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Hohner Pianet output buzzing?
Old 17th January 2012
  #1
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🎧 10 years
Hohner Pianet output buzzing?

I recently got a Hohner Pianet T and it sounds ok, needs some tuning and some of the notes are soft but I'm having trouble figuring something out...

At the moment I have no keyboard amp. I'm trying to run the Pianet through my sampler and it comes through with a buzz. I'm not sure if the impedance is wrong or if there is a problem with the audio inputs on my sampler or what.

I have new cable. Going to try running a different line input into the sampler to make sure it is the Pianet's fault.

Any help, please?
Old 17th January 2012
  #2
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1 Review written
🎧 10 years
Probably ground loop hum - common problem with unbalanced instrument cables.

Is everything power from the same AC receptacle? If your piano and sampler are in different rooms, for example, that is very likely to cause this. Try to power them from the same AC source.

I would record that with a passive transformer DI such as a Radial JDI, into a preamp - I find that transformers isolate these hum problems very well.

If it is ground loop hum, the basic problem is this: the piano and sampler both have ground connections. In a perfect world there would be zero ohms between their chassis and ground - but in an imperfect world there is some resistance, and the resistance may not be equal at different points. Electrons trying to escape to earth take the path of least resistance ... literally ... so you can get a situation where your instrument or equipment chassis is a conductor of flowing AC current trying to get to earth. Very weak, but enough to annoy your audio shields.

The other explanation i've heard is that the chassis grounds are connected electrically via the AC power cables, and also via the audio shields that connect each chassis. So effectively, you have a big ol' loop antenna connected to your audio cables, picking up the AC in the air.

It's probably a mixture of both ... because often fixing the AC power supply grounding (e.g. star-grounding in a good studio) cures the problem. Which suggests the first theory.

It's also possible the piano is close to a source of EMI such as a power transformer - try moving it and see if it changes. Similar to moving an electric guitar.

Hopefully it's not an electronic fault ... that's possible too, as parts deteriorate.

www.ebtechaudio.com
Old 17th January 2012
  #3
Gear Nut
 
🎧 10 years
I have a friends Pianet T at my house, they NEED to be plugged into an amp of sorts to get a good level and no hiss. I use my Acoustic 470 with it, the built in verb and trem are made for it!
Old 17th January 2012
  #4
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Thanks for the replies!

Kiwi, that was a great explanation of ground loop hum. Is there any way to fix this? I don't believe the Pianet is powered but it most likely gives an unbalanced output.

After reading a few pieces here and there it seems like maybe a DI box would help, something like a transformer to attenuate the signal or impedance.

Nathanael PCB, I would love to have a keyboard amp, maybe soon.

As for now I'm sure I must be able to get a cleaner sound.

Would it make a difference to use a balanced cable and use a mic input or is this totally wrong?
Old 17th January 2012
  #5
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The Pianet T is passive (no power) and has a fairly low level output. It's quieter than the average electric guitar. Treat it the same way you would treat an electric guitar - use an amp or if you're going direct use a DI.
Either way the best thing you can do is run an instrument pre-amp before your amplifier or DI. A pre-amp with built in EQ is even better because you can cut some of the low end sludge and boost the upper mids to make the pianet cut through a mix. Something as simple as a Boss EQ pedal is a good option.

If you're having hum issues it's most likely going to be the cable or the output jack on the pianet. Also, the body of the pianet isn't shielded so it's susceptible to picking up lots of noise from other equipment. If you have it sitting on another keyboard or have other gear sitting on it try moving everything around and see if the noise goes away.

Lastly, do yourself a favour and buy some new sticky hammers from Clavinet.com. I just replaced the hammers on mine and the difference is night and day. The volume, tone and evenness of all the notes across the keyboard has improved massively. It's the best $80 you'll ever spend.
Old 17th January 2012 | Show parent
  #6
Gear Guru
Quote:
Originally Posted by junkshop ➑️
Also, the body of the pianet isn't shielded so it's susceptible to picking up lots of noise from other equipment.
There you have it. It's an unshielded electric guitar. In the 4 Clavinets Stevie Wonder owns, all have been screened/shielded insides. Copper foil tape was applied insides to all surfaces and then grounded. That does 'wonders' on stage.
Old 17th January 2012
  #7
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Junkshop, would it help with the sheilding to use a balanced TRS cable? At the moment, I'm using unbalanced cable.

Going to:

1. Try TRS cable
2. try a different line source in my sampler
3. Try DI box and keyboard amp
4. Swap out the ouput in the Pianet (not personally)
5. Tune the very first octave which doesn't seem to work at all.
6. Buy Sticky pads!

Thanks, all.

The noise is more than a subtle hum, almost like a phaser type sound, really distorts the channel. Other than this, I love the sound. Will work really well with the sound I'm going for. I wanted an Electra actually but this will suffice as long as I can clean up the signal.
Old 17th January 2012
  #8
Registered User
 
1 Review written
🎧 10 years
Sorry to put you wrong about ground loop hum. I used to own a Hohner piano back in the 80's and should have remembered it was passive. (All my other pianos and keyboards have been powered). You don't get ground loop hum if there is no power supply connected to the AC ground. So this is basically like an electric guitar, and this will be an EMI problem, hence the need for shielding and one single connection to ground via your audio cable.

No need for balanced cable because this is an unbalanced instrument level output by design.

When you say a phaser sound - would frequency is it? Do you mean it slowly sweeps? Sometimes electric instruments can pick up weird EMI stuff that beats against the usual AC background hum ... I believe TV's can do that ...

Does the noise change when you move the piano? It might be too close to something ... or you might need to shield this internally as Jim suggests.

Being passive, impedance will be an issue. I'm guessing a good hi z DI box or instrument input on a preamp would help - or an instrument amp.
Old 17th January 2012 | Show parent
  #9
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🎧 10 years
Quote:
Originally Posted by Play ➑️
Junkshop, would it help with the sheilding to use a balanced TRS cable? At the moment, I'm using unbalanced cable.

Going to:

5. Tune the very first octave which doesn't seem to work at all.
As someone else stated - TRS will make no difference because the output of the pianet is unbalanced. When I talk about the pianet being unshielded what I mean is that the part of the pianet where the pick-ups are housed has no metal shielding. That means if it's close to anything that produces a magnetic field (like anything with a power transformer) it's likely to pick up that magnetic field and pass it along to your amp/di/what-ever as HUM. If the Pianet is sitting on or near any other gear try moving it. Does the hum go away? If so you've found your answer.

Before you do any tuning of any kind try this - take the lid of the pianet. Remove the pink sticky hammers and wash them in soap and warm water (I put them in a mason jar with soap and water and shake them around for a few minutes). Rinse them thoroughly with clean water and let them dry.

While the hammers are off clean any dust, rust and dirt off of the tines with rubbing alcohol and a q tip. Be gentle. Don't use anything abrasive on the tines and don't use anything harsher than rubbing alcohol. While you wait for everything to dry you can vacuum out the inside of the pianet. Once the tines are clean and dry put the hammers back on.
You can change the volume of the notes by placing the hammers closer or farther away from the end of the reed. The closer the hammer is to the front edge of the tine the louder the note will sound. You can also make notes louder by gently bending the pick-up closer to the tine.

This will likely sort out some of your issues with the lower octave. New sticky pads will probably take you the rest of the way.
Pianets rarely have tuning problems. Most issues are caused by dirty pads and rusty tines (both need to be clean and smooth to work as they should). Tuning is done by filing down the reed. It's a messy and dangerous prospect that you'll want to avoid at all costs.

Google is your friend for this stuff. There's a fair bit of info about the Pianet T out there.
Old 17th January 2012
  #10
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Thank you, Junkshop! Some of this does sound familiar, I've done a fair bit of reading.

At the moment, all I have is a 3m 1/4'' jack. I've tried powering the sampler in the living room and having the pianet ~3m away and I'm sure at first, the sound was gone.

I can't see why an amp would remove this sound unless it has a way to earth. Do you think I should skip to the DI box? The sampler's inputs are fine, super clean.

So either,

1. DI Box
2. Replace the output/sheild the output somehow

Is this the way to go?
Old 17th January 2012 | Show parent
  #11
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Quote:
Originally Posted by Kiwi ➑️
When you say a phaser sound - would frequency is it? Do you mean it slowly sweeps? Sometimes electric instruments can pick up weird EMI stuff that beats against the usual AC background hum ... I believe TV's can do that ...

Does the noise change when you move the piano? It might be too close to something ... or you might need to shield this internally as Jim suggests.
Its quite a wide band! Mostly in the mid range and yes, it slowly sweeps. The noise does change slightly with movement. As you'd expect, when making a bit of contact with the jack plug when inserting/removing it, the buzz seems to earth a bit through my body. When swaying the cable, there are some fluctuations as well.

I'm going to try a DI box next I think. Will be sure to let you know how it goes, thanks.
Old 17th January 2012
  #12
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1 Review written
🎧 10 years
Do you have a single coil electric guitar, and does it pick up the same sound?

I'm guessing it's airborne EMI, and maybe nothing you can do about it. Unless it's from a TV or something you can turn off. Try orienting the piano in different directions, or in a different room. EMI often comes and goes, as the offending equipment turns on or off. It could be miles away.

If your cable crackles as you move it, it may not be a high quality cable or you might have corroded connectors. Time for some Deoxit, and maybe a better cable. Try to get an iron-free cable and connectors if you can, because iron pickups up stray EMI.

People don't realise how important cables are, until they have a problems like this. Unbalanced cables just suck. It's also why the hifi audiophools are so besotted with expensive 'interconnects' - because problems abound.

A DI box sitting on the piano to allow a very short cable might help, as it balances the cable and at least helps to removes one source of noise ... but useless if your sampler doesn't have a balanced Mic level input ...
Old 18th January 2012 | Show parent
  #13
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Quote:
Originally Posted by Kiwi ➑️
Do you have a single coil electric guitar, and does it pick up the same sound?
Will try this ASAP, I think I have one somewhere.


Quote:
Originally Posted by Kiwi ➑️
If your cable crackles as you move it, it may not be a high quality cable or you might have corroded connectors. Time for some Deoxit, and maybe a better cable. Try to get an iron-free cable and connectors if you can, because iron pickups up stray EMI.
Thanks, I'll be sure to look for a high quality cable, I just got a cheap one for now which may have been in bad storage too.

Quote:
Originally Posted by Kiwi ➑️
A DI box sitting on the piano to allow a very short cable might help, as it balances the cable and at least helps to removes one source of noise ... but useless if your sampler doesn't have a balanced Mic level input ...
It has a balanced mic input. Hopefully this will do the trick. Will also try cleaning the Pianet connector as you said. If I could find the part I could get it installed quite easily.

If anybody has a suggestion for an appropriate DI box for this purpose, I'm all ears.
Old 18th January 2012
  #14
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🎧 10 years
I toured pianets and clavinettes extensively in the seventies and they were old temperamental pieces of junk back then.
But nothing else had that sound.

Standard maintenance items on pianets was resoldering everything and I mean everything on a regular basis, so that is a good place to start.

Be grateful - on a clav you would also be wrangling the sticky pads and tines!
Old 18th January 2012
  #15
Gear Guru
Stevie Wonder still takes D6's on the road and uses them live everywhere he goes.

They have been modified and rebuilt to hold up. The internals are all screened. Hammer tips have been replaced. One pickup went dead and was replaced. The preamps are all rebuilt, I posted the mods up for free at that Clavinet web site if you want to try them.

The cases were replaced with black tolex covered plywood. He takes 3 on the road, two are used and one as spare. Numero Uno, his personal D6 is fitted with custom preamps I built back in 1982 or so. It is a 2 band EQ, + - 15 db shelf and a sliding frequency control. The pickup switches are wired to two mini 3 way center off toggle switches, that allows all the pickup combo's including off.

Each are fitted with balanced active DI outputs and an effects loop for the mutron filter boxes. They run on two 9 volt batteries as that offers the best noise performance and ground isolation on stage.

Yes, he uses a Motief live instead of those wonderful modified Rhodes, but there is no substitute for the Clavinet.
Old 27th January 2012
  #16
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Can anybody help me finding the right DI Box for a Pianet?

Thanks!
Old 27th January 2012
  #17
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I think you mentioned you had guitars, so I assume you have a guitar amp too?

From my understanding on those pianet T's, they're supposed to sound great through guitar amps. Though I've never tried one personally. I'd ask some others to be certain before trying it, but my guess is you'll get the results you want through your guitar amp. No DI needed, unless you prefer that route.
Old 27th January 2012
  #18
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btw, you should be able to go direct into your audio interface with no buzz. If your sampler is an mpc, that may be your problem, IIRC the inputs aren't designed to record guitars direct, and the Pianet is kind of like a guitar because of the pickup, even though its a keyboard.
Old 29th January 2012
  #19
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Ah, Kaye, Thank you.

I think that may be it. The sampler is an ASR X Pro which is basically an MPC. I have a brand new RME UFX, would those inputs fare any differently?

I have just a toy electric guitar, I don't have an amp yet. I'm looking at one now and I will get a DI box too but I'm unsure whether DI boxes deal with instrument level and guitar levels the same as some of them seem to be marketed more at guitars. From what you're saying, I should be fine with any DI box, should I?
Old 31st January 2012
  #20
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It was the cable!

Sorry if it seemed like I wasn't reading your replies, I went over them all but usually replied after a long read of google.

I am waiting on a BSS AR133 Active DI Box and an undecided combo amp, looking forward to see how I can get it to sound.

I'm quite pissed off at receiving a broken cable.

The sound still has some slight fuzz to it but after the insistent pulse I was getting, I could call it pristine.

Thanks, all.
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