Topics

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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 / 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 / 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...

4

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 / 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 / Cembalet N Switch

« on: January 30, 2018, 08:34:27 PM »

I just got a Cembalet N that I am working on restoring.  It was super noisy when I got it, so I recapped the board and now I'm waiting for new pluckers and dampers to arrive in the mail.  It's a bit less noisy now that it's been recapped, but the switch on the left cheek block is a mystery.  It seems like it should be a tone switch, but the up and down positions are still super noisy and crackly.  Only the middle position sounds pretty clean (the entire instrument seems to have a bit of hum to it).  I can't quite determine where it fits in the schematic either.  I am using the 100mV output and the Cembalet has the original swell pedal.  Anyone have any idea what that switch is for or why those two positions sound like crap?  Thanks!

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Other Keyboards & Software Synths / Cembalet Pluckers?

« on: December 07, 2017, 02:04:06 PM »

Out of curiosity, who makes and sells replacement Cembalet pluckers?  I've heard that replacements are available, but obviously not through clavinet.com or Ken Rich.

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Other Keyboards & Software Synths / Pianet Sticky Pad Issues

« on: October 11, 2017, 11:28:50 AM »

Has anyone else ever had issues with their 'sandwich' style Pianet replacement pads?  I'm having trouble with a brand new set where the foam itself is tearing apart.  Could they be too sticky?  Keyshafts sitting too low?  Just wanted to see if anyone else has had these issues, since I have not read about anything like this happening with brand new pads. 

On a slightly related note, what methods are there to adjust the height of the keyshafts, short of buying the clavinet.com tool?

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

« on: September 08, 2017, 09:04:42 PM »

So I just got a Pianet L.  It wasn't working when I got it, so I got new sticky pads, then had a local amp tech (who just worked on an N) replace some caps, add a 3-prong power cord, replace the dead volume pot, and add the copper shielding tape.  The thing is, the Pianet is still quite noisy - a combination of white noise and mains hum.  It's nowhere near as bad as before the tech worked on it, but it's still quite noticeable, especially when plugging direct into a mixing board or PA (it's better through my Fender Deluxe).  I found that putting a AC ground lift adapter on the 3-prong cord actually reduces some of the lower frequency hum.  Mechanically, everything works perfectly.  Reeds all vibrate as they should, and Ken Rich's sticky pads work fantastic!

My question is this - is this amount of noise typical or acceptable for an older Pianet?  The only other kind I've ever played is a T, so I have no point of reference.  The instrument itself produces an audible buzz from the general area of the keyboard's electronics, and I wonder if this has something to do with the noise in the output.  I can upload some recordings of the noise if that would help.  Thanks!

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Other Keyboards & Software Synths / Pianet Model Names and Differences

« on: August 28, 2017, 08:52:51 PM »

Can anyone provide insight on what the different model names of the Hohner Pianet were supposed to mean?  Somewhere way back, I was under the impression that N referred to the Natural finish and that T referred to the Tolex finish.  This despite the fact that they were never produced at the same time.  Then I learned of the existence of the original unnamed model, the C, CH, L, LB, and Combo.  The first and last ones are seem self explanatory enough to me.  But what about the others?  It seems unlikely to me that N stands for natural, since all of the other early models have natural wood finishes, and from what I understand, all the models except the Combo came before the N.  I wonder if perhaps the letters stand for German words that are obvious descriptive words for the models, but get lost in the translation.

What are even the differences between the unnamed, C, and CH?  They all seem cosmetically identical to me.  Is it something different internally?  Isn't the N basically the same instrument, only in a slightly smaller case?

The only model name I can make an educated guess on is the LB, with B standing for Battery, since the LB is the battery-powered version of the L.  But of course, what does L stand for?  My guess on that one would be that it stands for Louie, since the L was the one used by the Kingsmen 

But seriously, any answers or guesses to these answers would be great to know!

Oh, and I almost forgot about the M - which a suppose stands for Modulator, Hohner's name for the phaser circuit built into the unit.