Hi everyone

Getting microphonic feedback in my Seymour Duncan equipped BM and looking for some advice ...

It's definitely the guitar - I don't have the same issue with either of my Eggles - one of which has the same pups but with black covers rather than the gold plated PAF style on the BM. I've turned the piezos all the way down and I still get the same problem, and there's no feedback through the hex circuitry into my VG88 so I don't think its the RMC system.

Is this a waxing job, or is there some other way to fix it? I've read a blog where someone swears that a thin coating of blutack in between the bobbin and the cover is the best fix.

Or should I just bite the bullet and replace the pickups - I hear a lot of good things about Iron Gear, many of the testimonials are from people replacing SD JB/Jazz pickups ... and if I do, should I risk metal covers again or go for zebra stripes which would also fit in with the vibe of the guitar

Thanks

Steve

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arK music

Hi Steve,

I'm sure ZenGuitar will know the answer here but I'll chime in with my recent experience in the meantime.....

I've has 2 sets of Irongears. The first set were Rolling Mills and they replaced the stock pickups in a PRS SE (the far east made ones). This change was well worth it - I much preferred them in the guitar.

The second set of Irongears were a Blues Engine and Dirty Torque set fitted in a Burny Les Paul clone. Again, fine pickups but TBH very little difference from the stock set...... I did quick recordings before and after the swap and you were hard pushed to spot the difference..... This really showed me the lottery that is pickup replacement - it's certainly possible to make vast improvements. Making little / no difference is equally possible. As is going backwards . For me with the Burny, I pretty much wasted £75. It's not that they are bad pickups - certainly not the case.... Just not the right choices here vs what was already there.

From my understanding, Irongears are well made, machine wound pickups made in the Far East and sold for £30 each. The standard range Seymour Duncans are also machine wound pickups made in the far east and they sell for double the amount...... I've had SD Jazz and JB sets before and I wouldn't say the Irongears were superior but then again I'd not say they were inferior either...... I suppose what I'm trying to say is that they are great budget pickups that can replace cheapie stock pickups on cheaper guitars and sometimes yield great results but it's not always the case...... So in your situation I'd be tempted to either get the SDs potted - if you like the pickup tone except for the microphones it's a safer bet!

What I DID do recently was had some scatter wound pickups made by Bulldog pickups. You're looking at £180 odd for the pair but what you get is a bespoke service. Ring Hayden up and tell him all about the guitar and the amp you're using it with along with what you're trying to achieve and he'll make you something special. He's transformed my Godin (which had Seymours in it) into a guitar that pleases me a lot more..... Again, I did before and after clips and the change in character was huge and in a direction that i liked..... I wanted it for home use only and wanted as much harmonic complexity and character as possible so he suggested either unpotted or partial potted...... He explained that it'd be useless to gig with but perfect at home..... He's bang on the money - I tried it at gig volume and it's feedback ahoy to the point of being unusable. But at home I absolutely love it.....

Gary

Hi Steve,

A couple of thoughts...

First up, is this a new guitar to you that always has this problem in your experience, or has it only just started occurring on a guitar you've owned for a while?

Second, it's worth checking the the mountings, not all microphony is due to the coils or covers, sometimes it can come from the height adjustment screws and springs.

Third, The standard SD Alnico II and JB are without covers but the BM 2.13i has covers fitted which SD can usually supply as an aftermarket part. Might be worth an email to Brian Moore to find ask them how they specify their pick-ups from SD, I know that SD pot some pick-up models but not all. BM should be able to advise whether or not the pick-ups they use are potted or not and if they are whether that is done before or after the pick-up covers are fitted.

Fourth, while I can see that Blutack might work in the short term, it does go hard and dry out over time and wouldn't want to trust it long term. I don't like the thought of dry, brittle, pieces of old Blutack breaking off and getting into the coils and potentially doing damage. Wax potting is proven and benevolent, it is safe for the coils and if the wax in a potted cover does come loose an experienced pick-up maker/repairer can often fix it with a little heat carefully applied.

As for changing pick-ups, I would treat that as a separate issue. If the existing pick-ups do a good job when working properly I would get them sorted. If you think a change would be worthwhile, try to get a clear idea in your head what you find the existing pick-ups lack for you and then give some of the pick-up companies a call and discuss the options. Metal covers generally work just fine, so they aren't really a risk. But they do change the sound of a pick-up slightly, that's one of the things the pick-up makers would consider when discussing alternatives, and it might be worth having a look at the FAQ's on the Seymour Duncan site (especially Seymour's own FAQ's, there are about 250 of them and they are unstructured but make interesting reading for a couple of days). I've also heard good things about Iron Gear, but haven't heard them myself yet. However, don't forget Bare Knuckle who could also help with repairs/potting.

Andy

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When the going gets weird, the Weird turn Pro.

Thanks Gary and Andy.

First a little background on the guitar is in order: I bought it specifically as a Guitar Synth controller a couple of years ago for a band reunion. The singer's voice had changed in the intervening 20 years so we transposed the set down a whole tone. As you can imagine, this wasn't exactly a good thing for tracking - even with my Axon - so the simplest thing was not to use it as a guitar at all and transpose the patches in the Axon. Of course, I now play mainly normal guitar with my VG88 filling in with the odd synth and acoustic guitars. The BM was languishing under my bed until I broke my GK3 again :-(

Gary: the pickups sound fine to me so I'm not looking to replace them out of hand. But while I don't have the kit to pot my pickups, I can solder ...

That's a really nice summary of your experience and the most level headed advice I've heard on the subject for a while. Thanks.

Andy: how would I establish if it is the springs and screws causing the problem? I'm not precisely sure what happens when a pickup goes microphonic - I'm guessing the sound causes some metal to vibrate in the magnetic field. If this were the case, then you could stop the vibration with a finger or a pencil or something I suppose.

I'll contact BM about the spec of the pickups. And a good call about the blutack! I've got to visit a luthier anyway about another guitar and he does a potting service so if it needs that, then I'll get him to do it.

If I had to complain about the pickups it would be the clean sound. My Eggle with SDs also has coil taps and while it doesn't make it sound like a strat, it does add some glass to clean rhythms and thins out lead sounds in a pleasant way. So I would be looking for a pickup that had more clarity for the clean sounds: there's an awful lot going on in the BMs control cavity - I'm not sure there would be room for a push-pull pot for a coil tap!

Thanks to you both again

Steve

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arK music

Quote arkieboy:

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Andy: how would I establish if it is the springs and screws causing the problem? I'm not precisely sure what happens when a pickup goes microphonic - I'm guessing the sound causes some metal to vibrate in the magnetic field. If this were the case, then you could stop the vibration with a finger or a pencil or something I suppose.

---

Exactly right Steve, sometimes you can get to the problem with a fingertip for testing, but other times it's deep inside the body of the pick-up. It has been suggested that Fender originally changed from springs to silicon tubing for pick-up mounting screws due to microphony issues. If the guitar has been lying in it's back in it's case under the bed for years it might well be the covers. A pencil with a rubber on the end might be handy, use the rubber to press on the pick-up covers and see if it reduces or changes the squeals.

Anyway, your tech should be able to sort it all out

And while you are seeing him, ask him to have a look at the wiring. There may be room for a push pull pot, but as you say it's pretty crowded in there and the extra height of the pot body might impinge on the circuits above. But there might be another option worth considering to give you some coil tapped options...

The BM uses a Fender style blade switch, if yours is a 3 way tele style you might be able to replace it with a 4-pole version of the 5 way switch. Jerry Donahue used this on his signature Fender, and it is used on his Peavey signature model now. Depending on how the volume and tone controls are wired you use two or 3 of the poles for the regular switching options, but that leaves one or 2 poles free for things like coil taps, series/parallel switching, and other tricks. It's worth looking at The Jerry Donahue schematics to see how he's used it, so here they are...





Of course these both have single coils, but he is doing some interesting things with capacitors and resistors that change the sound of the pick-ups in some positions. The way they work is by modifying the resistance, inductance, and capacitance of the pick-up to change it's transfer characteristics. For example, a small value capacitor in series with a pick-up makes it a little brighter and the best known user of this mod is Chris Squire with his Rickenbacker basses. With Humbuckers it's possible to use resistors and capacitors in series/parallel with the coils individually or together to make some useful changes.

You tend not to see these wiring options on production instruments or after market tone circuits because they take a little work to get right. The component values you need change depending on the electrical characteristics of the pick-ups, so it's rarely a plug & play option. But the upside is that once you've done the work you have a selection of distinct sounds available at the pick-up selector switch. Very simple to use, no messing around with push/pull pots, you eliminate all the potential switch combinations that are either useless or very similar to others, just the 5 (or 6, if you use rotary switch) sounds you need with the minimum of fuss.

Andy

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When the going gets weird, the Weird turn Pro.

... interesting

I'd settle for a five position switch wired to
* humbucking bridge
* outer single coil bridge
* both pickups outer single coil out of phase
* outer single coil neck
* humbucking neck

I'll have a word!

Steve

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arK music

That is pretty straightforward with the 4 pole switch. If it helps, this is the switch I was talking about. Available elsewhere too as Allparts are a little expensive.

If you search online for Superswitch wiring diagrams you can find some good examples of how to use it to get the options you want.

Andy

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When the going gets weird, the Weird turn Pro.