Author Topic: Lower than normal gain (Read 182 times)

bassman02 · « **on:** July 18, 2010, 02:06:23 PM »

Hello fellow Alembic owners!

This is my first post, and I'm also a bit of a novice when it comes to caring for an electric instrument. I'm having a bit of an issue with my Epic. It started out with a loose treble knob that I neglected to take care of in a timely fashion (bad idea :-( ). I found that when I jiggled or adjusted it, occasionally the signal would cut out completely. One Sunday morning as I was playing in church it got so bad I couldn't get a signal at all!

After a colleague pointed out this site, I was able to arm myself with enough information to feel confident in tightening the knob so that I now have a constant signal. The only problem is that now the overall gain is so low that I have to crank both the bass and the amp up to about 9-10 o'clock to get a decent output that cuts through the rest of the band. Previously about 7 o'clock on the bass and 5-6 o'clock on the amp would do the job.

I didn't see any loose wires anywhere. One other idea I have is maybe it is something with the ferrite tube, but I'm not really sure what the correct position for this guy is (especially which way the foam should be oriented). Has anyone else seen this particular issue or have ideas on troubleshooting? Thanks.

adriaan · « **Reply #1 on:** July 18, 2010, 02:30:03 PM »

Hi Travis, and welcome to the Club!

Whatever the problem is, it can't really be the ferrite bead - that's outside of the actual circuit, and just helps eliminate unwanted noises. Its exact position should not be critical, and the foam stops the bead from rattling against the backplate.

One remedy for many problems is to exercise the jack - plug and unplug 20 to 30 times (with the other end of the cable *not* connected to your rig, obviously). If that doesn't help, do post again!

dadabass2001 · « **Reply #2 on:** July 18, 2010, 03:56:55 PM »

Hello and welcome Travis,
You might also want to check to make certain you don't have the internal gain trim pot (a little blue box with a white adjustment in the electronics cavity) set too low. And it doesn't hurt to check your battery as well...

Mike

rjmsteel · « **Reply #3 on:** July 18, 2010, 04:26:54 PM »

Travis,
Mike has a really good point that I didn\t think of this morning.
Go to the forum main page, look under FAQ>Click on: Information Related to All Instuments>Click on, and review,: Trimpots...or The Blue Square (box) with a White Circle, and try to increase the output by adjusting the gain.

-Rich (Lakeland)

David Houck · « **Reply #4 on:** July 18, 2010, 06:47:47 PM »

Hi Travis; welcome to the board!

Just to review; on the treble control, you removed the knob and then you tightened the nut so that the pot is snug up against the shielding on the inside of the control cavity?

The pots and jack are grounded when they are snug against the shielding. Nothing else should be touching the shielding. Make sure that no printed circuit cards have moved and are now touching the shielding on the sides of the control cavity.

Do the bass and treble controls both appear to be working correctly? Do they sound like they are functioning the same as before the treble knob first became loose?

Is the volume control working correctly? Is there an even taper through its range?

Is the pan control working correctly? Does the signal move evenly from full neck pickup to full treble pickup?

bassman02 · « **Reply #5 on:** July 18, 2010, 07:26:30 PM »

Thanks everybody for all the input! I'll have to give everything a try when I get a chance and post back with the results.

It seems very likely to me that I may have made once of the circuit cards touch the cavity...

bassman02 · « **Reply #6 on:** July 24, 2010, 02:32:54 PM »

Hi guys,

I finally got a chance to try your suggestions, and I think I have corrected the problem...

I'm not sure exactly what solved it, but I opened the back cover up again. First thing was to check the battery power--fine. Next, I looked at the boards and none seemed to be touching any sides or anything...

I moved some of the wiring around to look around, and I also noticed that the connection (black, yellow and red wires) running from the gain control to the main board on the treble control seemed to be loose, so I pushed that in tighter.

Once I got everything together and plugged back in, the gain seemed OK--not quite as punchy and bright as the fretless I was comparing against, but I think much better (unfortunately, and stupidly, I didn't plug it in to play before I started).

I'm sure part of why the pop and punch is gone is that the strings are ancient, so I will change them as well.

Thanks again guys for all your helpful tips.

--Travis