PRIMOVA - GKMX-33 Project - The ultimate-No US-20 bug 3in/3out GK switcher

Started by CodeSmart, March 25, 2014, 12:50:21 PM

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CodeSmart

Finally got time to solder up the thing. So far so god, no smoke: +3.3V, +5V, +7,-7V alive and well.
The toggling MOSFET circuit for the Power switch works fine.
It works like GP-10 so the thing doesn't turn on when Power is applied until you press a putton, if pressing it again it turns it off.

Now time to see if I can get in contact with the Microcontroller to start verify the board I/O and try to get the LCD working  :D

But I got more gear than I need...and I like it!

Autana

Amazing!  it look simply promising and GAS triggering btw. Congratulations for this step getting close more to complete picture! 
GR-55, GP-10, GI-20, Godin xtSA, GodinNylon MultiAc, Giannini classical, 3 GK-3'd gtrs, Cube 80XL, Primova GKFX-21 (x2)

Fear just pulls you out of being true to music, which is coming from a place of love. Love is the opposite of fear. I stay away from anything fear-related.
- Tal Wilkenfeld -

gumtown

You soldered all that by hand? Frightening  :o

It is looking very good !
Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

whippinpost91850


CodeSmart

Quote from: gumtown on May 29, 2016, 05:18:21 PM
You soldered all that by hand? Frightening  :o

Yes it take a fair amount of hours, I'd guess a full working day. As I've moved from using rare chips, the amount grew...plus there's over 100 caps. If the board is noiseless I'll probably unsolder a few of them to see what can be omitted.

Anyhow, this will never be a cheap thing due to the amount of stuff to mount + over $100 USD in component cost (12 x AD5263 really drains the wallet).
But I got more gear than I need...and I like it!

sixeight

Quote from: CodeSmart on May 29, 2016, 11:00:23 PM
Anyhow, this will never be a cheap thing due to the amount of stuff to mount + over $100 USD in component cost (12 x AD5263 really drains the wallet).

These projects are never cheap unless you start to cut corners. But then you won't be happy with it afterwards. Really looking forward to the end product.

I will be in Sweden this summer. Maybe we can meet up. I will travel from Hyltebruk to Stockholm and back. With a bit of a detour it may just work...

CodeSmart

Quote from: sixeight on May 30, 2016, 08:34:57 AM
I will be in Sweden this summer. Maybe we can meet up. I will travel from Hyltebruk to Stockholm and back. With a bit of a detour it may just work...

Cool Sixeight, PM me the dates and we'll see what we can do. If it's a vacation trip I can recommend a route and some great places to stop (assuming you go by car).
But I got more gear than I need...and I like it!

CodeSmart

Started a bit of programming. The LEDs shine and the I2C bus controlled Quad DAC (MCP4728) is also working so now I have backlight on the LCD and GK VOL signal on the three GK outputs. The 2x16 LCD however is not showing text until after several minutes of initalization so something is weird. I use the same code as last year but now have a display from www.buydisplay.com (East Rising) and something is different. Will try other code asap.
At least great that the PIC24FJ256GB108 Micro Controller is working. So far so good :)
But I got more gear than I need...and I like it!

whippinpost91850


sixeight

I was looking through some old threads. Any progress on this project?

CodeSmart

MIDX-20 development and production came in the way :-(
But it's not forgotten.
But I got more gear than I need...and I like it!

CodeSmart


Finally fired up this old project again. The signal noise levels are quite good after a few fixes. First of all I got rid of the 25kHz switching noise from the -7V generation. It sounds good now and looks ok on the scope. Now it's time to write more code to see if any circuits in action (volume pots, display and DAC) generates audible noise. This baby got a lot of memory for extensive programming. I hope to reuse most of the menus and stuff I did over two years ago when I started this mission with a less powerful processor.

But I got more gear than I need...and I like it!

whippinpost91850


gumtown

Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

gibvictory


Frank

Looks great, I definitely want one when they're in production.  :D

CodeSmart



So what the heck is this?
Well, when developing something "GK", maybe its not the analog portion or the digital portion of circuits that's the real problem.

The real nut to crack is the power circuit!
You really need perfect power to get low noise analog audio on a mixed analog/digital board.

I wanted:
1. Possibility to decide if device defaults to ON or OFF.
2. When ON, a long push on a button would turn it off, and a short push would turn it on again (just like GR-55/GP-10).
3. When it turns on, I want the microcontroller to decide when to activate the analog voltages, this would make it possible to turn it on/off without analog pops or clicks.
4. When it its turned off, I would like to do certain things before it shut downs (to avoid pops and clicks).
5. If it's turned on too long (let's say 12 hours) I would like to turn the whole thing off by the controller.
6. I want to be able to generate rock steady, ripple free +/-7 volts from a 9VDC supply, providing at least 300mA or more.
7. I want to be able to generate silent ripple free 5V and 3.3V voltages for analog circuitry.
8. I want to be able to generate 5VDC for USB capable of at least 500mA and 3.3V voltages for microcontroller (100mA or more).
9. I want the supply to be as SILENT as possible to the outside world (regulations, emissions etc.)

This prototype board I put together tonight looks like it does what I want. It's the second incarnation (and still I managed to get wrong footprint for a couple of components  :P ) The -7VDC is generated using a 1.2MHz converter circuit and the recommended manufacturer PCB layout seems to do the job, abt. 500mA. The 7DC is regular circuits also at 500mA, Shut-off carried out by MOSFET transistors.
Got coils and inductors I've stole from other similar circuits to minimize emissions.

Input:
9VDC (to 12VDC)

Output:
+ 7VDC @ 500mA (software controlled on/off)
- 7VDC @  500mA (software controlled on/off)
5VDC digital @ 500mA (for USB)
3.3VDC digital @ 100mA (for controller)
5VDC analog @ 100mA (for analog circuitry)
3.3VDC analog @ 100mA (for analog circuitry)

Anyhow..., now I'll use this new power circuit for my new thing... 8)
But I got more gear than I need...and I like it!

cags12

Hey Robert - Is this board something you can sell? what size is it compared to a coin?

I have a project to adapt one of my Antares Luthier Kits as external pedal but the only thing that has prevented me to do anything is the power section I need to feed a GK kit. I have zero knowledge on how to create such circuitry and I am just looking something ready to integrate with the existing components of my ATG kit.

Cheers

chrish

Quote "Anyhow..., now I'll use this new power circuit for my new thing... 8)"

What new thing are you designing?

gumtown

Quote from: chrish on February 28, 2018, 04:30:21 PM
Quote "Anyhow..., now I'll use this new power circuit for my new thing... 8)"

What new thing are you designing?

Free "GR-55 FloorBoard" editor software from https://sourceforge.net/projects/grfloorboard/

chrish


CodeSmart

Quote from: cags12 on February 28, 2018, 03:15:41 PM
Hey Robert - Is this board something you can sell? what size is it compared to a coin?

I have a project to adapt one of my Antares Luthier Kits as external pedal but the only thing that has prevented me to do anything is the power section I need to feed a GK kit. I have zero knowledge on how to create such circuitry and I am just looking something ready to integrate with the existing components of my ATG kit.

Cheers

Small 9V battery to GK voltage converter board...

If the "only" thing you need is a small 9V to +/-7V  converter,
many things on this board should be removed and PCB (redesigned) size would be reduced to a fourth.
Also a smaller casing of the positive voltage regulator would be elected (500mA is overkill).
The current protype board is 5x8 cm

Justifying the efforts for just one board to Cags12 feels overwhelming.
Anyone else need this? Isn't it already available somewhere?

Of course I could partly mount one of my remaining boards and it'll do the trick...but that's an ugly solution.

But I got more gear than I need...and I like it!

cags12

Quote from: CodeSmart on February 28, 2018, 11:22:14 PM
Small 9V battery to GK voltage converter board...

If the "only" thing you need is a small 9V to +/-7V  converter,
many things on this board should be removed and PCB (redesigned) size would be reduced to a fourth.
Also a smaller casing of the positive voltage regulator would be elected (500mA is overkill).
The current protype board is 5x8 cm

Justifying the efforts for just one board to Cags12 feels overwhelming.
Anyone else need this? Isn't it already available somewhere?

Of course I could partly mount one of my remaining boards and it'll do the trick...but that's an ugly solution.

That's a good point.

No one has done this before? Where can I find a small PSU for GK that I can use in my project? Any suggestions?

I understand Robert the efforts for only me are not worth.

admin

Quote from: cags12 on March 01, 2018, 01:18:12 PM
That's a good point.

No one has done this before? Where can I find a small PSU for GK that I can use in my project? Any suggestions?

I understand Robert the efforts for only me are not worth.

Not saying this will yield low enough noise floor to be useful for a GK-13 pin preamp on a  Guitar
but its close

Id try this

https://www.ebay.com/itm/5V-6V-9V-12V-15V-24V-Positive-Negative-Dual-DC-DC-Step-up-Boost-Converter/282513241853



±6V :
Input voltage DC 3 ~ 5V,output DC ±6V(Deviation is ±5%)
Maximum input current 2A
Maximum output current : +Vo is 1A,-Vo is 200mA

cags12