Trident CB9054 B-Range Limiter - Schematics?

[kpearsall]

Any news on the boards ?

Firstly does anyone know how to fix not getting emails or notifications (even the top menu bar) to this thread? I'm truly sorry I didn't check for messages before.

Boards are gonna be about two weeks out. When they arrived, I noticed they were not the revised board, but the first edition I did a while back. It had some errors which aren't really fun to work around. They were sent back and the company admitted fault and are currently making the new boards. I fully expect them to be here in two weeks or less. I'm sorry if the extended timeline has thrown anyone off, it's certainly put a damper on a console build I'm doing.

In addition, since I haven't heard back about the chassis from Kid Squid and I'm on a bit of a time crunch, I've been working with another audio company in the US here, who has helped greatly with the mechanical drawings for the original chassis, and an early estimate should put each chassis module somewhere south of the $30 price point. I'll be ordering those early next month if anyone wants one I'll post here when they are ready. Unsure about the 8 channel rack chassis. May be easy enough to just stuff a backplane in a 3u case.

 

[Rob Flinn]

Thanks for the update.

 

[kpearsall]

Good news all around.

Boards should be delivered tomorrow. I'll try like hell to get them all out by end of week!
I'll fully inspect and note any issues I see. Hopefully that last issue is fixed. I should mention I need to update the BOM. The first wiring posts we designed for turned out to be too thin, and were hard to attach a wire to without desoldering the whole post. I widened these holes and their pads which should hopefully be a good size for wiring straight to the board as well. I don't recommend that method however, unless you are mounting them horizontal side by side instead of stacked. It's a LOT of wiring to remove just to replace a chip or something. fixed trimmer post sizing and spacing for better fit from first version.

I've also received the prototype original style chassis module. a few minor inconveniences we hoped to avoid, but that's why we prototype.The large meter hole was a bit too close to the bend so it didn't bend right and is holding the meter away from the face about .5mm. Not a big deal, but we're going to extend the cutaway at the extremes about 1mm so even if it doesn't bend right, it won't affect the meter. The bending and extra thickness of the material being used (.48 cold rolled steel) also changed the front width about 1mm or so, resulting in the meter being slightly wider than the face. Just moving the bend lines a hair to solve that. Face width will still be set at 45mm, with the meter hole cutout at 39mm.

 

[kpearsall]

Boards are in! Last chance to correct an address! Everything looks good

 

[Potato Cakes]

Just saw that this was updated back in November. Did these ship out? I did not receive mine yet.

Thanks!

Paul

 

[kpearsall]

Yikes! ADHD strikes again! packaged, addressed, labeled, and totally spaced the last part. On way to post office now. So sorry guys. I'll make it up to you if I can!! Working 20 hour days isn't healthy.

 

[Rob Flinn]

Hi Ken, Got the boards this morning. They look good, looking forward to getting stuck in to this project. Thank you !

 

[JMan]

Mine have arrived as well. Might be some time until I can get to building them, but in the meantime I will enjoy looking over and admiring the boards.

 

[jensenmann]

Boards arrived here, too. Thanks a lot, Ken!!!

 

[lowatt]

Hi All,
I think I might like to give this project a shot, and mount a pair in a 19" rack. Is it still possible get hold of a pair of PCB's? ..or was it pre-order only?
Thanks.

 

[peterc]

Mine arrived yesterday, thanks Ken

 

[kpearsall]

lowatt, this run was pre-order. I made extras but they're all taken. I did actually get orders for a good amount of completed units, so there will be another run. Those units will be going into custom consoles I'm building though, so not sure when exactly they'll be needed but I'll message you when I place the next order! Using what little free time I have to work on revisions to chassis, and paint/silkscreen.

 

[Potato Cakes]

The STMicroelectronics version of the UA741 has a maximum power supply rating of +/-22V, but the current TI version has this as +/-18V. Is there an actual design difference that would warrant a lower voltage for the TI version? Also the section of the schematic that has the 2N3054 and the +45VDC input, is this just to convert the incoming voltage to +24V? Can these parts be omitted if these boards are built into a 1U case that already has a +24V/0V PSU?

Thanks!

Paul

 

[kpearsall]

Hi Paul, it's only getting a single rail voltage instead of a bi-polar supply. I'm not an IC expert but I believe the 24vdc you send it, gets seen the same as +/-12vdc. the rating is for the differential, not only the positive. Otherwise from my understanding the vintage ones would be overpowered as well! Anyone correct me on this if I'm wrong? This has always been the way I understood it.

As for the power regulation, you are correct. As I stated earlier if you are using the regulator you only NEED to put about 30v into it. It expected 45v as that was the B+ throughout the rest of the console. If you already had a well regulated supply, just connect that to VCC and you're all good!

 

[Potato Cakes]

Thanks for getting back to me. I will wind up experimenting to see to get it work with a bipolar power supply like I do with the 1073 units I am building by substituting the 0V with a -VDC rail. In my case I am using a 48V rail (+/-24V) for the entire circuit. I am planning on integrating these boards for some clients and was trying to figure out how to most easily power this. I think what I'll do with the first one is power the board with the +24V and ground just to make sure the build works.

You are correct regarding IC power rating being the differential. There are some circuits where putting the -V side of the IC to ground causes issues but it usually related to something else in the design and not necessarily power.

Thanks!

Paul

 

[kpearsall]

ahh ok. Question makes even more sense in context of that situation. the bipolar power complication will obviously work for the chips, but unsure of how you would make the ground situation work with these modules in that console powered of bipolar rails. I would imagine less problems would ensue just keeping it on the positive rail as long as that's 24v.

 

[thakava]

Had an original pair, hard to calibrate, not alot of info around back then except pin outs - sounded "interesting" tho'

 

[Potato Cakes]

ahh ok. Question makes even more sense in context of that situation. the bipolar power complication will obviously work for the chips, but unsure of how you would make the ground situation work with these modules in that console powered of bipolar rails. I would imagine less problems would ensue just keeping it on the positive rail as long as that's 24v.

It seems the area in electronics at which I excel is causing problems...

I'll report back when start building these.

Thanks!

Paul

 

[Potato Cakes]

Looking over the schematic and I have a couple more questions. I do not see the connection for the Bypass OUT. Is this simply connected to the Audio In+ to hardwire bypass the entire circuit? If I am not using this for stereo operation, are the sidechain mixing trimmers needed? Lastly, I noticed there is no Attack Slow connection. Is this normal attack speed and the Attack Fast connection simply modifies it by bypassing R49?

Thanks!

Paul

 

[Potato Cakes]

Ordered components to fully populate the boards. Going to make two of them part of a channel strip. Has anyone completed their builds with these parts?

Thanks!

Paul