Help with Aguilar preamp wiring

[xgsjx]

Would someone be able to help me see where I’ve gone wrong with my wiring. 
the pickups are Aguilar AG4 P & J HC & the preamp is an OBP-2. 
I installed them a few months back & it sounds great. However, I’ve just discovered that the volumes are doing funny things. You can roll either pick-up on or off, but if you roll one right back, then the other, it doesn’t fade down like expected & the sound cuts off a good bit before it’s turned fully down.  I’m stumped as to where I’ve went wrong. 
I’ve tried to follow this diagram, but I’m at a loss. 

 

Here’s some pics of my mess in the cavity. 
 

 

 

 

 

I can get more pics if needed. 
 

Any help would be massively appreciated. 

[tauzero]

What value of pots did you use?

[xgsjx]

19 minutes ago, tauzero said:

What value of pots did you use?

The pots came with it as a bundle. 

[TheGreek]

I'm getting worried now...

I had an OBP2 installed in my Spector 6er - three different people had a go at fitting it before a new local luthier finally managed .

The process took a couple of months which affected my desire to play 6er....played it for less than an hour. 

 

I'm going to have to check if I have similar issues. 

[xgsjx]

If you don’t have any issues, could you take a pic of your pots?

[itu]

Looks a bit like a low power iron. Therefore I guess you have been warming the pots a bit too long, and the tracks may be in bad shape.

 

Pot covers need +50 W, contacts nearly anything from 15 W. Lead free has made soldering more complicated: higher temp needed, not so easy tin. Good resin helps, just like with 63/37.

 

If you just replace all pots and use a decent iron and tin, the system will work for years.

[itu]

Alpha pots, I wonder where are the values? Taking one off might reveal numbers and letters, like 250 kA (A means often Audio taper, but not always, as there are no standard codes). Measuring is an option.

[paul_5]

Values are usually printed on the front of the brown wafer, but they're only visible when you remove them from the bass.

 

They could be labelled as 100KA (100kΩ, Logarithmic sweep), but occasionally you'll get one that doesn't, at that point you'll have to desolder it from the wiring (after first labelling or some other means of identifying how to put it back - ask me how I found this out!) and measuring it. It's not generally a good idea to measure the value of components whilst they're soldered on place, as they can often be wired with other passive components (fixed resistors, diodes and capacitors) that can skew the reading.

[xgsjx]

8 hours ago, itu said:

Looks a bit like a low power iron. Therefore I guess you have been warming the pots a bit too long, and the tracks may be in bad shape.

 

Pot covers need +50 W, contacts nearly anything from 15 W. Lead free has made soldering more complicated: higher temp needed, not so easy tin. Good resin helps, just like with 63/37.

 

If you just replace all pots and use a decent iron and tin, the system will work for years.

Ahhh, I never thought about that!

My soldering iron is a Blue Point gas iron that I got back at the turn of the century when I was installing car security & multimedia. 
It’s a decent iron for a gas iron, but it did take a bit of time to heat the pots enough to put the earths on. 

I’ll try a new iron & get 2 new pots (I can pop em out to see the values). 

It’ll probably be next month, but I’ll report back once done. 
 

Thanks all. Really appreciated. 

[paul_5]

quick tip for soldering to the pot cases - they have a coating on them which makes it more difficult than it needs to be - a bit of abrasion with a brillo pad or something similar will remove this and the soldering is MUCH easier.

[xgsjx]

Yes, I usually do some scores with a Stanley like a # or rub it with a little sandpaper. 

[sandy_r]

 

If your controls cavity is fully shielded (and the lower, inside part does appear to be well-coated with conductive paint, so hopefully the cover has been similarly treated) then you shouldn't need to ground-connect the pot cases - just follow the diagram (ground from the jack sleeve connection goes to the OBP-2, the two Vol Pot 'minimum' lugs - it should also be used to provide the ground for the bridge and pickups)

 

As others have said, you should confirm the actual Pot values/types carefully, to make sure they match the OBP-2 wiring diagram - if the Pots came as a bundle it seems rather odd that they supplied 2 Tone Pots which were either not Linear taper (as required in the diagram) OR used a conflicting labelling standard from the other 2 pots they supplied at the same time

 

Edited October 12, 2023 by sandy_r

[xgsjx]

4 minutes ago, sandy_r said:

 

If your controls cavity is fully shielded (and the lower, inside part appears does appear to be well-coated with conductive paint, so hopefully the cover has been similarly treated) then you shouldn't need to ground-connect the pot cases - just follow the diagram (ground just to the OBP-2 and the two Vol Pot 'minimum' lugs)

 

As others have said, you should confirm the actual Pot values/types carefully, to make sure they match the OBP-2 wiring diagram - if the Pots came as a bundle it seems rather odd that they supplied 2 Tone Pots which were either not Linear taper OR used a conflicting labelling standard from the other 2 pots they supplied at the same time

 

Cheers. I’ll get a decent lekky soldering iron, check the pot values & order 2 replacement volume pots & try that. 
The other 2 smaller pots are for treble & bass. Those 2 work perfectly. 
 

One thing that I was really unsure of, is the grey wire coming from the J pickup. 
the P has a black & a white wire, but the J has a black, a white & a grey. I asked Aguilar about the grey wire & they was as helpful as going to the chippy & asking.  But from what info I could find, it seems to be another earth, which seems a little odd. 

[sandy_r]

8 minutes ago, xgsjx said:

...

One thing that I was really unsure of, is the grey wire coming from the J pickup. 
the P has a black & a white wire, but the J has a black, a white & a grey. I asked Aguilar about the grey wire & they was as helpful as going to the chippy & asking.  But from what info I could find, it seems to be another earth, which seems a little odd. 

...it's shown as grounded on their (passive) diagram - it's probably isolated shielding inside the pickup casing (ie. not part of the signal path) - the black wires from each pickup complete the signal path to ground

[BigRedX]

As has been discussed in the Earth Loop thread there should be a difference between signal ground (which should really be signal -ve) and electrical (screening) ground. Unfortunately standard two conductor guitar wiring doesn't allow for this.