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Speaker Distortion? Ampeg SVT Classic -> Ampeg 1540 HE

E

elks

Sep 14, 2007
1
0
#1
Hi all- new to this community, so hopefully this is the right place to post!

Picked up an Ampeg 1540 HE cab the other day, got a real deal on it... took it home and UH OH! I'm getting what sounds like speaker distortion at not too high levels (might be the reason for the deal!).

I'm playing my ampeg SVT classic 300 watts set to 4 ohms ouput through the Ampeg 1540HE (basically a 4x10 and a 1x15, in full stack form... rated at 400 watts, 8 ohms). With the master on the SVT at 6 or above and the gain at 4 the speakers start distorting, or "farting". The volume also isn't very loud (loud- but not 300 watts loud). I'm wondering if its a speaker problem? I don't think its a problem with the head, considering I experienced much the same thing with my SUNN 300T head (also 300 watts tube) when I switched that in.

Last thing to consider is that I play with my bass tuned down to C, and then the low C dropped down to A#. Could it be a problem with how low my bass is tuned? Tried a couple different basses and the cab seemed to have the same problem with all of them, though tuning remained the same.

Any thoughts you have would be great : )

Don
 
#2
Hey there,

I've used a 1540HE over the years, and it's a really rockin' and solidly build/sounding cabinet. I do believe the one I used had a lower wattage rating as yours though (I want to say 200 watts, for some reason), but that could just be bad memory on my part or a production difference. At any rate... I'm not sure what could be going on there, but I never experienced speaker distortion like that while feeding well over 200 watts (normally about 300) into the thing in full range mode. Speaking of... Are you running it in full range mode? Or spliting the signal into just one speaker group at a time (IE: 410 only, or 15 only)? I assume you are, considering the classis isn't really used for bi-amping. Perhaps its a problem with the crossover, then.

One thing you could do is try running your head through the 410/15 individually and listening to see if the distortion occurs then. Might be the drivers, but it definately sounds like something fishy is going on there... Hope this helps!
 
#6
Press lightly and evenly down on each cone to see if there is any rubbing or friction...if there is the speaker coils are shot...

Check that all the domed dust covers on the centers of the speakers are glued down ok and not vibrating

check that all the speakers are wired correctly..none with the wires mixed up and so out of phase..

Check that it has the right speakers in the cab!!
 
#7
before getting too excited about the speakers (aside from being really sure all are moving and are in phase..........

Check for AIR LEAKS.

They can sound EXACTLY like a torn or farting speaker.

Check all around the speakers, and around the jackplate, including the jacks themselves.

Also, be sure all cardboard tube ports are in place...... without the port tube, the tuning is all messed up (I didn't look up that cab, so I could be all wet there.... I don't remember if it has 'em).
 
#8
Jerrold Tiers said:
before getting too excited about the speakers (aside from being really sure all are moving and are in phase..........

Check for AIR LEAKS.

They can sound EXACTLY like a torn or farting speaker.

Check all around the speakers, and around the jackplate, including the jacks themselves.

Also, be sure all cardboard tube ports are in place...... without the port tube, the tuning is all messed up (I didn't look up that cab, so I could be all wet there.... I don't remember if it has 'em).
Click to expand...



you know i think one of those tube ports fell out and i remember thinking, why is there a TP roll in here?


in the case of an air leak, how would you go about fixing it
 
#13
I may have misunderstood your original post, but as far as I can understand, his cabinet cannot run at 4 ohms. It's 8 or 2 ohm loads. It's set to run full range at 400 watts handling at 8 ohms or 200w up top and 200w on the 115 @ 4 ohms each. Making a total load of 2 ohms. I thing rodl2005 was getting at this earlier. It is a relatively low power handling for any cab, but it looks like ampeg was pushing this alongside the tube amps they were offering at the time. The svt and the svt-ii. They were offering the option of running 2 of these cabinets at once. Full range, with a total load of 4 ohms (8 and 8) I hope this clears up any confusion instead of creating more.
 

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