AMB Laboratories DIY Audio

[amb]

It may be a problem. The way you have it means that the transformer's VA rating is being split, one half goes to the LCDuino-1, LCD display, motor pot, and four δ1/δ2 boards, and the other half for the 5V relay. 7.5VA is a bit borderline during startup of the LCDuino-1 and friends, and the 5V relay gets its own 7.5VA, which is capable of 7.5VA/9V = 0.83A of current, but it only needs about 1/10 of that. So much of that 7.5VA is wasted.

You can get around this either by going to a larger trafo, or wiring all the 5V consumers to the same rail, and connect the two secondaries in parallel for that rail (the second rail would then be unpowered/unused).

P.S. I get the impression that you are using two δ1 and two δ2 boards, right? If you're using only one of each, then 7.5VA should be enough. The recommendation for LCDuino-1 and only one δ1 and one δ2 board is a 5VA trafo, but that does not take into account the additional draw of the 5V relay.

[Boinger]

Ok so I did what you suggested wired them in parellel. Still wasnt latching reliably. So I turned the voltage up to 5.35 v i read somewhere that was safe ? is it so?

But at 5.35 they are latching more reliably now i havent had any misses and the various inputs/outputs seem to be working.

now the only issue remaining is volume... I bring it up to -12db and still relatively quiet until -.5db then suddenly gets full volume... no steps in between the step from -1 to -.5 is about atleast 3-5x louder(est). And on the step from -1 to -.5 at -.5 it the left becomes full volume but the right channel does not until 0.0

I think I screwed up my attenuation calculations?

And yes I do have a balanced setup = 4 boards.

[linux-works]

you still have psu issues.

if you have to turn up to 5.35 just to get a solid 4.8 or so out of it, there's too much droop.

do you have thick enough ground and vcc cables from the psu to the lcduino things?

5.35 is a bit high. 5.3 is ok but I would try to stay 5.1 or below and give it CURRENT, not voltage!

[Boinger]

Oh you know you might have just clicked something in my head... I am using cat 5 cable to connect my lcdduino to the d1/d2 boards (I dont think that will cut it huh?)

Oh and using 22g wire from psu to the lcdduino

[linux-works]

if you have too much voltage drop (sounds like it) then things won't always click when asked to

keep the wire from the output of the psu regulator, to the delta and lcduino, to be a foot or less in length. use reasonable wire in terms of thickness (not as thick as lamp cord but not as small as cat5 wiring, either).

[Boinger]

Ok i changed out the wire now i have the psu running at 5.25~ V and its clicking reliably...

So what about my volume issue? how do I fix that?

I have attached my resistor graph. I think this was based on what I read somewhere a while back I can't remember. But is this too conservative for speakers?

I have 4 balanced boards I think at either 4x or 8x gain. I can't remember which off the top of my head. I want to lean towards 8x because the speakers can get pretty loud.

[linux-works]

the atten values look fine. 20k is fine. balanced or 4x/8x gain does not matter. 127db at half db will cover anything.

are you sure that you are not feeding the output of your source into the output of the relay atten board? be really sure, as things will 'seem to work' until it gets close to an edge (iirc). a few times I was sure I had them right but then realized I did have them swapped.

check solder and double check for shorts or the wrong value in the wrong slot.

if you have a power supply or even want to use 5v, you can use a volt meter on the output of the atten and put 5v into one input. as you vary the volume, the voltmeter should go up and down (its a resistor divider, afterall). use a current limiting R in series with the power into the d1, just to be sure (1k spare R that you have around is fine). you just want to see the voltage smoothly go up and down and not have major jumps.

[Boinger]

I have my wiring setup like this

the ibus is going to the input on the attennuator and then the output is going to the b22 boards

is that correct ? From the wiring diagrams it looked like it was? My boards are stacked so the input wires are just on top of one another correct ?

[linux-works]

I think that's right.

check if your ribbon cables are ALL making connections. sometimes there are shorts or opens. check the soldering on the pcb.

its a lot of connections but if you have 'jumps' I suspect a wiring or soldering problem. it could be a wrong R in the wrong spot, too.

[Boinger]

Ok I think it may be a resistor in the wrong position problem... When decreasing the volume very slowly I noticed while generally getting quieter it suddenly gets loud and then gradually starts getting quieter again... this happens 3 times including the final step to full. You think it is a resistor in the wrong location?