I am building an amp in a Hammond 17x12x3" case. Part of the amp is a CS3310 preamp board with 4 RCA input pairs on a board. It looks like this:
I have it mounted on.... not sure what they're called but they are little plastic arms that isolate the boards and raise them by like 20mm. Anyways my question is should I try and drill 8 holes in the chassis for each input, and then use the 2 screw holes at the jack faces to further stabilize the connectors, or can I get away with a big hole? I tested the board with no "face bracing" and it seemed fine. I'm not going to be swapping connectors on this often if at all.
One concern I have about using the "face plate" screws is ground loop noise. Other than that I have no idea.
I have it mounted on.... not sure what they're called but they are little plastic arms that isolate the boards and raise them by like 20mm. Anyways my question is should I try and drill 8 holes in the chassis for each input, and then use the 2 screw holes at the jack faces to further stabilize the connectors, or can I get away with a big hole? I tested the board with no "face bracing" and it seemed fine. I'm not going to be swapping connectors on this often if at all.
One concern I have about using the "face plate" screws is ground loop noise. Other than that I have no idea.
"Stand-offs?" Not sure about the "Hammond case", but options that spring to my mind are:
You could cut a big hole in your case and drill 8 +2 screw holes in a plastic or metal cover that'll cover and support the sockets and hide the big hole. It might look a bit weird and would probably also need fixing to your case. There does not seem like there is much depth to play with in having anything other than a thin plate (and oversized holes) in front of those particular sockets though.
There is the possibility of replacing those sockets with individual RCA phono sockets and wiring them to the board individually, enabling you to make your own fitting arrangements of sockets and board in your chassis.
The best look with those existing sockets would be to drill 8 + 2 holes in your amp case, if you can. If you're able to mark it out accurately (masking tape, compassess and pencil, or hole guides and scribes, then you can drill it undersize and carefully file out to size with your marks to resolve drilling errors. The holes for your phono sockets should be as large as the outer rim on each of those sockets, so it'll fit flush and let as much socket protrude as possible.
Good luck and hope this helps...
You could cut a big hole in your case and drill 8 +2 screw holes in a plastic or metal cover that'll cover and support the sockets and hide the big hole. It might look a bit weird and would probably also need fixing to your case. There does not seem like there is much depth to play with in having anything other than a thin plate (and oversized holes) in front of those particular sockets though.
There is the possibility of replacing those sockets with individual RCA phono sockets and wiring them to the board individually, enabling you to make your own fitting arrangements of sockets and board in your chassis.
The best look with those existing sockets would be to drill 8 + 2 holes in your amp case, if you can. If you're able to mark it out accurately (masking tape, compassess and pencil, or hole guides and scribes, then you can drill it undersize and carefully file out to size with your marks to resolve drilling errors. The holes for your phono sockets should be as large as the outer rim on each of those sockets, so it'll fit flush and let as much socket protrude as possible.
Good luck and hope this helps...
Those jacks were meant to be mounted against a non-metallic panel and are the cheap versions of cluster jacks.
There are better versions with raised plastic 'rings' around each jack, along with a screw mounting hole in the plastic.
I'd suggest going with your second solution.... remove the cluster and individually wire short shielded leads to individual insulated jacks.
1 - you must fix the sockets to the panel for long term reliability.
2 - as stated last post, they should be insulated.
3 - If replacing the sockets, your probably best cutting them off the board first (sacrificing them) or you may well damage the PCB.
It probably doesn't matter if you unsolder the remaining lugs or leave them in place.
Usually the socket does not have the metal ground plate.
https://www.switchelectronics.co.uk...MIpOXpj5-9-wIVyN_tCh35ZQYJEAQYBSABEgKxffD_BwE
Might be a straight swap for the existing sockets then screw to metal case.
If your not confident of your drilling accuracy then make a template from scrap metal, test fit then use to position the holes in your case.
2 - as stated last post, they should be insulated.
3 - If replacing the sockets, your probably best cutting them off the board first (sacrificing them) or you may well damage the PCB.
It probably doesn't matter if you unsolder the remaining lugs or leave them in place.
Usually the socket does not have the metal ground plate.
https://www.switchelectronics.co.uk...MIpOXpj5-9-wIVyN_tCh35ZQYJEAQYBSABEgKxffD_BwE
Might be a straight swap for the existing sockets then screw to metal case.
If your not confident of your drilling accuracy then make a template from scrap metal, test fit then use to position the holes in your case.
Standoffs are the word. I'm not confident enough in my soldering skills to take this board apart. I do like the idea of a thin plastic interface between the connectors and chassis. That will be the easiest fix. Only question there is whether or not any plastics are better insulators than others, or if I can just get some Home Depot acrylic panels to work with.
I'd then suggest that you can create a hole in your case that the entire socket assembly fits through. This would enable you to get the sockets as far out through the case as possible. Knowing someone with a 3D printer would also be very helpful! Differences in plastic insulation I think are in the KV range, rather than the mV usually experienced at these sockets. Acrylic would do nicely.
However, it seems to me that there are 2 socket modules that would probably only have 5 soldered connections each and seem to be far away from sensitive circuitry on that pcb. Desoldering these terminals would be relatively simple and safe, given adequate (cheap) equipment, such as desolder suckers, desolder braid and rosin flux. A few of those gold plated sockets sprinkled about would enable you to best place your boards and have a smarter finish.
I have been meaning to learn how to desolder and solder PCBs, so I might do some trial runs on demo boards and then give this board a shot. I actually have a spare of these boards as well so that could work too. Having a bunch of those gold plated sockets on the back would be really cool. Anyways good to know I have options.
SMD removal alloy may be another option for resoldering multiple tabs, albeit a pricey one.
Kind regards,
Drew
Kind regards,
Drew
As I said, sacrifice the original sockets, we have already determined they are no loss.
Cutting through the lugs and unsoldering them one at a time - straight forward.
Unsoldering all at once while socket is whole - difficult and potentially PCB messed up.
Not saying you can't do it but why risk it?
Truthfully the connections on the PCB are pretty big and spaced out. It woudn't be too hard to desolder. I'm going to take the safe route this time though. Really don't want to ruin the board
I disagree with the notion that the RCA connectors must be isolated from the chassis. I get where the folks who suggest this are coming from, but there are other solutions. If a Class II power supply is used (i.e., one with no ground connection) the RCA connectors can connect to the chassis just fine.
You do want to use the mounting screw if you want the solder joints to last. The screw provides strain relief so that the insertion force of the RCA plugs doesn't stress the solder joints. Without some sort of mechanical support the joints will fail over time.
Tom
You do want to use the mounting screw if you want the solder joints to last. The screw provides strain relief so that the insertion force of the RCA plugs doesn't stress the solder joints. Without some sort of mechanical support the joints will fail over time.
Tom
I completely agree - it seems these particular sockets were obviously designed to be part of a ground plane - perhaps attached to a metalised plastic sheet, inside of a moulded plastic case, or something like that. Else, why have the metallic screw hole and excess metal around the sockets?
The issue with "cutting through the lugs" exposes your unsupported board to the stresses of cutting (side forces), sawing and/or grinding through thicknesses of plastic and metal too wide for standard electrical cutters. It's hardly more straightforward than just desoldering, in my opinion. Then you still have to de-solder afterwards... Perhaps the wonders of overusing rosin flux have not been universally discovered yet.
These boards are part of an assembled kit:
https://www.aliexpress.us/item/2251832640550136.html?gatewayAdapt=glo2usa4itemAdapt&_randl_shipto=US
If I was smart I would have bought the assembled unit and built different components........ but here we are 🙂
And yea I agree that cutting is no go... the solder connections on this are spaced out and juicy; I should be able to take them out with practice. But the path of least resistance for now is to just use the board as is and find a way to provide horizontal support. This has been a very informative discussion
https://www.aliexpress.us/item/2251832640550136.html?gatewayAdapt=glo2usa4itemAdapt&_randl_shipto=US
If I was smart I would have bought the assembled unit and built different components........ but here we are 🙂
And yea I agree that cutting is no go... the solder connections on this are spaced out and juicy; I should be able to take them out with practice. But the path of least resistance for now is to just use the board as is and find a way to provide horizontal support. This has been a very informative discussion
Try it as is. RCA grounded to case may make zero difference.
Or use insulating tape between RCA & case.
Or use insulating tape between RCA & case.
Ahhh!...
An "aliexpress" offering eh?
I'd never purchase anything from that site.
Being an old retired professional tech, I know quality when I see it.
Cracks me up... the statement of "high end" out of China..... LOL!
They make things LOOK pretty so you'll be impressed and buy them.
From the pics in the link, the board there is screwed to an aluminium back-plate in it's case. At the risk of turning this discussion over-informative; is your box 5-sided with a lid, or does it have removable panels, or something else? If you use these sockets, their vertical position on the back panel of your case will be determined by the height of your stand-offs.
Is it the electrical isolation, the prospect of aligning 8 +2 holes, or something else to do with your case that leans you towards opening up a big hole for the sockets and then covering them with a panel (you'd presumably have to put 8 +2 hols in)? It's generally a bit harder to cut slots than drill holes.
Have you thought about what to do for the VFD at the front? It looks like the one in China has a routed, smoked panel and hidden fixings for the VFD PCB and stand-offs. Is it too late to order a case to fit from the vendor?
Is it the electrical isolation, the prospect of aligning 8 +2 holes, or something else to do with your case that leans you towards opening up a big hole for the sockets and then covering them with a panel (you'd presumably have to put 8 +2 hols in)? It's generally a bit harder to cut slots than drill holes.
Have you thought about what to do for the VFD at the front? It looks like the one in China has a routed, smoked panel and hidden fixings for the VFD PCB and stand-offs. Is it too late to order a case to fit from the vendor?
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Like I said, if I was smart I would have just bought the assembled pre-amp, but I am not, so here we are lol. Doesn't make financial sense to get the OEM case at this point; I already have the big Hammond case. It is going to house a TPA3255 amp board, an ADAU1701 board and all the associated power conversion components, so I would need to get this OEM case, as well as housings for those other boards, and terminals + wires to connect them all, as opposed to the JST connectors they came with and will all run inside the case. This is my first amp so I'm cutting myself some slack for the awful planning. I tested it all and it works nicely so I got that far.
My main trepidation is the aligning of 8 + 2 holes. Again I can practice on some scrap metal first and then go from there. But I'd feel more comfortable doing the holes in a separate panel, so if I mess up I can just start over. With drilling into the case it's a one and done. I have all kinds of cutting tools so that just seems less daunting than precise machining by hand.
As for the VFD, I was going to build a separate housing to put it on top of the enclosure (and put it out of the reach of my toddler). That doesn't seem daunting at all; I already have a concept and materials for that as well as all the tools for it.
My main trepidation is the aligning of 8 + 2 holes. Again I can practice on some scrap metal first and then go from there. But I'd feel more comfortable doing the holes in a separate panel, so if I mess up I can just start over. With drilling into the case it's a one and done. I have all kinds of cutting tools so that just seems less daunting than precise machining by hand.
As for the VFD, I was going to build a separate housing to put it on top of the enclosure (and put it out of the reach of my toddler). That doesn't seem daunting at all; I already have a concept and materials for that as well as all the tools for it.
Just punch a piece of unclad fiberglass material like used for pcbs to make an insulating panel for the jacks.
The part drawings should have all the info you need to plot the holes.
Something like this one.
https://www.dynakitparts.com/shop/pas-rca-jack-kit/
You can practice drilling holes on a piece of MDF or hardboard. If you accurately mark things and use a proper drill press, you'll be fine.
Also, I've had very nice results making panels from MDF followed by spraypaint. It is easy to work with and creates a very nice finish. Of course, it doesn't provide any shielding, but that may or may not be a problem depending on your project and operating environment.
Also, I've had very nice results making panels from MDF followed by spraypaint. It is easy to work with and creates a very nice finish. Of course, it doesn't provide any shielding, but that may or may not be a problem depending on your project and operating environment.
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