Microphonic problem...

[ratspeak]

Seriously. I get my Aftermath set today, route the cr@p out of my guitar to fit them and go through hell with a stripped pot. I was hoping to get an NPD thread up with pics and soundclips, but alas, it is not meant to be. There's some serious microphonic feedback going on, and I refuse to believe it's the brand new BKPs. I don't know the first thing about microphonic problems, but my prime suspect is the grounding. I'm going to go through that now, but I have one other potential suspect: an old 3 way switch from a sqier strat. Is it possible that it could be microphonic (it hasn't been installed in a guitar for a decade, and I only just put it in now)? That's my main question, but any other suggestions would be appreciated.

[BigB]

Seriously. I get my Aftermath set today, route the cr@p out of my guitar to fit them and go through hell with a stripped pot. I was hoping to get an NPD thread up with pics and soundclips, but alas, it is not meant to be. There's some serious microphonic feedback going on, and I refuse to believe it's the brand new BKPs.

Well... shite happens.

I don't know the first thing about microphonic problems,

Mainly: mechanical movement of either the bobin (wire) or magnet. Wax-potting is supposed to prevent this as much as possible by making sure the wire won't move. You didn't ask for an unpotted pup, did you ?

but my prime suspect is the grounding.
I'm going to go through that now, but I have one other potential suspect: an old 3 way switch from a sqier strat. Is it possible that it could be microphonic (it hasn't been installed in a guitar for a decade, and I only just put it in now)? That's my main question, but any other suggestions would be appreciated.

I'm not the most knowledgeable guy around when it comes to electronic, but I just can't imagine how grounding or a switch, however bad, could make a pup microphonic.  :scratch: - if that's the case I'll learn something today.

[AndyR]

I'm in the same position as BigB - I'm no expert, but I'm not sure I've ever heard of microphonic stuff that didn't involve the pickup in some way (on the guitar this is, valves in an amp can go microphonic, but I'm not sure what the symptoms are for that - I suspect noise rather than feedback).

Years ago I used to find polepieces would do it - fiddle with the poles, and the squealing went away. I guess, by theory, that the whole pickup vibrating in it's mounting (ie the screws and springs holding it) could do it...

Anyway, I suggest getting in touch with BKP immediately - they'll be able to (and want to) put your mind at rest quickly.

[Frank]

You could test the pickup out of the guitar - just hold the hot and ground onto the tip and sleeve of a jack plug and see if the amp squeals.

[ratspeak]

That's a good point Frank. I tried wiring it directly to the output inside the guitar and still had the same problem, but I'm starting to suspect it's the way the pickups are mounted. I had to route the cavities to make them fit, so it's a little tight, and the pickup rings are also squeezing the pickups making them unable to take advantage of the give in the springs, similar to what Andy described. When I tap on the pickups with the guitar unplugged it makes a dissonant ringing noise that translates to microphonic feedback through an amp. Would routing the cavities larger and filing down the mounting rings solve that problem?

I didn't ask for an unpotted pickup and assume BKP makes potted pickups by default. Anyway, I just can't imagine it's a problem with the potting, but if it is the BKP team has told me they'll re-pot them free of charge. I'd do this right away, but I live in Canada and it's probably going to be a while before they get back. I want to try some other things, such as making more room for the pickups themselves.

[Transcend]

As has been mentioned wire the pickup to a output jack only outside of the guitar.

and see if you still get the same problems.

if you do then its definitely the pickup

[BigB]

BKPs are indeed wax-potted unless you specifically ask otherwise, and even then that's mostly for the vintage, low-output ones. Now there's always a possibility that something went wrong with the built or has been damaged during the shipping but from what you describe, the problem is very probably with the pups install. Try what Frank suggested and you'll know for sure.

 

[FELINEGUITARS]

I have had an isue or two over the years with the odd BKP being microphonic - even on high gain ones like Miracle man.

Not such a huge deal for me as i have a wax potting bath that I use all the time for potting older and non premium brand pickups for customers who are having issues, but I can certainly sympathise if you are across the seas and it's a bit of a task to send them back.

Obviously high gain amps just make it an issue so easily, and also playing the guitar in a small enclosed space like a bedroom/music room / small rehearsal room just gives you no escape from it

[ratspeak]

Ok, so I went through a lot of the steps you described and came to this conclusion: Everything single thing in the house is microphonic. I've tried four guitars, two amps (swapped preamp tubes in one), changed my location multiple times, swapped cables and checked the wiring for everything. So I tried other guitars and other amps and get the exact same. High volume squealing and ringing when I tap the instruments at all volumes. This is the weirdest thing I've ever encountered. This just started yesterday and I can't think of anything new in the house that could be causing it... Except for my little brother's RC car that transmits video and audio... Hmm... Could that be causing this insanity? What other things might be doing so?

[Transcend]

The RC car could be causing some problems

as your guitar could act as an anntena and pick up the frequencies.

[ratspeak]

Well, I popped the batteries out of his car and the problem is still there. I can't imagine what could be causing it, but I'm pretty much screwed until I figure it out.

EDIT: Well, I'm glad it's not the pickups. I found that after removing the batteries from the car and waiting a while the feedback was reduced. It's even more reduced now that I've unplugged the digital-cable TV. Still there, but less. I'm going to look into getting a power conditioner (I think that's what they're called) to reduce interference.

[Transcend]

ave yout tried it with other guitars? since unplugging other things etc?

what else has happened new that could have caused it?

My old CRT TV & PC monitor caused massive amounts of buzzing and hum but never feedback.

just having my monitor plugged in seemed to cause problems with my guitar amp which really annoyed me so i got rid of the monitor sharpish

[Frank]

Have you tried another amp?

Buying a power conditioner won't have any effect if the pickup is microphonic, all you'll have then is a microphonic pickup plugged into an amp running on nicely filtered AC. And what if you're playing a venue with nasty dirty AC mains supply?

I'd be looking to fix the root cause of the problem instead of chasing round the house fixing other things. If the pickup's squealing then try another amp, if it still squeals then you shoulkd maybe think about getting the pickup replaced or repotted.

[Transcend]

hes already tried other amps and guitars he knows that have no problem and the problem appears across everything

[hunter]

do you have feedback or noise?