speaker lightning !?

kim · Post by **kim** » Tue May 22, 2007 4:50 pm

so i kind of forgot about this but last week at our gig someone came up to me after our set to say that during heavy parts one of the speakers in my ampeg svt410HE cab was like.. lightning.. then a few minutes later someone else started talking to me about the 'cool light effect' in 'your bass amp'.. eh ?
i was hoping they were talking about the meter on the ashdown top but nop.. it was about my speaker cab...
so i'm kind of worried.. there were no spectacular light effects at the bar, just a lot of mirrors but no strobes or whatever so maybe something's wrong with the cab, does this sound familiar to any of you ?
maybe i'll get electrocuted at friday's gig..how exciting..

euan · Post by **euan** » Tue May 22, 2007 5:39 pm

Check out the docs on the cabs. I know some of the powered stage monitors I've used have built in light that glows very nicely when they are getting a bit overloaded.

kim · Post by **kim** » Tue May 22, 2007 6:12 pm

hm.. i didn't know about that.. so it might be perfectly normal then ?

i'm gonna send an e-mail to ampeg to ask them about it and wether i should have it checked out...

euan · Post by **euan** » Tue May 22, 2007 6:20 pm

I'm just saying it has been my experience for lights to come out from somewhere unexpectedly and for it to be normal. I'll have a look myself later. I'm currently finding out if my TT is dying on me already or if it's one of my non true bypassed pedals.

kim · Post by **kim** » Tue May 22, 2007 6:26 pm

oh noes.. not the TT, can't be....

speaking of.. i played thru a TT at a guitarshop today, thru an orange 410 cab .. they had a lefty tele at the store so i couldn't resist.. it really does sound beautiful.. after ten minutes or so there were about five people standing around the amp just nodding.. god i love it but can't afford it.

filtercap · Post by **filtercap** » Tue May 22, 2007 7:04 pm

From the product description on zzounds.com:

All enclosures feature dual Neutrik Speakon and 1/4 in. input/output jacks. Cabinets using high-frequency horns contain a variable-level attenuator. To prevent overpowering and damaging the horns, a resistive bulb is wired in series with the horn for protection.

Fooey. I thought you had Smokestack Lightnin' going there or something.

euan · Post by **euan** » Tue May 22, 2007 7:21 pm

There is your answer Heavium.

This is only really the second day I've had with the TT. I've swapped the preamp valves out and been playing sans pedals for the last few hours. Hopefully over the next week it wont comeback and I'll just buy a pair of new preamp tubes.

Going on what was happening, I'm thinking it was the PI tube going leaving me with silence or a rather buzz saw sound.

I never have much luck with new amps it seems.

kim · Post by **kim** » Tue May 22, 2007 7:52 pm

i got a reply from ampeg in less than an hour:

Hi Kim,
All Ampeg cabs with high frequency horns come with a fuse protection
circuit. This is basically a light bulb on the crossover that absorbs
excess energy and prevents your horn from blowing. You need to either
turn down your highs on the amp or turn down the L-Pad attenuator on
the back of your cab. I usually set mine at about 12 o'clock. If you
didn't have that protection, you probably would have blown the horn by
now.
Underpowering a cab can certainly cause this too. Your head is only
putting out about 170 watts into a cab that's looking for about 400
watts. You may be overloading your power section which would cause DC
to go to the cab. This is not good as you can easily blow a speaker by
underpowering it than by overpowering it.
Hope this helps, feel free to drop me a line anytime.....

Thanks for choosing Ampeg!!!!

Dino Monoxelos
Global Ampeg Product Specialist
LOUD Technologies Inc.

so... i kind of need to worry.. i'll try turning down some of the highs... i should've mentioned the sansamp bass driver preamp too tho.; since that might be what's pushing the cab too much.. or the 300watts @4ohm giving about 170watts @8ohms and the whole 'underpowered'-thing... but i think it's the sansamp since i've only used it live a couple of times and before that none has ever said anything about a glowing speaker.. so i'm going to try to set the level lower in the future.; if that doesn't solve anything it might be the top...

euan · Post by **euan** » Tue May 22, 2007 7:56 pm

Thats pretty beasting customer service.

Chico Malo · Post by **Chico Malo** » Tue May 22, 2007 8:07 pm

I had the same thing happen with one of my Ampeg PR410 cabs. As it turned out, I was overloading the cab. It has been fine ever since. I have to say, it looked pretty cool when the light was coming through the cab ports.

Post by **Doog** » Tue May 22, 2007 8:16 pm

heavium wrote: but i think it's the sansamp since i've only used it live a couple of times and before that none has ever said anything about a glowing speaker.. so i'm going to try to set the level lower in the future

Unless you're really hitting the preamp hard with a lot of volume or treble on the pedal, I doubt it's the Sansamp.

filtercap · Post by **filtercap** » Tue May 22, 2007 8:24 pm

Somebody explain to me how underpowering a speaker is going to blow it. Having a severe impedance mismatch between head and cab may cause problems, but that has nothing to do with wattage ratings. As long as impedances match, you should be able to run a 1-Watt amp into a 100-Watt speaker with no problems. Not to question the Ampeg Global Specialist, but "underpowering" is a new one on me.

A speaker's wattage rating is the maximum continuous power it can handle without breaking down, and likewise a speaker cabinet's wattage rating. An amp's wattage rating is the maximum continuous power it's able to put out -- generally when it's cranked and being fed a fairly hot signal. But if I have, say, a 100 watt amp and I set the volume and gain knobs at 2 and feed it an average-level signal, I'm putting nowhere near 100 watts of power into my speakers at the moment. Does that mean my speakers are in danger? What about all those people hooking their 1-watt project amps up to Marshall cabs? Are they about to melt their voice coils or something? Somebody educate me on this.

Edit: I'm talking about this here quote from Ampeg:

Underpowering a cab can certainly cause this too. Your head is only
putting out about 170 watts into a cab that's looking for about 400
watts. You may be overloading your power section which would cause DC
to go to the cab. This is not good as you can easily blow a speaker by
underpowering it than by overpowering it.

Post by **Doog** » Tue May 22, 2007 8:30 pm

You may be overloading your power section which would cause DC
to go to the cab.

Apparently.

I had a 300w 15" die randomly when being used with a 150w amp head, possibly the same thing happened.

kim · Post by **kim** » Tue May 22, 2007 8:34 pm

Doog wrote:
heavium wrote: but i think it's the sansamp since i've only used it live a couple of times and before that none has ever said anything about a glowing speaker.. so i'm going to try to set the level lower in the future
Unless you're really hitting the preamp hard with a lot of volume or treble on the pedal, I doubt it's the Sansamp.

treble..indeed..heaps and heaps of treble, and hitting the strings quite hard with a heavy pick.. the sansamp acts as a volume boost too (might be able to set the level so that it's not louder than the amp's volume).. maybe all of that is too much for the cab to handle ?..odd.

i like to have a lot of 'clang' in my sound, think Tool/Shellac.. a bright bass sound.. so it might be the sansamp indeed.. will test it at friday's gig, we've got about two hours for our soundcheck..should be enuff..

there's always some friends showing up at gigs so i can ask them to let me know when it starts again during our gig and then i could leave out the sansamp to find out wether it's the cab that is just underpowered or the sansamp pushing it too much.

filtercap · Post by **filtercap** » Tue May 22, 2007 9:58 pm

Heavium, the light in your cab is connected with the driver that handles the heaps-of-treble part of your sound, so it makes sense that powerful spikes in those frequencies might light up your cab.

Doog wrote:You may be overloading your power section which would cause DC
to go to the cab.

Apparently.
I had a 300w 15" die randomly when being used with a 150w amp head, possibly the same thing happened.

I'm skeptical. And I've had way too much coffee. Arg. Would the same thing happen if Doog had a 300W head, but ran it at 50%?

When somebody talks about "overloading your power section," that sounds like an impedance issue to me. I've heard of speakers acting as momentary DC generators and making the tranny/tubes suffer when impedances are mismatched, so maybe it can work the other way too. But with impedance off the table, I've never heard of a speaker circuit "overloading" an amp due merely to the speakers being able to handle all the power the amp can put out, and more. Skepticism runs riot in my brain. Til Mike shows up and sets me straight on this, I'm dialing everything up to 10 as a safety measure.

Captain Lockheed · Post by **Captain Lockheed** » Wed May 23, 2007 2:50 pm

Sorry, but IMHO that's the biggest load of nonsense I've heard all week. If there is sigficant DC on the output then DC-Blocking cap would have gone leaky surely ?

Then you've got a faulty amp on your hands.

I stand in all readiness to be correct here.

Captain Lockheed · Post by **Captain Lockheed** » Wed May 23, 2007 2:52 pm

Sorry,

In all readiness to be corrected.

Post by **Doog** » Wed May 23, 2007 2:57 pm

You may have mastered electronics, but the edit button is still there to be discovered!

Post by **Mike** » Wed May 23, 2007 2:59 pm

filtercap wrote:Heavium, the light in your cab is connected with the driver that handles the heaps-of-treble part of your sound, so it makes sense that powerful spikes in those frequencies might light up your cab.

Doog wrote:You may be overloading your power section which would cause DC
to go to the cab.

Apparently.
I had a 300w 15" die randomly when being used with a 150w amp head, possibly the same thing happened.
I'm skeptical. And I've had way too much coffee. Arg. Would the same thing happen if Doog had a 300W head, but ran it at 50%?

When somebody talks about "overloading your power section," that sounds like an impedance issue to me. I've heard of speakers acting as momentary DC generators and making the tranny/tubes suffer when impedances are mismatched, so maybe it can work the other way too. But with impedance off the table, I've never heard of a speaker circuit "overloading" an amp due merely to the speakers being able to handle all the power the amp can put out, and more. Skepticism runs riot in my brain. Til Mike shows up and sets me straight on this, I'm dialing everything up to 10 as a safety measure.

I'm not quite sure either. It sounds really fishy to blame a higher power speaker cabinet - that's just bollocks. How loud are yuo playing the amp heavium? Are you properly diming it?

Post by **Mike** » Wed May 23, 2007 3:02 pm

Mistaken Idiot wrote:Underpowering a cab can certainly cause this too. Your head is only putting out about 170 watts into a cab that's looking for about 400 watts.

This is complete claptrap. The cab isn't "looking" for anything. it's rated at 400 watts because that's what the speakers can handle before they are damaged by too severe movement of the voice coil. The only thing you can fuck up speakerswise is an impedance mismatch or not having a rating high enough for the head and overpowering them. Your cab is above minimum impedance right? I'm assuming since it's a bass amp that it is solid state...

I'm alarmed that they're talking such shit from a possible of responsibility.

speaker lightning !?

speaker lightning !?

Underpowering ?

re-underpowering.