Help Fixing Sub Woofer - AC hum problem

[AnalogHome]

I have a big Sub Woofer that a friend needs fixed. It is self powered and seems to work except it has AC Hummmmmmmm.

It is a Tantra TS-12, 500 W Sub-Woofer.

I replaced the linear supply bulk caps as they were bad - still no joy, still has hum. I have no schematics for the beast.

I was wondering - does anybody have any leads for a Sub Woofer replacement amplifier (100 or 200 watts would work - who needs 500Watts!?) ? The most expedient thing might be to just junk the current amplifier and fit another one.

Any ideas?

Thanks in advance.

 

[BradtheRad]

Checking filter caps was the logical first step.

Did you check the diodes near those caps as well?

It can happen that one faulty component stresses other components. When one component finally fails, did it fail of its own self, or because it was stressed by the root faulty component?

And then you can replace one faulty component, only to find that a second component is pushed into failure, due to having been stressed previously by the original faulty component (which you just replaced), making the second component unable to sustain normal operating stresses.

To test each diode you'll need to clip one lead to take it out of circuit. Then resolder afterward. You must test a diode for ability to pass several amps at forward voltage (since the power supply is providing several amps), and for high resistance to reverse V.

 

[Raza]

Hi,
One question, The Capacitors you replaced were Distended (swollen) ?. If Yes, then seems that the main bridge rectifier is also gone bad. If there are Diodes, you can check One by One and if a BRIDGE (any of the following shapes):

or some thing like these, check for not shorting any side or diode inside and if there are Four Diodes used check individual diode for not short circuited. If all are ok then:
Remove the pre-amplifier input to the main amplifier and if no more hum is heard, problem on your pre-amplifier side. Check for the proper shielding of the input wires or and improper ground connection.
Hope it helps a bit.

 

[AnalogHome]

Thanks for the help. I am really not interested in troubleshooting this more (My time is worth money) -Does anyone know of a decent 250 watt amplifier that I can put in the large enclosure (AC Powered)? I can find panel mount versions but they don't match the hole size that is there already and it seems easier to put something inside the speaker than trying to mess with the existing cutout.

Thanks again folks...

 

[jj_alukkas]

If you get any MOSFET amplifier with the power you need and a matching impedance, you could even consider placing it as a seperate amplifier outside the sub box. Placing a preamp close enough to a transformer will cause hum, sometimes grounding the input's ground to a real earth can solve hum and most of the times, it shud be the power supply, try running your existing amp from another power supply after disconnecting from the existing one.

 

[Raza]

Hi,
Just search the WEB and select the specification you want for the price you need.

 

[BradtheRad]

This is the sort of situation that has no easy path out. Because you're in for more work even if you find an amp that will fit the existing space.

You say the power supply is linear. Traditionally this type is easy to work with, having simpler circuitry.

Which is to say it may still be less work for you to test just a few more components that are easiest to troubleshoot... as compared to locating, purchasing and installing another amp.

After all your first post says the amps seems to work. It's not like the amp is completely dead.

 

[Cronoglous]

I have a big Sub Woofer that a friend needs fixed. It is self powered and seems to work except it has AC Hummmmmmmm.

It is a Tantra TS-12, 500 W Sub-Woofer.

I replaced the linear supply bulk caps as they were bad - still no joy, still has hum. I have no schematics for the beast.

I was wondering - does anybody have any leads for a Sub Woofer replacement amplifier (100 or 200 watts would work - who needs 500Watts!?) ? The most expedient thing might be to just junk the current amplifier and fit another one.

Any ideas?

Thanks in advance.

Hello do you still have the TS-12. I could use some parts from it. The transformer to be more exact. Please get back to me Greg 215-900-142 two