DDA S Series Mixer

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Andy Peters

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carburetordung said:
I would like to know if the insert send (jack output) could be used like a direct out (not cutting the signal path) ?
If there is a direct out on the board it might be possible to wire it to a female jack socket added on the back of the desk ?

I assume this has a single TRS insert jack with send and return on the one jack.

The easy way to do this is to make a special cable. TRS plug on one side, TS on the other (it's unbalanced out anyway). Use a standard guitar cable (single-ended, center conductor plus shield). On the TRS side, connect both tip and ring to the cable center conductor. Sleeve goes to shield of course. On the other side, Tip goes to center conductor, sleeve goes to shield.

TRS side plugs into the insert jack.  When you do this, the tied-together Tip and Ring shorted together acts exactly like the jack without anything plugged in (tip shorts to ring).
 
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Hello,

This is not an unique i/o insert jack, there is an insert "sent" jack and another insert "return" jack, separated.
 

L´Andratté

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There´s also the sowter 7026 which is a good 1:1 200R:200R transformer (very high end) which I have installed in my little Soundcraft B100. Works really well with the typical differential transistor input. Not cheap though.
 
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Hello,

My first questions were "I would like to know if the insert send (jack output) could be used like a direct out (not cutting the signal path) ?
If there is a direct out on the board it might be possible to wire it to a female jack socket added on the back of the desk ?"

Maybe a mod in order to send post-fader signal to "insert send" might be good for studio use, any ideas ?
 

Andy Peters

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carburetordung said:
Hello,

This is not an unique i/o insert jack, there is an insert "sent" jack and another insert "return" jack, separated.

You should be able to use the insert send jack as a direct output without affecting the rest of the channel operation. It's when you plug in a return that the link between the pre-insert stage and post-insert stage is broken.
 

tchgtr

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Feb 25, 2009
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Andy Peters said:
You should be able to use the insert send jack as a direct output without affecting the rest of the channel operation. It's when you plug in a return that the link between the pre-insert stage and post-insert stage is broken.

Absolutely. I have done this on my own with very good results.
 

tchgtr

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I also wanted to add to this thread that there are two different versions of the S Series boards, and the channel strips are NOT interchangeable between them, at least not without some major fiddling.
They can be distinguished by the number of FX and Foldback sends, and one connector has a different numbers of pins than the other.

 

IBarfoot

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Sep 25, 2018
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I just acquired one of these for not very much from a local Craigslist sale. There isn't a lot of info on the web about them, so I thought I'd start a thread here and see what happens. Fortunately, this one came with the manual and schematics.

This is a UK-made mixer from around 1990. The designers went on to Midas and Audient. The S Series is designed for live work, according to the DDA website (ddaconsoles.com), but I'm finding that it works and sounds great in my home studio. The one I have is a 24-channel version, but it's in a frame that can hold 32 channels, so the search is on for more channel strips. Schematics can be found at the website, but I will post some here for convenience.

PSU
The biggest problem with the mixer was the power supply. I took a chance on it when purchasing, as the PSU was obviously fluctuating quite a bit when I first examined the board. Meters were swinging about and the V+ and V- indicators on the PSU would go on and off. P48 seemed solid. First thing I did was recap the PSU.
Opening it up, I found one 12,000uf and one 10,000uf cap in the +- section of the supply. I'm no genius, but this seems to me to be asking for trouble, since we want the +- voltages to be consistent. The schemo calls for 10,000u in this place, but good ole' All Electronics had some 15,000uf Panasonics in stock, and in they went, as well as replacing all electrolytics in there with slightly larger values.
However, the voltages were still fluctuating wildly, and it took some more poking and prodding to discover that the problem was merely that the 2N3055/PN3055 transistors were not bolted down to their heat sinks properly. Perhaps the insulation between them and the heat sinks had shrunk over time. It was amazing to me that a light tightening of the nuts immediately solved the PSU problems, and ever since it has been rock solid.
It has a fan, which was not working, so I vacuumed it out and sprayed it with contact cleaner. Sure enough, with some coaxing it slowly started to rotate and get up to speed. Seems reliable now. I'm glad, because it was glued in place at the factory, and was going to be quite an ordeal to get loose. I imagine I will have to do this at some point in time...
Voltages are now @ + and - 17.3V. All good, except P48 is up around 51V!
I had a D series from new back in the day, seem to remember getting a bank loan for £10 grand to buy it. Anyway also suffered from PSU problems vey soon after purchase. Eventually tracked it down to the legs of the power transistors being cut very short and the use of nyloc nuts which when they got warm became loose. I also bought a second spare PSU as the board was going out on location, funnily enough it too suffered from the same issues as the original. A few slightly longer bolts, solder tags and star locking washers seemed to cure the problems though. It was great sounding console though way too heavy for my aging back to lift these days.
 

neil.johnson

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Aug 14, 2012
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27
Wow, interesting thread. I have a D that is going through a rebuild
On this one the rear panels were completely replaced by custom ones with four large Bendix connectors (as well as the power and remote sockets). Weird. So now I need to make up a full set of rear panels for every channel.

Neil
 

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