The official GroupDIY 511 Help & Support Thread

[janczmok]

Is anybody able to provide me a replacement Amphenol C091 with the small ALu Backplate ? It got lost in my workbench and i'd like to finish my PSU
and fire up the big box ...

 

[john12ax7]

You will need to check with Purple Audio for the details but the Action compressor has a stereo link switch on it.

Does anyone have any experience with the Stereo link jumper, meaning which compressors do work with it and which do not?, 500 series compressors are something new to me, i havent actually seen any 500 compressor with a stereo link switch on/off in it, so this must be a hardwire, which is ok by me, but dont know if it will work with any or most compressors....

 

[[silent:arts]]

added a note (thanks, Jeff) to the first page. it was mentioned before but is somehow lost in all the posts:

It should be noted that the 51x format is it's own special format. We utilize an 18 pin card edge connector instead of the 15 pin used by the VPR style racks. The extra 3 pins allow for bipolar 24V rails which bring many new and exciting possibilities to a 500 series sized module.

The top 15 pins of our rack line up perfectly with a standard VPR, 500 series module. With a little care seating, any 15 pin VPR module can plug right into the 18 pin card edge connector. They will be 100% electronically compatible. It should be understood that some VPR modules with a full metal enclosure may have an issue with the lower rear of the enclosure hitting into the larger 18 pin card edge connector. This will not allow these modules to seat fully into the 511 rack.

This far from the end of the world. We have a few solutions that can easily solve this problem.
1. Substitute 15 pin card edge connectors and dedicate those slots in your rack to the VPR modules with the full metal enclosure.
2. Remove the 3 sided metal enclosure and simply install your module without it. In most situations, there will be absolutely no difference in performance. This can be done with a 550, 550A or 550B EQ and the like.
3. Make a small notch in the lower rear section of the full metal enclosure allowing clearance around the larger 18 pin connector.

 

[kepeb]

I cant see that you would have an issue with joining them all at the 511.
but the back board will be joining the chassis at a different place.

if you just see the chassis connection as an extension from the psu casing.. then if any xlr pin 1 is jumpered to chassis - it wont be sharing the same common as the power ground on the way back to the star point in the psu.

 

[[silent:arts]]

the separated chassis / GND wires are not meant as a "spare"

and we wouldn't do all the extra work to include options if there would be only one best way

 

[jsteiger]

...or is it meant to have everything on the chassis isolated, till the last point where everything joins together at one point?

Yes! Keep them separate. They should only connect at the star ground point in your PSU.

Reading thru the Rane notes has helped me understand this and much more on these issues. http://www.rane.com/note151.html

Best, Jeff

 

[[silent:arts]]

yes, for 99% of installations you will connect chassis & 0V to the star ground in your PSU

 

[kepeb]

you can still put a sleeve around any internal wiring and take one end of that to the star point too.

 

[sahib]

Thanks, ive been reading the Rane document that Jeff posted, thanks for that BTW, just have one question. I had the belief that every time that chassis gnd joins signal ground it must be done at one point only, therefore it is why everything goes to a star ground. Rane strongly recommends that pin 1 be connected to chassis at the point of entry, i understand that BUT isnt that point at which the ground gets connected to the chassis also be connected to my star ground with an other wire?

Yes, the common practice is that the pin 1 connects to the chassis at the point of entry. Then the entire chassis becomes a one big ground plane. On that plane you can designate one point to have your star ground.

Another question, by terminating pin 1 to chassis at the point of entry, doesnt it leave the internal audio wiring with the shield disconnected from ground thus making it more sensitive to EMI such as the one emmited by a power transformer inside my enclosure for example? im talking about the cable that goes from my PCB to the XLR connectors, which so far ive been keeping the pin 1 or shield connected from the XLR all the way to my PCB signal ground...

It all depends where the power transformer is located. Unless you are using an EI type transformer, the ground wire is touching the power transformer and the cabling layout is in a mess you should not worry about it.  Check the layout on our case design. The transformer and all the mains connections are kept on one side of the case while all the DC outputs are on the other.

 

[kepeb]

thats right.
and i like pictures too
I think I would maybe extend from the chassis side and not connect at the pcb

EDIT: although, this would not be about the 511 build as there is no xlr audio signal present in the psu of course.

 

[ruckus328]

Hey guys, have a couple design questions, mostly regarding to Card Edge pinout and grounding.  I don't have a rack yet, waiting for them to come in, so don't have a board to look at.  First, trying to confirm what the different ground pins should be used for:

Pin 1 - "Chassis ground" - My question is is this typically ever even used for anything?  If I have board standoffs/mounting holes mounting the boards to the metalwork, should I ground these standoff points to Pin 1?  or should I just rely on the front panel mounting to the rack to sufficiently ground all the metalwork?

Pin 5 - "Common Ground" - Assuming this is audio ground.  My question is, Is Pin 5 on each channel tied together on the backplane PCB?  Or is Pin 5 on each channel kept segregated from each other and tied together at the Power Supply?  The reason I need to know this is, what should I do if I'm dealing with a stereo system (with seperate L & R grounds, but also common ground points for both boards)?  Seems it starts to get tricky when dealing with this, as how do I address the common ground points?
Should I route them directly to Pin 5 and rely on the backplane to tie them together?

Pin 13 - "PS Common" - Not quite clear what this is used for.  My assumption is it's a seperate ground point kept isolated from Pin 5 and tied to Pin 5 back at the Power Supply.  My guess is I would use this for things like relays, LED's, etc - basically anything I don't want touching my audio ground.

Any help would be appreciated.  Thanks.

 

[[silent:arts]]

Pin 1 - "Chassis ground" - My question is is this typically ever even used for anything?  If I have board standoffs/mounting holes mounting the boards to the metalwork, should I ground these standoff points to Pin 1?  or should I just rely on the front panel mounting to the rack to sufficiently ground all the metalwork?

nearly all modules I'm aware of have the top/back stand off mounting hole routed to this pin 1.
as far as I know Jeff was unhappy with some relay switching plops and solved it routing relay ground to chassis.
this information is unconfirmed, may be Jeff chimes in ...

Pin 5 - "Common Ground" - Assuming this is audio ground.  My question is, Is Pin 5 on each channel tied together on the backplane PCB?  Or is Pin 5 on each channel kept segregated from each other and tied together at the Power Supply?  The reason I need to know this is, what should I do if I'm dealing with a stereo system (with seperate L & R grounds, but also common ground points for both boards)?  Seems it starts to get tricky when dealing with this, as how do I address the common ground points?
Should I route them directly to Pin 5 and rely on the backplane to tie them together?

Pin 13 - "PS Common" - Not quite clear what this is used for.  My assumption is it's a seperate ground point kept isolated from Pin 5 and tied to Pin 5 back at the Power Supply.  My guess is I would use this for things like relays, LED's, etc - basically anything I don't want touching my audio ground.

nearly all modules I'm aware of have connected pin5 and pin13 to the same ground.
however, I'm playing with a tube module using DC/DC converters, my plans are to connect all audio grounds to Pin 5 and all PSU related grounds to Pin 13.

the 511 backplane has two ground planes, one is pin 1, the other is pin 5 and 13.
normally both end at a start ground point in the PSU case.

hope this helps

 

[jsteiger]

...nearly all modules I'm aware of have the top/back stand off mounting hole routed to this pin 1.
as far as I know Jeff was unhappy with some relay switching plops and solved it routing relay ground to chassis.
this information is unconfirmed, may be Jeff chimes in ...

Yes this is true. I had some mute pops on the VC528 until I fully separated the relay ground to use pin 1. At the same time, I also now use pin 1 for LED ground. And like Volker says, the top rear standoff always connects to pin 1 Chassis ground on my modules as well as all API modules I have seen.

I have started adding a 10R between pin 1 and my local module ground plane. For me this is 2 fold. First, it ensures local isolation on my card. Second is that if some user or other rack manufacturer has pin 1 floating in their rack, I still get a ground connection on pin 1. This is not optimum and should of course never happen but never say never. I do remember of reading that API had a batch of 6 space racks that pin 1 was floating. Maybe an error somewhere and maybe BS but I did reading it somewhere.

Hope this all helps!
Jeff

 

[ruckus328]

Volker Thanks.

Pin 1 - "Chassis ground" - My question is is this typically ever even used for anything?  If I have board standoffs/mounting holes mounting the boards to the metalwork, should I ground these standoff points to Pin 1?  or should I just rely on the front panel mounting to the rack to sufficiently ground all the metalwork?

nearly all modules I'm aware of have the top/back stand off mounting hole routed to this pin 1.
as far as I know Jeff was unhappy with some relay switching plops and solved it routing relay ground to chassis.
this information is unconfirmed, may be Jeff chimes in ...

Ahh, would make sense, as keeps relay ground as far away from audio ground as possible.  I've had alot of luck with running relays/LED's directly from the +/- rails, and never letting them touch 0V at all, which has pretty much become my standard practice now, as also makes for a nice and balanced system, granted this might not make much difference in a 500/51X rack, as other modules may or may not deploy this scheme, but is nice also as it gives more volts to play with and more options to run multiple relays in series and minimize current consumption.  Anyways, back on topic......

Pin 5 - "Common Ground" - Assuming this is audio ground.  My question is, Is Pin 5 on each channel tied together on the backplane PCB?  Or is Pin 5 on each channel kept segregated from each other and tied together at the Power Supply?  The reason I need to know this is, what should I do if I'm dealing with a stereo system (with seperate L & R grounds, but also common ground points for both boards)?  Seems it starts to get tricky when dealing with this, as how do I address the common ground points?
Should I route them directly to Pin 5 and rely on the backplane to tie them together?

Pin 13 - "PS Common" - Not quite clear what this is used for.  My assumption is it's a seperate ground point kept isolated from Pin 5 and tied to Pin 5 back at the Power Supply.  My guess is I would use this for things like relays, LED's, etc - basically anything I don't want touching my audio ground.

nearly all modules I'm aware of have connected pin5 and pin13 to the same ground.
however, I'm playing with a tube module using DC/DC converters, my plans are to connect all audio grounds to Pin 5 and all PSU related grounds to Pin 13.

the 511 backplane has two ground planes, one is pin 1, the other is pin 5 and 13.
normally both end at a start ground point in the PSU case.

hope this helps

OK, so Pins 5 and 13 are tied together on the backplane PCB, but where?  Do they connect together right at the cardedge connectors?  Or do they stay seperated and tie together at the PSU connector?

And if I'm understanding correctly, you're saying you'd typically tie Pin 5 and 13 together on the module?  If so what is the point to doing this if they are tied together already on the backplane?  This would create a loop.

 

[ruckus328]

Thanks Jeff.

I have started adding a 10R between pin 1 and my local module ground plane. For me this is 2 fold. First, it ensures local isolation on my card. Second is that if some user or other rack manufacturer has pin 1 floating in their rack, I still get a ground connection on pin 1. This is not optimum and should of course never happen but never say never. I do remember of reading that API had a batch of 6 space racks that pin 1 was floating. Maybe an error somewhere and maybe BS but I did reading it somewhere.

You lost me here.  If you're local plane is connecting to Pin 5/13 (which all the other modules will be also), then how does adding a 10R resistor between it and chassis ground get you any local isolation?  Maybe I'm misunderstanding.

 

[[silent:arts]]

OK, so Pins 5 and 13 are tied together on the backplane PCB, but where?  Do they connect together right at the cardedge connectors?  Or do they stay seperated and tie together at the PSU connector?

thermal pads at the card edge connectors directly to the same plane

And if I'm understanding correctly, you're saying you'd typically tie Pin 5 and 13 together on the module?

yes

If so what is the point to doing this if they are tied together already on the backplane?  This would create a loop.

you don't have to do this. but having a single ground plane makes life easier.
and it doesn't create a loop, it just uses two connections from one plane to the other.
if this creates a loop, no ground plane would exist ;D

 

[[silent:arts]]

You lost me here.  If you're local plane is connecting to Pin 5/13 (which all the other modules will be also), then how does adding a 10R resistor between it and chassis ground get you any local isolation?  Maybe I'm misunderstanding.

you never know the chassis the module you designed will live in ;D
if it is a chassis with pin1 unconnected Jeffs relays wouldn't work anymore.
but with 10R it is still somehow isolated

 

[ruckus328]

OK, so Pins 5 and 13 are tied together on the backplane PCB, but where?  Do they connect together right at the cardedge connectors?  Or do they stay seperated and tie together at the PSU connector?

thermal pads at the card edge connectors directly to the same plane

And if I'm understanding correctly, you're saying you'd typically tie Pin 5 and 13 together on the module?

yes

If so what is the point to doing this if they are tied together already on the backplane?  This would create a loop.

you don't have to do this. but having a single ground plane makes life easier.
and it doesn't create a loop, it just uses two connections from one plane to the other.
if this creates a loop, no ground plane would exist ;D

Ahhhhhhhh, it's a common plane on the backplane, I was thinking it was two seperate planes, tied together at the PSU connector.

This all makes sense now, think I got everything I need to know (if I had a backplane here this would have been obvious and wouldn't have had to bother you guys with all this) 

 

[jsteiger]

you never know the chassis the module you designed will live in ;D
if it is a chassis with pin1 unconnected Jeffs relays wouldn't work anymore.

Same goes for phantom powered mics! 

 

[[silent:arts]]

now this is the reason why we have all those "ground options" in our rack, isn't it.
since we don't know which modules will live in it ... ;D ;D ;D