Post pics of your builds.... - Page 361

Very cool stuff, linuxworks!

another mad scientist board: this time its a front-end to an spdif switch. it adds 2 coax-in ports that are fully transformer isolated. I'm trying out a new chip (for me), the 9637 diff driver chip that I'm hoping will work as well as the 3486 that I was using before (but takes up less room).



bottom side:



and the parts as a 'before' shot:



so far, the circuit has not been tested but I believe it will work. (famous last words..) power-on test will happen later this weekend. I never breadboarded this - THIS is my breadboard test

the inputs are just floating rca jacks (or bnc, if you want) and the outputs are TTL level based (ready for 'import' into a dac or switch).

edit: it works





I'm using junk wiring - but spdif still works. my dac is locking on just fine and things sound fine as well.

I tested both ports. when I move one wire over, the sound follows it. seems to work!

Hi all,
i am wondering where do you guys customize your front panels. I plan to buy some cases from hifi 2000, but customizing one panel costs more than the case already. is there any better place to do the panel work in the U.S? Thanks.

By "customizing" are you referring to machining work, or to marking the front panels?

k

I haven't used them personally, all though I hope I will eventually. But Front Panel Express seems to be very popular among Fiers.

Nice work as always; quick question though, what's the point of it? If you want balanced inputs to your DAC, you could simply use single gate 74HCU04s with enable pins and a common output? Then your control lines are however many bits you have inputs, and a single output to your S/PDIF receiver.

Another alternative is to draw up all holes in cad/drawing program from your component panel spec sheets. Get a local shop to cut them for you, it’s a very cheap alternative compared to FPE.

You probably mean customizing front panel service by HiFi-2000?
Yes, they can do that but it’s quite expensive and their (technical) ability is quite limited.
An additional problem is their limited English, that makes communications a real PITA… never sure what they are doing.

Get the local shop to do the front panel can be very cheap as mentioned by johnwmclean.
Another way to do it is probably buying an optional 10mm faceplate from HiFi-2000 and ship it to Front Panel Express (PFE) or Cam Expert in the US for milling and engraving.
Of course you have to use their software to make the design yourself. Still not cheap but it’s ways better than the service by HiFi-2000.

Some folks at this place don’t design anything themselves but just take the easy way and “borrow” other people designs, which results in all the “Gremlins” looking amps recently.

I was going to do that, but 10mm thick panels make optical and USB inputs a LOT more complicated. Thinner is definitely better for some connector types!

the point is that I'm putting together the building blocks of an spdif switch. there seems to be some need for this (I needed one, myself).

my first version worked and I'm trying some variations on the circuit to see if I can make it smaller and cheaper/easier to build.

here is the current prototype:



it needs to support both coax and opto in and both for output. it also has remote control ability and an lcd display which the user can put names of his devices, on.

this coax board is just one module in this system.

yes, there are a few ways to gate digital pulses from one input port to an output port. 74hcu04 is often used as the output driver more than an input driver, though.

the design for using differential rs422 receiver chips dates back at least 15 yrs now, its a time proven design, so I liked staying with it.

when I can get all the functional parts wired the way I want, I plan to have a DIY article on how to build it and program it. part of the goal is to make a 'how to work with controller chips' mini series of articles. the spdif switch is just one of the apps that lent itself to this task

I'm talking about front panels for amps in general. For DAC optical and USB connectors you are better off with the 3mm (or thinner)
stock back panel which come with HiFi-2000 enclosures (Slim Line, Galaxy (Max), Pesante).
Spending on expensive (optional) 10mm back panel for a DAC is not useful for some connector types and is wasting money to me.
However, you have all the liberty to do that in a free world!

I reached the same conclusion!

Thanks for all the information. yes, i meant the customizing front panel service by HiFi-2000. It seems that the better option is to go for local shop or Front Panel Express.

arduino LCD 'backpack' board, work-in-progress:












and its welcome banner at power on (lol)



(note, I stopped the photos at the point where I was *about* to do the lcd wiring. I wanted to grab photos before the board got too cluttered up. I'll show the lcd wiring in another post).

I did all that work today (took all day, too). one annoying thing about arduinos is that they have 'logical pins' and 'physical pins' (atmel ones). when you wire up an arduino entirely by hand, from scratch, you must deal with the atmel physical pins and know that when the software does a 'digitalWrite(9)', which REAL pin is this going to have to be wired to? its not real pin 9, that's a safe bet

this arduino sandwich (lol) just needs an IR 3-term module and it will have all the I and O it will need to be a general purpose front-end. leds and buttons can be added via i2c chips (just tap into 2 pins on the old arduino, which I've left open, for this very purpose).

its first job is to be the front-end for an spdif switch that I'm working on. the software is done and I'm re-working the switch hardware to try a few more things out.

at least the backpack board is now working. its kind of fun bringing a whole cpu up from scratch. its not hard, either, as you can see from the soldering. you don't even need a real pcboard or any kind of fancy wiring. these things only run at 16mhz, so its nothing really fast or requiring special building tech.

as promised, the back side of the board. a 3pin molex header is installed to allow the IR module to be easily disconnected.

all the wiring is done and the lcd 'talks' fine. there are 2 groups of lcd wires; one group handles the 4 bits of parallel comms and the other bundle is power, contrast, and 2 more control lines (6 total needed to talk to an lcd in 4bit mode).



the silver box is a 10 yr old (at least) radio shack part that I found lying around. even ancient low-grade IR modules are fine and they directly plugin to any digital-pin with no interfacing complexity.

the pot hanging out on the far left is for lcd contrast (its typical to have a pot do this and let the software dim the backlight via a 0..255 pwm value signal).