Ampeg SVT 4 Pro distorting...Help!

[PauBass]

At band practice last night my SVT 4 Pro stopped working, well it didn't stop, the sound volume dropped and distortion was comnig through instead of clean tone.
I use the Ampeg in mono bridge mode with the right cable, it's not the cab as I tried it with another amp and worked fine.

I tried the two power amps separately and I found the problem lies on power amp A, B works fine but A is the one not pumping enough volume and distorting.

Any ideas?

Edited November 5, 2010 by PauBass

[waynepunkdude]

I'm not a 100% but my 5Pro was doing a similar thing but with both power amp turned out to be the mosfets.

[PauBass]

[quote name='waynepunkdude' post='1013442' date='Nov 5 2010, 04:02 PM']I'm not a 100% but my 5Pro was doing a similar thing but with both power amp turned out to be the mosfets.[/quote]

Thanks!

Where did you have it repaired, please? Was it expensive?

[waynepunkdude]

[quote name='PauBass' post='1013575' date='Nov 5 2010, 06:17 PM']Thanks!

Where did you have it repaired, please? Was it expensive? [/quote]


These guys it was quite pricey but I had a full service done at the same time.


[url="http://www.panicmusic.co.uk/"]http://www.panicmusic.co.uk/[/url]

[PauBass]

[quote name='waynepunkdude' post='1013598' date='Nov 5 2010, 06:36 PM']These guys it was quite pricey but I had a full service done at the same time.


[url="http://www.panicmusic.co.uk/"]http://www.panicmusic.co.uk/[/url][/quote]

Great, cheers! I'll get in touch with them.

[Subthumper]

Hi, I did some work on a svt 4 this year and though it was a different fault it was a bad solder joint which having trawled through numerous forums seems to be a common problem on these, even though ampeg themselves dont seem to aknowledge this problem. Its the first place I'd look, though it ca be a time consuming process. Also make sure all the efects send and return sockets are clean and not causing problems. Check the fuses too as if it were a problem with the mosfets they would uaually blow. Look for the simplest solution first.
Good luck cheer Just

[PauBass]

[quote name='Subthumper' post='1016738' date='Nov 8 2010, 07:01 PM']Hi, I did some work on a svt 4 this year and though it was a different fault it was a bad solder joint which having trawled through numerous forums seems to be a common problem on these, even though ampeg themselves dont seem to aknowledge this problem. Its the first place I'd look, though it ca be a time consuming process. Also make sure all the efects send and return sockets are clean and not causing problems. Check the fuses too as if it were a problem with the mosfets they would uaually blow. Look for the simplest solution first.
Good luck cheer Just[/quote]

Thanks for the advice, I'll check everything you've mentioned.