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Peavey TNT amp is distorting...

Discussion in 'Amps and Cabs [BG]' started by invader3k, May 9, 2005.

  1. Hi all. I own a Peavey TNT 115S bass combo amp, which I bought new in late '99. It has always been very reliable, even though it's taken its share of abuse, being transported, etc. I have begun to notice recently that it seems to be making farty, distorting sounds. This is especially noticable when playing lower notes.

    It still powers on fine, and volume, gain, etc. all seem to work fine. I think it seems to be vibrating quite a bit as well. I keep it over at our guitarist's place, and always had his smaller Fender bass amp on top of mine (as a backup). Last practice, the Fender amp was actually _moving_ on top of my amp (and I wasn't playing any louder than normal). I also noticed at the last show we did, my picks, earplug case, and small tuner that I always put on top of the amp all ended up falling off.

    Someone suggested that a screw may have come loose from the speaker's surround? I haven't had the chance to look at the amp yet (it is over at our guitarist's place, since I don't really have room for it at our apartment). Anyone have any thoughts before I try to remove the grill cover and look at things? Thanks in advance...I really want to get this amp sounding good again, like I know it can. I know this is a fairly popular model, so if any of you own this amp or have used it, I would appreciate any tips.
  2. It could be that, but it sounds more like something is wrong with the speaker, maybe a crease or something im afraid :S
  3. Forrest27


    Nov 24, 2004
    "I also noticed at the last show we did, my picks, earplug case, and small tuner that I always put on top of the amp all ended up falling off."

    Ancient Bassplaying Anecdotes (for the springtime...)

    and i quote....

    "...aint that what supposed to happen ?"

    "... at least you didn't leave a pint (beer) there..."
  4. Heh...yeah, but usually that doesn't happen to the extent that it did the other night at the show.

    A crease huh? I don't know how that would have happened, but I'll take a look at it later this week and see.
  5. Joe Beets

    Joe Beets Guest

    Nov 21, 2004
    The Peavey has a reasonably low F.R. (fartage ratio) compared to many combo amps. What may be happening is that your band is playing louder and you may be playing more aggressively to keep up. Your amp may be reaching T.O.F. (threshold of farting). The only cure is to turn the bass EQ all the way down, get everyone to turn down the volume (highly unlikely) or get a bigger rig with more watts. Maybe someething like an amp head and a separate speaker cabinet. :eyebrow:
  6. or you are slow blowing the voice coil on the woofer by too much clipping. Insepct the voice coil. It should look like a brand new penny- nice shiny copper. If it is blackening, you need a new driver. Actually, you need a more volume or a little cooperation from your guitar(s) and drums.
  7. *bump*

    To follow up on this...guys, I don't think volume was the problem, I can always hear the amp fine, and only turn it up about half way. I inspected the speaker (at least on the outside), and it's in pristine condition. The TNT is loud enough to easily fill a decent sized room.

    I took it to Ward-Brodt in Madison (place where I bought it), and they supposedly fixed it. They said it was the "shelving controls". They said they cleaned them and tested the amp.

    It seemed fine a couple weeks ago, but at our last practice, it seemed really farty again, especially on lower notes (on the E string). It is also vibrating a lot...I place the amp on two wooden 2x4s since we play on a wood floor, and it is actually moving itself on the boards. Our guitarist has a smaller Fender bass amp we used to always keep on TOP of my Peavey (for ease of storage) and the Fender amp was actually moving on top of my amp! And the Fender bass amp weighs probably a good 60 pounds, at least. This was never a problem for the last year or two we've been practicing in his basement with this set-up.

    What should I do? I'm thinking of calling Ward-Brodt and demand that they look at it again...it's just a total bitch to keep taking it there to get it fixed because the amp weighs about a hundred pounds, and Madison is 45 minutes away, plus the amp is at my guitarist's who lives 15 minutes from me... :help:
  8. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Yeah, if it's not fixed, take it back and tell them. It's a PITA to do, but it's either that, fix it yourself, or take it someplace else. Or play with it as is. If I had to guess though, it sounds like you're speaker's starting to let go. But if it stopped for awhile, I dunno. Good thing I'm not a tech :p.

  9. I think the repair guys just sprayed the EQ sliders with pot cleaner. Big whoop, this isn't going to fix anything other than crackly pots.

    I agree that it's probably the speaker getting old and tired. Speakers do loose their resiliency after many years and they get flabby...like me!!!

    But there is hope. Well for the speaker at least. If this is a Scorpion or Black Widow speaker, look on the back and get the model number, then order a replacement basket kit from Peavey-it's half the price of a new speaker. Unscrew the magnet from the old speaker with the 3 screws, screw it onto the new basket, and you've essentially got a brand new speaker.

    Their "field replaceable basket assembly" as they call it, has everything but the magnet!!! New voice coil, new spider, everything, all you do is use your old magnet. Much cheaper than a new speaker.
  10. OK, to follow up on what has been posted this morning...

    Maybe it is the speaker, I'm not sure...how would I tell what kind of speaker is actually in their? Will I risk causing further damage if I unscrew the screws around the surround to remove the speaker? I really don't have much experience doing any of this...there is also really no way of getting inside the cabinet without removing the speaker...

    Thanks in advance for all the help.
  11. Nope, you won't damage a thing taking the speaker out--provided you don't slip with your screwdriver and put it through the speaker, or some other similar screwup (don't ask me how I know about the old screwdriver-through-the-speaker :D )

    Try to handle it reasonably carefully, by that I mean hold it by the metal frame, don't grab it by the paper cone!! You may need to take a flat-bladed screwdriver and pry the speaker loose from the wood cabinet, put the blade between the metal frame and the wood, don't be afraid to use a little force. As long as you just hold the speaker by the metal frame, you'll be OK.

    Look at the back of the speaker, it may say Scorpion or Black Widow or maybe Sheffield.
  12. OK, thanks for the input. I think I'm still going to call the place in Madison to see if they'll make good on this, but if worse comes to worse I should probably be able to get the speaker off myself. I know the amp inside is a Sheffield, as it says right on the front, so maybe the speaker is as well? What should I look for once I get the speaker off, to tell if it is damaged or not?
  13. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    The infamous object-through-the-speaker makes for killer distortion until the speaker literally tears itself apart. Don't ask how I know that, either ;).

  14. Selta


    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Look for creases first off (there's a thread around here with pics of a creased cone, if you need that). Also, lightly push back and forth on the cone, if you hear any noise, or feel any kind of resistance, then it's starting to go/already has gone. Lastly, take a ohm meter and see if you get infinite. If you do, the voice coil is open. That's all I know of to check speakers bar taking them apart. If all seems well with the speaker, then there's something wrong with the amp, but I'm leaning towards speaker, still.

  15. Joe Nerve

    Joe Nerve Supporting Member

    Oct 7, 2000
    New York City
    Endorsing artist: Musicman basses
    I've got a TNT... I think. I always forget cuz it's not in my house and I never really look at. It's 130 combo with a black widow 15. Anyhow, it's old (like 1978) so I don't know how different it is from yours, but it's been abused to all hell, and still functions excellently. Lo and behold however I HAVE experience F.P (farting problems - I love Joe Beets terminology) and believe I have resolved them.

    First, I used to hit the top of my amp with my fist and it would clear up - as if it had something stuck in it's throat. This didn't work all the time and I felt I was damaging the amp, so I kept searching for other solutions. Had my pots cleaned too. What wound up being the major culprit in my amp was that a couple of the pots, even after being cleaned, were scratchy or just plain screwed up. I'm still not sure which ones they are but if I jiggle and rock a few of them, the problem gets solved. I had a Peavey guitar amp that did the same thing. I think it's a common quirk with these things. Could be wrong too.

    The other thing, and this is a big "Uh... duh!", but I've been guilty of it, is that perhaps you need to freshen the battery in yer bass? I notice one of your basses is active. Is that the farting one? Sometimes a bass can run a long time on a half dead battery and make ya think nothings wrong. It took me 5 shows before I realized there was nothing wrong with my amp or Bongo when I just got it. Bass kept on ticking, just sounded like crap.
  16. Oh, it says Sheffield on the front of the amp? Then you have a Sheffield speaker: the speaker was made by Sheffield. The amp is still made by Peavey.

    I don't think these have the field-replaceable basket. So you'll have to get a new speaker.

    Take the old speaker out and see if it says if its 8 ohms or 4 ohms. You can get an 8 ohm Peavey Black Widow from American Musical for about $140....

    edited: this is IF the old speaker is going south. Yep, I agree, try the battery first. Also slide the tone pots back and forth a few times, that helps if they're scratchy. Then if nothing else works, think about replacing the speaker.

    All older amps can get scratchy pots, it's not limited to Peavey--Peavey just buys the pots from one of the big potentiometer manufacturers, like all the other amp companies.
  17. Well, the problem is not the bass...this problem has been happening lately while using my passive Fender P-bass.

    $140 for a new speaker? Geez, maybe I should just look at getting a new rig, since I've already spent about 70 bucks on repairs so far. I only paid about 500 bucks for the amp when it was new...
  18. They charged you $70 to clean the pots? Ouch, I hoped they at least kissed you afterwards.

    Well you don't have to spend $140 on a new Peavey speaker, you could buy an Eminence from Parts Express for about $60. Or a Carvin speaker, www.carvin.com Look at the speaker and see how many ohms it is. If it's 4 ohms I'd get the Carvin 4 ohm and pop 'er in for less than $100 IIRC.

    Much cheaper than a new rig, and the Peavey combos have been keeping the dance floors packed for years so your present amp certainly isn't a piece of crap. FWIW: in case the others didn't make this clear: when playing in the group, whether on stage or at practice, DON'T boost your lows, if anything you may want to cut them jsut slightly. Mids are your friend-that's what projects out and keeps the sound clear. Lows makes mud in the mix, eats up power, and makes speakers fart.
  19. Thanks for the tip on the Carvin speakers...I'll have to take a look...probably won't get to the guitarist's house 'til next weekend though, at this point.

    As far as turning up the lows...I usually only boost them slightly. I don't use the graphic EQ at all, as I don't really like fiddling with it. I usually turn the treble down from the "0" position just a little, and the bass up just a little. I wouldn't think that should fake for any kind of "fartiness."


    Mar 12, 2003
    USA, PNW
    Check the phase on the speaker wire. Sometimes the wire is accidently hooked up backwards by repair techs. This would cause speaker over excursion.

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