tnt 100 bass amp

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dlhughes
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Joined: Mon Jan 31, 2011 8:22 am

Re: tnt 100 bass amp

Post by dlhughes » Tue May 24, 2011 6:20 am

I have an older TNT100...before the line out was added. It's been working great, up until yesterday, when I cranked it up a bit more than my usual practice-amp-in-bedroom level.
Now, when I hit a note really hard, I get this God-awful crackling noise. Seems fine when playing lightly or with moderate attack, but if I pluck a string just a little too hard, it really makes an awful racket. There seems to be a definite sharp threshold on that. Below a certain signal level, fine. One tiny bit above it, and it crackles.
Oh, and it's definitely not the speaker. I plugged a different cabinet into the amp, and it's the same deal.

Any ideas on what I should look at?

TomCarlos
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Joined: Sun Oct 04, 2009 12:10 am
Location: Sacramaneto

Re: tnt 100 bass amp

Post by TomCarlos » Tue May 24, 2011 10:16 am

dlh....

As an amateur amp tech, I buy my fair share of old amps and work on them. There are a couple things I ALWAYS do - use DeoxIt 5 (with lubricant) to clean all the pots. Make sure you can easily turn every pot from side to side. Next, I use the regular ole contact cleaner and make sure all 1/4" jacks are clean and free from oxidation.

Ok... now the tough part... maybe this is a capacitor problem? Since caps are relatively cheap, you might invest in new filter caps in the Power Supply section? Even if this doesnt solve your problem, sooner or later, the caps will go bad. Secondary to that, you have caps all over the pc board. It is a big job to replace each of those. But again, it is an investment if you plan on keeping this amp for a while.

Lastly, you'd have to check the transistors. Do you have a transistor tester? If not, it's hard to get an accurate assessment if you are working with a volt-ohm meter.

My ole TNT 100 is working just fine... it's a simple yet sturdy amp, easy to work on.

Let us know the outcome...

Anyone else have ideas??

Tom

dlhughes
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Joined: Mon Jan 31, 2011 8:22 am

Re: tnt 100 bass amp

Post by dlhughes » Tue May 24, 2011 4:37 pm

Pots....hmmm...they are all kinda scratchy, and I remember I had a similar problem on an old Gorilla amp I used to have. Whenever the input signal got large, there'd be a crackling, and once I cleaned/lubed the pots, that 'mysteriously' went away. That'll be the first thing to try, I guess.
Probably wouldn't be a bad idea to shotgun all the caps, as well, one day.
But if there are any other ideas, I'm all ears. I love this ol' amp and want to keep it working as long as I can.

freegan72
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Joined: Tue Jul 11, 2017 9:55 pm

Re: tnt 100 bass amp

Post by freegan72 » Tue Jul 11, 2017 9:59 pm

It sounds like there is a more detailed version of the 1974 schematic out there than the one at the back of the user manual. Can someone help me out?

Thanks!

TomCarlos
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Posts: 56
Joined: Sun Oct 04, 2009 12:10 am
Location: Sacramaneto

Re: tnt 100 bass amp

Post by TomCarlos » Tue Jul 11, 2017 10:09 pm

Try this one...
Attachments
TNT_100_Schematic_1974.pdf
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