soundcraft 2400 channelstrip DIY

[nrgrecording]

[quote author="Xopek"]2 nrgrecording

About PSU
You have written a question, that a feed from SSl compressor will approach, but it gives out 15 volt. On your scheme of 17 volt. It is necessary to replace 7815 on 7817 (if such happen)?
And how on the account of a phantom feed in 48 volt?

In advance thanks for the answer.

P.S. Which transistors BC 550? bc550c or bc550b?[/quote]

Hi.

I used SSLtechs PSU (not the ssl compressor psu) which has +18/-18V/+48V. Works fine. You could use 7817 if you find them :wink:

I used the BC550 "C" transistors.

Regarding the pcbs... it would be cool to see finished units first to make sure that really everything is clear and correct. Although i don't think there is much interest. Who knows soundcraft consoles these days? :roll: :wink: But i really like the sound of the 2400.

Frank.

 

[Xopek]

Thanks for the answer!
Last question (though can be and is not present :roll: ): I prepare to construct two units in one case, what approximately should be force of a current what feed them? 0.5 amperes will suffice?
Once again thanks & :guinness:

 

[nrgrecording]

Hmm...
I checked the current when the unit was finished but can't remember exactly :?
I would use heatsinks and check the current with a finished unit... 7818 can do 1A each.. so 2A total current. That should be enough. Otherwise you could use 78S18 and 79S18 which have 2A each. 4A total current... thats much current :wink:
just a consideration...
if every channel of my soundcraft console needs 2A - i would need a (28+24+1)*2A= 106 Ampere power supply :green:
...so i think ssltechs psu will do the job

A friend of me has the channelstrip in his live rack at the moment, otherwise i would just measure the current...

 

[Neeno]

Frank... YOU ROCK !
Excellent project and great work ! (as always)

Cheeeeeeeeeeeeers :guinness:
Neeeeeeeeeeeeeeno :green:

 

[Xopek]

Whether it is necessary to select transistors TR1,2,3,4,5,6 specially? Simply they cost in cascade, and it has guided me at such idea. :roll:
I.e. Tr 1-6, 2-5, 3-4
Once again thanks & :sam:

 

[nrgrecording]

... at least I haven't matched them :wink: and compared to an original channel there was no audible difference.
Maybe someone could give an explication? I would bet the preamp will work with two transistors, i think the additional transistors are only to improve the performance?

Frank.

 

[Xopek]

ok...
thanks for you answer.

 

[gar381]

Hi Frank

I think this pre will work with 2 transistors..If you look at the schemo
for the soundcraft 800B..

Change a few part values from the 2400, drop 4 transistors
and you got it. The 800b pre sounds great. I am dieing to try making
one for your 2400 versions... I bet its even better! Really nice
work Frank.

GARY

 

[nrgrecording]

Hi Gary.

Thanks for the information! Haven't seen a 800b schematic before.
Regarding the 800b... i'd been told that the live desks were a bit noisy, i didn't noticed that with my 2400's. (my one has newer caps in it) Do you thinkthe 800b sounds bad or noisy?

Frank.

 

[gar381]

Hi Frank

The only real noise problem that we use to have with ours was psu
related. If the psu was set to 120v and the line voltage would sag
below about 115v we would get a lot of 60hz. I think the regs
were not fed enough volts. We ran our psu's on the 100v setting
and never had that problem after that. This was the days before the
cheap rack mount power conditioners that are around today.
This seemed to be a Soundcraft problem as our old 400 had
the same problem. Hiss type noise was a very slight problem
with 32 channels in the mix at high gains only.

There was a local studio here that had a 1600 (a 800b with a patch bay
built in for studio use). Its noise was well below the noise of his
tape machines and seemed not to be a problem.

GARY