A pair (x2) of Precision pups wired out of phase... possible?

[warwickhunt]

I've picked up a bass that has a pair of SD active P style pups in; they are the old style with the mini-switches and they aren't an identical matching pair. I'm 99% they are non-original to the bass (routes too big and the original advertising for this bass back in 87 shows it with EMGs). When I've plugged the bass in and tried it I'm bitterly disappointed with the tone and the first thing that sprang to mind was that someone had wired them incorrectly! The tone is quite thin and lacks punch even with the bass EQ whacked up full. I immediately did an A/B with my Warwick SSI and the tone was massively different (the standard SSI being big, fat and full sounding).

First off the bass and treble EQ works so I know that the active EQ is working (old Warwick MEC style), as is the volume and pan. The pan allows me to pan as it should and as expected it is thinner on the rear pup than on the bridge pup but none more so than I'd expect. I'll try getting this checked asap but I wondered if it would be a characteristic of out of phase wiring that would produce a thinner tone and is there an easy way to verify this?

Cheers.

[neilb]

IIRC, you cannot wire P pups out of phase, it does not matter which way round they are. Seems to me the problem lies in the other wiring, poss a dodgy tone cap?

[warwickhunt]

[quote name='neilb' post='830936' date='May 7 2010, 07:18 PM']IIRC, you cannot wire P pups out of phase, it does not matter which way round they are. Seems to me the problem lies in the other wiring, poss a dodgy tone cap?[/quote]

Cheers Neil.

So a pair (i.e. double what a Precision would have in) can't be wired out of phase with each other... can they be wired in some way that would cause the thin sound or is that a characteristic of the wiring or dodgy preamp (not sure I can ascertain if it is a dodgy cap as it is an epoxy sealed black box).

[deksawyer]

Any pickups can be wired out of phase if there are more than one of them. If they sound weak when solo'd then the problem lies elsewhere as a single pickup (usually!) can't be out of phase with itself.

D..

[warwickhunt]

[The Bass Doc]

Out of phase? - maybe, but there is also the possibility of the pre-amp not matching the impedance of the SDs.

Seeing that different pickups have been installed previously suggests that the pre has stayed put and and other pickups (whether active or passive) would not necessarily mate with the circuit.

[warwickhunt]

When trialled A/B against a standard SSI this bass sounds like it lacks a lot of Oomph but when played in isolation at Howie's today it wasn't 'that' bad! I 'think' Howie and I have established that these pups are not quite matched to the MEC circuit so I'm going down the route of returning the bass back to the original spec with EMGs (maybe even MECs as in my opinion they are virtually identical).

Any body got any EMGs or MECs for sale or want to buy some SDs?

[stevie]

[quote name='warwickhunt' post='832094' date='May 9 2010, 12:31 PM']When trialled A/B against a standard SSI this bass sounds like it lacks a lot of Oomph but when played in isolation at Howie's today it wasn't 'that' bad! I 'think' Howie and I have established that these pups are not quite matched to the MEC circuit so I'm going down the route of returning the bass back to the original spec with EMGs (maybe even MECs as in my opinion they are virtually identical).

Any body got any EMGs or MECs for sale or want to buy some SDs? [/quote]

These Duncan actives are a bit different to others because they carry on working when the battery is flat. I suspect that the active circuitry is bypassed when the supply voltage drops below a certain level. The sound you get in passive mode is relatively weak and a bit thin, not unlike what you have described, although useable in an emergency. I wonder if you have nine volts going to each pickup to power their inbuilt amps.

I tried to use them in a bass with its own active circuitry and it wasn't very successful. I think they need to be wired up to passive controls, which gives you the benefit of a buffered output to your amp but not the benefit of active tone controls, as the dip switches mounted on the pickups don't do a great deal.

[warwickhunt]

[quote name='stevie' post='832990' date='May 10 2010, 12:51 PM']These Duncan actives are a bit different to others because they carry on working when the battery is flat. I suspect that the active circuitry is bypassed when the supply voltage drops below a certain level. The sound you get in passive mode is relatively weak and a bit thin, not unlike what you have described, although useable in an emergency. I wonder if you have nine volts going to each pickup to power their inbuilt amps.

I tried to use them in a bass with its own active circuitry and it wasn't very successful. I think they need to be wired up to passive controls, which gives you the benefit of a buffered output to your amp but not the benefit of active tone controls, as the dip switches mounted on the pickups don't do a great deal.[/quote]

Ah! Now that does make some sense Stevie. However, you can get PJ pairs that are intended to be used in a bass together and I assume that they are driven by a single 9v battery?

Time to send SD a friendly email I think.

[stevie]

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