Messages

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Other Keyboards & Software Synths / Re: Cembalet N Squealing Noise

« on: September 25, 2019, 09:19:01 AM »

The foam dampers do seem to help. I took an evening a couple weeks ago and ripped all the felt off and glued some cubes of foam weatherstripping in their place. The clicking is gone, and only occasionally does that squeal show up. Overall the noise floor of the instrument seems higher than it used to be - still thinking that the dampness got to it. I'm gonna try to leave a small dehumidifier inside to see if that helps. Won't hurt it at least.

Book looks great! I'll have to add it to my Christmas list lol

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Other Keyboards & Software Synths / Re: Cembalet N Squealing Noise

« on: September 10, 2019, 07:17:21 AM »

I might try out some foam and see how that works out. How is your Cemablet coming along?

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Other Keyboards & Software Synths / Re: Cembalet N Squealing Noise

« on: September 08, 2019, 10:50:49 AM »

You're right - it was something in the harp. I pulled back all of the dampers, and the squealing noise was much quieter, and the static and clicking was gone. Just to be sure, I disconnected the harp from the preamp, and sure enough all the noise was gone. Now, I took your advice and cleaned each gap, but then I realized that the place this had been stored for the past five months was my parents basement (long story), which is pretty damp. So I took the hair dryer to the harp for a few minutes, cleaned the gaps again, replaced the dampers, and voila, no more squealing. Only the tiniest of clicks here and there. Thanks for pointing me in the right direction!

I can't help but wonder though if those felt dampers are to blame for the noise. As I had said in another thread, every key would make an audible click when activated until I grounded the copper damper holders. The felts have little stray fuzzies on them (they're felt, after all), and I can imagine that it wouldn't take too much for some of those fuzzies to come loose and wreak some sonic havoc on the pickup. Perhaps it's time to try making some dampers out of foam instead...

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Other Keyboards & Software Synths / Cembalet N Squealing Noise

« on: September 06, 2019, 11:16:53 PM »

My Cembalet N has been in storage since April, and when I pulled it out earlier this week, it was noisy as all heck. Specifically a squealing/oscillating sound, accompanied by some random clicks and pops. It's loud enough to be noticeable while playing. I had noticed the squealing noise a couple times before it went into storage, but it was never anywhere near as loud and constant as it is now. Any idea what might cause this? All of the components on the board are new, except for the transistors, rectifier, and Beyer transformer. Also, this happens in any room in the house and with any amp, so it's unlikely that it's interference.

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Other Keyboards & Software Synths / Re: Cembalet CF

« on: February 19, 2019, 07:45:50 AM »

I think I got it the noise nipped. I ended up taking apart the actual switch and loaded it up with some DeOxit. This tamed most of the noise from tapping around that area of the instrument. Since it seemed less that something was loose electronically and more that something was loose physically, the only other thing I could think of were the couple dozen screws on the underside of the case that hold the harp and key rail. Sure enough, every single one of them was super loose, and tightening after tightening them, I could tap anywhere on the instrument without any awful sounds!

So we're 90% there. That last 10% are several reeds in the first octave that are rusted and cracked beyond repair. I've gotten in touch with a pump organ repair guy locally who will supply me with old pump organ reeds to try out, it we can get the bad ones out. There's so much corrosion in that area though, it is really gonna be a challenge. It looks like someone stored the instrument on it's backside for a long time, while water dripped right down into the middle of the lowest octave, since there's water damage to the wood in that spot too.  Otherwise, this Cembalet has cleaned up brilliantly!

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Other Keyboards & Software Synths / Re: Cembalet CF

« on: February 14, 2019, 06:46:25 AM »

Yeh, I even went in and cleaned them again just to be sure.

This is a vid of it at it's worst:

https://youtu.be/whTme0fxNRA

A friend that was over last night, and he wonders if maybe a wire inside the right cheek block is pinched or crossing or something, since it sounds like a loose connection. I wonder if the mains switch itself is bad. When I got the instrument, the switch wouldn't always power the instrument up, like you'd have to switch it a few times to get it to "catch" - although there doesn't feel like there's anything physically wrong with it. After cleaning it with DeOxit, it now works properly 100% of the time. I should have a 3-prong cord coming in the mail today, so if I have time tonight I'll pop that on there.

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Other Keyboards & Software Synths / Re: Cembalet CF

« on: February 12, 2019, 09:25:07 AM »

I had to make a trip to NYC last month, so I decided I would bring it to a place that serviced my Hohner organ when I lived down there many years ago. Turns out there were three things wrong: first, I had the capacitors reversed   Fortunately I had taken a picture of the board in it's original state to confirm this. My bad! Second, the bridge rectifier symbol on the schematic was reversed, so the last tech installed the new one backwards - not like he would have known better. Third, it needs a working vibrato lightbulb to get any sound at all, even with the vibrato off.

So that's left me to put the mechanical part of the instrument back together. Nearly half of the reeds needed to be tuned to some degree. The lowest G G# and A seem to have corroded beyond repair. So I've set those aside for now and focused on the other 58 notes that are functioning.

The five highest keys are what is giving me the most trouble now. They have an excessive amount of static and popping when activated and released. Before, it was some keys in the middle of the keyboard that when pressed would sound like a loose connection would get looser and hum and crackle - with and without the harp cover on. Same thing happened by tapping on the treble end of the chassis, near the mains switch. This seemed to be solved by (of all things) tightening the screwed-on wire connections to the mains indicator lamp. Where the mains wires came into the chassis was also a screwed connection, I tightened these as well. So now it's just the crazy static on those five notes, which still kinda sounds like something coming loose. I wonder if I should ground the copper damper holders like I did on the N, since this has a different pickup system. Stefan (plucker-maker) says he's never had to ground those on his instruments. My only other thought at this point is to replace the original mains cord with a three-pronger and eliminate that screwed connection for a more stable solder joint.

You can hear some of the noise in this video. It's usually worse though:

https://www.youtube.com/watch?v=o66NOglsirY

It already has a nice sound to it - brighter than the N. I just gotta get rid of those bad sounds and I think I'll have a real neat sounding instrument!

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Other Keyboards & Software Synths / Re: Cembalet CF

« on: November 28, 2018, 08:07:35 PM »

Once he finally got around to it looking at it, he found that the bridge rectifier was shot. Replacing this brought the rest of the board back to what he thought was appropriate power, including at the AF101 transistor. But at the connections to the pickup and reed bar - nothing. He doesn't think there is anything wrong with the transformer either, so he is stumped at this point, as am I.

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Other Keyboards & Software Synths / Re: Cembalet CF

« on: October 26, 2018, 09:54:26 PM »

Ah, that makes sense. I actually brought it over to my trusty amp tech who knows more about this stuff than I do. I passed along your tip to him in case it helps (he, like me, is more familiar with the other Pianet models). I will let you know how he fares with it. Is there a possibility that the transformer coil could have gone bad?

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Other Keyboards & Software Synths / Re: Cembalet CF

« on: October 24, 2018, 06:12:15 AM »

That's what I originally thought, and made sure that no reeds were touching the tabs, but the same thing happened even when the preamp was removed from the keyboard. There's no visually obvious shorts on the preamp board.

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Other Keyboards & Software Synths / Cembalet CF

« on: October 23, 2018, 07:38:09 PM »

Hey gang, just got a Hohner Cembalet CF! Not a C, but a CF. Of course, I'm having some issues with the electronics right out of the box (as expected).

http://hohner-cembalet.com/hohner_cembalet/Cembalet_CF.html

It powers up and does nothing but hum - no keyboard signal. Replaced the e-caps and resistors, same deal. The original volume pot had been removed and jumped together. Installing a replacement 250K pot did not make a difference, and does not affect the hum level when turned.

The vibrato bulb is burned out. I have a Cembalet N which does not have a working vibrato bulb, this does not stop the keyboard from working, it just means that I don't have a vibrato option, so I am assuming this one must work the same, and that the dead bulb is not my problem.

There is no voltage at the pickup. My DMM shows continuity between the pickup and the reeds. Even with the preamp unhooked from the pickup and reeds, their hookups on the board still show continuity, so it's not anything with the harp itself. I've never seen any of the other non-Pianet T Hohners behave this way. But this model has a strange coil thing in parallel with the reeds and pickup, which if I'm understanding the schematic correctly, would explain the continuity.

Anyone have experience with these? The Pianet CH is apparently the same design. What's the next thing I should look at here? I'll look closer at them, but the transistors seem to have appropriate voltage readings.

Thanks!

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Other Keyboards & Software Synths / Re: Pianet Sticky Pad Issues

« on: September 28, 2018, 11:56:34 AM »

Sorry for reviving an old thread, but I've continued to have issues with this and have given some thought about a solution.

I have a Pianet N that has been fitted with KRS pads since I got it about 6 months ago. Recently it seems like I'm repairing a torn pad at least once a week. Most of the time it is the foam itself tearing, sometimes it's just the leather coming unattached. Many of the pads are super compressed as they rest on the reeds.

Ozdoc notes that the felt strip the the keyshafts rest on would have been originally uncompressed. The felt strip, especially on this model, is extremely compressed under the keyshafts.

Here's my thought - why not move the felt strip about 1/4" left or right? The felt in between each keyshaft is unaffected by a keyshaft resting on it for 40+ years. The sticky pads would need some time to decompress to the correct height, and I'm sure I'd have to do some minor adjustments to certain keyshafts. Ultimately, the sticky pad would not be doing the felt strip's work of keeping the keyshaft at it's proper level, and I hopefully won't have to worry about breaking a pad every time I play the darn thing.

Has anyone tried anything like this? What were the results?

On a positive note, the pads that I started repairing with spray adhesive nearly a year ago have a 100% success rate!

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Other Keyboards & Software Synths / Cembalet Static Discharge and Shielding

« on: August 01, 2018, 08:33:46 AM »

For all six or seven Cembalet owners out there...

I've noticed that my Cembalet produces that annoying static discharge "click" that also plagues the electrostatic Pianets fitted with silicone sticky pads.  It used to be that if I did a gliss of the full keyboard every so often, it would get rid of the clicks while I was playing.  But it was getting to the point where this didn't really help anymore, and my playing was continually accompanied by those annoying clicks.

I already had the keyshafts grounded with copper tape a la Pianet, and while this does reduce the overall noise, it did not eliminate the clicking.  The solution?  The copper brackets which hold the foam (or in my case, felt) dampers need to be grounded as well.  To do this, I simply ran another piece of copper tape along the brackets, and connected it to the shielding of the case.  Problem solved!  Make sure you leave enough tape between each copper bracket, otherwise activating one key might activate it's neighbor as well. 

I want to mention that I did this in preparation for recording samples of the Cembalet with my engineer buddy.  My goal at the moment is to get samples for my Nord so the Cembalet doesn't have to leave the house for gigs.  If there's any interest, I'd be happy to share the samples!

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Other Keyboards & Software Synths / Re: Dead Pianet N

« on: July 30, 2018, 09:04:46 PM »

The gig went pretty well, I even brought the Hohner Symphonic organ out too!  Never paired those two before, but it worked.

I never got around to reopening the Pianet to mess around with the reed.  Here's the funny thing - I brought the Pianet to the rehearsal on Wednesday, and it seemed like the note (middle G FWIW) was back to normal.  Compared it against the neighboring notes, and it didn't notice any difference in volume.  And it's been fine since!  Wasn't an issue at the gig, and I've been playing it at home with no problems. I can't explain what happened, but I'll take it.  Any anyway, I now have a nice set of small strong magnets (thanks Amazon) in case I do need to re-magnetize any reeds in the future, either on my N or my T.

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Other Keyboards & Software Synths / Re: Dead Pianet N

« on: July 25, 2018, 11:02:02 AM »

It just occured to me that the Pianet N is electrostatic, in which case the magnetism shouldn't matter(?)

That's what I figured too...but according to a former Hohner tech who used to post on the clavinet.com message board, the N reeds were magnetized.  He says something about it in this post: https://www.tapatalk.com/groups/clavinetdotcommessageboard39332/viewtopic.php?f=3&t=917&p=3019&hilit=magnetize#p3019

Even Aaron who runs clavinet.com recommended re-magnetizing the reed.  So there must be something to it. 

What I don't understand is how my cleaning the reed with a wooden-stick cotton swab would suddenly cause the reed to lose it's magnetism, because the note was fine before I did this.  Last I checked, wood and cotton weren't magnetic!  Stranger things have happened I guess...

I have a gig with it this weekend, so I'll wait to mess with it until after the gig.  I'll let you know how it goes.  I'm skeptical about unscrewing the reed too, as I heard those screws are prone to break.  But maybe a squirt of liquid wrench on the screw might help it come out easily.

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Other Keyboards & Software Synths / Re: Dead Pianet N

« on: July 25, 2018, 07:06:34 AM »

I ended up bringing it over to our local amp genius, and he found two things that likely caused the problem.  First, the bridge rectifier was what had smoked.  He replaced that, then found a broken trace on the board between the photocell and the transistor before it.  Once those were fixed, it was up and running again!  Best part now is that the volume level doesn't drop when the vibrato is switched on, like it did before.

One small (unrelated) problem remains though.  Has anybody every attempted to re-magnetize a reed?  There's one note that is still super quiet after ruling out all mechanical causes.

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Other Keyboards & Software Synths / Dead Pianet N

« on: July 23, 2018, 03:24:12 PM »

Since it had worked wonders on removing the remaining background noise on my Cembalet N, I decided to replace all the resistors on my Pianet N (version II).  I recapped the Pianet when I got it a few months back, but it seemed that the hiss and static was increasing a bit, so I thought I'd be able to take care of it by replacing the reistors.  Well, I plugged it after replacing the resistors to be greeted with a loud hum.  Shut it off, removed the lid, and smelled a distinct burning smell...but no sign of anything burnt.  The only problem seemed to be that the ground pin on the volume pedal socket broke off.  Reconnected that again, turned it on again, this time with the lid off.  Everything working fine.  Replaced the lid.  The hum was back, so I figured that the lid must be shorting something out.  The only thing that looked like it would be touching the lid was the metal case of one of the transistors.  Moved that out of the way, replaced the lid, everything worked fine again.

...Except the vibrato depth was weak.  So I went back in to tweak the vibrato depth level, and as I adjusted it one way, the bulb started to slowly dim out, and the power for the entire Pianet shut off too.  The fuse blew - easily replaced, as I had a direct replacement lying around.  Turned it on again, played well for about 10 seconds, and the bulb began to dim out as the sound faded out to be replaced by a hum.  Shut it off and turned it back on again two more times, same thing.  Although the third time I took the bulb out to see if that would change anything - it didn't.  The fourth time I powered it back up, I got nothing at all. 

After letting it sit for a few minutes, I tried it again.  This time it worked for about a minute before fading out, fading back in, and ultimately fading completely out again.  The unit is still getting power, because the mains light stays on even after the sound disappears.

Any ideas what I should be looking for to bring it back to life?  I guess the moral of today's story is to just deal with the hiss...

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Other Keyboards & Software Synths / Re: RMI 300a issue

« on: June 19, 2018, 07:17:13 AM »

I'm not that big a fan of the RMI sound, but that is one beautiful looking instrument you've got there! Congrats!

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Other Keyboards & Software Synths / Re: Pianet L Preamp Stopped Working

« on: May 30, 2018, 10:14:45 AM »

Turns out that a wire near the voltage regulator pot was crimped against something and shorting out the whole circuit.  Uncrimping the wire brought the Pianet back to life!  Odd thing is that this wire was nowhere near the area where that film cap sparked and started the whole problem.  This was discovered by the tech who originally worked on it for me, after he determined that the transformer was OK, and that the problem might have been in one of the transistors.  He eventually started looking for a bad connection or short and found it.

It's no wonder they switched to PCBs starting on the N models.  The L preamp just seems downright primitive compared to the later preamps.  It does have a different sound than the N, which I can't quite describe, but I do appreciate the difference between the two.  Now if only I could solve the buzzing problem, this L would be perfect...

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Other Keyboards & Software Synths / Re: Pianet L Preamp Stopped Working

« on: May 14, 2018, 09:37:18 PM »

I was looking at it wrong - the cap he added was between the E300/C5 diode and the ground.  And that diode is reading OL in both directions.  Still no voltage coming from the transformer to the E300/C5, but I think it's safe to assume that the diode is shot.  Any ideas on locating an equivalent? The zener and the AC107 are measuring normal. 

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Other Keyboards & Software Synths / Pianet L Preamp Stopped Working

« on: May 13, 2018, 08:37:10 AM »

I really should stop poking around in these things...

The amp tech who initially replaced all the e-caps when I bought the Pianet L added a small film cap between the zener diode and ground (I think), since he thought it might help with the noise. It didn't really, so at one point I disconnected it by just disconnecting one of the leads from the board.

Well that came back to bite me today when I was poking around trying to see something, the clipped lead of the film cap came into contact with where it had been clipped off, made a tiny spark, and no more sound.  Now, in the past when I've done work on the preamp, sometimes it doesn't work when I turn it back on.  The solution to this has been clipping a lead from the pickup itself to the tip of the output jack.  This was a suggestion from the same amp tech who worked on it, and it worked every time.  But not this time.  Tried it several times, and no sound ever came back to either the speakers or the output. 

The Pianet is definitely getting power, since the transformer buzzes like it always does, and the pickup is getting 140 volts as usual.  But there doesn't seem to be any voltage going to the preamp section.  The irony of this is that the reason I was in there was to draw a diagram of the preamp so that I can try to have a better understanding of how it works!

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Other Keyboards & Software Synths / Re: Pianets - are they usually so noisy?

« on: April 26, 2018, 11:59:30 AM »

If I can find replacements for the other transistors for a decent price I'll pick those up and try them out.  Maybe they'll take care of the bit of background noise that is still left.  Otherwise, I'm quite pleased with where it's at now!

The speakers never worked on my L either.  When I got it, it looked like the originals had been replaced by a pair of 3X5 ovals which were both dead.  A couple weeks ago, I was lucky enough to find a pair of 4 ohm 3X5 ovals, which I hooked up and seem to work nicely.  It's a weird sound though, having them point towards the floor.  Very muffled.  They sound brighter with the lid open.  Kind of a strange design when you think about it.  It's not like I would ever use the speakers to record with, but it's neat to have the speakers available so that I don't have to drag an amp into the living room when I want to play.

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Other Keyboards & Software Synths / Re: Pianets - are they usually so noisy?

« on: April 26, 2018, 07:15:05 AM »

Sorry to bump this old thread, I just wanted to give an update in case this info can help anyone else, since there's not much out there about the Pianet L...

I've slowly been replacing all of the (non-e) caps and resistors, and that has helped reduce much of the background noise.  Still noisier than I would have liked, but I figured that this was probably going to be as good as it will get.  In the meantime, I acquired a Cembalet N and a Pianet N version II, both of which work perfectly.  Almost no background noise, and a strong output signal.  This got me thinking about the L again, but this time I brought it to the attention of the Solid State Guitar Amp forum.  Someone over there suggested that the next logical spot to look would be the two AD130 transistors.  Lo and behold, this was the key to solving my problem!  Replaced both trannys and adjusted the trim pot on the preamp so that the collector of the second AD130 read 7V.  I would now say that the L has an acceptable noise floor, and a reasonably strong output signal.  Most importantly, it no longer distorts when playing more than one note at max volume! 

It seems to me that the L might have been the first solid state Pianet, so I can imagine that the preamps in subsequent models are improvements over the ones that came before.  Except for the T, which they seem to have forgotten to even install a preamp !

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Other Keyboards & Software Synths / Re: Hohner Clavinet Production Survey

« on: March 05, 2018, 08:08:39 PM »

Has anyone ever seen this website?

http://www.hohner-clavinet.com/hohner_clavinet/

I wonder if the people behind this site have any of that information that could be of assistance in a production survey.  Go to the links tab at the top to see their pages for Pianets and Cembalets.

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Other Keyboards & Software Synths / Re: Cembalet N Switch

« on: February 12, 2018, 07:15:32 AM »

So I figured out why those tone switch positions sounded so bad.  On a whim, I tried plugging into the amp from the 300mV output.  According to Stefan, who sold me the new pluckers, the 100mV output is only for the CP amplifier, and the reason for the poor sound from the tone switch is because that output is meant to interact with the CP amplifier in a certain way.  Either way, I will stay away from that output from now on!  Now I have three nice and subtly different tone filters to choose from.  Still no luck on the vibrato though, but that's OK.

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Other Keyboards & Software Synths / Re: Cembalet / Pianet Vibrato Clicking

« on: February 07, 2018, 06:44:34 PM »

That's what I originally thought.  I've tried experimenting with moving the sensor further and closer to the light and it seems to make no difference.  Neither does having the harp cover on or off.

I have been using the 100mV output to my amp, but on a whim a few minutes ago, I switched to the 300mV output.  Now there's no clicking when the vibrato is on, but the slight volume drop is still there.  On the plus side, all three tone switch positions sound much better through the 300mV output.  When I was going through the 100mV, only the "up" position was usable without tweaking the amp (the "middle" was dull and bassy and the "down" was thin and tinny). 

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Other Keyboards & Software Synths / Cembalet / Pianet Vibrato Clicking

« on: February 07, 2018, 02:22:16 PM »

My new Cembalet N is finally in playable condition!  The only major problem now is the vibrato.  When it's switched on, there's almost no intensity to it - instead there is a light clicking sound (which is more noticeable with the tone switch on 'high'), and the overall volume of the instrument drops just a bit.  The tremolo lightbulb works and the entire board has been recapped with the appropriate caps.  The rate trim pot changes the rate of the clicking, but the intensity trim pot seems to have no effect on the clicking.  This Cembalet seems to have the older version preamp with the germanium transistors.  Has anyone else ever experienced this?  So far I haven't found anything on the boards about a clicking vibrato.

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Other Keyboards & Software Synths / Re: Cembalet N Switch

« on: February 01, 2018, 03:29:08 PM »

Yes they are!  Definitely gonna have line that whole cavity with copper tape...

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Other Keyboards & Software Synths / Re: Cembalet N Switch

« on: February 01, 2018, 06:58:54 AM »

Turns out that the cheek block can be removed by unscrewing it from the bottom of the instrument!  Attached are pictures of the small board I found hidden inside there.

From what I can gather, this board creates a high pass filter (switch down) and a low pass filter (switch up).  The center position is probably the unfiltered sound of the Cembalet.  My next step is to replace the components on the filter board and see if that cleans up the sound. 

Curiously, the back of the board identifies it as a "Pianet/Cembalet N Filter."  Has anyone else ever seen one of these installed on a Pianet?

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Other Keyboards & Software Synths / Re: Cembalet N Switch

« on: January 31, 2018, 07:43:28 AM »

I've taken a closer look at the schematic and there's definitely no switch on it.  The switch is wired directly to the pins of the swell pedal jack and nothing else. I'm hoping that I can access the switch and get some Deoxit in there and see if that clears things up.  I'll keep you updated.  You really hit the nail on the head about the electronics working great as an antenna for picking up interference!  My Pianet L does the same thing.  Maybe if I get them going at the same time I can pick up some Canadian radio from across Lake Ontario!  I've had an amplifier or two do it...