S800 Support Thread

Siegfried Meier said:

Unfortunately, those of us with the 8 channel case have no choice really than to solder wires to each module and to the pots, so repair work will be a little bit more difficult...not a big deal though.

How are you guys grounding?  Input XLR of each channel connected together to star ground of the IEC?

Thanks,
Sig

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Hey Sig,

I'm also building an 8 channel, I still think having the XLR's and PSU on Moulex will help if you have o do repairs other wise you have to cut off/desolder the XLR/PSU wires, yeah the switches and pots are off board but it will still allow for easier servicing in time.

Cheers

Matt

Oh ya, I'm definitely also using molex connectors for the XLR's and PSU - should have said that.

Can anyone comment on the grounding scheme?

Thanks,
Sig

Not completely done yet, but enough to show&tell. The EQ sounded dirtier than expected. Lot´s of character, and really fun to play around with.

as for the calibration, the trimpot should be fairly close to 5K. - which is the mid value. So there´s not much turning needed there.

lower mid sweep goes from aprox 180 to 2K (and not 100hz to 1k5 as the front says).  upper mid - goes from 2K and all the way up to 20K+  So if you are gonna make your own front, these are better numbers compared to the standard RC.

the HP switch has a very musical rolloff, sounds great and starts at around 100hz

Will try some different caps types on the lower mid freqs. Thought they sounded a bit sloppy. Dont remember the name of those caps-types.  The other freqs sounds cool.  - where mostly Wimas are used.

There´s still a small 100hz hum going at -89db.  mmmm,  well. Probably caused by an over-dimensioned toroid (!!). Will get a new one, and put it in a proper case.  For the power-supply I´ve used one of JLMs psu-board.  will follow any post here about the grounding of the S800 with great interest.

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Had most of the parts in stock already. They are from all over the place. But the knobs and some of the caps are from Banzai.  The big on/off button is from an old tapemachine

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Big thanks to Collin for the pots, and of course an even BIGGER thanks to PeterC !!!!!

How are you guys grounding?  Input XLR of each channel connected together to star ground of the IEC?

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That is how I plan on doing mine.

Congrats to inputoutput, I think you have posted the first completed unit... well almost completed, just got to rack em up  ;D

Back to some more helpful info.

It seems that the following rings true RE the SPDT switches:

High Freq
Switch In = 8K
Switch Out = 12K

Low Freq
Switch In = 60Hz
Switch Out = 120Hz

Low Cut
Switch In = Bypass
Switch Out = 50Hz Cut

This has been tested by ear with my prototype... but hey, my ears may not be all that great 

Matt

Plowwwwww!!!!InpoutOutput : what a beautiful front panel!!!Bigup!!!
Did you use Panasonic audio (electro caps)??
I really appreciate the report!
Thx.

NYDELIG Wonderful front panel!!

yes, those are panasonics. 

For the filters I would highly recommend Wimas. A/B tesed a few other types of filmcaps on one of the boards, and the Wimas felt better. Compared left/right up against each-other. wimas ruled among those I had available.

Got the yellow 8n2 cap from Banzai.

I´ve actually also tested tantalums on the 22uF spot. Difficult to hear any difference. tants are cool, and I do actually miss them, cause they look better... mmm

I´m quite thrilled at the moment. Just found a cute small 24V toroid in my closet, which fitted inside the case. No need for an external PSU anymore.

star-grounded everything, and when I lowered the +V the hum almost went completely away!  On one side it disappeared. Seems like it is a good idea to adjust the voltages as a part of the calibration-process. There was a "golden spot" where the hum was at its lowest.

inputoutput, sooooo slick!  Will the PSU be external?  And how deep is that chassis?

Does any one have part numbers for the pots?  They seem to be eluding me.

hi substitute,
contact colin at audio maintenance he has the pots for this project (he migh still have the entire kit which makes things extremely easy).  very fast shipping too.
and colin is very kind and helpful.
regards,
grant

Thanks, my kits from Colin actually showed up today.  For some reason I got the mistaken impression that the pots weren't included.  Hopefully I won't overlook the obvious too many more times...

I am getting parts together for the Green PSU,
would this toroid work for an 8 Channel s800 eq?

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=TE51402018-ND

thanks

Howard

Knarleybass said:

I am getting parts together for the Green PSU,
would this toroid work for an 8 Channel s800 eq?

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=TE51402018-ND

thanks

Howard

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$103??????  You gotta be kidding me man.  Do yourself a favour, and read this entire thread.  You'll find the info you need.

Sig

matta said:

substitute said:

-The kits do not include PSU components or jacks, correct?

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Correct, they also do not include the Moulex headers and ALL switches.

substitute said:

-The PSU is the same as the green mic pre, so that BOM mentioned earlier will get me where I need to go, right?

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Correct, not looked at the BOM but the original BOM will have the parts to set the PSU to 15VDC rails, you can swap out 2 resistors and push it up to 18VDC for a little more headroom if you want.

substitute said:

-There's no front panel layout yet, affirmitive?

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No

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Can you tell me what resistors to swap out to make it +/-18 volts?

I switched the 2k2s to 2k7s and got 18.25v on one side and 18.35v on the other.  The formula for the regulators spit out much closer to 3k, but the 2k98 i used gave me over 19v.

lower mid sweep goes from aprox 180 to 2K (and not 100hz to 1k5 as the front says).

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Hello!

Just measured mine and LMF goes from 100Hz to 800Hz. So i am missing half of the range up to 1k5!!
The other bands work like they should!! Do i have a fault at C11/12 or R18/19 ???


Has anybody else measured the bands already?

Any ideas are welcome!!

Thanks,
Wolfgang

stitch-o said:

very quick question:

the 8200 and 3300pf styrene caps at C5 & C6->is there a specific polarity?
the parts in Collin's kit seem to have a blue designation for positive side on the part but I
can't seem to find this answer...

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Slenderchap said:

Polystyrenes are unpolorised....

Colin
www.audiomaintenance.com

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True , but the band on the part designates the outside of the foil , if i'm correct. I've read that in some designs it is necessary to respect the correct orientation of the 'inner' and 'outer' ends of the cap...

On the S800 PCB,  each polystyrene is allocated a round pad and a square pad , suggesting that in this circuit there is a preferred/suggested way to connect these caps.

Can anyone confirm if this design is fussy about that, and if so , which way around is correct?!

Cheers

nEon



PS just found this,from the main man:

PRR said:

If it has a band on one end, that is the Outside Foil. It will work either way, but maybe less stray capacitance if the outside foil goes to the less sensitive side of the cap. If one leg is grounded, outside foil should go to ground. If one side goes to an opamp output, outside should usually go there. But considering the typical size of a 120pF cap, it probably does not matter.

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Hey Guys,

Hopefully these pics will inspire you to get your EQ's done.... just finished my first today.

Purusha's cases are great but must warn you a PITA to work with RE trying to mount the front panels... the side where the BYPASS switch is is VERY tricky to mount and it doesn't help that the screws Purusha provided only have 3-4mm of thread to play with, maybe next time longer screws?

Another thing to be aware of is that pots are slightly recessed behind the PCB's so when mounting to the front panel it causes the thread to be misaligned, forcing the pots to pull up somewhat, making it a little harder to use the pots as the shaft catches with the front panel... a washer on the pot side should act as a spacer giving you straight pots that are free to friction.









Unit is star grounded, XLR's grounded at PIN to chassis, NO hum/noise, VERY quiet unit even with the torrid closer than I would have liked...

Cheers

Matt

looks great matt!! Too bad about the little quirks on the design but it seems you created solutions for the issues! Wish mine was even close to being at that stage and it would be gettin some use!

Ok.... so here a re a few things that may help y'all....

As I shared above the pots don't fit that well with jut a nut and or even the OMEG lock washer as the PCB is wider than the pots so to solve this I purchased a couple spring washers from the hardware store... see the pic below, works like a charm!



Cheers

Matt