Taming Seymour Duncan Livewire metal bridge active pup

[Deleted]

Hi,
i've had this guitar with this seymour duncan livewire metal set for many years... The bridge pup always was way too hot.. It was kind of bearable back in the 90's with the amps available back then, but today with all the new amps, modeling, etc.. out there, nobody needs that much power.

So i thought instead of dropping this, in favor for blackouts or maybe EMGs, to give a shot to some modding.


I found this :


Would you recommend going this path?

Or should i go and straight connect some 200 Kohm resistor from pup hot parallel to the ground? (resultting in 66KOhm total resistance with the volume all way to 10)

[newey]

I'd recommend some experimentation. Any approach to attenuating the pickup involves compromises, and only your ears can determine whether the compromises are ones you can live with.

Just like turning down the volume, you'll cut output but also change tone. At what point does it get too muddy?

Anyway, experimentation is easily done with a few resistor and a guitar cord, although your first option may be easier if you can sacrifice an old cord.

Or should i go and straight connect some 200 Kohm resistor from pup hot parallel to the ground? (resultting in 66KOhm total resistance with the volume all way to 10)

In your diagram, that's essentially what R2 is doing. According to the table, with R2 at 242K you'd have -3dB. Of course, there's R1 as well, at 29K. But the difference between 242K and 200K is likely to be minimal.

[ashcatlt]

I thought the whole point of an active pickup was that you can do all kinds of rude things to them before losing tone. Any clue what the nominal impedance is on these things? Anywho, you found a voltage divider, which is exactly what you need. The appropriate values are the question. We need much more info to be absolutely sure. I'd be willing to bet that 10K trimmer would work fine, and let you dial it in a bit.

[Deleted]

Hi Newey, I think the balance between neck/bridge is correct at about 70% of the volume. In other words, in order to get the same volume output with neck pup and vol at 10, with bridge pup i'll have to turn the volume to 7.

Jan 6, 2014 20:46:52 GMT -5 newey said:

In your diagram, that's essentially what R2 is doing. According to the table, with R2 at 242K you'd have -3dB. Of course, there's R1 as well, at 29K. But the difference between 242K and 200K is likely to be minimal.

Thanx, any clue about why we need the R1?

[Deleted]

Jan 6, 2014 21:26:42 GMT -5 ashcatlt said:

I thought the whole point of an active pickup was that you can do all kinds of rude things to them before losing tone. Any clue what the nominal impedance is on these things? Anywho, you found a voltage divider, which is exactly what you need. The appropriate values are the question. We need much more info to be absolutely sure. I'd be willing to bet that 10K trimmer would work fine, and let you dial it in a bit.

Thanx Ash,
those pups are no longer in production, the pups Seymour Duncan now sell are called Blackouts and are more refined, modern, and also with a pin for the user to control 2 levels of power. So i suspect finding the specs would be not easy.

The way i see it, and as i have experimented with the vol knob, is that about 70-60% is just right, balances well and produces nice output (on par with hot humbuckers : think Dimarzio super distortion, fast track2, EMG 81, etc...).
So my question here is, why would i need the voltage divider , and not just straight connect a 200KOhm resistor parallel from pup's hot to the ground (equivalent of vol to 65%)? What does R1 do? Why isn't R2 alone sufficient for the job?

I forgot to say that current pots are at 100KOhm.

[JohnH]

Jan 7, 2014 1:13:24 GMT -5 @pyrros said:

Jan 6, 2014 21:26:42 GMT -5 ashcatlt said:

So my question here is, why would i need the voltage divider , and not just straight connect a 200KOhm resistor parallel from pup's hot to the ground (equivalent of vol to 65%)? What does R1 do? Why isn't R2 alone sufficient for the job?

I forgot to say that current pots are at 100KOhm.

The output impedance of the pickup is probably only a few k. Putting a 200k across it would probably only reduce the output by a very small amount, like taking a 1.5V battery and putting a highish value resistor across it, it doesn't reduce the voltage much. You need two resistances to make a voltage divider. Say you had two 100k in series from hot to ground. The total output from the pickup is not reduced much, but each resistor drops half the total voltage, so if you take the output from across just one of them, you get half.

[newey]

The way i see it, and as i have experimented with the vol knob, is that about 70-60% is just right, balances well and produces nice output (on par with hot humbuckers :

If the guitar has individual volume controls, why not just leave the one at 60-70%?

[Deleted]

Unfortunately it is HH, 1 vol, 1 tone configuration.

The more i think about it, the more i understand what Ash, John and you said. The vol pot is a voltage divider by design. So, i think if i set R1=30KOhm and R2=70Kohm, so that Vfinal = Vorig * (70/(30+70)) = Vorig * 0.7, i would have replicated the behavior of a vol pot at 70% right? R2 alone just would not work unless it had some silly low value.
My initial thought was to bleed some signal to the ground using just one (small-ish) resistor from pup's hot to the ground, thus in parallel with the pups hot. But then the amount of the bleed is not easily controlled this way, R1 would be 0, so Vfinal = Vorig * (R2/0+R2) = Vorig.

So i guess the voltage divider is the way to go!!

thanx a lot guys! i'll try that out and let you know..

[newey]

Ash's suggestion is to use a trim pot to "dial it in". That's a good suggestion, can save you a lot of time and frustration. You use the trim pot to get the output you want, then measure the resistance across the trim pot at that setting. This gives you the final number you want, and you can then select resistors accordingly.

[Deleted]

Hmm and why not leave the trim pot in the cavity and use it permanently? Also isn't 10K a lowish value, if we consider the vol pot is at 100KOhm?

[ashcatlt]

The top resistor is actually the series total of the pickup's impedance and R1, so if you remove R1, you have to set R2 based on the unknown value.

Technically R2 is is also the parallel value of whatever is hanging in parallel to it - like everything downstream from this point! That's a lot to try and figure. It works out that those things impact the total less when they are much larger than the resistor you're using for R2.

Since the pickup's Source Z is probably very small, and the load Z is not bigger than 100K, 10K seems to me like a decent "eyeball" value. It also happens to be a pretty common value for V controls on active pickups.

You wont lose treble from a too small value because the source is not inductive - the inductance of the coil is hidden behind the active electronics. It is, in fact, capacitive since there must be a "coupling cap" in series with the output. A too small value might suck some bass out of the signal. I'm willing to bet (the cost of two trim pots) it won't be noticeable in this case, but the potential is there. If you really want to be sure about that part you could try it with a 10K resistor across the pickup and see if it seems thinner.

Note that 70% rotation on the pot might not be 70% resistance. It depends on the taper. You could measure between the lugs, but it would need to be out of circuit... It's so much easier to just stick the trimmer in there, turn it till it sounds right, then tape it off. If you change your mind on the balance later on you can readjust.

[Deleted]

Ash thanx a lot, I am nowhere near your level, but I am very confident that you are correct, so I'll go straight for a 10K trim pot

[Deleted]

Bought a 10k trimmer, also two 47K and 100K trimmers just in case, also i got 30K and 70K resistors!! seems like its gonna be fun tonite!

[Deleted]

I got the thing installed tonight. A little bit tougher than i thought, because those 25 years old pot would not take any soldering at all. Finally after a lot of sweat, cursing and the like i got it installed. For some reason, i went straight ahead for the 100 Kohm option, as it seemed intuitively right : no treble loss. I adjusted the trim at about 30%. That means that R1 would be around 70 Kohm and R2 arounf 30 Kohm. So, in the linear sense, this would be equivalent with a volume pot at dial 3 to 4.
Now the sound : I understand why i hated the bridge pup all those years, cause even with bearable output i dont like it clean: huge mids, now bottom end, undefined highs, annoyingly insensible attack. The neck pup of the same set, shines on cleans. Now at least i can play this guitar, i can switch to the middle position and get some OK tones. Even the bridge clean can be useful at certain amps settings. In any case it is not this noise it used to be.
Now distorted : this is where the mod paid off the 0.8 euros i paid for the components!! I absolutely now love the bridge pup distorted. Now it is tight, nicely sounding with the amp presets i also use for the rest of guitars. No more special treatment for this damn bridge pup.
All in all, i like this guitar much better now, and will be the 4th electric to be played, besides the aria, ibanez and carvin. No more rusting in the case!

However, i am starting to think that an upgrade to either the new seymour duncan blackouts, or the new EMG X-series will be due sometime in the future.

That's all from the eastern front!

Thanx Ash, John, Newey for their valuable help!

[newey]

Glad you got it worked out to your satisfaction, Greek!

[Deleted]

Hello again gang!
This pup is just too midrange (like having a wah pedal in the middle)
Can I just bleed some mids out of it? Is it even feasible?

Thanx!

[newey]

GD-

We've had some discussions of a passive mid cut control, although I can't find the link at the moment. With an active pickup, you're pretty much on your own. But I don't see why the same basic idea wouldn't work with an active pup.

Passively, the mid cut control is accomplished by adding an inductor (1 henrie to about 1.5 seems to be the recommended value). The inductor is soldered in series between the tone pot cap and ground. Often, a resistor is used across the tone cap as well, to sort of "fine tune" the effect

There are also some commercial kits for this mod, the best known is one from Torres Engineering here in the US.

Now, if you don't want a pot to control the mid cut, the trimpot idea ash suggested originally sounds like a good way to "dial it in". Set it where you want it and then just tape it off in the cavity.

So, the issue is component values for an active system. Perhaps you can get some idea by using a 5spice sim or other program?

I've had a number of projects gathering dust for a couple of years now, as real work has ramped up to about 90 hours/week. But, if I ever get those off the workbench, one future project I've wanted to try is a Strat with 4 pots- Vol, treble cut, mid cut and bass cut controls. I've always been curious to see how well these things work in a passive system.

[Deleted]

Thanx Newey,
once again you are really helpful! If i wire in series with the cap, this will affect the neck pup as well (it is 1 ton, 1 vol ,3-way toggle configuration). What if I wire a separate inductor just for the bridge pup? Will there have to be a cap as well?

Anyway way this pup sounds so compressed and artificial sounding, even after the divider mod e.g. like the distorted tone of Django Reinhart, that I think I should get an EMG 85 or EMG 81 for this position.

[newey]

Here's the link I was thinking of, it was staring me in the face- from the "John's Tones" section.

guitarnuts2.proboards.com/thread/7358/passive-mid-boost-cut-circuit

BTW, since this is an active pickup, you might be able to do an active mid-cut pot running off the preamp/buffer- which might well work a whole lot better than the passive solutions. However, this presupposes that you can access the preamp- if it's one of those active pups where the preamp/buffer circuit is integral to the pickup, that may not be possible.

[Deleted]

Feb 22, 2015 9:45:25 GMT -5 newey said:

Here's the link I was thinking of, it was staring me in the face- from the "John's Tones" section.

guitarnuts2.proboards.com/thread/7358/passive-mid-boost-cut-circuit

BTW, since this is an active pickup, you might be able to do an active mid-cut pot running off the preamp/buffer- which might well work a whole lot better than the passive solutions. However, this presupposes that you can access the preamp- if it's one of those active pups where the preamp/buffer circuit is integral to the pickup, that may not be possible.

thanx!, as you assume this is a closed pup. No easy access to the internals. Its a fantastic pup tho for those guys with retro classic amps who want crazy mid-boosted EVH-type distortion.

[newey]

Sorry, GD, I didn't see your reply before my last post.

What I was suggesting is leaving your tone control alone, and building a separate mid-cut circuit with a trimpot, cap and inductor (and maybe a resistor as well). This could then be set to attenuate the mids as desired, then left permanently set to that level, and stuffed into the cavity, just as with your first mod discussed above.

But, read the other thread to see where the issues with these things lie.

[Deleted]

definitely will!

[Deleted]

In the spirit of tone shaping with the SD actives,
I was wondering if I could shape the tone of the livewire metal bridge pup with a unit like the Artec EX3 or EXP.

Does any friend from here have any experience or even a theory with such a combination?