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Messages - drpepper

#1
I would be tempted to rig up some batteries to power the preamp. That would remove any ground loops.

Good luck, Dean
#2
Wow! That is beautiful piano!

Does it all work?
#3
Quote from: JanneI on March 27, 2017, 11:46:56 AM
Here's my unverified veroboard layout. I figured that since I don't have much time I could just share this if someone likes to try it out. A wise move would be draw a pcb with 9mm alpha pots with same mounting holes as in mk1 panel.. Maybe I'll do it someday :)

Thank you for sharing this Janne. I built this circuit and it works well. I did spot a little error that the C2 negative leg needs to go to pin 7 of the opamp.
I made a couple of tweaks adding a switch to hear the difference between some of the cap values posted here. 

I have posted what I modified, though I have just butchered the previous version in paint.

I also posted a little video of it working here:
https://youtu.be/3hgq8O1YwS4
#4
The Wurlitzer Electric Piano / Re: Hi I'm New Here!
September 28, 2021, 04:46:49 PM
Quote from: jam88 on September 28, 2021, 09:40:11 AM
Quote from: christine1117 on September 27, 2021, 09:25:21 PM
If I knew what kind of steel they're made of, I'd give it a shot at making my own.
I understand your comment about wanting to make reeds. I'm a retired mechanical engineer/metallurgist and have owned a number of Wurlitzers, continuously since the 1960's. Before the resurgence of interest in these pianos, I decided to make my own reeds. Identified Wurlitzer's original steel supplier and alloy, plotted the geometries, and pursued the process to shape the reeds that would prevent stress-raising/decarbing/annealing. Wound up making hundreds of reeds of all styles. I considered selling reeds as a cottage industry in my retirement, but decided against complicating my leisure.

I had the advantage of being employed for decades by defense contractors, with access to CMM, solid modeling, FEA, FFT harmonic analysis, metallurgical laboratory, etc. Also, my position gave me enough weight with vendors to source small quantities of the alloy steel from the European steel producer. (I needed pounds, they like to ship TONS.)

So now I have hundreds of reed blanks, sitting on the shelf, both 120-style and 140/200-style. The unit cost was fairly negligible.

Where I'm going with this:
Reed steel is VERY hard. Not easy to effectively shape without serious capital equipment. Unless you have access to industrial processes, I'd advise against trying to make your own, just for a few reeds.

When you take this deep a dive into reeds, you begin to discover many, many things that Wurlitzer got wrong WRT reed longevity :'(.

This sounds interesting, have you posted your findings somewhere?
Would love to learn more on what Wurlitzer got wrong.

But I agree the metal needs to be really hard, I hear people have had some success with hacksaw blades, but for a for a small number of reeds I would just stick with a vender produced reeds.
#5
Other Keyboards & Software Synths / Re: DIY Electric Piano
September 15, 2021, 03:19:28 AM
I have started to move from my single note piano to a short scale piano.

Link:
https://youtu.be/QObFDnf8hXM

#6
A little update on the project.
Some small improvement to the action and parts created so far.

The main improvement is a spring/clip that reduces key bounce.

I just need to make a few copies of everything created so far.

Link:
https://youtu.be/cp38zGdgmxI

#7
Hi Gotkovsky,

I'm not a Rhodes expert but your wiring looks to be the same approach I plan to take with my piano.
This is the same as Fender Rhodes wiring, though for a different number of pickups.

I know the stage piano used a 10k pot, but I would be interested to try a larger pot.
Guitar volume controls sometime use 500k pots.
There might be some potential to get a hotter signal with a larger pot.
#8
Springs

This week I have been making springs.
I would be interested if anyone else has tried this.
There are a lot of springs in these piano, it takes some time to make them all.

https://youtu.be/Z-ntcRvU_U4

#9
This is looking closer and closer to being an playable instrument.
Cant wait to see how this turns out.

You ready to move to mass production yet?
#10
Hammer Tips

This is the latest update.
I have decided to go along the direction of felt hammer tips as I really enjoy the sound of the early fender Rhodes with felt hammer tips.
Though I have created a shape for the felt to fit around allowing plenty of strike energy to be transferred and the dark attack to also be present. 

https://youtu.be/4tXZq4aoTZM

#11
Quote from: gotkovsky on June 12, 2021, 03:59:58 AM
Congrats on the progress! Love the stack of tone-generators assemblies at the end of the video, I also have a box full of these haha.

I also tried using bicycles spokes a few days ago just for the sake of it and had pretty good results, it's nice to see that you went further with material experimentations!
Thank you - yes I thought I would try a few ideas. They all seemed to give good results, though the fence wire I think will fail the first due to being much softer material. I am glad you enjoyed the pile of tone generator assemblies, I would be interested what is in your pile, what worked? and what you learnt?

Quote from: gotkovsky on June 12, 2021, 03:59:58 AM
Did you try using the thread that's already on the spokes for assembling with the brass block? That would require to machine the brass block on the other side to attach the spoke just like on a bicycle rim though, so I'm not sure that would be a time saver compared to  brazing. I think the Rhodes tine are press-fitted into the block, right?

Ah - interesting idea. I guess my only issue with that is could they unscrew with use - some thread adhesive would work to stop that. I had an idea looking at the spokes the other way. Having the thread at the end nearest the pickup, then a tuning nut/spoke nipple could be used for tuning. The precision of tuning would be so much better.

The reason I chose brazing was I think if there are any gaps in this joint then the sustain will suffer.  Though it is a softer metal, what does it do in fatigue? it's all experimentation.

Quote from: gotkovsky on June 12, 2021, 03:59:58 AM

Were you able to hear and/or measure an improvement in sustain with the spoke alone, versus the spoke associated to the tone bar?
That's an interesting question -  I didn't test this, if I get chance ill post some results.

Quote from: gotkovsky on June 12, 2021, 03:59:58 AM

Did you have a good result with your reed and tone-bar assembly that can be seen at the end of your video?

I only had a little mess around with these but yes, I think there is some good potential with these. The goal was that wurli sound with rhodes sustain.
My plan it to complete this tine piano, then revisit this idea.

Quote from: gotkovsky on June 12, 2021, 03:59:58 AM

I'm also very curious to know what program you are using to simulate natural resonant frequencies in a CAD environment. I'm pretty new to 3D modeling (I'm working with Rhino), and I'd love to learn to use a tool that could do that.

Thanks, and congrats again, so far it looks amazing!

The CAD software is Freecad. This has a bundled finite element solver, which I used for the frequency stuff. Feel free to message me for help or if you want I could create a guide on how I set it up. I would be interested if running this analysis on your reed bar and see what small changes could help.

Keep up the good work, look forward to hearing yours in action!
Dean
#12
Here is the next instalment:

Tine and tonebars

In this I create my own tuning fork Fender Rhodes mk1 inspired design.
I have tried to understand this part in as much detail and share what I have found.
If you have any information or corrections that could be useful for me or someone else taking on
a similar project, please let me know.

hope you enjoy!

Link:
https://youtu.be/XugQ9BgsVpI

#13
Amazing work again.

I would hold off the final tuning until the pickups are there. As the magnetic field may change the acceleration the reeds will be subjected to - which will change the frequency.

For the natural frequency of the rail absorbing the energy of some of the reeds. My guess would look at stiffening it. Do you have space to add a plate at the rear of this? so you can make it an L-section?
#14
Looks great - I can't wait to hear this.
#15
Quote from: epluznante on May 20, 2021, 03:17:55 PM
amazing work man!
Thank you, hopefully we get something useable at the end of this. Still lots of things to work out.

I have upload the next instalment, where I create damper arms.
I am trying 3d printed ones, though will move to aluminium if this is an issue.

https://youtu.be/dRznq3ap3Xs

#16
Ok, good to know.

The next thing I would try is move the spring to the same length for each of the tines. The photo of the 54 shows the spring closer to the end, so it will have a  larger pull on the magnet. The pickup will also be more likely to pick up any vibrations of the spring.

I know it wont be in tune now, but I suspect this is how venders can make new tines match any piano. By creating new tines with the springs at the same length ratio as adjacent tines.

Modifying this ratio will change the sound. You could take a piano, remove 1mm from all tines and then retune. What does this do to the the sound?

All guesses but interested in what you find if you test this.
#17
Interesting how the tone bar twist is reversed for the 54. I doubt this would make a difference, though does this imply a different manufacturer? is there any other differences between them. Might be interesting the swap the tonebars to see if they have an affect.
#18
Looking forward to seeing the preamp go in.
And the cheek blocks look amazing.
D
#19
Yes - You raise some good questions.
I don't have the answers but I do know the feeling of old audio gear and the fear or fire.

My guess is a fuse would help stop an instant short, but where a value of a resistor drifts and something then runs hot, would it still work?
#20
It's really starting to take shape, looks amazing!

Is your plan to mount the pickups the same as a Render Rhodes?

Looking forward to hearing what this sounds like.
#21
Quote from: gotkovsky on May 18, 2021, 06:44:22 AM
Once again, that's super cool! What are your plans for the tone generators? Do you want to use Rhodes tines or are you thinking about making your own?

Thank you! My plan is create my own tone generators. I have a few ideas and prototypes, but I am not certain what I will go with just yet.


Below is the latest version where I create a pickup in the style of a fender Rhodes pickup.

Link:
https://youtu.be/NThxo_2onsE

#22
I have uploaded part 3. I have created a test bench with spare Fender Rhodes parts.
This allows me to change the spares and compare how my designed parts perform.
There is same sound difference, though I think this is due to impedance when compared to a Fender Rhodes.

Link:
https://www.youtube.com/watch?v=vQPBL-JfnQo

#23
Do you know if it has the original caps?
#24
I have now uploaded part 2.
In this part I look in detail at a mk1 key and try to create my own basic version.

Link:
https://youtu.be/nTUWjyOdyq0

#25
Hello,

If anyone is interested in creating their own electric piano or just following a project.
I have created a video on the first part of my attempt to create my own electric piano.
I have modelled my own hammer design, inspired from the a hybrid Fender Rhodes design.

This has been designed to be 3d printed.

Link to video:
https://www.youtube.com/watch?v=INKy_MSkNs8






#26
Hi Cookymonster,

Yes my piano is an early 1975 also. If you are not happy with the bump mod, you should try without....

Interesting we got the pretty much the same solution. I am sure, covered in felt it will feel about the same.

I am still trying some new shapes, but agree that this is an improvement, I am not 100% convinced it's perfect.
The does reduce the hammer throw distance, but I am not sure what that actually means.

I don't expect to achieve the same action feel as a wurli, just something that I can enjoy more. 

#27
I have created a new video on my custom bumps, for the Fender Rhodes mk1 action.
It also shows how to download them in you are interested in trying them.

https://www.youtube.com/watch?v=3wjBQh6KYJY
#28
Quote from: sean on April 01, 2021, 04:56:02 PM

Hmmm... if the STL file were available online, this would easily justify the purchase cost of a 3D printer.


Thanks Sean, if this post doesn't tempt you my next 3 might....haha. I have a few more ideas in the works.


#29
Quote from: mjbarber431 on April 01, 2021, 08:28:18 AM
I'm really not an expert on Rhodes' actions, but one thing that may concern others is the reduced hammer throw distance, as you can see that the mod noticeably sits the hammers above the other notes. This may actually reduce dynamic range by reducing the max velocity of the hammer. I suppose the next step, then, would be measuring the output and "bark" from a standardized hard strike on the modded notes compared with unmodded or bump modded notes. Additionally, your dampers will not mute with as much force if your hammers are resting high enough to tension the bridle straps, so watch out for that. Other than that, which may or may not matter, more power to you! I'd love to see more reports on this as you perfect it.

Thank you

Two good points there,
Reduced hammer throw - yes, if the pedestal is the only thing changed the volume and ability to get bit drops off. But I lowered the escapement and this brought up the volume and bite. I suspect a bit of bite is lost thought I am still playing with shape and escapement. I was able to get the volume to match the unaltered keys, that was how I measured it. Though agree might be worth looking at this more.

Reduced damper force - Once more if the pedestal was the only thing changed the notes still dampen, but there is noticeable loss in force. Reducing the escapement solved this issue also. 

But playability and dynamic range is so much better, at this point in the video I go from whisper quiet to a bit of bite.
https://youtu.be/MUY0o2_SuRw?t=461
This wasn't an option before.





#30
I have been playing around with my action on the 1975 mk1 Rhodes, hybrid hammer, flat pedestal piano.

The bump mod improves it, but it doesn't feel natural to me or what I want.
I have tried to measure the improvements the Bump Mod offers with a rig I have setup.

This has led me to design my own bump/mod and I think I like a lot more - I have got action feeling similar to my WurliTzer action.
I still want to play around with the shape a bit more.

I have put what I have created in this youtube video
https://www.youtube.com/watch?v=MUY0o2_SuRw

I am interested in what others with more experience think of my idea.

I did have to setup the escapement lower for this setup, but I finally have a dynamic range as seen in the video.
#31
Just out of interest what is wrong with the current amp?
If you consider your wurli as an investment you might deprecate the value more than you save going cheap.
#32
I am looking forward to see how this works out. So far it looks amazing.
I have been working on my own rhodes/wurli inspired DIY piano design but it needs some work.
#33
The lever is stiff enough you cant feel a difference, I think if you put all your weight on it there might be issues, but  the same could be said for the original pedal.
Yes it would be easy to make changes to lower the pedal or change the shape - there is no reason its this high that I can tell.

Green was just PLA I had at hand that wouldn't look too out of place. 
#34
My Goal was to create a 3D printed Wurlitzer sustain pedal that would be affordable. The original design is reasonably basic, a wooden box with some cast fittings and what I guess is a motorbike clutch cable. When the pedal is pressed it pulls the cable that then pulls the exposed threaded rod on the bottom of the Wurlitzer piano and disengages the dampers.
With the prices of electric pianos sky rocketing, so have some of the accessories, there are original Wurlitzer sustain pedals for sale now with a buy it now that's higher than I have paid for complete pianos.


Pedal Design


End Fitting Design

Parts List and Costs
•   PLA 1.75mm Filament £15/kg Total £4.52
o   Pedal – 56g - £0.84
o   Enclosure – 200g - £3.00
o   Access Door – 12g - £0.18
o   Cable Clamp – 1g - £0.02
o   Hose Clamp – 5g – £0.08
o   End Fitting – 17g - £0.26
o   Ferrule – 9g – £0.14
•   1x Spring
•   1x Bicycle Brake Cable – £3.99
•   1x 2mm Aluminium Sheet - £6
•   1x Self Adhesive Velcro Hooks
•   4x M3 x 20mm Socket Head Cap
•   2x M3 Nuts
•   2x M5 15mm Hex Head
•   2x M5 Nuts
•   1x ¼" UNC Nut *
•   1x M6 x 35mm Hex Head bolt
•   2x 3mm x 15mm Wood Screws
•   2x 3mm x 30mm Wood Screws

Note* - This nut is the most important item to get correct. Using the wrong size will damage the piano as it will damage the threads on the piano. A M6 nut will feel like it fits for a turn or two then it starts to damage the piano.
The parts I haven't put a price on are stuff I have laying around. Though I don't think these would add to much so I have assumed £5 for these are any good fastener specialist could gather up for you.


Pedal – Part Design


Pedal – Cable Clamp
Two M3 20mm bolts clamp the brake cable to the clamp. These do not require nuts as the tolerance is tight allowing the bolts to thread into the pedal.


Pedal Hinge
M6 35mm Bolt provides a pivot for pedal.


The clamp plate above the pedal features a bracket to allow the spring to connect the pedal and the enclosure.


Spring Connection on Pedal


Enclosure – Cable Outer Clamp
The enclosure has a removable side panel, that allows all the clamps and bolts to be inserted and adjusted.


Side Access Panel


End Fitting - Assembly

The brake cable needs to be threaded though the ferrule and then the ¼" UNC nut can slot into the end. The end fitting has a clamp to hold the brake cable outer. 2 x M3  20mm bolts are used in the clamp. The end fitting a little longer and wider than the original as this now made of plastic, the extra size makes up for the loss in material strength.


3d Printed End Fitting


Finished 3D Printed Pedal


Finished Pedal next to original Pedal
The 3D printed part is created in layers, these show up in the photos and can be felt with a finger, but during use this only adds grip.


Comparison with Original

Weight
Overall the weight of the peal has dropped significantly.
Changes:
•   Steel replaced with aluminium for base plate
•   Rubber replaced with Velcro for grip surface
•   Metal replaced with plastic for pedal
•   Metal replaced with plastic for end fitting
•   Small diameter cable and housing

Print Time
•   22 hours.
o   Pedal – 3 hours
o   Enclosure – 13 hours (Compromises in print settings were made to reduce this)
o   Access Door – 1 hour
o   Cable Clamp –  1hour
o   Hose Clamp – 1 hour
o   End Fitting – 2 hours
o   Ferrule – 1 hour


The Enclosure Mid Print

Function
As the pedal geometry is based on the original the pedal feels the same as the original. After a couple of hours playing, I saw no issues. 

Summary
The pedal performs just like the original for a fraction of the prices of a replacement. Will it last another 50years – I doubt it. Can it take the same load as the original – I also doubt it.
Does it cost a fraction of price and do the job it needs to – yes.

#35
Some photos might help
#36
Does anyone know the dimensions of the Rhodes pickup bobbin? I want to make some and don't really want to butcher a working one for science.
Alternatively anyone in the UK have a dead pickup I could buy?
I hope you don't mind me posting this on this post but I think it ties in with spec.
#37
My advice would be to have a go at doing it yourself.

There is a range of knowledge in the previous threads here and across the web and if you have any issues just post them on here.

These instruments needs require regular work as they adjust over time and being able to quickly open the lid to adjust the voicing of one tine that sounds out will allow you to keep playing.

As far as I am aware there is nothing that can really be done to these that can't be undone (correct me if i am wrong).
#38
Just a thought... could you chrome the tone bars? that wouldn't add too much mass and would look pretty amazing.
Personally though I would just leave them as they are.
#39
When I bought my Rhodes suitcase it had foil taped to the inside of the harp cover, I asked the owner is to reduce hum?
and he said no it was due to the club he regularly played at the stage was the same side of the venue as where the taxis waited to pick people up outside.
The taxi radios would get picked up by the piano and the radio would play over the PA.

I believe he said this worked so I would try that for cheap easy fix

#40
I would imagine it wouldnt be that hard

110v power tools all require a heavy duty 240v to 110v transformer to operate, you cahnge the us socket to one for those?

http://www.sitebox.ltd.uk/tradesafe-33kva-intermittent-rated-transformer-input-240-voltoutput-110-volt-oTRANS33?paid=googlepaidproducts&gclid=CjwKEAjwvPepBRCoqo37teOD1XsSJAC7v6WQpAZRE3nNIExQTxfDTkegtvZaOFE5uZm8dXt4PkAwPhoCA7bw_wcB

I think some of these may give out a little audio hum - something to look out for
#41
looks like some interesting work

The orange cap looks to be a filter cap - this will filter out any noise a poor power supply will generate.

Under it I notice some power resistors - I would guess these are to drop the input voltage to the correct voltage, but since I guess you don't know what the mod input voltage was these will be of little help.

The power socket on the front is also the output as there are 4 pins. (ground, +dc, left out and right out)

Changing this back to stock doesn't look too hard as it looks like maybe only mods on the power supply

I have recently taken on a similiar project here -
http://ep-forum.com/smf/index.php?topic=8500.0


#42
is the old one safe?
does it have an earth?
#43
The phase is determined from the magnet polarity and the direction of the windings, you will need to work out if your winding match the standard setup to determine which orientation is needed for the magnet
#44
I use a twin reverb and think it is fine at low volumes, sure the louder it gets the more amazing it is. It does eat up a good amount of space but think it is worth it. If you want some sound samples  I can send you them.
#45
I thought it could be a good idea to ask what people are currently keeping in their lids and what they ideally would keep in there if on tour. If you bought a piano have you aquire anything unplanned in the lid? Are there and stories of lid treasure saving the day?

Currently in my lid is-
Spare tines
original logo of the rhodes
spare hammer tips
spare damper with felts
glue

When I aquired my piano it contained the missing parts for the piano action which was nice.
So nothing that exciting. What's in yours?
#46
One issue I am working on with the rhodes is that when a note is ringing out and I release my finger from the key, the damper engages, but on a couple of notes it makes a quark noise, does anyone know the cause of this? Is the angle of the felt wrong?
#47
looks really good
looking forward to seeing this finished
what is your plan with legs? and electronics?
#48
thank you for this
i will put it to good use!





#49
great work!

i need a table saw :( life would be so much easier with one

#50
I have given this amp a good going over and it still needs a bit more tweaking but I thought I would share what I have done so far as I am sure this group has its fair share of vintage equipment that requires continuous love and attention.

removing the pan cover reveals the filtering caps

i am sure all amps will have some form of filtering caps, they are there to filter out any noise from the power supply

i like that fact they are made of card....

on closer inspection they are bubbling and leaking, which is bad

some treasure in the post

its impressive how much smaller modern caps are, if you are changing caps on anything, help the next person to look at it by placing the information on the outside

after putting in a new set of tubes and caps the amp is silent when it should be and sounds amazing


the amp also now runs much cooler, i would guess that some of the caps where leaking dc current which was cooking the tubes and pushing the power transformer much harder than needed.  remember to check your caps! reading online advice says to replace them every 10 years!