Hello. I've tried a couple of amps now, and I still seem to be getting a very quiet volume output, even when the levels are high. I'm also getting no lows through the sub.

This unit will require an amp. I have set up several mixers and I
do not watch output level numbers, you can get desired volume using amp. It does no good to drive input levels high output levels high and the turn down amp. Lower your inputs so no light flashes set master gain to -6 output and then raise amp volume. I have set up 16 mic mixer set individual levels and the feed to main mixer and controlled levels with one fader. I have taken mixes from main mixer to another mixer to control audio on video feed. A good band does not let member's set their levels . the audio person set levels, bad bands have members to set own level with resultant a mess that gets louder and produces sub par event. Remember good bands sound good and bad bands only sound louder, and bad

The cracking and humming sound is because of the improper earthing

Hi, if your not plugged into your amp via a dedicated phiono input, Ie CD or Aux then you need a preamp to boost the line levels. Cheers john. Styluscity

From the description the subwoofer is the problem, since the item is new return it to the place of purchase, this is a manufacture issue.

Realize that the number on the volume control is only relative... it means nothing regarding what the amp can produce. With a high level output guitar you can easily drive the amp into distortion at very low volume control level settings... what counts is the actual output sound volume and specifically the voltage output going to the speaker. Once the amp reaches saturation, any further input just pushes it into distortion or "flat topping".
An oscilloscope on the output will quickly show when amp starts to flat top.

Poly Switch
All full-range loudspeakers are fitted with a self-resetting
poly switch that protects the high-frequency driver from
damage caused by excessive power.
If a loudspeaker cabinet loses high-frequency output, immediately
remove power from the unit and wait for two to three
minutes. They should allow the poly switch to reset. Reapply
power and check the performance of the high-frequency
driver before continuing with the power reduced to a
level that does not cause the poly switch to interrupt the signal.
On the SW115V/SW118V/SW218V sub woofer, the Poly
Switch protects the woofer and a similar routine should be
followed if its output is lost.

Thermal issue is shutting down amps till temps moderate. You must be driving your system too hard. And check out your tone control settings especially the bass. Every 3 db boost forces amp to double power at that frequency so if you are already blasting at 100 watts, a 3 db boost will compel amp to put out 200 watts, etc. Very easy to overdrive and overheat amp. You might want to try blowing air over output stages to improve cooling at high volume levels.

You are lucky that you have good protection circuits - otherwise by now you would have blown the output stages.

You must first isolate the stage that is causing your problem. Start at the master volume control by injecting a signal using a screwdriver. If you get a good level of hum from the speaker then output and phase splitter stages are ok. Work your way back to the front end by touching the screwdriver to inject hum into the input grid of each valve in turn to isolate weak stage. Check anode and cathode voltages on valve of suspect stage. Check cathode bypass capacitor and anode/grid coupling capacitor for open circuit. If fault in output stage check screen grid resistors for open circuit. WARNING high voltages exist in valve amps, keep one hand in your pocket and do not hold on to the chassis while testing.

The gain dial is not a volume control. The gain dial is used to compensate the output level of your car radio head unit. all car stereo units output are not alike. If you set this gain level too high, it will cause major distortion (clipping) to the audio output of you speakers when cranked up. This excessive distortion WILL eventually, or even quickly damage or blow your speakers.

I personally blown speakers this way no not properly setting this. (lesson learned, I guess :| )

4 longshots to try, in case you haven't allready: 1. try connecting using a different cable 2. what are you trying to connect to the VCR out? note that CD players(other personal players as well) have a headphone jack and a line out jack, and you dont allways get the same vulume output from them. 3. in case you do have it connected to the line out, try connecting a different device, because some players have lower volume levels than others, which bring me to 4. some players have a setting that lowers volume level in order to protect your hearing when using headphones. you might have to disable that. I never ran across any receiver that let you adjust volume levels of individual outs, but it might be possible that a part needs replacement, or to get amped up, have more power directed to it. consult a service man. offcourse if you're still under warranty use it, go complain... Good luck!