Crossfire VR2000D Sounds terrible

[Mr. Old School]

Hey guys and mr. Babin. I bought a VR2000D off eBay some time ago. When I received it I promptly powered it up to see it immediately go into protection! What a nice suprise but seeing it was from eBay I was not too amused!

I brought it to a technican who discovered that 6 pieces he mentioned were power mosfets were blown. He replaced them on the spot and it fired right up.

Four months later I finally decided to try different sub setups so I unpacked it, hooked it up to the first, second and then the third set of subs. Once again to my suprise they all sounded horrible.

I would describe the sound as muffled and just plain flat and extremely distorted.

The first setup was 2 MTX Black Gold 4ohm in a sealed box

The second was 2 White Rock subs in a bandpass box

The third was 1 12 inch Earthquake magma in a sealed box

I retried all 3 setups with my Autotek 2 channel amp and all sound the absolut opposite of the VR2000D.

If anyone could point me in the right direction without being too technical I would really appreciate it.

[Perry Babin]

Can you run a test tone (sine wave) through it slowly increasing the volume to see if it sounds clean/undistorted at any level?

If it sounds OK at very low levels, but is distorted at higher levels, it could be that one or both of the switching power supplies is damaged. You could measure the rail voltage to see if it's producing reasonably high voltage (plus and minus 90v would be in the ballpark).

Many times, the legs break on the rectifiers (and other semiconductors) and cause this sort of problem.


??? Hey guys and mr. Babin ???
I'm not one of the guys?

[Mr. Old School]

I have no testing equipment available and honestely do not even know what a sine wave is. I will just collect as much info as possible before I go into the shop again so I actually understand the termonology and can maybe point the technican in the right direction.

I did notice that on the first fix that there was 1 of the 3 legs broken on each mosfet. The technician claimed this could have been caused by extreme vibrations!?!

??the guys and perry??---I have read many of your amp fix posts and you do know your business.

Any idea what a fix of this magnitude could cost? Thanks

[Perry Babin]

This is a 100Hz test tone (sine wave).
http://www.bcot1.com/images/100hz.zip


If the amp has broken rectifiers, it may only cost a few (insert the local currency equivalent of a few $US here).

It appears that the amp uses relatively inexpensive TO-220 transistors so even if you have to replace a large number of devices, it won't be extremely expensive to repair.

The parts break due to poor mechanical design. There is too little support for the heavy components and it places too much stress on the legs of the heatsink mounted components.