Soundcraft Series 600 channel adjustment ??

Hi,

I have a Soundcraft Series 600 that I have recapped and used for a while. I've had some problems with it the last week. Some channels seems louder than others. Tonight I did a check. All channels were set exactly the same. I put a sine wave through each channel and checked the meter. Not one channel read the same. Some were a lot louder than others. Why is that and how can I adjust them to behave the same? The "low" channels also sounded thinner and not so good as the ones that sounded ok. I can't find a trimpot or anything to adjust on the cards. What should I do?


Thanks

Richard

AFAIK, there's no adjustments at all in the 600-series channels.

What you experience may just be minor differences in pot tracking and tolerance?

What magnitude were your differences? Are they within publizised specs for the desk?

Were they frequency dependent? A channel with unexpected roll-off in the low end could point to worn-out electrolytics.

Jakob E.

Hi,
The Insert jacks can sometimes cause problem. Try to put a Jack in it several times, just to see if somethings changes.
Some bad solders on rear panels, or looms and connectors between rear panels and modules can make you troubles too...

My 600 had the same problem...16 of the channels had more gain than the other 8. Within each group, they were consistent...the low ones were all down by the same amount. Are yours consistent?

Turns out they were two different revisions of the hardware.

Go download the Schems from Soundcraft (the input strips in the 4th file). The last update note says: R12 and R13 (Feedback to the emitters of the input transistors) switched from 75K to 36K.

Also not that the schems are wrong, at least for my strips: there isn't an IC6 anywhere to be found.

Byron Jacquot

Thanks,

I checked one more time and found that the pad switch seems to be one of the problems. I had to put out a low (-20dbu) signal not to overload the channels. For example one channel (at 1khz) now reads -17 at the vu. After pushing the pad switch a few times it's now up to almost 0. Guess I should start replacing those Alps switches with new ones.

I checked with the pfl/solo-switch in to bypass the faders. When I switch it off again, sometimes the pfl-light goes on and off for a few seconds. Should I replace those switches too?

Thanks again.

Richard

Check the solders before.
You can also sacrify 2 or 3 faulty switches to see if intern contacts are dirty or not.
If yes, you know what to do ...

Those older Soundcraft boards can be improved by installing a new copper grounding bus. Eddie Ciletti has a description for this mod in a 200B (which is pretty similar to the 600) on his page:
http://www.tangible-technology.com/articles/200b.html
Another bug in those boards are the bus wire and connectors.
:guinness:

Thanks,

Replaced pad switch on 12 channels. Major improvement!!! :grin: Found a few bad line/mic switches and pfl switches too. Guess replacing those will make things even better.

I'll try those other things later.



Richard

We have had the same problem with a 500 monitor one.
After cleaning the faders and connectors on the back (insert renewed) the problem was gone.
We further renewed all the capacitors and the ics that are on it.
Because 500 was pre 600 and has a lot of the same schematics perhaps it also works for the 600.