Double Bass Schaller pickup feedbacks, crackles, etc. Defective unit?

[eukatheude]

So I just mounted the thing with some adhesive tape. If I let a note sustain, it feedbacks in the course of 2 or 3 seconds - save for some which have zero sustain. Some notes, like the open G, feedback immediately.
I also got some inconsistent crackling (ie. not reproductible at will, at least as far as I know having tried it for 5 minutes just now.) and very unpleasant distortion if I dig in. Also, the volume on the G is much higher than the other strings, no matter how I set the polepieces. Those seem to have almost no effect on the strings volume, and if I screw the G one on the bottom, the pickup either crackles constantly or is just plain muted.
I tried mounting it a bit lower, but it doesn't seem to have changed much.
I've never had a magnetic pickup behave like this, and this one is supposed to work the same way as an EB pickup... what do you think?
Of course, cables and amp are fine with other (electric) basses etc. etc.
I'm using Helicores and the bass is a cheap one. My first thought is about just sending it back.

 

[DoubleMIDI]

Maybe the jack of the Schaller is oxidized?

For testing I would prefer a clamp to fix the Schaller at the end of the fingerboard or screw as intended into the fingerboard which I did with my old cheap plywood bass.
As far as I can remember there is only one coil in the Schaller with adjustable poles to get closer to a string if the sound of this string is too weak. So the coil must be OK.

What about your strings, do they have a steel core? If not they might not work well with the Schaller.

 

[Jay Corwin]

If it's mounted with adhesive tape, then it's probably rattling around every time you play a note. That could be causing all kinds of noise. This pickup is also a single coil, so no hum canceling.

When you dig in it distorts....well that's kind of how magnetic pickups respond on a bass guitar. That is the harder you play, the greater the output from the pickup, so depending on the gain settings in the chain it sounds normal.

And lastly, any deficiencies to the bass are going to get amplified just as well as the stuff you want to hear. So if there are problems inherent to the bass, then they will be that much more noticeable through an amplifier. If you find that something is either weak or wonky playing acoustically, be prepared to be driven nuts trying to get rid of it amplified.

 

[DoubleMIDI]

To reduce non-linearities, better don't get too close to the strings with the polepieces. You get a weaker signal but less distorted when you play loud.

 

[eukatheude]

It's not a piezo, it shouldn't be affected by vibration AFAIK. I will try clamping and see what happens but I doubt this is the case.
It distorts A LOT and VERY UNPLEASANTLY. And I've never had this kind of distortion on an EB - and back in the day I used to play it like I was trying to smite the strings into something...
I should mention I'm a DB newbie but I've been playing electric for about 12 years, which doesn't make me an ultra expert but I'm no idiot either. I also do all my work on my basses, including electronics. That just goes to say that I'm not that guy who's using a faulty cable or forgot his fuzzbox on...

The output jack is one of those horrible plastic things, which if it hasn't failed now it soon will. If I end up keeping the PU, I'll put a switchcraft jack in it.

The bass does not have horrible dead spots; there are some weaker zones but it doesn't seem like the ones that are problematic while amplified are the same. I will need try it with more attention tomorrow and also through headphones to eliminate possible room problems - most of the feedback seems to be coming from the bass resonating with itself, as I can physically feel the string vibrating stronger.

I also tried lowering the pole pieces to almost no effect. I also tried lowering the position which it connects to the FB and it's a little better but still very far from good or balanced (G string in particular is very loud compared to the other strings, even with the polepieces at their extremes. Have I mentioned the pickup goes completely silent if I screw down completely the most treble-side polepiece, and starts working again if I bring it up a bit?


The only possible thing that could be an error on my side is that I intentionally mounted the thing backwards in order to get better contact on the FB, (I'd really like to avoid having to ruin the FB since this bass will likely get sold in the future but the PU will not, provided I can get it to work properly...) because I found forum evidence of people doing that with velcro mounting and having zero issues: Mounting a Schaller mag pickup
I will try flipping and clamping and see if it's better.

Right now the strings are about 8mm away from the polepieces, except for the G string which is 1.2cm and still sounds much stronger than the others.
The pickup itself is as low as it can possibly be on this FB, tape or not.

 

[DoubleMIDI]

Right now the strings are about 8mm away from the polepieces, except for the G string which is 1.2mm and still sounds much stronger than the others.

Is this a typo?
If the distance between string and pole piece on the G is 1.2 mm and 8 mm for the others, what do you expect?

And you didn't tell us which strings you use since this might be important.

 

[eukatheude]

I think I out what's causing the pup to go silent... When screwed completely down, the pole piece shorts with the volume pot's lugs, which is some truly bad design I have to say. Especially since they could have just rotated the pot by 90°, which is what I'm about to do.

Is this a typo?
If the distance between string and pole piece on the G is 1.2 mm and 8 mm for the others, what do you expect?

And you didn't tell us which strings you use since this might be important.

Yep, my bad. 12mm, now I corrected it.
I did tell you which strings I use. In the open post. D'addario helicores hybrid, which have a steel core. They are also new (1 month).

 

[eukatheude]

I did find some guys saying that their polepiece would rattle in their posts. I had noticed that mine are also very loose, so I will look into this too. I will also try building a little contraption with an old&cheap P pickup I have laying around and see if I have the same issues.

I am frankly astonished since Schaller tuners are great and this pup is arguably a "classic". How can it be such a mediocre product (and it's not cheap!) is truly beyond me.

Meanwhile, pictures: one shows the mounting direction, the other shows that it's as low as possible, the last one shows the polepiece (not completely screwed in) about to contact the pot.

 

[DoubleMIDI]

I did tell you which strings I use. In the open post. D'addario helicores hybrid, which have a steel core. They are also new (1 month).

Sorry, for some reason I missed that.
So the strings should be no problem.

Are you left handed? If not I would rotate the pickup by 180 degree so that you have the pot on the E-string side. That's how I have mounted mine. At least worth a try.

 

[Jay Corwin]

It's not a piezo, it shouldn't be affected by vibration AFAIK. I will try clamping and see what happens but I doubt this is the case.
.

I know it's not a piezo, because I read your OP. However if the pickup is rattling around as the strings are moving, it does not matter if it's magnetic or not. It will still cause undesirable effects. The pickup is supposed to be the fixed part of the equation.

 

[eukatheude]

Wasn't able to do the tests I wrote about in the last posts, came home too late and I don't wanna wake up anyone. Will update.

Sorry, for some reason I missed that.
So the strings should be no problem.

Are you left handed? If not I would rotate the pickup by 180 degree so that you have the pot on the E-string side. That's how I have mounted mine. At least worth a try.

NP, it happens.
Nope, right handed. I mounted it that way to have better contact surface with the FB, but I will try this too indeed.

I know it's not a piezo, because I read your OP. However if the pickup is rattling around as the strings are moving, it does not matter if it's magnetic or not. It will still cause undesirable effects. The pickup is supposed to be the fixed part of the equation.

It doesn't seem to be rattling. I used some not-quite-industrial-but-strong adhesive, and I also played some open notes while holding the pup with my hand... Will try clamps but I don't think that is the problem, or at least all of it.
With some internet search I found out some guys talking about their polepieces rattling, thus causing both my issues. Said polepieces are also supposed to be covered in threadlock or similar (check out the Gollihur pics) while mine aren't. Something I can fix of course, but if the unit turns out to be defective I don't want any more gunk to clean off before shipping it back...

 

[Mark Gollihur]

I want to address some things I noticed in reading this thread; I may be mistaken about a few things, so my apologies.

1. I don't agree that the coil shorting out against the jack is "bad design" - the coil is not intended to be lower than the outer edge of the pickup. If you have it recessed so far that it is actually deep "inside" the pickup shell, that's too low. You should move the entire pickup back if it's too close when set level with the top surface of the pickup.
2. To that point, your string height looks REALLY low. Like, electric bass guitar low. If that's not just an optical illusion thanks to the angle of the photo, this might be part of your problem as well, as you have to have the pickup very close to the strings as a result. Probably too close. See other posts above, where some folks mentioned having the elements too close and it disturbing the magnetic field.
3. It's not unusual to have lessened response from the lower strings with Helicores - we even specifically mention them on our Schaller page:
   "(Note: though I have my concerns with the E string; seems as if its response is somewhat lower than the other strings, at least the Orchestra and Hybrids I tried seemed that way.)"
4. Mounting the pickup "upside down" should have no ill effects; all four elements, AFAIK, are identical and are not each tailored for a specific string. Mounting it securely so that it doesn't wobble, however, does matter.
5. To that point, I think that what sevenyearsdown said about "rattling" wasn't so much a noise, but rather a physical movement (wobble) of the pickup because it's not mounted with something "solid"; this movement/vibration could affect how well the strings are picked up, since the magnetic field created by the pickup is "wobbling" and therefore inconsistent.

 

[eukatheude]

I want to address some things I noticed in reading this thread; I may be mistaken about a few things, so my apologies.

1. I don't agree that the coil shorting out against the jack is "bad design" - the coil is not intended to be lower than the outer edge of the pickup. If you have it recessed so far that it is actually deep "inside" the pickup shell, that's too low. You should move the entire pickup back if it's too close when set level with the top surface of the pickup.
2. To that point, your string height looks REALLY low. Like, electric bass guitar low. If that's not just an optical illusion thanks to the angle of the photo, this might be part of your problem as well, as you have to have the pickup very close to the strings as a result. Probably too close. See other posts above, where some folks mentioned having the elements too close and it disturbing the magnetic field.
3. It's not unusual to have lessened response from the lower strings with Helicores - we even specifically mention them on our Schaller page:
   "(Note: though I have my concerns with the E string; seems as if its response is somewhat lower than the other strings, at least the Orchestra and Hybrids I tried seemed that way.)"
4. Mounting the pickup "upside down" should have no ill effects; all four elements, AFAIK, are identical and are not each tailored for a specific string. Mounting it securely so that it doesn't wobble, however, does matter.
5. To that point, I think that what sevenyearsdown said about "rattling" wasn't so much a noise, but rather a physical movement (wobble) of the pickup because it's not mounted with something "solid"; this movement/vibration could affect how well the strings are picked up, since the magnetic field created by the pickup is "wobbling" and therefore inconsistent.

Hi Mark, thanks for commenting. I should mention that, why I am complaining about the product, I only mentioned you since I've used your site as an info resource only, as buying overseas wouldn't be very convenient. So I'd like to point out that this is not a complaint about your store, since it might sound like that's the case.
Replies below

1. I did not know that; unfortunately Schaller provides no instructions whatsoever. Even on their site, mounting instructions for this pickup redirect to generic guitar pickups instructions - in German only.

2. Not the case, I think. Measured from the top of the string they are all in the 1 cm ballpark - for your convenience, that's a bit more than 3/8 inches. I'm a DB newbie as mentioned, but I'm using as reference Rufus Reid's Evolving Upwards as in the first pages he talks about his setup. Measured from the center of the strings, they are (from E to G) 7/16, 3/8, 3/8, 1/4 inches and he also mentions that he could easily go lower, but prefers it this way to allow better dynamics. The pickup itself is as low as it can go, and from what I can "measure" by eye, mounting it via the screws would not get it any lower. I did raise the bass side a bit in order to compensate for the E string.

3. When I checked your page again (after buying the pup) I did skip the section about strings since I already had them on and already knew - from your site - that I needed steels. Heh, should have bought spiros. Anyway, with the pickup mounted a little higher on the bass side it's much better. I can also compensate a bit with technique, so it works. The real problem is the feedback if I let the note sustain.

4&5. It is quite solid, and I tried keeping it steady while playing open notes. Will try clamps though.

What do you think about the loose polepieces, by the way? Would you recommend using thread-locking paste?

I tried the pup again this morning with more reasonable (but usable) volume (I was pushing my amp and 4x10 to almost max, with the cab in a corner) and it's better. It still feedbacks if I let an open note sustain, though, even at fairly low volume. What is supposed to be a good distance from the strings to the polepieces?

 

[DoubleMIDI]

Feedback coming into the strings is normal if you place the cab pushing against top or back of the bass. Raise the cab, maybe angle it a bit and turn it away from the bass.
The feedback comes from shaking the top which shakes the bridge shaking the strings. And the string you just played had the same frequency as the amplified note, so you got a high resonance there leading to feedback.

 

[eukatheude]

Which reminds me... Tomorrow is NCD

 

[Mark Gollihur]

Hi Mark, thanks for commenting.

I didn't think you were complaining about us, but thanks for clarifying.

1. Yeah, their instruction is a little lacking.

2. Thanks for giving me a better idea of the actual setup - the photo was a little tough to judge on.

What do you think about the loose polepieces, by the way? Would you recommend using thread-locking paste?

I think you could probably make less of a mess of it by using a piece of teflon tape wrapped around the threads. But if you do threadlock, use the "non-permanent" version and use it sparingly.

I tried the pup again this morning with more reasonable (but usable) volume (I was pushing my amp and 4x10 to almost max, with the cab in a corner) and it's better. It still feedbacks if I let an open note sustain, though, even at fairly low volume.

Here's some choice feedback tips from our tip sheet that may help...

#1 -- Avoid placing your amp speaker directly behind you, aiming at the bass; the bass vibrates with the amplified sound, picking it up just like a giant microphone, and if it doesn't feed back, you're still reintroducing your amplified sound back to your bass. Reflections of the sound off adjacent walls have the same effects. Corner placement typically reinforces bass frequencies and can make them boomy, further adding to the problem.

Try placing your amp speaker alongside you, in the same plane as the bass, so you can hear but so the speakers don't aim at and excite the bass body. You could also consider placing the it on the opposite side of the stage at a slight angle so you can hear. Finally, try putting the speaker on a stand if it must be directly behind you, higher up and at an angle to avoid aiming it at the bass’ body.

Cut back a bit on lower bass frequencies (around 30-60hz. on a graphic EQ; the low open E string is 42hz.), roll back your bass’ tone control a bit, or use a properly adjusted high pass filter (rolls off frequencies below a set point. That satisfying stage thickness may be hurting your clarity out in the room, and can initiate feedback. BTW, you’ll find 1000 hz to be the frequency band where most finger noise resides... but you may not want to kill it completely, as it can add desired definition and attack.

Cut the monitor frequency response thinner, adding in strong midrange but with the lows cut back so you can hear your intonation without exciting the bass body; it's not a pleasant tone, but it beats feedback and not hearing yourself. Let the PA (if there) fill in the bottom.

Feedback eliminators such as those available from Sabine, Behringer and others may help, but they can be expensive and may not always be effective in a good way. They typically automatically detect the frequency causing the problem and cut it back – which may not be good for your sound and can reduce the volume of specific note ranges. However, some players find them very useful.

Notch filters or parametric equalizers can also help you find and cut back a problem frequency due to their precision. Is an A or Bb the main problem? Welcome to the club — that's one of a typical bass' favorite resonant frequencies.

Extremes — Some Rockabilly guys go to great lengths to avoid feedback since they are competing head-to-head with a loud drummer and guitarist. If you are playing this loud, some radical steps may be in order. One amazingly simple assist is placing a small Nerf football between the bass body and tailpiece - it works!

What is supposed to be a good distance from the strings to the polepieces?

The ideal distance can only be found through experimenting, as everyone's bass, strings and playing style can differ widely. But I'd start with the elements level with the fingerboard and tweak from there.

 

[eukatheude]

Thank you. I guess I had expected it to perform like an EB would, since Schaller market it as a no-feedback-whatsoever pickup.

By the way, I largely prefer the sound of the cheap piezo I already had on. Would I be better off getting a refund on the Schaller and investing the cash in a better piezo/a preamp, or do you think that the Schaller allows volumes which aren't achievable with a piezo+pre setup?



EDIT: Testing with the new cab (EBS neo 2x12) on top of the old one, I actually get more bass and volume out of the piezo - which is arguably a Shadow SH712 (previous owner did not know) that isn't even really well mounted. When I got the bass it was stuck in place with some horrible wood splinters (ie. http://www.talkbass.com/attachments/img_20150714_223143-jpg.652153/ ). I made a couple of rough shims out of some teak wood leftovers and the sound is greatly improved.

Feedback is about the same between the two pups, though I do appreciate having a knob on hand's reach when needed. Yet I was hoping for much more. As it stands I'm strongly inclined towards just getting my money back and building fdeck's pre.
Or maybe spend that money on a Bassmax or a Big twin/Double big twin - and still build the pre of course.



Haven't gone into detail about what I'll be playing, I just realized. The priority is loud 60's rock and roll with the band that's providing most of my income (and in which I'm playing EB at the moment). The guy who played with them before me used one of these Schallers, but I don't know him personally.
Also, I'd like to have the "jazziest" sound possible since I'm also learning jazz with some other guys on the weekends, and I really dig the stringy sound.

 

[Francois Blais]

Are you still using the Schaller pickup, @eukatheude ?