4U or 5U 500 series frames

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

john12ax7

Well-known member
Joined
Oct 15, 2010
Messages
2,463
Location
California, US
Looking to make some modules longer than the standard 5.25" 3U, but keep the 1.5" width so they line up with standard 500 series racks.

Any metal work like this exist? Don't even need backplane or edac, just a rack with front panel mounting holes  and rear i/o cutouts.
 
I am not sure if there is something off the shelf but I started a work on 4U height last autumn but due to other commitments had to shelf it.  Plan was to include tube application too (in cooperation with Ian /ruff records). 

You can probably make something using off-the-shelf parts from Schroff  but the rear panel is the main issue. Better option would be to use the top and bottom plates of an existing  500 rack an and make new side panels. You'll need to somehow support the rear panel in few different places too.

If there is sufficient interest I could look into getting some made.

 
Just an Idea:

Why not going to 6U???

This would still allow to have 2 'Standard' Modules on top of each other by using a small bracket to link them.
In addition  it would be possible to crate stereo channels without leaving the API norm/51x norm.

One simply needs two (existing) backplanes.
Between these there even is some (limited) space for HV lines in case someone is going to create tube - based modules.

It's basically like the industrial VXI/VME racks - see this drawing:
https://www.distrelec.de/de/baugruppentraeger-pentair-schroff-24562-440/p/11079983?channel=b2c&price_gs=55.4897&wt_mc=de.cse.gshop.de.-&source=googleps&pup_e=1&pup_cid=35896&pup_id=11079983&gclid=COq80JqOu9ICFU8o0wodwoUJZQ
 
There is no limit but that's a lot of board space to fill.  It could offer possibilities for channel strip type of modules but that can also be done by using two racks. The idea of 4U is to have a slightly bit more space then 3U so that the front panel controls can be spread out in modules that have a lot of knobs.

 
I think that 1.5" is too narrow, thus my 71X format (2").  It allows you to stagger controls for more density (daughter board).
Just my $0.02.

Trident A-Range
http://www.groupdiy.com/index.php?topic=48493.0

API
http://www.groupdiy.com/index.php?topic=46630.0

Neve Dual Mid 1084
http://www.groupdiy.com/index.php?topic=40610.0

Neve 1081
http://www.groupdiy.com/index.php?topic=50463.0

Plus a couple more.......
Best,
Bruno2000
 
2" would be cool.  Lots of transformers would fit in 2" that won't in 1.5". 
 
bruno2000 said:
I think that 1.5" is too narrow, thus my 71X format (2").  It allows you to stagger controls for more density (daughter board).
Just my $0.02.

Trident A-Range
http://www.groupdiy.com/index.php?topic=48493.0

API
http://www.groupdiy.com/index.php?topic=46630.0

Neve Dual Mid 1084
http://www.groupdiy.com/index.php?topic=40610.0

Neve 1081
http://www.groupdiy.com/index.php?topic=50463.0

Plus a couple more.......
Best,
Bruno2000

Dual SSL 9K w/HPF and M/S decoding
https://groupdiy.com/index.php?topic=65340.msg827997#msg827997

Dual 1073 mic pre w/HPF
https://groupdiy.com/index.php?topic=65339.msg827996#msg827996
 
Bruno,  what racks are you using?

The Schroff euroracks seem like a good solution,  build it any width you want.  But they are only 0.2" increments so no 1.5" option.  Plus they tend to be 3U or 6U.

Perhaps a solution would be universal top and bottom panels,  and then different size sides and rear panels.
 
bruno2000 said:
I think that 1.5" is too narrow, thus my 71X format (2").  It allows you to stagger controls for more density (daughter board).
Just my $0.02.
........................
Bruno2000

Myke has already asked me to make a case for your backplane.

Our original starting point was 1.4" and 2". Ian needed 1.4" and Jim's modules were 2".  With 1.5" 500 standard things were getting out of hand and we decided to stick to 1.5" and 2". In 2" we get 8 modules on a rack which fits in perfectly from a mixer point of view.

My plan was to use 44 way (2x22) card edge connector which would provide the 4 buses that Ian required. Then a separate connector below for the HT and heater. This had not been selected yet.  As it required high current rating I have to give it a good thought.

The card edge connector would keep the same pin 1 position as 500 so that the rack would also accept 500 modules. For this I planned an adapter panel for stepping down from 2" to 1.5". Quite a costly thing though.

Of course with two separate pitches for 1.5" and 2" things get a bit out of hand on the backplane. So designing something similar to our current 500 series would be quite challenging. However, we definitely decided to have provision for input/output transformers on the backplane  which would also take the strain from the design of the modules if the available PCB space did not permit them.

But more importantly the issue became with the rear panel. It is not possible to have the XLRs following two separate pitches. So, the options are either to have two separate, 8 and 11 slot rear panels, or  to use individual, single slot width panels in 1.5" and 2" depending on the format one wants to use.

I will get back onto this and see where we end up.



 
For the front mounting holes,  perhaps have holes on 0.5" spacing,  would make 1.5" and 2" both possible with a single piece of metal.
 
The cases I used actually have a 16.5" opening.  I used that last 0.5" for a small panel containing Phantom Power switches and Power Indicator LEDs (+/-24VDC, +/-16VDC, 24VDC relay power, and +48VDC)
YMMV.
Best,
Bruno2000
 
sahib said:
I will get back onto this and see where we end up.

Good to see this being discussed. Is the 1.5 inch simply for 500 compatibility? I am not wedded to 1.5 inches and I quite like the idea of 2 inches because is makes front panel layouts so much easier. My current modules are 2.8 inches wide simply because that is the minimum width I can mount the tubes horizontally which is goo for saving PCB area but  which is not compatible with anything else. I am now working on vertical mount tube versions which will fit in as little as 1.4 inches but 2 inch modules with 8 to a standard subrack is very attractive.

Maybe it is time for a 2 inch standard that works with tubes and semiconductor designs.

Cheers

Ian
 
Hi Ian,

I was about to e-mail you to alert you to the thread.

I have ditched 500 compatibility altogether.  2 " width and 8 slot on a rack.

I am sketching out the schematic at the moment. I'll report back in a couple of days.


 
sahib said:
Hi Ian,

I was about to e-mail you to alert you to the thread.

I have ditched 500 compatibility altogether.  2 " width and 8 slot on a rack.

I am sketching out the schematic at the moment. I'll report back in a couple of days.

Works for me. Any support you need just ask.

Cheers

ian
 
Just for ref, this is the pinout that I have used for my modules using the 22/44 edge connector.
1/A IN 1 +
2/B IN 1 -
3/C SGND (shield)
4/D OUT 1 +
5/E OUT 1 -
6/F INSERT SND
7/G INSERT RTN
8/J +48 VDC
9/K +24 VDC
10/L -24 VDC
11/M AGND
12/N DGND
13/P -16 VDC
14/R +16 VDC
15/S +24 VDC FOR RELAYS & LEDs
16/T POWER RETURN FOR RELAYS & LEDs (connected to AGND at Power Supply)
17/U LINK
18/V OUT 2 -
19/W OUT 2 +
20/X SGND (shield)
21/Y IN 2 -
22/Z IN 2 +

Best,
Bruno2000
 
sahib said:
Hi Ian,

I was about to e-mail you to alert you to the thread.

I have ditched 500 compatibility altogether.  2 " width and 8 slot on a rack.

I am sketching out the schematic at the moment. I'll report back in a couple of days.

How high will this be 4U, 5U? Even though I started this thread,  I would be open to another modular format.

2" fits nice as 8 modules in a 19" rack. Lots of front panel real estate.  The downside is large channel counts can get very wide.  It also almost forces the use of a daughter board for the pots
 
I have started as 4U. Extending it to 5U is not a problem but to me it is unnecessary. 

I am currently going through the data for the  card edge connector options. I originally thought of keeping the HT and heater supply connection separate. However, there is a 32 way (2 x 32)  power connector in  2.5mm pitch with a contact resistance of 10 mOhm and 12A current rating. Also the dialectric withsanding voltage rating is  DC1000V and insulation resistance of 5000 MOhm. I have ordered samples. So I am not ruling out using a single  card edge connector.
 
john12ax7 said:
  It also almost forces the use of a daughter board for the pots

I always have great difficultly achieving a decent, attractive font panel layout when all the controls have to be mounted on the main PCB. It is also inflexible; you have to layout the whole PCB just to change one control. I am not a fan o daughter boards either; they are a mechanical nightmare. I think the solution is to completely separate the controls from the main board. Use vertical mounting pots and switches fitted to  a PCB that fits parallel to the front panel. Mounting can use either pot/switch shafts or dedicated stand offs. Large ecpensive main board is unchanged for variants, only the parallel board changes.

Cheers

Ian
 
Back
Top