10-2011, 10:06 AM

What do you mean different? All the speakers are 4 ohm. I'm running the B1RE @ 4ohm = 300 watts. The new spekear is a 4 ohm speaker too. The Ampeg cab 4x12 is originally rated to be 400 watts @ 4 ohm, one speaker stop working, so i replaced with a Eminence Delta.

Bass_Pounder · #5 09-10-2011, 10:28 AM

Quote:

Originally Posted by Derick Joel

What do you mean different? All the speakers are 4 ohm. I'm running the B1RE @ 4ohm = 300 watts. The new spekear is a 4 ohm speaker too. The Ampeg cab 4x12 is originally rated to be 400 watts @ 4 ohm, one speaker stop working, so i replaced with a Eminence Delta.

So, the other three speakers are Delta's too ?

If not, then yeah - it's different.

Also, did you wire it up correctly ? - Test it with a multimeter to ensure the whole cab is still 4 ohm ?

Derick Joel · #6 09-10-2011, 10:31 AM

Oh ok, and no I didn't test it.

What should I do, I don't have any idea about the info on the other 3 speakers, what should i do to find the exact same model as the others?

will33 · #7 09-10-2011, 12:05 PM

A. Get the old one reconed.

B. Buy a replacement from Ampeg.

C. Replace all 4 so they are the same.

Do you know for sure they used 4ohm drivers with series/parallel wiring?

If you don't know what's going on with the other 3, they could be 16ohm drivers wired in parallel. That may indeed be the case, series wiring usually takes out 2 drivers if one blows.

Derick Joel · #8 09-10-2011, 12:32 PM

I don't really know for sure, I'm kinda a newby in this stuffs, I checked all speakers individually and each one indicates that are 4 ohms, but like you said when that one speaker blown the speakers next to it stop working which means they were wired parrallel, right? lucky one of them still works the other died. Appreciating all the help guys.

**B-string** · #9 09-10-2011, 12:55 PM

You really need to try the B1RE with a different cab to find out is the amp is ok first. Patch a guitar cord from the effects send to effects return if it sounds the same with a different cab. Could be unrelated to your blind speaker swap.

One more thing....sure you don't have any weak batteries in the bass or effects?

Derick Joel · #10 09-10-2011, 01:20 PM

I'm using the 1spot power supply for the Big Muff pi and the Line 6 FM4.

**B-string** · #11 09-10-2011, 01:24 PM

Quote:

Originally Posted by Derick Joel

I'm using the 1spot power supply for the Big Muff pi and the Line 6 FM4.

Ok nice, but is it healthy? Try going straight into the amp with nothing in the signal chain. Bass--cable---to amp.

will33 · #12 09-10-2011, 01:33 PM

Quote:

Originally Posted by Derick Joel

I don't really know for sure, I'm kinda a newby in this stuffs, I checked all speakers individually and each one indicates that are 4 ohms, but like you said when that one speaker blown the speakers next to it stop working which means they were wired parrallel, right? lucky one of them still works the other died. Appreciating all the help guys.

If the other ones are labellel 4ohms and you replaced one with a 4ohm the amp will still see the same cab even if the mismatched speakers don't work that great together. Double check the cab wiring, make sure there isn't a short somewhere. Like these other guys said, start the process of elimination, changing one piece at a time, until you isolate the bad component. It may not be the cab. Start by eliminating all the pedals, plugging straight into the amp, checking the bass battery and using different cables one at a time, proceed from there. Different amp/same cab, different cab/same amp, etc.

Derick Joel · #13 09-10-2011, 04:50 PM

Bass without pedals sounds fine, Problem is when the Big Muff Pi comes in, but Big Muff Pi dont do the same in my Ampeg 2x10 combo.

**B-string** · #14 09-10-2011, 04:54 PM

Hmmmm gain adjustment get bumped by mistake?

Derick Joel · #15 09-10-2011, 04:55 PM

A friend told me could be the amp, B1RE is forcing too much because the Eminence Delta 500 watts handling. B1RE head runs @ 300 watts. Just that one Eminence Delta hold up to 500 watts + the other three speakers it might be too much for the head.

**B-string** · #16 09-10-2011, 04:59 PM

Quote:

Originally Posted by Derick Joel

A friend told me could be the amp, B1RE is forcing too much because the Eminence Delta 500 watts handling. B1RE head runs @ 300 watts. Just that one Eminence Delta hold up to 500 watts + the other three speakers it might be too much for the head.

Sorry your friend needs an education.

He is just plain and simple WRONG.

The amp could care less if you hooked it up to a 1000 watt resistor, it will do the same work.

Derick Joel · #17 09-10-2011, 05:04 PM

Ok, thanks for all the suggestions, I really appreciated.

will33 · #18 09-10-2011, 05:16 PM

Quote:

Originally Posted by B-string

Sorry your friend needs an education.

He is just plain and simple WRONG.

The amp could care less if you hooked it up to a 1000 watt resistor, it will do the same work.

+1

Problem is the pedal, likley the output cranked too high. It will act different with different amps. Adjust the pedal so it's the same volume with the pedal on and off. Turning the pedal on should only add dirt, very little if any volume. If the pedal has some tone you like with the gain high, compensate by turning the input gain on the amp down when running the pedal. The screaming was likely the pedal making the signal way too hot going into the amp, can damage stuff that way.

Derick Joel · #19 09-10-2011, 06:13 PM

Btw, I'm using 1/4, should I start using speakon instead?

**B-string** · #20 09-10-2011, 06:22 PM

Quote:

Originally Posted by will33

+1

Problem is the pedal, likley the output cranked too high. It will act different with different amps. Adjust the pedal so it's the same volume with the pedal on and off. Turning the pedal on should only add dirt, very little if any volume. If the pedal has some tone you like with the gain high, compensate by turning the input gain on the amp down when running the pedal. The screaming was likely the pedal making the signal way too hot going into the amp, can damage stuff that way.

Thats what I'm thinking.

Quote:

Originally Posted by Derick Joel

Btw, I'm using 1/4, should I start using speakon instead?

Speakon are always better than 1/4" for outputs.