Bare Knuckle Pickups Forum
At The Back => Time Out => Topic started by: Twinfan on January 23, 2012, 05:55:22 PM
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OK, so it's non-BKP related but someone may be able to help hopefully!
I have reissue PRS T&B pickups in my SE Custom 24 which work fine but the output is WAY low. Much lower than my Modern Eagle. All looks OK:
* Neck pickup reads 8.4k through a guitar cable, same with the Sweet Switch on or off
* Bridge pickup reads 10.3k, same with the SS on or off
* I fitted a new (reading 475k) CTS pot when I rewired it
* The red (split) wires are no used and taped off
* The pickups are designed to work with a rotary switch, so one has a flipped magnet. To combat this, I've switched the hot/ground leads on one of the pickups.
It's almost as if the individual coils of each humbucker is out of phase with itself as there's no bass or power.
Any ideas folks?
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Sell it :band4:
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Switch the Hot/Ground leads around again and see if that works?
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I had them that way originally, but the in between position was out of phase a-la-Peter Green. Not sure what the output level was though....
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Can't think what's going on here!
Is red definitely the coil-split wire? I guess it must be, based on your DC readings.
When you say WAY low, how WAY is WAY? Like almost inaudible? Could it be a fried pot?
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It's low as in single coil low, as if the coils are in parallel maybe? I read the leads DC resistance before I fitted the pickups and red is definitely the split for both pickups.
Odd huh? I've fitted pickups plenty of times now and never had an issue like this. Just the usual not working or out of phase in the middle position. I'm well confused!
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I don't see how you could "accidentally" wire a humbucker in parallel or in phase with itself, though....
Were they secondhand pickups? Could a previous owner have messed about with them?
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Does the guitar hum more than other guitars? And if you have a single coil switch, is the guitar louder in single coil mode than in humbucker mode?
If the answer to both questions is YES then you got the coils linked with improper phasing. If the pickup has a four conductor wire, desolder the two wires soldered together and check which one is the hot coil. Reverse these two wires. You should be back in business then.
Cheers Stephan
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If the pickup has a four conductor wire, desolder the two wires soldered together and check which one is the hot coil. Reverse these two wires. You should be back in business then.
PRS use a single "coil-split wire" - i.e. "green and white" (in BKP colours) are joined at the pickup, not at the end of the cable. So you'd need to dismantle the pickup if this is the problem! :(
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They're brand new pickups Phil. The only thing I can think is that the CTS pot is doing something weird.
I'm going to connect the bridge pickup directly to the output jack at the weekend and see if works OK. If so, I'll add the toggle switch/sweet switch/volume pot one at a time to see where the issue kicks in. If it's still not right straight to the output jack then both pickups must be faulty in some way. Magnet issues maybe?
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I'm going to connect the bridge pickup directly to the output jack at the weekend and see if works OK.
I think that is the only thing you can do. The original T and B pickups seem to have a reputation for being bright and harsh.
This clip seems to confirm that http://www.youtube.com/watch?v=IVNF-VU7FIk (http://www.youtube.com/watch?v=IVNF-VU7FIk)
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I've no problem with the tone of them, but tiny output is no use to anyone!
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If the pickup has a four conductor wire, desolder the two wires soldered together and check which one is the hot coil. Reverse these two wires. You should be back in business then.
PRS use a single "coil-split wire" - i.e. "green and white" (in BKP colours) are joined at the pickup, not at the end of the cable. So you'd need to dismantle the pickup if this is the problem! :(
Oops - of course you are right. In that case a phasing problem seems to be unlikely. The direct link test should then be more fruitful. If the direct linkage of the pickup works, add the volume control. If it still works, add the tone control, switch and so on until you find the culprit.
Cheers Stephan
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Yep, that's the plan! I'll give it a go on Saturday afternoon.
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Right - bridge 'T' pickup direct to the output jack reads 10.4k and sounds the same :?
Original pickups back in and T&Bs back to PRS UK I think.....
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Hi Dave,
I have original T&B pickups and they sound great. It sounds like there was some mistake in the production of these. Do you have a polarity detector (Stewart MacDonald make one for a few dollars), it would be interesting to see if they've got the magnets in the slug coil messed up.
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Weird! :?
I predict a "they seem fine to us" situation, unfortunately....
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It sounds like there was some mistake in the production of these. Do you have a polarity detector (Stewart MacDonald make one for a few dollars), it would be interesting to see if they've got the magnets in the slug coil messed up.
Hi Phil - exactly the conclusion I've come to. Magnet strength-wise, they seem pretty low and as they have magnetic slugs I wonder if they've got the polarity the wrong way round - that would then give a humbucker with coils out of phase with itself. Which would probably sound really thin and horrible and have low output.
I'm sending them both back to PRS UK to see what they say.
The original SE pickups are now back in and sound fine, so there's nothing wrong with all the other components or my soldering skills!
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Just to close this off, there was a faulty batch of T&B reissues - probably the first batch made. Mine is one of 4 faulty sets that came to the UK. I've sent mine back for replacements which are on their way from the US and I should get them in a couple of weeks.
Sorted :)
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So in effect it was a "known problem"? If they knew there were faulty sets, why didn't they weed them out and return them to PRS? :?
Good that they're sorting the situation out, anyway.
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I don't think they knew exactly how many sets were affected. My theory? As I mentioned a couple of posts ago T&Bs have magnetic slugs and I think they got the polarity the wrong way round. Usually slugs are just cold rolled steel so their orientation doesn't matter. As these are different, I wonder if they weren't labelled up properly and/or not labelled at all so they got thrown into pickups any which way.
If the QC test just checks the DC resistance all looks fine and they get shipped out. It's only when you install them in a guitar you realise there's a problem.
There's been no issue with an exchange, so it's been a bit of hassle uninstalling them and re installing new ones but it'll be sorted in the end. Everyone makes mistakes, but as BKP know it's how you deal with customers that's important!
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Fully agree - mistakes can happen. The important thing is how you deal with them.
Cheers Stephan
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I didn't really pick up on the slugs themselves being magnetic, although you did mention it!
Interesting! Is that all 12 poles, like a Duncan Stag Mag, or just one coil? Is there still a bar magnet at the base of the pickup?
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There's a bar at the base for the screws, but the slugs are magnetic like a single coil. It was to help with the stratty split tones, and explains why they're bright pickups...
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I've got a really old Schaller pickup called a "Golden 50s Super" (I think!). It has 12 magnetic slug poles and, if I remember right, sounded hugely warm and fat (although I was probably using it with a weedy DiMarzio PAF in the bridge position :lol: ). Never tried it split, but I assume that's what it was really designed for.