sahib

Re: 4U or 5U 500 series frames
« Reply #40 on: March 10, 2017, 12:30:03 PM »
I have a question regarding the mechanical aspects. I use Eurorack  for several reasons but one is because it provides card guides for the PCBs which the 500 system does not. Ideally I would like to be able to use the backplane with standard Eurorack front and rear horizontal extrusions in mixer builds because their card guides fit into these.  At the same time, I would like DIYers to be able to build the boards and fit them straight into one of your racks. The problem is, I do not know if the intended depth of the new standard PCBs wll be the correct for the spacing required to fit the Eurorack card guides. I could make boards for mixers a different depth so they are Eurocack compatible but I would rather not have to. I like the additional mechanical integrity that card guides give so I would also rather not do without them.

Cheers

ian

Hi Ian,

I am planning to incorporate the guide rails. Could you please send me the data for the exact guide rails you are referring to, or link to it?


ruffrecords

Re: 4U or 5U 500 series frames
« Reply #41 on: March 10, 2017, 03:37:46 PM »
Hi Ian,

I am planning to incorporate the guide rails. Could you please send me the data for the exact guide rails you are referring to, or link to it?
Each manufacturer has slightly different guide rails. Their extrusions are different too, and that is where the fixings for the guide rails are. I will see if I can find  typical example.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

john12ax7

Re: 4U or 5U 500 series frames
« Reply #42 on: March 11, 2017, 08:41:34 PM »
Did some sketches for some conceptual module faceplates. In some cases 2" width is nice, in others  it's unnecessary.

So thinking of some sort of hybrid version.  Is there something that would make sense? Like a .700" grid so 12 1.4" or 8 2.1" modules.  Or a .667" grid? Maybe something else?

Also for connectors what about shielded lan cat5 connectors? They take up little space and it's an inexpensive way to hook multiple racks together.  Lots of db25 or xlr cables can get expensive.

Just throwing out some ideas.

ruffrecords

Re: 4U or 5U 500 series frames
« Reply #43 on: March 12, 2017, 07:36:12 AM »
Just been looking at the card guide issue. All Eurocard compatible sib-racks use the same basic method of construction. A pair of aluminium sides are connected together with horizontal extrusions and the top/bottom front and back. The PCBs are a standard size so all the manufacturer has to do is make sure that a backplane fitted to the rear extrusions ensures the front panel of a standard PCB mates properly with the front extrusions. He can make his extrusions any shape he likes and include any other features ge likes. The most common feature is the ability to snap in card guides. As each manufacturer's extrusions are different so are all the card guides. Attached is a pdf summarising the ones available form just four manufacturers. What this means is that the distance between the top surface of the backplane and the rear surface of the front panel is a fixed quantity.

Obviously I wold like this new 2 inch system to be compatible with standard Euroracks so I can use the same boards  for building mixers bi it would appear this is not possible unless the distance from backplane surface to rear surface of front panel is the same as in a Eurorack.  This seems to me to be too much of a restriction on the new design.

Fortunately there is a glimmer of hope. I have discovered that some manufacturers make variable length card guides for situations where people need to make non-standard depth cards. I will ivestigate this further.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

sahib

Re: 4U or 5U 500 series frames
« Reply #44 on: March 12, 2017, 01:33:11 PM »
Did some sketches for some conceptual module faceplates. In some cases 2" width is nice, in others  it's unnecessary.

So thinking of some sort of hybrid version.  Is there something that would make sense? Like a .700" grid so 12 1.4" or 8 2.1" modules.  Or a .667" grid? Maybe something else?

Also for connectors what about shielded lan cat5 connectors? They take up little space and it's an inexpensive way to hook multiple racks together.  Lots of db25 or xlr cables can get expensive.

Just throwing out some ideas.

I do not mean to discount your idea but with the hybrid width things start to get out of control.
I think we should stay firm to  2" as this gives us the freedom of using variety of vintage and new transformers which can be quite larger  particularly in tube based designs. It also gives us the even number of 8 slots and everybody is happy.

In terms of the connectors  I would again like to stay within the industry standard.  2m 8 channel SubD25 to XLR ready made cable costs under GBP 30.00.  A panel mount IDC SubD25 costs only a couple of quids.

The other factor we should consider is that SubD25 is already a necessary evil from cross talk point of view. So making the connections anymore compact than that will present even greater risk.

In response to your request in your previous e-mail about keeping the 500 depth to make it easier to adapt existing 500 designs, there is no problem with it.

However, the main problem is the card edge connector positions. We can not keep the existing position of the 500 card edge. Firstly the 500 card edge is 15 pin. We have a maximum rack aperture of 162.6mm and we can not fit 2 x 15 pin card edge as they come up to 168mm.

However, supplying an edge connector adapter card solves the problem. If the user wants to utilise  existing 500 designs then they can chop the fingers and hard wire the existing board onto the edge connector adapter.




Obviously I wold like this new 2 inch system to be compatible with standard Euroracks so I can use the same boards  for building mixers bi it would appear this is not possible unless the distance from backplane surface to rear surface of front panel is the same as in a Eurorack.  This seems to me to be too much of a restriction on the new design.

Fortunately there is a glimmer of hope. I have discovered that some manufacturers make variable length card guides for situations where people need to make non-standard depth cards. I will ivestigate this further.

Cheers

Ian

Ian,

There is no problem with that. As I mentioned before we have the audio and power backplanes sitting forward at the required depth and the connector backplane at the back. The audio and power backplanes will be mounted onto a separate frame which will be fixed to the top and bottom panels. We can provide a number of mounting positions  which allow different depth options.

I have already advanced quite far on this. I am planning to complete the mechanical design in a couple of days and then move onto the backplane designs.

« Last Edit: March 12, 2017, 01:38:45 PM by sahib »

ruffrecords

Re: 4U or 5U 500 series frames
« Reply #45 on: March 12, 2017, 04:11:05 PM »


Ian,

There is no problem with that. As I mentioned before we have the audio and power backplanes sitting forward at the required depth and the connector backplane at the back. The audio and power backplanes will be mounted onto a separate frame which will be fixed to the top and bottom panels. We can provide a number of mounting positions  which allow different depth options.

I have already advanced quite far on this. I am planning to complete the mechanical design in a couple of days and then move onto the backplane designs.

Just to be clear, are you planning separate audio and power Backplanes?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

sahib

Re: 4U or 5U 500 series frames
« Reply #46 on: March 12, 2017, 05:43:27 PM »

That's the plan. The reason is the HT. Although we are dealing with small currents, but in case there is a fault and the connector contacts get damaged it would be costlier to replace the entire board.

The other option is to use 44 pin (2 x 22) for the audio  + solid state power rails,  and 12 pin (2x6) for the tube power rails. I can then make only the tube power backplane separate.  Also if it is not required then it won't get fitted. The total length for 44 pin and 12 pin is 160mm and they still fit.

ruffrecords

Re: 4U or 5U 500 series frames
« Reply #47 on: March 13, 2017, 12:48:31 PM »
That's the plan. The reason is the HT. Although we are dealing with small currents, but in case there is a fault and the connector contacts get damaged it would be costlier to replace the entire board.
Is this a concern about hot plugging? I use 2 part connectors at present and have not had any issues with hot Plugging.  However I have no experience of this with a PCB edge connector. Is it really any different?
Quote
The other option is to use 44 pin (2 x 22) for the audio  + solid state power rails,  and 12 pin (2x6) for the tube power rails. I can then make only the tube power backplane separate.  Also if it is not required then it won't get fitted. The total length for 44 pin and 12 pin is 160mm and they still fit.

I don'the mind either way.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

sahib

Re: 4U or 5U 500 series frames
« Reply #48 on: March 13, 2017, 01:15:44 PM »
It is about the possibility of hot plugging but perhaps I am being unnecessarily careful. I'll make the card edge connector PCB a single one. There will be 22 (2x22) + 6 (2X) edge connectors.

A further jiggling allowed to get the jack connectors all lined up at the bottom. Final version of the rear panel attached.

john12ax7

Re: 4U or 5U 500 series frames
« Reply #49 on: March 13, 2017, 01:58:46 PM »
If there are fixed pcb guide rails what length would be optimal? 160mm?

Where will the edge connectors be located relative to the 2" width? On the center line or offset some distance to the left or right?

Since this is a new format,  would it make more sense to just use the din style connectors? A 64 or 96 pin connector would allow for lots of potential future options as well.


sahib

Re: 4U or 5U 500 series frames
« Reply #50 on: March 13, 2017, 06:44:13 PM »
I have not checked the guide rail lengths yet.

The card edge connector centre is off-set to the left of the module center and it is dictated by the stand-off used for PCB mounting. On 500 standard we use M3x6mm which I am adhering to. The material thickness for the L plate is normally 0.8mm but I have opt for 1mm for a bit of additional rigidity.

I have shown the front panel in full size but you would never do that as the modules will not fit. Taking 0.4mm on either side will be sufficient. Therefore I have made the L plate width exactly 50mm. Now, if you are going to have a screen cover over the module you then reduce the RHS by the thickness of the screen cover.

Nothing stops us from using 96 pin connector and adding more  functions but  we are limited by the rear panel space and it currently gives us everything that a rack is expected to do. So, I am not really sure what we can do with the additional features. However, I would not like to sound like opposing your ideas, so I would like to hear what the rest of the members think.


« Last Edit: March 13, 2017, 06:47:29 PM by sahib »

sahib

Re: 4U or 5U 500 series frames
« Reply #51 on: March 13, 2017, 06:49:33 PM »

It seems we can squeeze in another SubD25 at the rear panel.

john12ax7

Re: 4U or 5U 500 series frames
« Reply #52 on: March 13, 2017, 08:22:11 PM »
I think 5mm is too small for the L bracket to pcb distance.  A current problem with 500 series is some transformers will bottom out forcing you to do a cutout on the bracket. For example a Cinemag CMOQ. So for a new standard might best to get rid of the old restrictions.

I think Ian is using DIN for his builds. Bruno used the edge connector for his.  Not sure what would be best for a new design. Anyone used both and have a strong preference?.

If you have 6 dsub then you could have 8 channels stereo in / out.  Plus 8 balanced aux in and 8 balanced aux out.

I'm not saying all these functions are even necessary.  Just things to think about.  Feel free to say no :)

sahib

Re: 4U or 5U 500 series frames
« Reply #53 on: March 14, 2017, 05:35:29 AM »
......

I'm not saying all these functions are even necessary.  Just things to think about.  Feel free to say no :)

Ha ha ha. I am turning into my son. His default response is so much no that I once told him that I would give him £5 more for his pocket money and he said no.

Your point on the stand off height is valid but generally the area to the left of the PCB is a dead area. So, it is better to keep it as minimal as possible. I generally use (plastic based) spacers to raise the transformer off the board. But you still have a valid point and again we should hear what the members say.

With your additional functions you are leaning towards mixer application which is great. But do not forget you have to get all of these onto the backplane PCB and that may not be possible. With 6 SubDs the house is already crowded. However, I will have a better idea of this once we start to laydown the connector backplane. Otherwise we have sufficient space to get another row of 6 SubDs.
« Last Edit: March 14, 2017, 05:40:07 AM by sahib »

ruffrecords

Re: 4U or 5U 500 series frames
« Reply #54 on: March 14, 2017, 11:38:58 AM »
It is about the possibility of hot plugging but perhaps I am being unnecessarily careful. I'll make the card edge connector PCB a single one. There will be 22 (2x22) + 6 (2X) edge connectors.

A further jiggling allowed to get the jack connectors all lined up at the bottom. Final version of the rear panel attached.

How close, vertically are the pairs of XLRs? Is there enough room to allow for the release buttons?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

ruffrecords

Re: 4U or 5U 500 series frames
« Reply #55 on: March 14, 2017, 11:50:16 AM »
I have not checked the guide rail lengths yet.

The card edge connector centre is off-set to the left of the module center and it is dictated by the stand-off used for PCB mounting. On 500 standard we use M3x6mm which I am adhering to. The material thickness for the L plate is normally 0.8mm but I have opt for 1mm for a bit of additional rigidity.

Do we need an L bracket? In 500 series it provides rigidity in the absence of guide rails but we do have guide rails.  For screening a flat plate will do and is much easier to make/standardise.
Quote
Nothing stops us from using 96 pin connector and adding more  functions but  we are limited by the rear panel space and it currently gives us everything that a rack is expected to do. So, I am not really sure what we can do with the additional features. However, I would not like to sound like opposing your ideas, so I would like to hear what the rest of the members think.

I use 32 pin 0.2 inch spacing DIN connectors. The more pins you use the greater the insertion removal force. 96 pins are too tough to use without an ejector which we probably want to avoid. 48 pin versions are available with, I think, 0.2 inch pitch.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

ruffrecords

Re: 4U or 5U 500 series frames
« Reply #56 on: March 14, 2017, 11:57:55 AM »
Ha ha ha. I am turning into my son. His default response is so much no that I once told him that I would give him £5 more for his pocket money and he said no.

Your point on the stand off height is valid but generally the area to the left of the PCB is a dead area. So, it is better to keep it as minimal as possible. I generally use (plastic based) spacers to raise the transformer off the board. But you still have a valid point and again we should hear what the members say.
Edcor XSM transformers will mount on PCB surface inside my standard 2.8 inch modules. I will check if they will fit in 2 inches. Softer do some nice PCB mounting output transformers. Holder got them to make a 2k4:600 one for his big tube mixer. I will check their height.
Quote
With your additional functions you are leaning towards mixer application which is great. But do not forget you have to get all of these onto the backplane PCB and that may not be possible. With 6 SubDs the house is already crowded. However, I will have a better idea of this once we start to laydown the connector backplane. Otherwise we have sufficient space to get another row of 6 SubDs.
I think you said backplane and rear panel PCBs are separate. How do they interconnect?

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

sahib

Re: 4U or 5U 500 series frames
« Reply #57 on: March 14, 2017, 02:01:29 PM »
How close, vertically are the pairs of XLRs? Is there enough room to allow for the release buttons?


I do not use the ones with latch. It is a retaining clip type. Otherwise I'll look into a different  rear panel layout. We have some free space on the left. I may be able to position the XLR pairs side by side.


Do we need an L bracket? In 500 series it provides rigidity in the absence of guide rails but we do have guide rails.  For screening a flat plate will do and is much easier to make/standardise.

My mind drifted here. Normally we do not need them. On our tac modules we only have screen plate.


Edcor XSM transformers will mount on PCB surface inside my standard 2.8 inch modules. I will check if they will fit in 2 inches. Softer do some nice PCB mounting output transformers. Holder got them to make a 2k4:600 one for his big tube mixer. I will check their height.I think you said backplane and rear panel PCBs are separate. How do they interconnect?

Cheers

Ian

They will connect through ribbon cables. So both sides will have boxed headers or the XLR backplane can have fixed pcb transition + ribbon, and the card edge backplane can have boxed header.  So, if you do not need the XLR backplane you can still interface through the boxed headers.

ruffrecords

Re: 4U or 5U 500 series frames
« Reply #58 on: March 14, 2017, 02:30:41 PM »
I do not use the ones with latch. It is a retaining clip type. Otherwise I'll look into a different  rear panel layout. We have some free space on the left. I may be able to position the XLR pairs side by side.
OK.  If I build a lunch box I will use yours. If I build a mixer I will need a custom one anyway.
Quote
My mind drifted here. Normally we do not need them. On our tac modules we only have screen plate.
OK!
Quote

They will connect through ribbon cables. So both sides will have boxed headers or the XLR backplane can have fixed pcb transition + ribbon, and the card edge backplane can have boxed header.  So, if you do not need the XLR backplane you can still interface through the boxed headers.
OK

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

ruffrecords

Re: 4U or 5U 500 series frames
« Reply #59 on: March 15, 2017, 07:16:04 AM »
I have spent some time looking in more detail at the eurocard standard. Verotec provide a good description of the basic mechanics  with some handy detail drawings. I think it would be very good if the new system could be made compatible with the eurocard standard. To do this should not be difficult.  The main thing to get right is the total of the depth of the PCB plus it's mating connector; in other words the distance from the front edge of the PCB to the top surface of the backplane. For eurocard,  the standard pcb depth is 160mm and the two part connector stack is 12.7mm. So if you could arrange it so that when the PCB is plugged into your backplane,  the PCB front edge is exactly 172.7mm from the backplane surface it would be compatible. Is this possible?

Cheers

Ian

Edit: I have just looked at the CAPI data sheet and  for a 500 series connector  and I see it is exactly 12.0 mm tall.  So if you make the dimension of the new PCB from its front face to the top of the connector equal to 160.7mm then it will be Eurocard compatible.

Cheers

Ian
« Last Edit: March 15, 2017, 02:08:58 PM by ruffrecords »
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'