Sound problem with a 4-slot cab

Hi there!

I got my candy cab last Thursday and I have been enjoying it a lot, but I have a number of small problems with it, the first of which is sound.

The headphone jack integrated in the cab (it's a MVS-U4) works flawlessly and the sound quality I get out of it is perfect, but if I use the speaker's speakers, the sound is not at all good. The right speaker is quieter than the left one (in the sound test), and sound comes out garbled every now and then. Not always though, it seems to vary depending on the sounds being emitted (gets worse with music I think), and also it is less noticeable on higher volumes, which I find strange.

Any ideas what the problem what be, and how to correct it? I have browsed through many recent and older threads already, but I can't find a solution.

-Wiring?

-Speakers?

-PSU?

-Sound chip?

-MVS board in need of cleaning? (I got it VERY dirty indeed)

Any help will be much appreciated.

-Wiring?

Make sure that the speakers are wired like this


-Speakers?

You could switch them around to confirm

-PSU?

Measure the 12 volts, is it dropping as you turn up the volume.

-Sound chip?

Probably OK, is it getting hot.
http://www.boomspeed.com/ttooddddyy/HA13001.gif

-Cleaning?

http://www.hardmvs.com/html/slotCleaning.htm
http://www.hardmvs.com/html/cleaning.htm

Hope this helps.

I have checked the wiring and it seems to be correct. I don't have a multimeter at hand and I don't think dirty carts/connectors are the problem, I have already cleaned them all.

The speaker which is quieter is the left one, I got that wrong before. That is one of the problems, the other being that I get noise every now and then. Particularly noticeable with music at low volumes.

Any ideas?

Any ideas, anybody?

It is possible that there is much dirt in your volume pots. I know my pots make some crackling during volume adjustment.

To check this, jump the input pins and output pins of the slider pot, straight across from one end of the pot to the other end, don't cross the channels. If you do this with a short length of wire you will get full output of sound (very loud), and possibly you could blow your speakers. So I would put something like a 100k ohm resistor in there.

Then try the sound check and see if your speakers are the same loudness (make sure you used the same level of resistance on each side when jumping the pot ). If one side is still louder it is likely that you have other problems. Double check the wiring, also check that both speakers are 4 ohms (many jamma cabs come with 8 or 6 ohm speakers but MVS require 4 ohm).

cheers,
-DT

The 2-slot you sent me was modded for mono (I restored it to stereo): check the solder side of the speaker volume regulator and see if a trace is cut and two pins are soldered together.

dogtoy said:

It is possible that there is much dirt in your volume pots. I know my pots make some crackling during volume adjustment.

To check this, jump the input pins and output pins of the slider pot, straight across from one end of the pot to the other end, don't cross the channels. If you do this with a short length of wire you will get full output of sound (very loud), and possibly you could blow your speakers. So I would put something like a 100k ohm resistor in there.

Then try the sound check and see if your speakers are the same loudness (make sure you used the same level of resistance on each side when jumping the pot ). If one side is still louder it is likely that you have other problems. Double check the wiring, also check that both speakers are 4 ohms (many jamma cabs come with 8 or 6 ohm speakers but MVS require 4 ohm).

cheers,
-DT

Click to expand...

Thanks a lot for your reply!

Regretfully I have no resistors available, and my tech skills are close to zero. I have doubled checked the wiring and it seems correct. Both speakers are 4 ohms, I had already checked that.

Could I run sound from the heaphone output to the speakers? If so, how? The sound I get from the headphone jack is perfect, but I would like to avoid using external speakers.

try reversing the connections to the speakers (r to l and vice versa) and see which speaker is lower - if it's the oppisite one, it's a wiring or amp issue. If it's the same one, then the problem lies in the speaker itself.