Author Topic: P bass pickup electronics won't work (Read 221 times)

warrior_joe_007 · « **on:** August 08, 2007, 08:17:07 PM »

OK so I have an Alembic p bass pickup with one filter and one volume. I tested everything in my friend's bass who also has the same setup. I tested the 3 parts seperately (filter, pickups, volume.) The filter and the pickups work fine. The volume control doesn't work. I checked my wiring and resoldered to the jack so many times that I need a new jack. So is there any way I can return just the volume assembly and the jack and get a new one. I hope so because I am in college and there is no way I can afford to buy a whole preamp. Thanks, Joe

dfung60 · « **Reply #1 on:** August 08, 2007, 10:01:12 PM »

Man, two guys in college with Alembic P-pickups? :-)

If you're really sure that the pickups and filter are working correctly, then replacing the volume knob and jack is pretty easy and cheap. The original stuff that would have come in the kit would have been a Switchcraft jack and probably a relatively expensive Clarostat pot. You can order new parts from Alembic (which will probably end up being fairly pricey) or replace these pieces with a standard pot and jack. A real Switchcraft output jack will probably be less than $6; a workable pot is probably about the same (a sealed, laser-trimmed conductive plastic Bourns or Clarostat pot will probably be more like $20-30).

You want to read the pot value from the back of the pot or measure it with an ohmmeter (you can read the value across the outer two lugs). You also want to look at the type of shaft that the pot has (diameter, smooth, splined, etc) so your existing knob will fit on. If you're trying to keep the existing knob and feel, then it will probably save you time to just order another from Alembic.

I think the output jack actually has a much higher chance of failure than the volume pot. If you have a short or wired the battery switching wrong, then the entire thing won't work. Perhaps it's worth checking that part over again, or even putting in a new output jack first.

Good luck,

David Fung

warrior_joe_007 · « **Reply #2 on:** August 09, 2007, 04:25:51 AM »

Oh my friend is not in school. He is the one who sold me the bass though. Yeah I am pretty sure it has failed. I don't know where to find a jack that has 5 connections to it though. The volume pot is connected to a small board that has a resistor and a cap on it also. I beleive it could be the jack so I would try that first but I don't know what exactly to get. I also checked to make sure that the wires are in the correct place by looking at my friends setup.

adriaan · « **Reply #3 on:** August 09, 2007, 04:35:49 AM »

The jack should actually be a switching jack - insert the plug and the power comes on.

David Houck · « **Reply #4 on:** August 09, 2007, 12:20:55 PM »

It might be a Switchcraft L113.

warrior_joe_007 · « **Reply #5 on:** August 10, 2007, 05:30:12 AM »

OK I think it is an L113 after looking at the diagram. How much do they cost at Alembic? I found a place with a decent price but I have to order a bunch to get them.

Also how much would the volume control be if I had to get that. Could I send it in for repair?

keith_h · « **Reply #6 on:** August 10, 2007, 07:01:36 AM »

You need to discuss the cost of parts directly with Alembic. If you give them a call they can provide all of the information and ensure the part number is correct.

Keith

dfung60 · « **Reply #7 on:** August 12, 2007, 06:01:35 PM »

Ah, a 5-pin output jack...

Alembic was using the good stuff when they set up the parts kit for your electronics. The regular three conductor jacks are normally called stereo jacks - left and right signal hots and a common ground, as used for many years on headphones before they got walkman-sized.

When you see a five-pin 1/4 jack, the additional two contacts are connected to a dedicated switch, which can be used to switch your battery power on and off when a plug is inserted.

Most instruments are only mono output, but clever designers realized that they could use the extra channel of a stereo jack to switch power, which is why instruments with active output often have 3-pin stereo jacks. The 5-pin jacks are only needed when you actually have two output channels coming from the instrument, which these days is usually an acoustic guitar with both piezo and magnetic pickups.

You'll probably find a 5-pin jack hard to track down in regular stores - if you want an exact replacement, it will be easiest to get it from Alembic. If your instrument is mono out, you can switch power with a 3-pin jack. Write back if you want to know how to do that.

David Fung