Author Topic: High Pitched Squeal (Read 199 times)

ifredoto · « **on:** October 02, 2009, 03:24:25 PM »

I have a 1980 LSB1 and am the orignial owner. I have gone through several 5 pin cables over the years and have recently encountered an issue. A high pitched squeal which stops when I disconnect the 5-pin cable. When I plugged it back in, it started again. This isn't the forst time this has happned. I changed to a back up cable and didn't have any issues for the remainder of the gig. I did have the module board worked on some 20 years ago and was wondering if anyone else had similar issues .Is the cable or the comdule board

811952 · « **Reply #1 on:** October 02, 2009, 04:06:19 PM »

turn the filter knob and see if it quits. mine does that sometimes if the q is at maximum.

John

the_mule · « **Reply #2 on:** October 03, 2009, 12:04:05 AM »

If you try John's suggestion and it seems that the problem is there, you could tweak the trimpots on the backplate for that particular pickup: http://club.alembic.com/Images/16271/50896.html?1208917987

I had the same problem with the bridge pickup of my Series I with the filter and q to the max and I managed to solve it with a small adjustment of the hum balance trimpot and the pickup height.

Good luck!
Wilfred

David Houck · « **Reply #3 on:** October 03, 2009, 03:17:27 PM »

- Does it always squeal with the one 5-pin cable, but never with the other?

- Does it squeal with a 1/4 cable?

- How long has this been happening?

- Does it squeal when the selector switch is on neck pickup ony? Bridge pickup only?

811952 · « **Reply #4 on:** October 03, 2009, 03:31:16 PM »

-Does it do it on the job?

-Does it do it with a knob?

-Does is do it in a pinch?

-When it does it do you flinch?

-Does it do it over there?

-Does it do it in a chair?

I couldn't resist. Sorry.

John

David Houck · « **Reply #5 on:** October 03, 2009, 03:38:42 PM »

Actually, it's a pretty good troubleshooting list!

2400wattman · « **Reply #6 on:** October 04, 2009, 12:36:10 AM »

Sounds like an application for a prostitute to me, but that's me and if anybody here KNOWS me I would think of something like this, me thinks!

slawie · « **Reply #7 on:** October 04, 2009, 01:09:13 AM »

Wow Dr. Seuss is a club member!

slawie

811952 · « **Reply #8 on:** October 04, 2009, 12:24:20 PM »

Does he play a Series I?

Does he play it just for fun?

Does he gig with it for free?

Does he gig and charge a fee?

John

ifredoto · « **Reply #9 on:** October 04, 2009, 02:46:42 PM »

I have tried flipping switches and turning knobs and the only thing which will stop the noise is disconnecting the cable. It has also happened once using the 1/4 but coincidentally, the batteries went dead so after I changed the batteries, no noise.

I will try the trim potts as I have cleaned everything else except those.

David Houck · « **Reply #10 on:** October 04, 2009, 03:19:40 PM »

So it happens with both five pin cables?

811952 · « **Reply #11 on:** October 04, 2009, 05:00:39 PM »

I might suggest re-seating the connections inside the body. Being an older instrument, it's entirely likely that there may be oxidization that's throwing the whole mess out of specification..

John

ifredoto · « **Reply #12 on:** October 04, 2009, 05:37:35 PM »

Hasn't happened with Alembic cable yet. It might be too soon to tell. I will check the trim potts and inside body connections to see if that helps.

Thanks for the suggestions.
Ian

811952 · « **Reply #13 on:** October 04, 2009, 06:09:15 PM »

That's a beautiful bass you've got there...

John