thinking o fdoing some 1073's. Canadian group buy?

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Jim, we all appreciate your efforts already. Don't worry, man. This is good.

Regarding your dilemma, I understand the temptation to just design the passive EQ portion and insert it into Martin's circuit. It's tempting because martin's board is working and it eliminates all the design and testing he's had to go through and means that all the testing would be confined to the EQ board. That would probably work great.

But -- I think Chris' all-on-one-board approach may be better in the long run. It's comprehensive. It allows complete control and troubleshooting as one unit. It may be easier to build in the end as well.

Either is fine, but remember how time consuming these become.

Some questions which might help clarify what to do:
Chris, what is the status of your design? Could we just make some PCBs of it? What changes would you make?
Martin, what's your feeling about having an EQ made to mate with your boards? What issues and potential problems are there? It seems there would be some wiring involved.

cheers
:guinness:
 
Hi tommypiper, thanks for the reassurance! :thumb:

I've been in contact with Martin and I have his blessing and his co-operation on modding the board to mate with mine (his time permitting). There should be very little wiring between the 2.

Chris and Martin have been the inspiration for this dream of mine.

Chris has slightly modified a 1073 and added portions of the 1084 EQ.
He uses 1 main board and another board for the EQ switches. Chris acknowledges that there is 1 or 2 slight errors in the switch board design. These shouldn't be too hard to find. The advantage is its all done and ready to go, so yes its tempting. However its still a 2 board design.

I'm sure Chris will chime in soon. I believe he encourages us to use his design. If we do go this way we have to reserve some free boards for him too!

I'm now looking at using PCB mount Grayhill switches (except for Gain). That would be the only way to have everything on 1 board (except pots and gain switch) and on paper it is looking like a mess but doable. Otherwise we have to use either link wires or a large connector as Chris has done.

The board needs to be small enough to fit 2 in 1 case with or without power supply.(external power supply? Why not?)

My boards would have to piggyback on top of the others. This may mean more than 2U, so be ready. Would a double sided board be the best way to go to avoid a bunch of jumpers? Anything wrong with jumpers?

I hope all this back and forth doesn't piss Chris or Martin off. Both those designs are amazing feats! I'm doing this to see if one can come up with a final solution for a 1073.

Also I want to apologize because the title (besides the embarrassing spelling errors) should have been named more appropriately "In search of EZ1073".

jim
 
Hi,

Yeah no problems. I think it should potentially be much easier with the board that I did because I already have a working and functional unit here. The errors are very minor, it would only require me to pop the lid and have a look at what jumpers I made to get it to work. As I said it was only the HF selection that was a problem.

I'm not sure if anyone has had a close look at the PCB PDF, but I tried (for my sake) to make it as easy to troubleshoot as possible. Hence I have already numbered the connector lines to and from each original board to match the schematic. Essentially I placed the 5 existing boards on to a single one, and then worked out from the schematic how to connect them all up.

Don't forget, I didn't have an original 1073 to work with, so the main schematic was all I really had to go on. I like the 'all on one board' approach as it works out to be easier and cheaper.

And on the subject of the edge connector - it was pretty simple to do actually. I thought it would be alot more trouble than it actually was, the parts were all sourced from Farnell so I probably still have the Farnell part numbers (and that would make things much easier still).

But hey, it all depends on what everyone wants to do. As I said, etching the big board was a pain in the neck, but if people can work out how to get it done by a commercial outfit it would be much better.

Cheers

Chris
 
Chris - You are right, it makes more sense. So this is what I'm thinking. I'll make a 1073 using your layout to start. Its the easiest way to go for now and I'll hopefully gain enough experience to maybe decide what improvements (if any) there are to do). Also creating a possible matching board for Martins's EZ1290 will come easier.

This will get things moving and decisions will be based on actual tests rather than my intuition.

1) You say you are not using the original gain switch design and that it doesn't need the line input transformer as it uses the mic transformer. what is the drawing you are using? Making a pcb for this switch is where I can contribute something worthwhile.

2) Can you get back to me with the errors on the switch board?

3) Chris, I think you say you want to build one too. Do you want me to make you a board set too while I make mine? I don't even know how I am going to make them. I may do it myself.

4) I started a BOM of the EQ related boards but I am not through. Do you have one for your board?


jim
 
Chris, thanks for generously sharing your design.

Jim, Grayhill switches are wonderful. Use them if you can.

Don't worry about fitting everything in a 2u or 3u. That will work itself out and it's not going to make or break the project. People still make LA2s with one channel in a 3u, afterall.

Also, edge connectors or some wiring between two boards is not a big deal as long as it's simple and straightforward. It may be more trouble to put pcb mounted switches on the same board with everything. Not a big deal either way. If Chris has a separate switches board already, I would start with that.

I have not seen Chris' project so I can't comment beyond generalities mentioned here. I was surprised to learn that it runs the line in through the mic in transformer? I would recommend at least making it an option to use a separate line input transformer like traditional units. That way people can choose either way. There's magic in them line in irons. :grin:

Yeah, having the gain switch on a board with its resistors will be easier than the traditional gain switch, fo' sure, good idea.
 
[quote author="tommypiper"]Chris, thanks for generously sharing your design.

Jim, Grayhill switches are wonderful. Use them if you can.

Don't worry about fitting everything in a 2u or 3u. That will work itself out and it's not going to make or break the project. People still make LA2s with one channel in a 3u, afterall.

Also, edge connectors or some wiring between two boards is not a big deal as long as it's simple and straightforward. It may be more trouble to put pcb mounted switches on the same board with everything. Not a big deal either way. If Chris has a separate switches board already, I would start with that.

I have not seen Chris' project so I can't comment beyond generalities mentioned here. I was surprised to learn that it runs the line in through the mic in transformer? I would recommend at least making it an option to use a separate line input transformer like traditional units. That way people can choose either way. There's magic in them line in irons. :grin:

Yeah, having the gain switch on a board with its resistors will be easier than the traditional gain switch, fo' sure, good idea.[/quote]

Hi,

I'm busy at the moment but have uploaded a couple of files - the extended gain switch was found on the Neve 1063. I think it's much better than using two transformers - it works a treat.

http://www.linear-recording.com.au/neve/Neve1063.jpg
http://www.linear-recording.com.au/neve/Neveswitch-1063.pdf

Cheers

Chris
 
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