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Messages - valentenet

#1
Hi Jenzz

Was exactly what I did before.
I'm going to move the transformer far away from the cabinet to check if it is causing interference. I'll also try another power supply.


Thanks.
#2
Dear all, how are you?

I know this topic has already been explored a lot. I read all the discussions as well as videos and other forums, but I still come across the problem of electrical network noise or perhaps a ground loop and I would like to exhaust the attempts and discussions about this problem.

I'm working on a Rhodes Suitcase 80w - Peterson design (4 pins). I re-capped it in addition to other components except the power transistors, which are very good (apparently) and the 0.01uF capacitors next to the power transistors.
I redid all the wiring with good new shielded cables in addition to the connectors, I carefully recovered the printed circuit boards, tracks and soldering points.
Result, the piano is incredible and so is the amplifier. In isolation, the piano works without noise when connected to outputs other than the suitcase amp. The problem occurs when I connect the two together then the hum appears.
To know:

1. The piano has the stage conversion kit (VINTAGE VIBE
Fender Rhodes 4 Pin Cheek Block Power Supply).

2. When using the piano in stage mode (without the suitcase amplifier) connected to other amplifiers (e.g. Fender Rumble) or on the soundboard with a D.I. the sound output is perfect, leaking a minimum line hum that is totally tolerable and equalizable.

3. When turning on the amplifier without the piano connected to it, there is absolutely no noise, hum or hiss, completely clean.

4. When connecting the piano to the amplifier, the mains hum (60hz) is immediately audible, regardless of the piano's volume. The hum does not change with the piano volume, it has a fixed volume. Of course, if you increase the volume, the hum is disguised. But if you connect the amp outputs to a soundboard (concurrent with the amplifier), even with a DI the hum comes through very strong.

5. Some ground loop tests (unsuccessful) were performed such as:
5.1 Isolate (cut) the ground wire of the 4-pin cable between the piano and the suitcase ampli.
5.2 Isolate (cut) the power supply wire (25v) of the 4-pin cable between the piano and the suitcase ampli and use the external VV source.
5.3 Connect the piano in stage mode using P10 cables connected between the piano and the suitcase ampli (without the 4-pin cable) and use the external VV power supply.
5.4 Isolate the fixation of the p10 jacks from the ampli suitcase housing body.
5.5 Add more filtering capacitors to the source input (4x 3300uF).
5.6 Add capacitors to the 25v output to reduce possible ripples if the voltage drops.
5.7 Test another (electronic) keyboard connected directly to the ampli suitcase.
5.8 Use power sockets with a grounded line filter (from the studio), invert the poles and test by eliminating the ground as well.
5.9 Turn off all other equipment in the surrounding area, lights, move the piano, also testing other amps to make sure there was no grounding fault in the space.
5.10 I reanalyzed all the wiring, disconnecting the internal circuit from the housing body (both the pre and power amp).
5.11 Temporarily removed the VV stage conversion kit from the instrument.
5.12 I checked all the harp connections, possible differences in grounding, poor contact, oxidation and damper grounding.

In conclusion, I did not obtain any change in the result. It's a mystery!

My next guess is to try to make a modification to the preamp output by installing a sound isolator module (with transformer or octocoupler), or perhaps changing the entire powersuply with a new, more modern circuit.

Has anyone ever experienced this? Has anyone tested a sound isolator between the pre and power amplifier? Or am I the one who is too obsessed with this hum and in this case it is inherent to the instrument?

Thanks

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#3

Quote from: Tines&Reeds on February 10, 2023, 08:40:50 AMI think there is a sketch up model of a key frame somewhere on the internet. Google for it and you might find it...

Thanks @sparkletop, i will look for.
#4
I have an MK1 on my workbench to restore. It was attacked by termites and I am redoing almost all the wooden parts.

One major part that's gone entirely is the front keyframe. I replaced the bad parts and now I'm going to redo the holes. But there was nothing left to use as a hole reference to drill new ones. I was already looking for someone with a similar rhodes here in Brazil to get the measurements and design a new model, but still without success.

I'm looking to see if there are any templates/blueprints available that I can use as a reference to guide new holes?

Wonder if anyone can help me?
#5
Hello guys, I'm the creator of Valente.

I'm sorry for not replying earlier. This project has consumed me absurdly.
It is a dream that is gradually leaving the paper, or the workshop. I've been working on it for many years.

We are in a debutante moment, still beginning. Gradually arriving, soon more in your hands.
It is really the beginning of everything, this is the first message, the site has just been made and we are still preparing videos and material for launch.

But in respect for the EP-Forum and all of you who somehow resemble me, be it in creation, maintenance or music, I dedicate this first degree contact exclusively to this house.

The Valente Piano is not a copy of Rhodes, nor Wurli, nor any other EP. We built an instrument to have its own personality, character and besides being a light and easy EP to be carried by a person.

We wanted to design a new experience, this is what we present and share with the world now. We know that there will be criticism and that there will be novels, somo people will love it, some maybe, but the most important thing is it exists.

Soon we will bring more news. We are planning a way for everyone to get their hands on Valente at some point.

We will try to upload videos on the web in the coming weeks. For now there are some little testing on my @valentenet profile.

Do not hesitate. Please ask questions, get your doubts answered. I will try to answer as soon as possible.
#6
Hello Mitch. I hope it´s not too late to try to help you.

I also have many DIY projects and I can try to exchange some of my experiences.

They are very superficial suggestions, more conceptual to you start your project. You should use these informations and after try some modifications and empirical tests for improovements.
The pianet it´s a nice option to start what you are looking for. I recommend in special the Pianet T to use as a reference. This pianet have a very simple design, mechanical parts and also the electronic circuit.

REEDS:
For you project I recommend you use Accordion Steel Reeds. They are vey easy to find and are very cheap. They are thinner than wurlitzer reeds that is better to get the sound using pads. To get the notes start testing differents sizes and putting some load with a soldering iron and tin, and removing the excess with a file, exactly as they do to wurlitzer reeds.

STICKY PADS:
You can make your pads using a soft silicon rubber, the same used to make silicon molds. Look for "DIY pianet sticky pads" on the web.

PICKUPS:
The pickups are very simple to do. You need to make a bobbin using plastic caps, a "iron" pin for the pole piece (the same as used for the metal structure in buldings constructions, something around 3 or 4 millimiter of diameter), a piece of magnet (neodymium disc) , some bond glue and copper wire (the same for guitars, something between AWG 36 to 39).
Make the bobbin set - glue the caps in to the iron pin.
Use a electric screwdriver or a drilling machine to roll the cooper wire in the bobbin. I believe that something around 1500-2000 turns may be ok. If you cannot count the rolls, you can try checking the final resistance using a multimeter device, somenthing around 100-200 ohms should be okay.
Fix the magnet piece behind the pickup. You can use a bond glue just to the magnet stay in place.
Use a aluminiun strip to fasten the pickup on place. You can use some stick tape. Tie it well. Bend the strip to find better harmonic positions, closing it to the reed and moving up and down, exactly as they do in Rhodes piano.

Note that the Pianets T has very low impedance pickups, doesn´t have magnets, and the circuit needs a transformer do correct the output impedance. Making pickups with magnets bring you to a more interesting results.

HARP:
You can use a steel bar to fix the reeds. Cannot be very light otherwise the reeds don´t get proper oscillation. Try to use something with the section around 1 x 1/2 inch. You can try differents metals, copper and brass are easier to work and make the screws. Aluminiun too but probally you will need a thicker bar.
To fix the reeds on the bar, make the holes on the bar and use a thread forming tool, preparing it to receive the bolts. As the reeds holes are too small, I recommend you use a thin bolt, some around 2.8 to 3mm, or a M3 screw and thread forming tool. Use a ALLEN SOCKET CAP or a HEX machine STEEL bolt, need to be a nice and hard steel.
You will need a spacer sleeve, as the Pianet also have. It´s important to settle and accomodate the reed and garantee that it will sound properly. I recommend use a screw nut, with a measure little bit bigger than the bolt, example a M4 nut. Use a nylon insert lock nut upsidedown, they have a special design shape that improove the clamping torque.

I attached some pictures to illustraste the ideas for you.

I hope it help you. God luck.


https://youtu.be/-TR8yQiWPyg

https://www.youtube.com/watch?v=FfC5bjZfjC0