Balanced to unbalanced board

[sbelyo]

We're try to get to 10 sets on the balanced input switch board.  Anybody else want to jump in?  We need 3 more

 

 

[kevin gilmore]

i will take a set of input boards please

[sbelyo]

42 minutes ago, kevin gilmore said:

i will take a set of input boards please

You're in...

[MLA]

I'm in too.

[sbelyo]

cool...  I can get the price down now I think

[sbelyo]

I found out that the switchboard needs a microprocessor (arduino etc) to control it.  same signaling as the original attenuator board.  The idea is no standing power on the relays.

Could someone familiar with this setup take a look at the board just to double check it?

[kevin gilmore]

soren wanted this, work in progress

 

[sbelyo]

can somebody who is familiar with this board take a look at it

http://gilmore.chem.northwestern.edu/boards/baseboardbal4.zip

It just needs to be checked so I can send it off to be quoted and close up the group buy.

[kevin gilmore]

soren also wanted buffers and a place for the attenuator on the board, which makes the board a fair bit bigger, and thus more expensive. if people think that is a good idea, or have other ideas i am certainly willing to modify. But i think that the smaller board is a better idea

[MLA]

Smaller board fits my needs better, but I would of course be fine with a bigger, more feature rich, version.

[cspirou]

Would the buffers be installed vertically like on the ubal/bal board? I feel like it might be an issue with stacking one board over the other in that case. I am not likely to use it either because I'll already have the ubal/bal boards.

However I would use an interface for the digital attenuator. I am totally fine with the switch board as is but I wouldn't have an issue with extra features either.

[jose]

I prefer a small board too

[sbelyo]

does it look ok to send to the board house?

 

[MLA]

25 minutes ago, sbelyo said:

does it look ok to send to the board house?

 

As far as I can tell; yes. Not an expert on how to set up the MAX4820 though.

[fat joey]

I second Soren, all in one better than you second multi world

[mypasswordis]

Is there a schematic and BOM for the recent group buy ubal/bal and diamond buffer boards?

[kevin gilmore]

here is the unbal/bal to bal board

 

diffinput3.PDF

[mypasswordis]

Just making sure, the CCS LEDs need a 1.7Vf for all associated resistors (or vice versa)? 

[kevin gilmore]

does not really matter as long as they are matched

 

[mypasswordis]

Drew up a little relay board for I/O since the one in the recent group buy one didn't quite fit what I wanted to do. Mainly it was that I needed to use I2C instead of SPI and I want to try stacking XLRs sideways to save space on the back panel. Any suggestions on how to improve it are appreciated. 0.3mm width traces

 

 

 

 

[Pars]

Looks good. My only suggestions would be:

1. fatten up the traces a bit
2. possibly flipping RN1 and swapping U1 with U2 might clean up the routing and number of vias. Or not.

 

[mypasswordis]

U1 needs to be close to RN2 which is not really a resistor network, it's a DIP switch to change the I2C address but it uses the same footprint and I was lazy.  Will look into it anyway, thanks. 

[UFN]

Consider using jumpers (i.e. 2x3 header) instead of the DIP switch to set the I2C address?.

It should be a bit smaller and once you set the address I doubt it's going to change, so jumpers should be fine

//UFN

[mypasswordis]

I looked into it and the relays and headers dictate the length of the board so I can't save anything there and it would probably only shave about 1-2mm off the width of the board, which probably isn't enough to do anything. Plus the DIP switch hearkens back to my horrible memories of grade school flip-flop truth table quizzes. 

[mypasswordis]

A little breakout board for the AD5254 digital potentiometer... so I can dynamically bias the Dynalo through my phone (through a uC). 256 step resolution but lowest full wiper resistance seems to be 1k so 3.9 ohm per step.