Done with passive piezos - will only buy active piezo systems (convince me otherwise)

A while back, I made a post about how I was plagued with hum issues on my Risa Uke Solid.

The usual solutions offered were:
-Shielding issue?
-Problem with your mains power?
-Use an external preamp or DI box?
-Noise gate pedal?

The problem appears to affect all passive piezo pickups similarly, at least in the setups I am exposed to.

Interestingly the hum disappears when I use any battery powered amplifier. However, I don't think it is practical for me to only use battery powered amplifiers.

I recently setup a pedalboard to use with my various electric instruments (including electric guitar), and this was the dealbreaker for me. When I plug any passive piezo instrument through them, the hum would be unbearably bad.

And then I plugged in my really cheap Mahalo electric ukulele, with that really cheap Mahalo Chinese preamp. And guess what?
Perfect signal, no hum.

How can such a cheap active option outperform relatively expensive passive systems by so much?
Even if I use an external preamp, the moment the external preamp then connects to an amplifier that is connected to mains power, the hum is back!

After hours and effort, I just made an executive decision for myself.
No more passive piezo instruments.

I've listed all my guitars and ukuleles with passive piezos on the local community sales website (Gumtree Australia). The hell with them!

I will only buy active systems from now on.

Passive piezo pickups are intended for use alongside external preamps. In an active setup, the preamp is built into the instrument. Either way, a preamp is an essential component of the system.

If you want to use an external preamp and avoid an onboard battery, choose passive. If you want to avoid using an external preamp and are okay with periodically replacing a battery, choose active.

So it sounds like, when you use a passive pickup, then need to use an external preamp with it, you in effect have an active system anyway.

I know some don't like active systems because they add weight to a uke. But, if I'm always using a strap, any extra weight is a non-issue for me, YMMV. If plugging in, I like my uke with an active system; it's all right there. I prefer not futzing with a clip on preamp, extra cables, reaching to the preamp on my side to adjust it, etc.

bacchettadavid said:

Passive piezo pickups are intended for use alongside external preamps. In an active setup, the preamp is built into the instrument. Either way, a preamp is an essential component of the system.

If you want to use an external preamp and avoid an onboard battery, choose passive. If you want to avoid using an external preamp and are okay with periodically replacing a battery, choose active.

Click to expand...

The Mi-Si is an active pick-up without the battery.

Ukecaster said:

So it sounds like, when you use a passive pickup, then need to use an external preamp with it, you in effect have an active system anyway.

Click to expand...

That's what I thought too, but I've been finding that a hum is still generated with an external active preamp.
In my case, it seems if I connect the originally passive piezo instrument to anything that is connected to mains power, a hum is generated somehow.

My theory is that perhaps interference will occur even in the lead between the passive piezo and preamp, whereas for an instrument with a built-in active pickup the passive signal has a far shorter distance to travel to its preamp.

Whatever the cause, I just don't find passives feasible nor convenient for my setup at home.
Maybe if I invested the money into an expensive preamp like LR Baggs ($200+) and maybe one of those fancy power-supply systems like a VooDoo Lab power (also $200+) I may achieve some results. But it just seems like a big investment for such a narrow application (in my case, *just* for my passive piezos).

Whereas any active pickup system with a cheap in-built preamp alleviates the issue.
It feels like it would be far less headache for me in the long run just to stick with active systems in my ukes from now on.

I'm sure there are solutions out there for passive piezos, but I've been tackling this issue for years and have decided it's just not worth it any more.


I'm sure passives have their place and their advantages. Just for me personally, I've now formally decided they're not for me.



My amp + pedal setup has no such hum issues on active piezos and passive magnetic pickup systems.

Good point about the Mi-Si, Hoosier. I forgot about that option. It does require recharging, but if I understand the technology correctly, it's a capacitor rather than a battery.

Ukecaster, the principal advantage of passive pickups is that they offer the user flexibility of preamp/DI box pairings. Many players like this additional flexibility and the more advanced functions and/or higher quality construction of dedicated preamps/DI boxes.

Kissing, active pickups are certainly more convenient. I perform at venues where I use XLR out to run to a mixer, so I need at least a DI box regardless of my chosen pickup type. Once you are committed to a DI box, a preamp/DI box isn't that big of an additional step, and I really like the functionality of having a higher-end preamp/DI box onstage. For these reasons, I prefer passive pickups.

kissing said:

I've listed all my guitars and ukuleles with passive piezos on the local community sales website (Gumtree Australia). The hell with them! I will only buy active systems from now on.

Click to expand...

You can replace the passive pickup with an active anytime, in fact, depending on the design of the passive, it could be connected to a preamp. I buy those "cheap" (that function perfectly) active preamp/pickup systems direct from China and installed them myself.

---

8 tenor cutaway ukes, 5 acoustic bass ukes, 10 solid body bass ukes, 7 mini electric bass guitars

• Donate to The Ukulele Kids Club, they provide ukuleles to children's hospital music therapy programs. www.theukc.org
• Member The CC Strummers www.youtube.com/user/CCStrummers/video

bacchettadavid said:

Good point about the Mi-Si, Hoosier. I forgot about that option. It does require recharging, but if I understand the technology correctly, it's a capacitor rather than a battery.

Ukecaster, the principal advantage of passive pickups is that they offer the user flexibility of preamp/DI box pairings. Many players like this additional flexibility and the more advanced functions and/or higher quality construction of dedicated preamps/DI boxes.

Kissing, active pickups are certainly more convenient. I perform at venues where I use XLR out to run to a mixer, so I need at least a DI box regardless of my chosen pickup type. Once you are committed to a DI box, a preamp/DI box isn't that big of an additional step, and I really like the functionality of having a higher-end preamp/DI box onstage. For these reasons, I prefer passive pickups.

Click to expand...

I don't know how much I can get out of my MiSi, because I've never run it down, but I can go a whole weekend, maybe nine hours of plugged in playing, on one charge. It takes two minutes to charge it up, probably about the same amount of time it takes to change out a nine volt battery or to dig out and hook up a preamp to a passive pickup. I'm a MiSi fan.

I have passive K&K pickups in my guitars, and will put them in any Ukes I decide to amplify. I have a “belt clip” K&K pre-amp as well and that combo has always yielded excellent results.


Scooter

I'm sure there are those better versed at this issue, but have you swapped the piezo leads to the output jack? I have no clue if that will do anything, but it is a thought.

John

Thanks for the advice everyone.
I decided, as a last ditch effort, give this external preamp/DI a try:

https://www.ebay.com.au/itm/Joyo-AD2-PreAmp-and-DI-Box-Pedal-for-Acoustic-Guitar-New/401605585535?

If it still hums with this one at the start of my effects loop, then truly I am selling all my passive piezos!

Just what I need, another pedal to add to the chain (currently: Korg Miku -> Vintage distortion -> Ultimate Drive -> Looper).

Maybe the preamp would also benefit my electric guitar too, for the hum/hiss present at high distorted gain

I'm a big fan of the MiSi too, but recently installed a JJB passive "twin spot" type pickup in a vintage uke because I didn't want to change the bridge set up. I have a K & K twin in another vintage uke and love the sound, but it's actually too "hot" for my liking ie. strong output and prone to feedback. The JJB is a bit tamer - and still a beautiful sound. I go direct into a Roland AC33 amp and LOVE what I hear. And eliminating the need for another box (ie pre-amp) is a lovely simplicity.
Confidence in your amplified sound is SO important to your playing. In fact I decided I like it even better than the MiSi.
It's a strong, natural sound - and cheaper than the K & K.

I have a MiSi pickup in the uke I play every Sunday at church. I do not use a DI box. I'm connected via an XLR cable to the church sound system. The church sound guy got me hooked up when I joined the band. I asked if I needed a DI box & was told no. The XLR cable is hooked up to this big box that sits on the floor in the band area. The large mixing console is in the back of the church.The only pedal I have connected is a tuner pedal that functions as my on/off switch. I'm not savvy about sound systems, so I've included pictures of the set-up. The sound is great.

So far, I've never run out of juice with my MiSi. I'd guess I'm playing a total of 1-2 hours per week between practice & actual plugged in time at church on Sunday. I recharge for 2 minutes every other month just to make sure.

kissing said:

Thanks for the advice everyone.
I decided, as a last ditch effort, give this external preamp/DI a try:

https://www.ebay.com.au/itm/Joyo-AD2-PreAmp-and-DI-Box-Pedal-for-Acoustic-Guitar-New/401605585535?

If it still hums with this one at the start of my effects loop, then truly I am selling all my passive piezos!

Just what I need, another pedal to add to the chain (currently: Korg Miku -> Vintage distortion -> Ultimate Drive -> Looper).

Maybe the preamp would also benefit my electric guitar too, for the hum/hiss present at high distorted gain

Click to expand...

Try hitting the Ground Lift on your Pre. Also, what kind of cables go into the pre, and what's coming out? That could be a variable.

update, fyi: https://forum.ukuleleunderground.com/showthread.php?136425-Passive-Pickups-Round-2-discovered-an-EXCELLENT-and-easy-pickup-option!

The preamp/DI didn't fix the issue, nor did the built-in ground lift/anti feedback feature.

I use good quality instrument cables amd patch cables that do not hum when used with active pickups and passive magnetic pickups.

However, I did post a Part 2 to this topic here:
https://forum.ukuleleunderground.co...iscovered-an-EXCELLENT-and-easy-pickup-option!

I found that a particular brand of passive piezo transducer didn't suffer from the hum.

kissing said:

The preamp/DI didn't fix the issue, nor did the built-in ground lift/anti feedback feature.

I use good quality instrument cables amd patch cables that do not hum when used with active pickups and passive magnetic pickups.

However, I did post a Part 2 to this topic here:
https://forum.ukuleleunderground.co...iscovered-an-EXCELLENT-and-easy-pickup-option!

I found that a particular brand of passive piezo transducer didn't suffer from the hum.

Click to expand...

I saw the other thread, but that doesn’t resolve the issue you have.

Personally, I find it hard to believe passives are the problem in your signal chain. There has to be another root cause. While my preference is actives, and I run through a pre with a DI, I’ve run passives without issue. For some reason, general consensus seems to be actives don’t need a pre, or more specifically, a DI.

In other words, to convince you otherwise as requested, I’d identify WHY they hum in your system. Sorry I don’t have any more for you at this point with the little info given on your chain ie: where is the DI in the chain, what happens when you bypass the pedals, etc. Pics and video would help a lot. Easy for me to say what works for me, but that doesn’t help unless you’re running George L cables, for instance.

I just think you still have an issue, or potential issue. But, if you’re good with where you’re at, that’s cool.

Kekani said:

I saw the other thread, but that doesn’t resolve the issue you have.

Personally, I find it hard to believe passives are the problem in your signal chain. There has to be another root cause. While my preference is actives, and I run through a pre with a DI, I’ve run passives without issue. For some reason, general consensus seems to be actives don’t need a pre, or more specifically, a DI.

In other words, to convince you otherwise as requested, I’d identify WHY they hum in your system. Sorry I don’t have any more for you at this point with the little info given on your chain ie: where is the DI in the chain, what happens when you bypass the pedals, etc. Pics and video would help a lot. Easy for me to say what works for me, but that doesn’t help unless you’re running George L cables, for instance.

I just think you still have an issue, or potential issue. But, if you’re good with where you’re at, that’s cool.

Click to expand...

Thanks for taking the time to look at my issues.
I am experiencing the problem on a Roland Bass Cube 20XL.
I am using a JOYO AD-2 Acoustic Guitar active preamp powered by a Caline-5 Power source (running it on 9V made no difference to my results).

I have some generic (but good quality) instrument cables, but I can assure they are not the problem by simple method of deduction.
These cables have zero issues when played with magnetic pickups and active piezo pickups. If they aren't a problem with those other types of pickups, then something is clearly inherently wrong with passive piezo's, as that is the only variable I am changing.

I suspect that passive piezo units are more susceptible to interference, possibly in the mains power itself (50 cycle hum comes to mind).
Magnetic pickups and active piezo pickups on the contrary are designed in such a way to inherently resist this kind of mains hum.

It's interesting you mentioned George L cables.
I actually have one, and after reading your post, I got it out and substituted it into the line that goes from instrument to the pre-amp.
Very astonishing results. It made the problem 100 times worse, making an unbearably loud hum that triggers the clipping warning light on my external preamp! Weirdly enough, no such hum when used with magnetic and active pickups. For some reason, pairing the George L with the passive undersaddle pickup seems to light up the interference hum like a Christmas tree on steroids.

What a strange result this is.


Nevertheless, at this stage, I basically see passive undersaddle piezo's unsuitable for my needs.
Further process of coming up with convoluted solutions like getting something to modify my mains power itself, etc are undesirable.
I should just be able to plug my amp and preamp into any power outlet and not experience excessive amounts of hum.

As discussed in the other topic, I found a particular brand of passive transducers that is a lot more quieter than undersaddle piezo's I've been using.
They are very quiet, and would only hum slightly if I crank up the gain and volume to overload levels.

kissing said:

Thanks for taking the time to look at my issues.
I am experiencing the problem on a Roland Bass Cube 20XL.
I am using a JOYO AD-2 Acoustic Guitar active preamp powered by a Caline-5 Power source (running it on 9V made no difference to my results).

I have some generic (but good quality) instrument cables, but I can assure they are not the problem by simple method of deduction.
These cables have zero issues when played with magnetic pickups and active piezo pickups. If they aren't a problem with those other types of pickups, then something is clearly inherently wrong with passive piezo's, as that is the only variable I am changing.


It's interesting you mentioned George L cables. . . It made the problem 100 times worse, making an unbearably loud hum that triggers the clipping warning light on my external preamp!


Nevertheless, at this stage, I basically see passive undersaddle piezo's unsuitable for my needs.
Further process of coming up with convoluted solutions like getting something to modify my mains power itself, etc are undesirable.
I should just be able to plug my amp and preamp into any power outlet and not experience excessive amounts of hum.

Click to expand...

Your problem is someone else’s problem as well, and some of us are here to help.

First thing if you haven’t done it, check out #2 on Booli’s Page. He’s taken the time to link threads for a reason.
http://bd.entropyadept.com/faq.html

I see couple potential areas to address or at least research, if you want:

The Roland doesn’t have an XLR IN. AC 60 does, for example.

The pre doesn’t have a ground lift. I’d use a known quality pre, like a ParaAcoustic DI, which I always have 2 my bag, plus a Venue on the side. Booli has a cheaper recommendation on his link, but I’ve never used it.

Sorry to be redundant, but my experience tells me to mention cables, because I’ve seen so many failures. Yes, yours may work with certain pickups, but those are not your issue. Usually, store bought cables tend to be of a quality that can be improved (which is why I make my own, because I can, using cables that shield and Neutrik connectors). And you proved it with your “high quality” George L’s, right (I gave all of mine away)?

The bottom line and I totally agree with you, is that you SHOULD be able to plug in without hum, even running 50 cycle around you.

For conversation, Mogami Cables are always recommended in my research, with Canare taking a back seat for electrics because some experience high freq padding. I can’t tell the difference, so I use Canare because I like the braided shield, pvc shield in the GS6 and the concept of their StarQuad XLR. For me, they’re quiet as well. And, those are not necessarily high end cable like Zaolla or Evidence, more along the line of mid Lava Cable I’d guess, or Bayou Cable specifically.

I have owned in the past a Behringer preamp/DI which did have a ground lift switch. That did not help the issue. The hum would reduce by a really subtle single decibel or so.

The JOYO preamp I am using now has an "anti feedback" pedal switch and a dial to control it, which appears to have the same effect as the Behringer's ground lift did.

Do I wanna spend like $300+ on a LR Baggs external preamp just to see if it eliminates hum? Or perhaps a $200+ fancy power source like a Voo Doo Labs one? Not in particular. It seems to be a lot of money to spend on a device that may or may not fix a problem I have on passive undersaddle piezo's only. Mind you, my cheapest instrument, a Mahalo acoustic-electric with a $10 built-in Mahalo preamp resolves the problem, as would any generic Chinese preamp, like Belcat. Getting an expensive preamp like the Paracoustic seemed excessive in comparison.

But in conclusion, I did find a solution. The only instrument I have left that has a passive undersaddle piezo is my classical guitar, for which I found a Peterson passive transducer which has been relatively low on hum in a side by side comparison. I wonder what this passive transducer does differently to minimise hum, with all other variables being equal?


Edit: my new uke on order is the Seagull acoustic-electric nylon from TheUkuleleSite. Being setup by them as we speak!