02-02-2016, 04:28 PM
(This post was last modified: 02-02-2016, 04:39 PM by ppppenguin.)
Here's the audio router being tested. Controls are a hex switch for data and croc clip lead for latch enable.
I only tested inputs 1-10 as that's all we'll be using and all I've fitted phonos for. You can see the phonos nicely bodged on to the interface PCBs. The top row of input phonos sticks up slightly above the 1U rack so will need a blank panel above it. Not a problem.
On the main router PCB you can see:
2 groups of 8 input buffers (left and right), nearest the edge connectors. We're only using the left channels. Good old mono.
2 sets of 8x 4051 8:1 mux to give 16x4 routers. I nicked the far right one to replace a duff one on the left channel router.
Beyond the 4051s are 2 sets of 4x 4042 quad latches. I nicked the far right one to replace a duff one.
Furthest away are the 2 sets of 4 output buffers.
The pairs of chips in the near corners are level shifters. They take 5V controls and translate them to the 12V needed for the 4042 and 4051. As I said earlier, the designers were very naughty using the 4051s on +/-12V when the abs max rating is 18V. I wonder how they justified that to themselves. You really need +/-12V for professional audio. Actually you really want more than that, +/-15V or even 18V if you're serious about dynamic range.
Should now go back to the video router and a full check on all crosspoints. Then I can get on with building the interface and button panel.
I only tested inputs 1-10 as that's all we'll be using and all I've fitted phonos for. You can see the phonos nicely bodged on to the interface PCBs. The top row of input phonos sticks up slightly above the 1U rack so will need a blank panel above it. Not a problem.
On the main router PCB you can see:
2 groups of 8 input buffers (left and right), nearest the edge connectors. We're only using the left channels. Good old mono.
2 sets of 8x 4051 8:1 mux to give 16x4 routers. I nicked the far right one to replace a duff one on the left channel router.
Beyond the 4051s are 2 sets of 4x 4042 quad latches. I nicked the far right one to replace a duff one.
Furthest away are the 2 sets of 4 output buffers.
The pairs of chips in the near corners are level shifters. They take 5V controls and translate them to the 12V needed for the 4042 and 4051. As I said earlier, the designers were very naughty using the 4051s on +/-12V when the abs max rating is 18V. I wonder how they justified that to themselves. You really need +/-12V for professional audio. Actually you really want more than that, +/-15V or even 18V if you're serious about dynamic range.
Should now go back to the video router and a full check on all crosspoints. Then I can get on with building the interface and button panel.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
