Salas hotrodded blue DCB1 build

[Salas]

Originally Posted by johnwmclean

I was not aware of this rule. Salas please take down my post if you feel you need to.

I made them into attachments. There is a direction to use attachments not very big than linking big from pic host services. Jason will have to find a way of auto resize possibly. Attachments stay on DIYA server when some links expire and the threads look empty after some time. And they show up fast without changing the frame size.

[johnwmclean]

Thanks for correcting my post Salas. I'll use the attachment feature for future posts.

[merlin2069er]

Very nice, I've got a couple of dcb1 buffers, maybe I should take a look at building a balanced pair?

How much extra work would that be?

[johnwmclean]

merlin2069er,
The majority of the work is in extra buffer, which you already have. You will need to double your spec for the tx or use two like I did. If using a volume control it needs to be a 4 channel, I’m not including a volume in my build, I will either build a stand alone unit or work on a digital solution, paying attention for matched impedances for balanced advantage.

[merlin2069er]

That's great, I do have the extra transformer. But I have no idea how to wire these up as balanced input / outputs.

Are there any schematics available?

[johnwmclean]

Here is a diagram;
Salas hotrodded blue DCB1 build

Changes I have made from this this diagram are as follows;
1) I’ve dropped the volume pots altogether.
2) XLR pin 1 on I/O ties to chassis only.
3) Both signal grounds on each board are referenced to chassis ground via a ground loop breaker.

[merlin2069er]

I've got a CD player with balanced outputs. Would I need a amp with balanced inputs if I were to add the balanced dcb1 buffer to the mix?

[Tea-Bag]

Originally Posted by merlin2069er

I've got a CD player with balanced outputs. Would I need a amp with balanced inputs if I were to add the balanced dcb1 buffer to the mix?

I would think to take full advantage you would.

I am too cheap for that myself.

[johnwmclean]

Up and running! Here are the results.

Board 1.
All LEDs working.
Relay clicks.
Across 3.3ohm resistors 1.938v & 1.688v
Output 10.28V & 10.28V
Offset -0.7mV and 0.6mV

Board 2.
All LEDs working.
Relay clicks.
Across 3.3ohm resistors 1.904v & 1.690v
Output 10.29V & 10.27V
Offset -1.3mV and 0.1mV

My mills 3,3 R resistors are getting pretty hot!
Everything else heats up nicely, nothing too hot atm.
So I’m around 360mA with 3.3ohm, a fair way of my desired 600mA.

Is there a problem?

[mravinsky]

Why about 360mA?
First board: 1.938/3.3 ~587mA and 1.688/3.3 ~512mA.
Second board: 576mA and 512mA. But this depends on the Mills resistor value, 3 Led string and the first mosfet, as well.