Rich_S
HomeGrownToneBrewologist
I spent all my free time this last week repairing my kid's bass gear. His newish Squier CV P-Bass needed a real-deal Switchcraft jack, so I did that. Then I noticed that the locknut had fallen off the input jack on his Fender practice amp while little sister was using is as a vocal monitor for her diva routine. The nut has been on and off the plastic PC-board-mounted jack so often that the threads are gone, and it was getting wobbly. Though it wasn't sis' fault, I figured I'd better I set about replacing the amp's input jacks. Fortunately, the original jacks were large enough that removing them left room for a couple of Switchcrafts without having to cut clearance holes in the PC board. Flying leads to the board keep mecahical stress from being tranmistted to the solder joints.
THEN, Drew came to me saying his new (old) big amp, a 90s Peavey TNT130 was making weird noises. After a little testing side-by side with my guitar amp adn speaker, I norrowed the problem down to his Black Widow 15". THis was strange, because it was working fine when I bought the amp earlier this summer, and he's barely played the amp since then. Speakers don't just die on their own, and this 130-watt amp doesn't really have the power to cook a BW, anyway.
Gently pushing on the cone make a rubbing noise, and weirder still, it felt sticky. I had to push a little harder before it would let loose and move. Great - it seemed I'd have to spring for a new 15" for this supposedly "bargain" amp.
A call to Parts Express revealed that the replacement basket assembly is still available (you don't recone Black Widows, instead, you remove the whole front frame/suspension/cone/voicecoil assembly) for $82. Or, we could replace the whole driver with a new Emi Neo unit for $115. (This was tempting because it would shave 10 pounds off the amps weight; it's a beast).
Since pulling the BW apart is so simple for the non-speaker-reconing-professional, I decided to open it up and see what's what before I sprang for a replacement. Glad I did. The driver has a vent hole in the back with a heavy screen over it. What I found inside was that in addition to the screen, they had a little plug of gray foam to prevent dust from getting inside the voice coil. Problem was, after 20 years, the foam had mostly turned to dust, and a big hunk of it was floating around loose inside the voice coil, behind the center dust cap.
Worse yet, some of the foam had gotten into the air gap in the magnet, and had melted into sticky black goo. This is what I felt, pushing on the cone; the goo was sticking the voice coil to the magnet. So, I gently cleaned the goo off the voice coil with Q Tips and lighter fluid. To get the goo out of the magnet gap, I had to resort to an X-Acto knife, then cleaned the resulting crud out with masking tape.
To keep dust out, I replaced the foam by gluing a piece of flannel fabric over the vent hole. Then I put it all back together, and woohoo! It worked! Degraded old foam not withstanding, the Black Widow is a great design. Any other speaker would have required a re-cone.
The TNT130 is one of those amps Peavey just plain got right. I borrowed one for my brief foray into bass-playing back in the early '90s, so I knew it was a good one. For a combo amp, it has a great set of features, including effects loop, fully parametric mid controls, output protection (limiter and thermal cut-out) and a crossover, so you could bi-amp just by adding an external power amp and a couple of 10s. It was a pleasure opening it up and seeing everything neatly laid out on sinlge-sided PC boards, not to mention old-school discrete output transistors. Very easy to understand.
So; I'm a proud papa this morning. Drew's back in a position to dominate his budding band's volume wars (if they ever get a rehearsal scheduled), and this bullet-proof old classic is running again for zero cash outlay.
THEN, Drew came to me saying his new (old) big amp, a 90s Peavey TNT130 was making weird noises. After a little testing side-by side with my guitar amp adn speaker, I norrowed the problem down to his Black Widow 15". THis was strange, because it was working fine when I bought the amp earlier this summer, and he's barely played the amp since then. Speakers don't just die on their own, and this 130-watt amp doesn't really have the power to cook a BW, anyway.
Gently pushing on the cone make a rubbing noise, and weirder still, it felt sticky. I had to push a little harder before it would let loose and move. Great - it seemed I'd have to spring for a new 15" for this supposedly "bargain" amp.
A call to Parts Express revealed that the replacement basket assembly is still available (you don't recone Black Widows, instead, you remove the whole front frame/suspension/cone/voicecoil assembly) for $82. Or, we could replace the whole driver with a new Emi Neo unit for $115. (This was tempting because it would shave 10 pounds off the amps weight; it's a beast).
Since pulling the BW apart is so simple for the non-speaker-reconing-professional, I decided to open it up and see what's what before I sprang for a replacement. Glad I did. The driver has a vent hole in the back with a heavy screen over it. What I found inside was that in addition to the screen, they had a little plug of gray foam to prevent dust from getting inside the voice coil. Problem was, after 20 years, the foam had mostly turned to dust, and a big hunk of it was floating around loose inside the voice coil, behind the center dust cap.
Worse yet, some of the foam had gotten into the air gap in the magnet, and had melted into sticky black goo. This is what I felt, pushing on the cone; the goo was sticking the voice coil to the magnet. So, I gently cleaned the goo off the voice coil with Q Tips and lighter fluid. To get the goo out of the magnet gap, I had to resort to an X-Acto knife, then cleaned the resulting crud out with masking tape.
To keep dust out, I replaced the foam by gluing a piece of flannel fabric over the vent hole. Then I put it all back together, and woohoo! It worked! Degraded old foam not withstanding, the Black Widow is a great design. Any other speaker would have required a re-cone.
The TNT130 is one of those amps Peavey just plain got right. I borrowed one for my brief foray into bass-playing back in the early '90s, so I knew it was a good one. For a combo amp, it has a great set of features, including effects loop, fully parametric mid controls, output protection (limiter and thermal cut-out) and a crossover, so you could bi-amp just by adding an external power amp and a couple of 10s. It was a pleasure opening it up and seeing everything neatly laid out on sinlge-sided PC boards, not to mention old-school discrete output transistors. Very easy to understand.
So; I'm a proud papa this morning. Drew's back in a position to dominate his budding band's volume wars (if they ever get a rehearsal scheduled), and this bullet-proof old classic is running again for zero cash outlay.
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