Alembic Guitars Club

Connecting => Miscellaneous => Topic started by: terryc on September 06, 2012, 03:14:08 PM

Title: Help from any amp engineers - Trace Elliot BLX80
Post by: terryc on September 06, 2012, 03:14:08 PM

Okay people, maybe you can help..maybe not
Haven't used my Trace Elliot BLX 80 amp for a while, anyway doing a bit of practicing and the sound enclosed appeared on power up. It increases when the output level control is turned up but not the input gain. I have too the amp out of the cabinet and sprayed switchcleaner and checked the speaker lead as well.
Output stage gone?, shot smoothing caps?, power transisters gone? Any suggestions welcome
Sound is very short as I  can only upload 150Kb.
Thanks

Title: Help from any amp engineers - Trace Elliot BLX80
Post by: terryc on September 07, 2012, 02:41:06 AM

Any suggestions guys??

Title: Help from any amp engineers - Trace Elliot BLX80
Post by: tomhug on September 07, 2012, 09:28:26 AM

Hmm - deleting double post. See below.
 
(Message edited by TomHug on September 07, 2012)

Title: Help from any amp engineers - Trace Elliot BLX80
Post by: tomhug on September 07, 2012, 09:29:49 AM

I have a Trace Elliot AH500X. It had noise on startup and intermittently that may be similar to yours (hard to tell from the sound clip). Turned out to be thermal cracks in the capacitor solder.
 
It wasn't an expensive repair as I recall, and has been fine ever since.

Title: Help from any amp engineers - Trace Elliot BLX80
Post by: terryc on September 07, 2012, 12:04:11 PM

Cheers Tomhug..will await a few more repsonses before I get the multimeter and soldering iron out

Title: Help from any amp engineers - Trace Elliot BLX80
Post by: bigredbass on September 07, 2012, 10:46:48 PM

Back in the 80's when Trace were the big deal, I was always amazed that they could stick a black light fluorescent tube on the front of the things without BIG noise.  Only Brits would do this . . . . IMHO, though, that input gain with the  marked under/OK/over LED's was brilliant.
 
J o e y

Title: Help from any amp engineers - Trace Elliot BLX80
Post by: terryc on September 08, 2012, 12:02:44 PM

Okay when I switch the graphic out of the amp the noise disappears..I can live with that as it is only a practice amp in my spare room buit your suggestions are still welcome

Title: Help from any amp engineers - Trace Elliot BLX80
Post by: keith_h on September 09, 2012, 06:45:18 AM

Try cleaning all of the pots, switches and 1/4 connectors with something like Caig's DeOxit. Your Effects In/Out and Line In/Out have switch contacts on the 1/4 connectors that can oxidize. This oxidation can cause problems like you describe. Also having dirty pots in the Graphic EQ can cause similar noise problems. I would also reseat any connectors going between PC  boards, controls, etc.  
 
Keith