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Old 7th October 2017, 05:08 PM   #11
rsavas is offline rsavas  Canada
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yes I am aware of Bryan's great work and have reviewed some his code, for me it is hard to follow as Bryan is a seasoned programmer.
With coding many times it is easier to write your own code than try to use someone else's code and expect to modify it to suit your purpose, it not as easy to copy s/w as some h/w is to do.

I guess it comes down to who is writing, maintaining and adding additional code/features to your pre-amp project?

front end to what, a tuner? Silicon Labs Si4735,4770 are self contained radio's, no front end is required.
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Old 7th October 2017, 05:24 PM   #12
jwilhelm is offline jwilhelm  Canada
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I was referring to the front end of the preamp, controls, display ect. I'll be writing my own code. I prefer to use an open source format like Arduino where there's lots of support and anyone can read and modify code as required. Bryan's package where he's tying all systems into a network is very cool. Using simple GPS style packets is very slick for less experienced coders to interpret. The whole package works very well.
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Old 7th October 2017, 05:38 PM   #13
rsavas is offline rsavas  Canada
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The bottom line is that Arduino is "C" language based and uses the standard gcc avr compiler, as is contained in Atmel Studio7. If you like the Arduino dev platform, best of luck with that, but realize it is "C" and it is not really required. If it is what you are comfortable with using to get the end result of a working pre-amp.

Last edited by rsavas; 7th October 2017 at 05:46 PM.
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Old 7th October 2017, 05:53 PM   #14
jwilhelm is offline jwilhelm  Canada
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Quote:
Originally Posted by rsavas View Post
Jeff,

I looked at the design a bit. From my design experience I can suggest that you need to step back and work on/consider the user interface(s) and control sections. I think that you are putting the horse in front of the cart. I had a similar issue with my portable design where I did not think the whole design through before committing to h/w first.
I know it is exciting to get H/W in your hands, but pls consider the big picture first.
Have some doc like a block diagram is a great way to have an design overview so that you can best figure out design partitioning and have other do a review.
I can see an issue like putting the mcu on the PS assy, where is your user interface/display functions being put?

Stay away from 5V control, it is legacy = PITA, most I2C and other control I/F's chips are only 3V3! You are not using Arduino H/W so stay away from it. Arduino is intended for using there H/W and adds a level of abstraction to coding, so inexperienced "C" coders do not have to fully understand register level coding access. Thus there is no reason to use Arduino, stick with either Atmel Studio 7 for "C" coding or BASCOM-AVR, which is what I suggest if you want others to help coding unless they have enough "C" experience.

Where is the turn on/off audio muting being done?
I will offer my portable documentation to use as an example if it is of use to you, if I can ever get it to load, if not I can email it to you. I have your email, so I will just send it to you that way.
The microcontroller in the supply is just controlling the supply. It will look for an on signal from the front panel or the rear panel, or wifi, whichever is required, it will start the supplies up in the proper sequence, then it will communicate to a front panel controller that the preamp is ready to run. The main controller will send out a reset to all the digital devices and ensure they are set to operate correctly.

The PA2310 has a mute function, the DAC has a mute function and the outputs of the output buffer board have relays which can provide muting as well (this is where I plan to mute it). All digital controls can operate on 3V3 or 5V. Valery and I have been experimenting with Arduino Due and ESP boards that operate at 3V3 already.

I'm undecided on front panel volume control. I don't want to use a pot to directly control the volume. I may use one as an input to an AD converter for an input to a microcontroller. I don't want to use a cheap encoder. Those thing feel way too rough when rotating. Bryan found some very smooth industrial optical encoders that we've been experimenting with. They are much higher resolution, and will actually freewheel if you give them a spin. I might actually just use simple buttons though. it's much easier to write software for, and the front panel controls will never be used anyways.
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Old 7th October 2017, 06:01 PM   #15
jwilhelm is offline jwilhelm  Canada
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Quote:
Originally Posted by rsavas View Post
The bottom line is that Arduino is "C" language based and uses the standard gcc avr compiler, as is contained in Atmel Studio7. If you like the Arduino dev platform, best of luck with that, but realize it is "C" and it is not really required. If it is what you are comfortable with using to get the end result of a working pre-amp.
I'm getting fairly comfortable with C now. There's a lot more info available on the internet for C based coding than any other format. Another bonus using C is my daughter just started studying computer engineering in college. The first programming language they learn is C, so we've been teaching each other a few things. She got her first amp running last week. Now she's hooked and is building a VHex+
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Old 7th October 2017, 06:07 PM   #16
rsavas is offline rsavas  Canada
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I am really happy with the cheap encoders in my design, not sure why you think the encoder has to have high resolution, the s/w handles the resolution of each step as in say the volume stepping of each click or step.
Sometimes depending on the complexity of the pre-amp firmware, menus can be a PITA, esp with a small screen.
If your UI is a cell phone that sends control, it is that GUI that has the menus and functions as required to make the pre-amp work as intended. If no cell phone or battery is dead, then you are SOL for control, it is a design decision for functionality and control.
I myself would never use a pre-amp/stereo/tuner, that needs a cell phone to operate, but then again I am old school :-) as I do not even own one.

Writing "C" code for a mcu and a high level computer(PC) are not necessarily the same, as you are not concerned with low level register level coding, you have drivers and a API for that. I can almost predict that when you get experienced with gcc avr, you will find that arduino is a waste of time.

Last edited by rsavas; 7th October 2017 at 06:12 PM.
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Old 7th October 2017, 06:18 PM   #17
jwilhelm is offline jwilhelm  Canada
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I wasn't after higher resolution with the encoder. This actually makes them more of a PITA to read. I hate the grinding feel of most encoders. The industrial ones are mounted in ball bearings. Kia or Mercedes, personal preference.

Check out Bryan's presentation and you will see what I'm talking about. YouTube I want multiple options to control the preamp, none of which involve my lazy a$$ getting up out of a chair at the end of the day. IR remote, phone, tablet, PC, whatever. Anything can control the system. Bryan's well on his way to a very slick home automation control.
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Old 7th October 2017, 06:26 PM   #18
rsavas is offline rsavas  Canada
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Sure, if you are running with Bryan's implementations, he has released his code to be used as open source, then you are off to the races. All you need to do is understand his code and modify it to work with your hardware.

Good luck
Rick
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Old 7th October 2017, 10:43 PM   #19
rsavas is offline rsavas  Canada
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1)On the PS/mcu schematic, I see a net called "GND" connected to J1-6(ICSP conn) and the un-named part Q2-9(ULN2xxx?), where else does this net connect too?
2) You are putting regulated voltages through fuses F7-9, why? The SMPS regulators, U1,3,4 have OCP. If you need the fuses, then why not monitor the o/p after the fuses to see if they blew or not. I think you have some spare pins on the m328, adc0-3
3) Does Y1, have internal phase shift caps? More expensive part than a reg xtal. Probably can use the int rc osc fuse option on the m328 and not even need a xtal.
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Old 7th October 2017, 11:11 PM   #20
jwilhelm is offline jwilhelm  Canada
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These boards are all just first round proof of concept boards basically. I just put them all together quickly for prototype testing with the intention to test what works and what doesn't then design a final version. The schematics are pretty much just cut and pasted circuits from other designs to get up and running quickly. There will be some anomalies in the schematics.

On the power supply schematic, all grounds are common, whether marked GND or digital GND.

The fuses were an afterthought in case I make a mistake while connecting hot during testing. The final design will monitor these outputs.

The resonator does have internal caps. These are cheap and really easy to install. AWSCR-16.00MTD-T ABRACON | Mouser Canada

I've already found an issue with this board design. I've used this same switching regulator circuit with this same Atmega328 circuit a few times recently. This was all cut and pasted from a previous design. On this board programming was very sporadic and the processor would run fine, then stop working completely for no apparent reason. I finally figured out the Atmega328 didn't like the supply and needed a bead in series with the supply to operate. Silly problems like this are why I do multiple versions and don't sweat the little stuff in the first round.
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