C|24 Analogue levels way out??

[justinhill]

I'm integrating the analogue side of my new old C|24 and the first thing I noticed was the control room output seemed lower than I expected, and the headphone output was too low to use for detail editing. This being a bit subjective, I looked instead at the cue input/output, which is line-level.

If I send a sig gen signal from a pair of Pro Tools outputs to the C|24 cue in connection and then return the signal from C|24 cue out to a pair of inputs on Pro Tools, I find a level difference of -16dBFS with the C|24 cue level knob at the 'nominal' 2 o'clock position, and still -10dBFS even with the knob flat out.

I haven't done a similar check with the control room i/o but to my ears the difference is probably the same.

Is this a fault with my C|24 or something endemic to the product? It seems completely weird that there should be such a massive level drop going into the unit and it totally disrupts my plans for how to use the thing.

[justinhill]

I should have mentioned - I did get Pro Tools to update the C:24 firmware to the most recent version, and I did reset 'analog routes' and 'monitor gains' to default.

I've just checked the studio LS output and it's even lower than the cue output.

[its2loud]

Sounds like your monitor section outputs are trimmed down.

Check out page 65 of the manual

https://cdn-www.avid.com/-/media/avi...uide_41362.pdf

Assuming the levels from your Pro Tools interface are correct. No info was provided from you on that part.

[justinhill]

Originally Posted by its2loud

Sounds like your monitor section outputs are trimmed down.

Check out page 65 of the manual

https://cdn-www.avid.com/-/media/avi...uide_41362.pdf

Thanks for your reply. I reset all the trims, in fact I set the whole desk back to factory default. In any case, there is no trim function for cue out...

[its2loud]

Originally Posted by justinhill

Thanks for your reply. I reset all the trims, in fact I set the whole desk back to factory default. In any case, there is no trim function for cue out...

And you’re positive that the actual analog signal coming into the C24 is correct levelfrom the interface?

Do you have some way to measure it? Route it back into Pro Tools? -20 going out = -20 going back in

[justinhill]

Originally Posted by its2loud

And you’re positive that the actual analog signal coming into the C24 is correct levelfrom the interface?

Yes of course I should have made that clear. I've checked my interface on numerous occasions and I'm confident it's working within specs. I know the multicore I'm using to perform the tests is good because I tore it out of a working part of the studio. I know my Pro Tools session is set up right because I can plug the test output straight round to the test input and see unity.

I read the C|24 front to back several times before buying the desk. I did notice it has no specifications for any of the analogue sections. Gawd knows what I'll find when I decide to check out the line mixer and mic pres...

[its2loud]

Originally Posted by justinhill

Yes of course I should have made that clear. I've checked my interface on numerous occasions and I'm confident it's working within specs. I know the multicore I'm using to perform the tests is good because I tore it out of a working part of the studio. I know my Pro Tools session is set up right because I can plug the test output straight round to the test input and see unity.

I read the C|24 front to back several times before buying the desk. I did notice it has no specifications for any of the analogue sections. Gawd knows what I'll find when I decide to check out the line mixer and mic pres...

Sounds like everything I would check. Maybe try doing the reset routing, gain and trim controls again as described on pages 119-120.

I don’t know if the monitor/cue outputs are gained down by factory default. It’s possible there is some gain staging you’ll have to do there but that wouldn’t make much sense to me.

[justinhill]

Originally Posted by its2loud

I don’t know if the monitor/cue outputs are gained down by factory default. It’s possible there is some gain staging you’ll have to do there but that wouldn’t make much sense to me.

Indeed, and there's the nub of my thread. If some C|24 owner can tell me their cue in/out at least is within shouting distance of unity then I'll know I have a faulty desk. But if people chime in and say 'oh yeah you should expect this' then I'll know I have to work around it.

[justinhill]

I've just had a conversation with an Avid-certified repair shop. They feel confident that the monitor board needs replacing. Apparently the op-amps die, and also lubricant used in the IDC ribbon connectors leaks out and damages the PCBs.

They confirmed that everything should be roughly at unity if the thing is working as it should.

An exchange monitor board is £450 including VAT and should fix my problems.

[its2loud]

Sorry to hear that. Probably not something you were hoping to hear but it least it’s a fix.