DDA " S" Channel Host? ( Schematics posted at bottom of thread..!)

[Snatchman]

8)

 

[Snatchman]

Here are the specific schematics sent by Snatchman.   I may end up reworking this thing for him a few channels at a time.  Comment away.

channel
master
PSU

Hello..Happy New Year..Hoping to get started on this soon. Anyone wanna take a shot in the new year?... ;D

 

[Snatchman]

;D...

 

[helterbelter]

Hi snatchman,

already tried the BB opamps ? I noticed that the OPA404  might be an upgrade for the TLO74 in the EQ . Somebody's selling those in the black market section. I haven't yet recapped mine by the way. Too busy !

paul

 

[lolo-m]

Hi, happy new year !!!
DDA serie S or D (exactly the same circuits  : ) are really close to the MIDAS XL3-4 series. The main difference is the use of 5332-4 in the MIDAS everywhere in the signal path. Trust me, I've got some schematics that proove this...
DDA serie S or D have got real problem with the electrolitics that are getting dry... At the end of their life a Serie S caps I repaired were having a gap on the top... We decided to change every electrolytics on the 3 DDA the company owned ( I bought the D serie later from them ). A real improvement in security of use, because those drying electrolytics are creating a loss of bandwidth and later a real nasty distortion...
I don't know the PSU you've got, but if it's the 2 Unity tall one, you can really improve the desk sound changing it for a D serie PSU (really more simple (only one ground/earth... and bigger current feed capacity). I did this for my desk and hell yes, that's a real improvement !!!
I'm still trying to know what are the audio transfo brand and type used in the MIDAS XL3-4 series... I quite sure they'll fit the boards in the DDA... This will be the TOP mod to do, with a huge investement in iron !!! MIDAS XL3-4 series are really top quality FOH desks, closer to a studio desk than any other FOH desk.
I hope this will help you...

 

[RedNoise]

Hi lolo-m !!
Any chance you got the serie D psu schemo???Really interesting!
By advance , thx!
;D

 

[Snatchman]

Hi, happy new year !!!
DDA serie S or D (exactly the same circuits  : ) are really close to the MIDAS XL3-4 series. The main difference is the use of 5332-4 in the MIDAS everywhere in the signal path. Trust me, I've got some schematics that proove this...
DDA serie S or D have got real problem with the electrolitics that are getting dry... At the end of their life a Serie S caps I repaired were having a gap on the top... We decided to change every electrolytics on the 3 DDA the company owned ( I bought the D serie later from them ). A real improvement in security of use, because those drying electrolytics are creating a loss of bandwidth and later a real nasty distortion...
I don't know the PSU you've got, but if it's the 2 Unity tall one, you can really improve the desk sound changing it for a D serie PSU (really more simple (only one ground/earth... and bigger current feed capacity). I did this for my desk and hell yes, that's a real improvement !!!
I'm still trying to know what are the audio transfo brand and type used in the MIDAS XL3-4 series... I quite sure they'll fit the boards in the DDA... This will be the TOP mod to do, with a huge investement in iron !!! MIDAS XL3-4 series are really top quality FOH desks, closer to a studio desk than any other FOH desk.
I hope this will help you...

Hey lolo-m. Thanks alot for the reply..If you look in the first page of this thread, you can see my schematic of the DDA S PSU. Take a look if you will and see if this is the PSU that you speak of..So.. the S series and the Midas XL3-4 has about the same circuitry. Is this good?... ???..I've never heard a XL3/4 so I'm just wondering is the " S" is comparabale in sound quality. BTW..the " S" has TLo-72/74s and 5534s also.. Don't sound bad tho'.. ;D..Anyone else wanna share their thoughts..?....Greatly appreciated.....

 

[helterbelter]

I don't know the PSU you've got, but if it's the 2 Unity tall one, you can really improve the desk sound changing it for a D serie PSU (really more simple (only one ground/earth... and bigger current feed capacity). I did this for my desk and hell yes, that's a real improvement !!!

I think i've got the D series PSU, bought it as spare, but I didn't use it. I recently sold it, but the buyer didn't show up to collect it....yet.

 

[Snatchman]

I don't know the PSU you've got, but if it's the 2 Unity tall one, you can really improve the desk sound changing it for a D serie PSU (really more simple (only one ground/earth... and bigger current feed capacity). I did this for my desk and hell yes, that's a real improvement !!!

I think i've got the D series PSU, bought it as spare, but I didn't use it. I recently sold it, but the buyer didn't show up to collect it....yet.

Hey helterbelter.. Do your PSU have a cooling fan.? Will this supply work with my " S" ( Standard) console? ( they made the PA version also which has a few more bells/whistles so it may be more current..)..If it'll work and the buyer backs out wanna sell it to me.?... ;D..Thanks..

 

[lolo-m]

The big PSU is 3 or 4 Unity high (don't remember), and have got a cooling fan... The output is on a HARTING connector 10 or 12 pole (don't remember again)... This is what I call the D series PSU.

The small PSU is only 2 U high and didn't have a cooling fan inside. the output is on a round connector (really difficult to solder because it is too small IMO :). This is the S series PSU. To be honnest, some of these PSU were sold with some D series desks and the DDA page have only one PSU schematic for the 2... As soon as I can I will check my schematics to tell you the differences (they're not at home).

 

[Snatchman]

The big PSU is 3 or 4 Unity high (don't remember), and have got a cooling fan... The output is on a HARTING connector 10 or 12 pole (don't remember again)... This is what I call the D series PSU.

The small PSU is only 2 U high and didn't have a cooling fan inside. the output is on a round connector (really difficult to solder because it is too small IMO :). This is the S series PSU. To be honnest, some of these PSU were sold with some D series desks and the DDA page have only one PSU schematic for the 2... As soon as I can I will check my schematics to tell you the differences (they're not at home).

Hey lolo-m. Thanks for the reply. The PSU I have is the 2-space one. It has a cooling fan, but look like it was an add on. I heard that DDA was having problems with these PSU overheating, so could explain the added on fan. It's noisy for my purpose ( control-room).. I'm trying to get a quieter fan for it.. What is the serial number for your 2-space PSU? Maybe you can sell this one to me.. ;D..Thanks..

 

[lolo-m]

The PSU I have is the 2-space one. It has a cooling fan, but look like it was an add on. I heard that DDA was having problems with these PSU overheating, so could explain the added on fan.

I've got both the 2 space PSU and the big one... On the 2 space PSU's we were using, we haded a fan because concerts in south of France with a big and hot sun is really nasty for electronics... I wouldn't care if it was in a studio use. I would just unplug the fan !!! Or maybe you're in a really hot studio with the air at more than 30°C ( 86°F )  ;D !!!
If your PSU's working don't bother with buying another 2U PSU... The 3 I know are the same for the +17/-17 V the only differences is on the 48V ( one is discrete, the other two TL783 ). We tryed a mod with bigger caps with no real improvement on one PSU, another mod changing the transformer with no more improvement (but we didn't take a really bigger voltage for the +/-17V so)... The main problem we had with these PSU was over heating in extreme weather conditions, and most of all ground problems... But I still don't understand the role of 3 grounds  !!! One is the audio ground, one is the electrical ground and another is the metalwork ground  : :!!! On the D serie PSU, there is one star grounding starting into the PSU. More simple, more logical and more stable .

the S series and the Midas XL3-4 has about the same circuitry. Is this good?...

Yes it is good, the MIDAS XL4 is the best sound-reinforcement desk ever IMO .

Looking for some input on modding , rechipping , caps, etc. from anyone that can/will participate!... 8)..Thanks...

Except recaping the first mod to do is to change the first TL072 (preamp one ) for a 5532... At least, every TL072 for a 5532, every TL071 for a 5534, and every TL074 for a OPA4134...

 

[helterbelter]

[/quote]Hey helterbelter.. Do your PSU have a cooling fan.? Will this supply work with my " S" ( Standard) console? ( they made the PA version also which has a few more bells/whistles so it may be more current..)..If it'll work and the buyer backs out wanna sell it to me.?... ;D..Thanks..
[/quote]

I checked it, it's a D/S series PSU. 2 units 19" enclosure. No fan, but provision is made for placing a fan (bolts, cutout). It has the round rearconnector described by Lolo-M, but it has only one single earth. I have no mating connector (that's why I didn't use it), but I measured the voltages at the PCB terminal, it's working correctly.

Well, I have to ask the guy that bought it, but don't forget that shipping it can get quite pricey....

 

[lolo-m]

I checked it, it's a D/S series PSU. 2 units 19" enclosure. No fan, but provision is made for placing a fan (bolts, cutout). It has the round rearconnector described by Lolo-M, but it has only one single earth.

I'm sure it has got a kind of 3 different 0V or ground ... Look at the schematics and you'll understand... There's more than 4 wires out, isn't it ?
But if I do remember well, the big PSU isn't a lot different (except the double of power transistors): the mains ground is separated into 3 different wires but without this weird RC network... I must check this... I didn't try but I'm quite sure that if you've got ground problem with it, you can modify it for a simple star grounding.

If someone need schematics PM me with your email in, what you need, and I'll send you what I've got...

 

[Snatchman]

Hey guys. Thanks so much for your input and advice..! I'll like to get another PSU for a spare anyway..Give me a PM for what price you me ask for it..BTW..I'm not much Of a DIY.. :-[..but in the summing buss, is there room or even feasible to use the 990 op-amps?.. Thanks..

 

[helterbelter]

There's more than 4 wires out, isn't it ?

Nope, 4 wires in total. But maybe the previous owner modified it, I don't know.

 

[helterbelter]

Hi,

Lolo-m, I know what you meant with the different 0volts and chassis. The 0 volts are tied together, and the chassis is led to the ground of the power inlet. I have restored it this way.

I've checked my whole PSU, because Snatchman wants to buy it. We both want to be sure it's working properly of course ! But now something else arose.....

So, I have a question to you, and all of you DDA m/s/d series console owners :

The PSU schematic of the S/D series consoles, mentions that the +V and -V should be 18 volts. Both of my PSU's (internal M and external S/D series PSU's) measure 17,5 volt when set maximum..... I know 17 volts will be enough for the console, but could it be that my PSU's aren't up to the specs anymore ?

Greetings, and thanks in advance for your replies,

Paul

 

[lolo-m]

If I do remember well, the S serie PSU deliver +17/-17. Schematics are talking about +18/-18, but the 2U PSU does deliver +17/-17. I will check this tomorow, but I'm quite sure mine is labelled +17/-17 on the front plate. Anyway even if this seam to be correct, if the PSU is old I would suggest to change the electrolytics. It can't hurt !!! It won't change the output voltages but new caps will give better mains rejection... Maybe with a bigger capacitance value  :... Technology have made lots of progress in the size/capacitance domain.

 

[helterbelter]

Ah, thank you !

I looked into a recap already, but all the caps are well within specs. I actually think it had a recap just before I bought it, about 2 years ago.... Maybe I'll do a recap after all, but that's up to Mr. Snatchman, he has to pay for it, hahaha 

But I only wanted to be sure the voltages are right, and apparently, they are.

Snatchman ?!? Any other questions ?

 

[Snatchman]

Ah, thank you !

I looked into a recap already, but all the caps are well within specs. I actually think it had a recap just before I bought it, about 2 years ago.... Maybe I'll do a recap after all, but that's up to Mr. Snatchman, he has to pay for it, hahaha 

But I only wanted to be sure the voltages are right, and apparently, they are.

Snatchman ?!? Any other questions ?

Heey Paul.. No.... ;D... I sent you an e-mail...!