Alembic Guitars Club

Alembic products => Owning an Alembic => Troubleshooting => Topic started by: germansal on April 26, 2018, 07:28:07 AM

Title: Series1 noise
Post by: germansal on April 26, 2018, 07:28:07 AM

Hi my79 series 1 bass got some kind of mass noise that disappear when I touch the backpkate or the power supply,how can I solve this????

Title: Re: Series1 noise
Post by: JimmyJ on April 26, 2018, 07:53:04 AM

Yikes!  What kind of noise, a buzz or a squeal?  Are the LEDs lit?  Can you try the 1/4" jack to see what happens?

Title: Re: Series1 noise
Post by: germansal on April 26, 2018, 08:10:01 AM

hi jimmy no leds,and check it out with jack and same stuff and by the way when i open completely the filters noise goes less but when the filter start to close noise increase,like a mass noise

Title: Re: Series1 noise
Post by: lbpesq on April 26, 2018, 09:13:45 AM

"...noise that disappear when I touch the backpkate or the power supply..."

Sounds like a grounding issue to me.

Bill, tgo

Title: Re: Series1 noise
Post by: mica on April 26, 2018, 10:40:30 AM

Did this just suddenly come up?  Is it the same in all locations you're tried (have you tried in more than one location)? Can you email me a large picture of the electronics cavity?

Title: Re: Series1 noise
Post by: germansal on April 26, 2018, 02:14:37 PM

Ok mica I will

Title: Re: Series1 noise
Post by: mica on April 26, 2018, 03:03:23 PM

Was your bass ever refinished?

Title: Re: Series1 noise
Post by: mica on April 26, 2018, 03:28:25 PM

Also, can you send me a picture of the other side of the preamp card? We noticed that the pickups were hardwired to the board, which is OK, but need to check how they are connected now.

Can you plug in the bass with the backplate off like in the pictures you sent, and then touch each pot individually and let me know if the sound is the same as when you touch the backplate?

Other things I noticed in the pictures is that there is a ground wire connected from the ground flag of the 1/4" jack to the backplate, which is OK, but it's not original.

How long have you had this bass and what is the service history since you had it?

Title: Re: Series1 noise
Post by: germansal on April 26, 2018, 04:32:46 PM

Hi Mica i dont know WTF but i ve removed the preamp card as you ve  told me and by the way moved the ground wire and now the bass is incredible QUIET...

Title: Re: Series1 noise
Post by: germansal on April 26, 2018, 04:36:01 PM

i THINK ANYWAY THATS SOMETHING IS GOING ON INSIDE MY BABY...KEEP ON EXPLORING

Title: Re: Series1 noise
Post by: mica on April 26, 2018, 05:37:12 PM

Glad it's quiet now, but wonder what is going on.

I received your new picture with the other side of the preamp card, thanks.

I was concerned about the possibility of the refinish because it looks like there is finish covering the silver shield on the lip of the plate recess. There appears to be no contact between the shield and the backplate. The ground wire that was added doesn't look like it was soldered to anything, just a lug on the standoff of the preamp card.

There is a splice with a new red wire length and one of the pickups and its connection to the preamp card that looks a little strange. Do you know what the brownish stuff is around each of these connections?

Title: Re: Series1 noise
Post by: mica on April 26, 2018, 06:19:49 PM

When you reinstalled the card, did you put the added ground wire on the standoff like it was before?

Title: Re: Series1 noise
Post by: germansal on April 27, 2018, 11:45:56 AM

I've put it the same way it was in the pic