S800 Support Thread

[mitsos]

Thanks Peter!
Would 25V do the trick?? (8 x S800)

The 25V is the maximum rating of the cap, so it should never see more than that, right?  If you run your circuit with a 15V trafo, you should be fine, because, after rectification, the caps will see about 21V (15V x 1.414).  If you do 18V, you may want to consider 35V caps, because at best, you will be running the 25V ones at the limit (25V after rectification).  In this case, if your mains goes over 220 (or whatever they use in France), your power trafo's output will also rise and could easily shoot you into the danger zone for the 25V caps. 



(Edited for clarity)

 

[RedNoise]

Thanks Peter!
Would 25V do the trick?? (8 x S800)

The 25V is the maximum rating of the cap, so it should never see more than that, right?  If you run your circuit with a 15V trafo, you should be fine, because, after rectification, the caps will see about 21V (15V x 1.414).  If you do 18V, you may want to consider 35V caps, because at best, you will be running them at the limit (25V after rectification).  In this case, if your mains goes over 220 (or whatever you use), your power trafo's output will also rise and could easily shoot you into the danger zone for those caps. 

Thanks Mitsos!

 

[substitute]

Hey guys, I'm having a little trouble with my green PSU, I'm using the amtek 236103 which is spitting out 18V but I'm getting +/- 11VDC coming out of the psu.  Initially I had the 2k7 resistors installed as mentioned earlier, then I changed to the 2k2's that the BOM calls for with no change in voltage.  I'll spend some more time tonight experimenting with different resistor values but beyond that I really don't know how to trouble shoot this. 

THANKS

 

[craigmorris74]

I want to double check somthing before I attempt it.  I've got a Urei graphic EQ that I hate with a 36V power supply, and a Power One 48V supply that turns down to 36V.  I want to make a couple of stereo S800's, any reason these wouldn't be suitable.

Thanks,
Craig

 

[substitute]

The recommended voltage is 15-18v, double that seems like a lot... to me. 

P.S. got my PSU working

 

[craigmorris74]

Wouldn't 36V give +18 and -18, or am I just incredibly, hopelessly confused?
Craig

 

[substitute]

It seems like when threads get really long it can be hard to get people's attention, you might want to make a new post about adjusting your supply to +/- 18v that isn't really project speciffic.  I'll try my best to help though, I get confused a lot.  I can't seem to find any info on the "power one", but measuring the DC voltage on the S800 hundred boards by putting the com lead of my meter on the ground terminal and the hot lead on the + or - V terminal I measure +/- 18v respectively.  So, if you can get those measurements coming out of your supply, seems like a deal.

 

[Brolik]

The power supply that is spitting 36v isn't much good unless you can get the +/- voltage out of it.  If you had a 36v transformer with dual secondaries you'd be on your way, then using a simple greenpre psu or something similar would work for you (although it would prob run pretty hot if it was dual 36v secondaries).  The price of a power supply kit is so nominal ($22 on diypartssupply.com) that there's little reason not to start fresh as far as I can tell.  between that and a small 20v dual secondary transformer, your talkin $40-50.  Prob leave off the +48v too as we are talking about an eq and not a pre... Hope that helps?

 

[craigmorris74]

Yep, the 36V supply won't work. Got a bit confused there.
How about using the Urei supply, as the schematic shows a +18 and -18 (See schematic below)?  Just trying to use the stuff I have available before spending any more money.

Thanks,
Craig

 

[substitute]

looks pretty right on to me.  You should probably measure the voltage it puts out just to make sure it's on the up and up. 

 

[craigmorris74]

Getting about +-18.3.  Would that be too high?
Thanks,
Craig

 

[substitute]

I'm using the green PSU with the 2k2 resistors swapped out for 2k7 as mentioned earlier in this thread.  The + rail is a little over 18 and the - is a little less and the EQ's run great.  Sounds like your good to go.

 

[craigmorris74]

Excellent, thanks for the help, substitute.

Craig

 

[rascalseven]

Finally finished my own 8-channel:

A long time in coming.  This is what I wanted when I drew the first schematic back in January 2008.  Thanks to PeterC for doing the layout and making pcbs, and to Purusha for making the 8-channel case a reality (and for making it look nicer than my original concept to boot!).

Took me awhile to get time enough to finish 8-channels for myself, but now it's done, and I'm really looking forward to using them on some upcoming rhythm sessions.

Peace to all,

JC

 

[3nity]

looks really nice...i have 2 finished boards waiting to be racked but not enough cash to complete it!! arg...

 

[Hammond]

Sorry for the stupid question,
In the Purusha dual case there are 4 metal corners, what's are these for?
Thanks :

 

[Hammond]

no one? :-\

 

[RedNoise]

To Hammond :
1U??? 4U???
Have you got pics of your metal corners?Have you looked into the "S800 mounting instruction thread" ??
With pictures it will be easier I think.

 

[Holger]

Finished my S800 today.

This project was very time consuming...
Will never again do a project with 10000 off-board wires, but  I was young and needed the case 
I used a JLM AC/DC, I shielded the channel 8 XLRs with µ-metall.
I like the EQ.

Edited 07/31/2011: relinked pictures

 

[MikoKensington]

That stacking technique is a "why didn't I think of that" build.  Looks great!