EZ Tube Mixer Support Thread

[anjing]

For the backplane receptacle Ian and Holger are using these http://uk.farnell.com/jsp/search/productdetail.jsp?SKU=1656165 that's the one i will get if i ever need some more. The current draw of the heaters for one card is around 450mA.

The pcb bracket you linked are the ones i use. Funny in north america at Newark they are only 1.31$. Be aware they are not a perfect fit because they have a bezel.(i can post a pic if you want to see)They work fine but it might bother you if you like precision. I'm not aware of cheaper ones...

I'm curious as to why one want's to use cassettes? I'm not sure anyone found a suitable cassette yet for the eurocard module with the connector, as far as i know Holger uses one for his 3u eq.

Regards,

Pierre

 

[ruffrecords]

Ian, I saw you were using the expensive harting DIN connectors at about £9 each.
I don't know if you know that they do another for £3.50, part numbers:
receptacle: 2289392
connector: 109-6838
I bought the cheaper ones and it fits the eurocard just fine. Only difference as far as I can tell is that the current rating (for the connector at least) is 2A...I think the more expensive one is 6A? I don't know if this is problematic.

A lot of this is down to Farnell's poor search engine. If you search for 32 way 5.08 pitch you only get the expensive ones. As Holger discovered most manufacturers make 2.54 pitch connectors with only every other pin fitted making it a 5.08 pitch connector with a lower current rating. The plug you identified is the one I use at present. The receptacle is one I had not come across before. It looks like a 2.54 pitch connector with every other pin fitted and as you rightly point out it is a lot cheaper than the £9 ones I was using originally. Holger found an even better receptacle for less than £1. Check out this post:

http://www.groupdiy.com/index.php?topic=51829.msg669134#msg669134

I've been looking for the module cassettes, but I can't find them on farnell - does anyone know if you can get the cassettes from farnell?

Farnell do not do 14HP cassettes. The 14HP one Holger is made by Schroff:

http://www.groupdiy.com/index.php?topic=51829.msg659775#msg659775

I've also lost the thread where Ian mentioned the PCB-front panel brackets. There was a cheaper one and an expensive one..I think this is the expensive one:
http://uk.farnell.com/schroff/60807-181/bracket-to-fix-pcb-to-panel/dp/2292872

But can't find the cheaper one?

I think those are the only ones we have been able to find from normal distributors. The plastic ones are made by the various sub-rack manufaturers but I have not seen them at places like Farnell.

Cheers

Ian

 

[ramshackles]

Thanks for clearing that up

I've not decided anything about cassettes...just investigating all options.

Farnell's search engine is just pants. I generally just resort to narrowing down by category until there are few enough choices to browse through.

 

[anjing]

Hello Ian!
  I hope all is fine for you and it's nice to see your back! I just was reading your blog http://www.eztubemixer.blogspot.co.uk/2013/06/power-supply-assembly-in-my-larger.html and i'm really looking forward to see what happens with your power supply. I was just exploring the idea of putting my power supply inside the console before i saw your post...my mixer probably qualify as small in the end i will probably have only 9 modules.

Regards,

Pierre 

 

[ruffrecords]

Hello Ian!
  I hope all is fine for you and it's nice to see your back!
Regards,

Pierre

I am still on holiday at the moment but I can post to the group from my tablet. I'll be back home tomorrow.

Cheers

Ian

 

[Holger]

Cassettes:

On the right is a Fischer 3 RU 14 HP cassette without ventilation. I use them for I/O and EQs. Bürklin stocks them for ~17€. The black ones from Fischer recently came in. They are ventilated, the amp card fits into. I will test the temperature behavior in the next week.
The price is 19€ directly from the manufacturer. Lead time was 4 weeks...

 

[audiomixer]

Cassettes:

On the right is a Fischer 3 RU 14 HP cassette without ventilation. I use them for I/O and EQs. Bürklin stocks them for ~17€. The black ones from Fischer recently came in. They are ventilated, the amp card fits into. I will test the temperature behavior in the next week.
The price is 19€ directly from the manufacturer. Lead time was 4 weeks...

Cassettes .....

consider this scenario: in 50 years from now young guys are going to tear your cassettes apart and rack that stuff ;-) vintage will ne the new cool then - ;-)

- Michael

 

[Holger]

Michael, that's possible 

More modular fun:

received my back plane PCBs today. Now I can connect my modules in a more reliable way. The additional components like relays are for solo functionality. I hope it works...

 

[ruffrecords]

Am I right in thinking the motherboard is two modules wide? Very handy as it means you can easily do 4,6,8 or even 10 slot wide mixers with the same motherboard. How do you plan linking motherboards together?

Cheers

Ian

 

[Holger]

Motherboard is a nice word. It's 128.4 x 128.4 mm, so (a bit less than) 2 modules wide. I think I will made a couple of shielded patch cords to connect the buses. For the supplies I need to conceive a central distribution system to feed the boards individually.

 

[ruffrecords]

One more question Holger. I notice you have a number of two and three pin headers on the PCB for making connections elsewhere in the mixer. This is a very good idea as it simplifies overall construction and maintenance. I have considered doing this several times in the past but I have always decidied against it. The reason is I always have problems connecting wires to the plugs. I don't like crimps and soldering is always messy. Then I usually manage to get one pin in the wrong hole and cannot get it out without damaging the cable or the connector. How have you overcome these problems?

Cheers

Ian

 

[anjing]

Hi Holger,
 
    Looks very neat and tidy...Whats the motivation for making 2 channels at a time?  I guess you could have dc regulators for the heaters for each motherboard?

Regards,

Pierre

 

[anjing]

One more question Holger. I notice you have a number of two and three pin headers on the PCB for making connections elsewhere in the mixer. This is a very good idea as it simplifies overall construction and maintenance. I have considered doing this several times in the past but I have always decidied against it. The reason is I always have problems connecting wires to the plugs. I don't like crimps and soldering is always messy. Then I usually manage to get one pin in the wrong hole and cannot get it out without damaging the cable or the connector. How have you overcome these problems?

Cheers

Ian

Hi Ian,
    I feel the same way, I used molex connector for my pan circuit and it got me swearing more then often. I guess with the right crimper(wich i don't have) and a lot of practice it might get easier. I looked up tutorials of youtube and looks easy once you have the right technique. I even saw you can buy bulk already crimped hookup wire by the hundreds on ebay. But that's no help when you need shielded cable...

Regards,

Pierre

 

[ramshackles]

Could an option be to use screw terminal blocks like these?
http://uk.farnell.com/te-connectivity-buchanan/282834-3/terminal-block-pcb-3pos-30-16awg/dp/1769842

Certainly much easier than crimping, but is the contact good/strong enough?

 

[ruffrecords]

Could an option be to use screw terminal blocks like these?
http://uk.farnell.com/te-connectivity-buchanan/282834-3/terminal-block-pcb-3pos-30-16awg/dp/1769842

Certainly much easier than crimping, but is the contact good/strong enough?

I use those for the power stuff because of their current carrying capability but I am not so sure about using lots of them for signals. They take quite a while to hook up. The nice thing about Molex for signals is they are easy to connect and re-connect if only I could wire them up in the first place!

Cheers

Ian

 

[ruffrecords]

Hi Ian,
    I feel the same way, I used molex connector for my pan circuit and it got me swearing more then often. I guess with the right crimper(wich i don't have) and a lot of practice it might get easier. I looked up tutorials of youtube and looks easy once you have the right technique. I even saw you can buy bulk already crimped hookup wire by the hundreds on ebay. But that's no help when you need shielded cable...

Regards,

Pierre

I am with you on that one Pierre. I find it hard to hold the too, the crimp and the wire with only two hands. Then there's the fact that microphone cable is stranded. Should you tin it first? Then the screen is usually much bigger than the signal ones and as often as not won't even fit in the crimp. So you cut off half the strands and try to tin those and fit them in but I am always worried they are going to break off. What we need is a reliable PCB mounting alternative to an XLR.

Cheers

Ian

 

[Holger]

One more question Holger. I notice you have a number of two and three pin headers on the PCB for making connections elsewhere in the mixer. This is a very good idea as it simplifies overall construction and maintenance. I have considered doing this several times in the past but I have always decidied against it. The reason is I always have problems connecting wires to the plugs. I don't like crimps and soldering is always messy. Then I usually manage to get one pin in the wrong hole and cannot get it out without damaging the cable or the connector. How have you overcome these problems?

Cheers

Ian

I have a good crimp tool. It's time consuming but there are not so much alternative solutions.

 

[Holger]

Hi Holger,
 
    Looks very neat and tidy...Whats the motivation for making 2 channels at a time?  I guess you could have dc regulators for the heaters for each motherboard?

Regards,

Pierre

Pierre, as Ian said, I can build multiples of two easily. The next reason is the price, I've paid some 9€ for each PCB at an order volume of 20. As mentioned earlier, I don't need per board regulators because I have the THEL 10A regulated board in my PSU.

 

[ruffrecords]

Pierre, as Ian said, I can build multiples of two easily. The next reason is the price, I've paid some 9€ for each PCB at an order volume of 20. As mentioned earlier, I don't need per board regulators because I have the THEL 10A regulated board in my PSU.

That is a good price for the PCBs. Did you stick to 1.6mm thickness?? I used 2.5mm for mine for some added strength.

I decided to give crimping another go. I have ordered a load od 2 and 3 way Molex KK series connectors and crimps plus a 'proper' crimp tool. I am going to spend a couple of hours just crimping twin screened cables to see if I can master it.

Cheers

Ian

 

[Holger]

...
That is a good price for the PCBs. Did you stick to 1.6mm thickness?? I used 2.5mm for mine for some added strength.
...

1.6mm thickness. Another advantage of the relatively small PCB size.