GlenSound Mixer Frame

[ruffrecords]

Hi Ian, you have probably seen this document, but for those reading along at home...

I have not seen a version of that for a very long time (pre 3000 series). Just what I need. Many thanks.

Cheers

Ian

 

[ruffrecords]

So I have stripped the mixer down to the bare frame and tried a couple of my standard modules in the top section:

Looks OK. But there is a problem. If you look round the back you will see that my modules are so deep they stick out the back:

by a good 20mm or so. Not sure how to fix this right now. Possibly some spacers would do it temporarily.

However, there is a more subtle problem; the distance between the top and bottom extrusions is larger than in the DIN standard racks, so my modules will attache at the top but not at the bottom. Also the motherboard at the rear cannot be attached top and bottom either. The difference between the two is small, no more than 2mm but it is enough to give me a problem.

Ho hum.

Cheers

Ian

 

[ruffrecords]

I just happend to have some regular 84HP extrusions in my hand and laid them across the width of the mixer. To my surprise the mixer is quite a bit wider than a normal 19 inch rack. In fact it is 98Hp or 19.6 inches. By a lucky coincidence, my standard modules are 14HP wide and 14 divides into 98 exactly 7 times so I can fit an extra module in. The Glensound modules are exactly half this width so 14 fit across the mixer width.

Cheers

Ian

 

[ruffrecords]

I measured the gap at 22mm so I got myself some 12mm and 10mm stand offs and used them mount the motherboard off the back of the Glensound. Looks a bit ugly round the back but it does work.

More difficult is moving one of the extrusions  up a couple of mm so it meets the DIN standard. How do you make an M4 hole 2mm away from en existing M4 hole?? I suppose I could just file a round slot in the right direction until it fits.

I remember back in the 60s during my apprenticeship in the aerospace industry they used to fill holes in aluminium sheet with Aradite loaded with aluminium filings

Cheers

Ian

 

[Humner]

More difficult is moving one of the extrusions  up a couple of mm so it meets the DIN standard. How do you make an M4 hole 2mm away from en existing M4 hole?? I suppose I could just file a round slot in the right direction until it fits.

How about making a "mating flange" that fastens to the existing spaced holes, but includes holes that are the distance needed for your modules? You can also make the flange 22mm(or so) thick so the motherboard at the rear can be situated in its normal position as well.

How to make this flange is another story, not to mention what to make it out of, but maybe a good idea to throw around.

 

[ruffrecords]

How about making a "mating flange" that fastens to the existing spaced holes, but includes holes that are the distance needed for your modules? You can also make the flange 22mm(or so) thick so the motherboard at the rear can be situated in its normal position as well.

How to make this flange is another story, not to mention what to make it out of, but maybe a good idea to throw around.

I was thinking along those lines too. There is a very thick (0.25 inch) cladding cheek that mates with the basic frame and I was originally planning to put that back after making the mods but you cannot do that if you use a flange on the outside of the cheek - maybe inside might work? The cladding cheeks are so nice I am thinking about using them on their own to make another frame - two consoles from one!!

Right now I have used stand offs and filed the extrusion holes into slots so I can move them to the correct position. This seems to work OK - I had it running 6 modules for a few hours this eveing to test a power supply and nothing blew up but I really would like to make the back end neater than it is. Flanges look promising, Thanks for that.

Cheers

Ian

 

[ruffrecords]

I've been thinking some more about this. I definitely need to add a flange to extend the rear, first to make it look presentable and secondly to stop people electrocuting themselves on the HT running along the back of the of the motherboard!!

I have abandoned this idea of using 7HP modules for the time being. Instead I can use twin line amp (TLA) modules to make twin mic pres, each with toggles for phantom/phase and pad plus a 47K REV LOG pot for gain (from 26dB to 60dB). So I am leaning towards the first four modules being twin line amp dual mic pres which gives us 8 mic inputs. The three remaining module slots could also include a pair of TLAs acting as bus amps. They don't need much if anything in the way of front panel controls so I think it would be good to use the space for a couple of good sized VU meters.

Between the top section and the faders is another sloping section. There is not enough depth for my regular modules so I need to think of something shallow but useful to go in here. Present thinking is along the lines of a simple 2 band EQ (the simple 3 band did not work out) plus HPF and, if I can find the room, a pan pot, foldback and echo send pots. The space currently includes a scribble strip but I think I will remove this and use it for the EQ/routing.  The right hand three slot of this (below the VUs) can be the monitor switching and foldback and echo send masters.

Lastly in the fader section I can use the original 8 P&Gs for channel faders in the first for slots. Again the last three slots can be used for master faders and anything I have forgotten.

Time to get some paper and start drawing.

Cheers

Ian

 

[ruffrecords]

Here is my first stab at a console layout. I am starting to get the hang of this 2D CAD thingy.

Cheers

Ian

 

[Timjag]

Wow that thing takes me back to radio Essex days! Sorry if I missed something but you're going to put your valve designs in the frame? Or restore the boomy old BBC sound(nothing wrong with that btw!)

Looks good btw isn't it made from eurorack?

 

[ruffrecords]

Wow that thing takes me back to radio Essex days! Sorry if I missed something but you're going to put your valve designs in the frame? Or restore the boomy old BBC sound(nothing wrong with that btw!)

I am going to build one of my valve designs in it. Part working mixer, part test bed for new stuff.

Looks good btw isn't it made from eurorack?

It is, more or less.  It is almost exactly 500mm wide which is exactly 7 of my standard modules wide. The extrusions are very eurorack like and have the standard M2.5 fixings for modules. They are just not quite the eurorack distance apart so I have had to tweak it a little. The cosmetic end cheeks are fascinating. They are about a quarter of an inch thick and they have been nylon dipped - virtually indestructible.

Cheers

Ian

 

[Timjag]

Haha doesnt surprise me, beeb and ex-beeb technicians had a very shall we say, withering view of DJs operating or even being near consoles!

I think they thought they were all a bunch of Alan Partridges.

 

[ruffrecords]

I think I now have a solution to mounting my modules safely in the top section of the Glensound frame. I discovered that the vertical spacing between fixing holes for the extrusions in the side plates seems to be the same for all manufacturers (the horizontal pitch for fixing extrusions at different distances from the front is manufacturer specific). This means I can literally bolt a pair of standard side plates onto the top section of the Glensound so it sticks out far enough to be able to contain my modules and also leave space for a rear connector panel (see attached pic. This has the added bonus of ensuring the top an bottom rails are also the correct distance apart. The only problem is the gap between the side plates is a bit larger by the thickness of the Glensound side cheeks. Fortunately I have some spare 108HP rails left over from another mixer project so I thought I might cut these down to fit - all I would need to do is tap one end.

So a step in the right direction towards turning this into a tube mixer.

Cheers

Ian

 

[ruffrecords]

I found an even better solution for mounting the backplane PCB. I found some deep extrusions which, when fitted using the existing fixing holes, provides backplane mount very close to the ideal spot. All I had to do was add a standard insulating spacer and the fit was exact. Attached pic shows an edge view with a module plugged into the backplane.

Cheers

Ian

 

[Timjag]

...and acts  as a handy cooling system 

 

[ruffrecords]

...and acts  as a handy cooling system 

Except the rear of the back-plane carrying the 300V HT is exposed. There is some more metalwork to add to complete the transformation.

Cheers

ian