Adding a volume control

[HotHead]

Hi
I have a Craig cht742 subwoofer (output 30w) and speakers. The volume used to be controlled by the receiver but the receiver is no longer working.
I'd like to use the speakers connected directly to the tv audio out but they play at full volume when powered on.
Is there a simple way to solder a volume control directly to the sub and control all out audio?
Any help or direction would be appreciated.

[momaka]

Re: Adding a volume control

I'm not quite sure what exactly you're trying to do. Is the TV going to be sending the audio output to the subwoofer and then the subwoofer to the speakers? Also is there an amplifier in the subwoofer?

[budm]

Re: Adding a volume control

Can you post the pictures?

[999999999]

Re: Adding a volume control

More detail may help, all of the following could be wrong.

Is the amp for the satellites built into the sub? Since you wrote they play at full volume, implying that's pretty loud, I'll assume so. I'm also assuming the TV outputs a line level signal that is non-adjustable from the TV menu or remote.

Do you need independent adjustments for left, right, both front and rear, and center? If so, it is quite a bit more complex to do, then you'll have to reverse engineer the circuits used, break traces and tap into those at the appropriate portions of each subcircuit to add pots.

If not, if an equal reduction in volume is acceptable, then yes you can add a stereo (preferably log not linear...) potentiometer between the audio input jacks on the sub and the rest of the circuit. You might even be able to just salvage the pot out of the receiver and put it in the sub. "IF" the amp placement is as I suggested above then it may only be moving the pot from before the length of audio cable connecting the two, to after it (substituting TV as source).

[HotHead]

Re: Adding a volume control

Thank-you for the replies and here are a few pictures. I hope they are clear enough.

momaka, yes the t.v. will be sending the audio to the sub (2-ch) and then the sub to the speakers. I believe it does amplify.

999999999, i do believe that the amp for the speakers are in the sub, new here so forgive me if i am wrong but the amp is the 7ic s at the bottom. No? The output audio of the t.v. through the jacks are not adjustable from the remote or t.v. menu.

I don't think i'll need independent adjustments as i will not be using the 5.1 but only the 2-ch option. I think trying to tamper with the 5.1 would be out of my league, for now.

An equal reduction is what i am looking to achieve but wasn't sure if it was possible to just add a pot before the cable goes into the sub and have it work. Also would a 25k pot(stereo, log) be sufficient?

Again, thanks for the help.

[999999999]

Re: Adding a volume control

Yes you can use a 25K dual gang log pot, or even two separate 25K single gang log pots for some attenuation of L vs R channel. Personally, I'd just drill a hole in the sub housing or back-plate and mount it there rather than having to build a separate box with connectors to have it before the cable gets to the sub, but either way would work.

Having it in the rear does seem less convenient since you're going to have to go over and adjust that knob any time you want the volume to change.

[budm]

Re: Adding a volume control

Does your TV has headphone output? What brand id the TV?
The 7 ICs in the units are for sub woofer and 5 speakers (2 IC are setup as bridge output for driving the sub woofer speaker, the other 5 are one IC per speaker, 5 speakers).