Ampeg Svt3Pro w/ Acoustic B410 and B115

Mezmerized · #1 05-10-2011, 08:44 PM

Hello fellow musicians, and masters of tone.

First and foremost, you guys have the best community of knowledgeable people I have yet to see on the internet. And that is why I bring my questions here. Please work with me as I am the drummer in my current project, but have prior knowledge of bass and bass gear.

Our bass player likes to change gear around like he changes underwear, but Ill give you a rundown of what he currently is/was using for his bass rig.

A Behringer Bass V-amp Pro
A Peavy IPR3000 Power amp.
Thru-
Acoustic B410 NEO
Acoustic B115 NEO

Not the worst bass set-up for the price, and does not sound bad at all. I happened across the deal of a lifetime (or so i feel) at a small pawn shop not far from where I live.

Ampeg Svt3 Pro
Korg DTR-1000
DBX 166XL
Gator Rack Case
Speakon Cables, and Patch Cables

300$'s later out the door I ran

Took it to practice with me the next day to show off what I had, in all matters of the word "stolen" from the pawn shop. Hooked it up the the acoustic cabs and we were off and running.

After about 20 or 30 minutes of playing around with the setup the bassist decided that he liked the sound and asked if he could use it for shows and practice and such and of course I couldn't say no... So we head out for a show the following weekend, outdoors, not much for a PA system, but still sufficient to get the job done for the show.
During the show I notice that he is almost constantly adjusting and playing with knobs on the amp. After the show he tells me he is going to switch back the the Vamp setup, I ask why, he says that he is getting too much "Speaker Fart" at higher volumes as he is out of headroom on the ampeg?

So my questions to the masses is?

Is this a speaker issue, I.E (the amp doesn't have the power to prouduce the volume he is wanting without amp distortion)

or

Is this an Amp issue, I.E (the speakers for some reason cant handle the power at those volumes causing speaker distortion)

Or neither.. I really love the sound of the Ampeg over the Vamp and would love for him to continue using it, but would like to resolve this issue.

erock0138 · #2 05-10-2011, 09:10 PM

Wow! What an awesome deal, I wish I came across something like that for once. Anyways, I'd check out the wattage rating on the head, compared to the wattage on the cabs, along with the impedance. It'll say 300 watts at 4 ohms, if your cabs are 200 watts,that could be your issue. If you didn't have it mic'd through the p.a., obviously you'd have to have it at a higher volume, which could result in speaker damage. because your head is pushing out more than the speakers can carry.

will33 · #3 05-10-2011, 09:11 PM

Speakers can get pushed into distortion with far less power than their wattage rating. That amp doesn't have the power of the IPR either and may have been turned up to clipping/distortion. Trying to carry the gig with no help from a PA may have induced some combination of the two. Also when playing outside it always sounds thinner or weaker than the same rig inside. Sometimes you just deal with it and don't push things too far.

erock0138 · #4 05-10-2011, 09:11 PM

I'd also say that more than likely, it's not that your head is under powered, but perhaps over powered. Especially with it being at a high volume.

prd004 · #5 05-10-2011, 09:23 PM

Wattage shouldn't be a problem. THe SVT III-PRO is 425 watts @ 4ohms and your cabinets are rated at 400 watts each, so that's not the problem.

Sounds like it might be a bias issue, there have been a few threads about this on here. Just a guess, but that's a simple inexpensive fix, and judging by the steal of a deal you got on the amp, you'll still be waaaay ahead.

I've been playing an SVT-III PRO for sixteen years and they are great amps! If the Vamp sounds better, than there is something wrong with yours. I've never had a bias issue with mine but others have.

JimmyM · #6 05-10-2011, 09:54 PM

Quote:

Originally Posted by prd004

Wattage shouldn't be a problem. THe SVT III-PRO is 425 watts @ 4ohms and your cabinets are rated at 400 watts each, so that's not the problem.

Sounds like it might be a bias issue, there have been a few threads about this on here. Just a guess, but that's a simple inexpensive fix, and judging by the steal of a deal you got on the amp, you'll still be waaaay ahead.

i would agree. over time, the biases of the mosfets drift, and it has to be readjusted by a tech. it could also be a possible tube issue, but since this is common with 3 pro's, i'd bet this is the problem sooner than the tubes. you should be able to run it as clean as you want it, but if you can't, it's usually a bias issue.

stiles72 · #7 05-11-2011, 12:47 AM

+1 to getting the bias checked. I gigged my pair of 3-Pros for about ten years with no issues, and then all of a sudden they started sounding farty and distorted. After I got the bias adjusted they were back on track.

Zakm0n · #8 05-11-2011, 09:49 AM

I'm the bassist in question (hey Brandon!) And this is what i want to know. The cabs are 400 watts each, the amp is 475watts at 4 ohms. The farting noise, was it the amp running out of headroom and clipping or the cab not being able to handle half their rated wattage? The ipr amp puts 475 per channel at 8 ohms, which is how i set it up. I've run it all the way into the ddt limiter and never heard any farting, and it was much louder than the ampeg. So am i thinking right when i say the ampeg doesnt have enough headroom?

JimmyM · #9 05-11-2011, 09:52 AM

Quote:

Originally Posted by Zakm0n

I'm the bassist in question (hey Brandon!) And this is what i want to know. The cabs are 400 watts each, the amp is 475watts at 4 ohms. The farting noise, was it the amp running out of headroom and clipping or the cab not being able to handle half their rated wattage? The ipr amp puts 475 per channel at 8 ohms, which is how i set it up. I've run it all the way into the ddt limiter and never heard any farting, and it was much louder than the ampeg. So am i thinking right when i say the ampeg doesnt have enough headroom?

no, did you see the parts about having the mosfets biased?

BassmanPaul · #10 05-11-2011, 09:57 AM

My first thought is the poor mixing of a 4x10 and a 1x15. The 4x10 will bury the 1x15 in every regard. I'll bet that the 1x15 is what is farting and not the 4x10. Leave the 1x15 at home and try again. If you must have two cabs get another identical 4x10.

Zakm0n · #11 05-11-2011, 09:58 AM

I did, but still, can the 475 ampeg watts do as much or more than the 950 peavey watts? it's actually a 210.

mazdah · #12 05-11-2011, 10:05 AM

How were you gain, tubegain and master set?

will33 · #13 05-11-2011, 10:08 AM

In a 15+210 the 3pro should have enough power to push each to it's clean limit. If mosfet bias is a common issue in 3pro's, I'd at least pay a bench fee and give it a checkup. Preamp tubes and bass batteries are cheap diy fixes if you want to check that first.

KramerBassFan · #14 05-11-2011, 10:35 AM

Its possible that the Acoustic cabinets just can't really put out that much at all.

I've got a newer Acoustic 1x15, and it can't take much power at all. As in, i can easily get it to fart out with a 100w tube amp, not even pushing much in the way of Low end.