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Old 12th October 2012, 03:28 PM   #21
AndrewT is offline AndrewT  Scotland
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Quote:
Originally Posted by redjr View Post
..........This project is the first where I've used XLR jacks and hence do not have any prior working experience with them. My question is; I bought and used the plastic style that have 2 adjacent holes for mounting and securing to a plate. It appears that these screw holes are not threaded and therefore you would need to used self-tapping screws, or a nut. Is that the case? Also, it appears they are 2mm in size. Can someone confirm these two little facts about XLR jacks? ...........
I just pulled out two different makes of faceplate XLR sockets.
Both easily take a 3.5mm diameter screw. But the head of a 3.5mm countersunk looks big and to my view rather ugly.
The 3mm countersunk looks nice.

Do you know how to convert from and back again between inches and millimetres?
2mm is only 78.74mil (thou in UK).
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Last edited by AndrewT; 12th October 2012 at 03:32 PM.
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Old 12th October 2012, 04:50 PM   #22
Bonsai is offline Bonsai  Taiwan
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$750 for a preamp that probably sits comfortably in the $5k to $10k commercial bracket sounds like a bargain to me.

Really looking forward to your feedback on the sound and your final construction.
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Old 12th October 2012, 05:19 PM   #23
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Hey Redjr,

I tapped my XLR's with a 4-40 tap and used the corresponding screws. Not hard,but takes a while because there are so many. Used black screws to match my rear panel. Thought about the self tapping but decided against them for fear of splitting the plastic.

I bought a small break to bend some aluminum for shielding the power supply. Turned out great. Last thing I want to do before I consider the project finished is to put something akin to Dynamat on the chassis for some vibration control. After that, it's on to the next project- either an Aikido pre amp, a PoddWatt integrated amp (already have most parts and pc board designed) or a Cavalli EHHA revA. Plan to end up with all 3 but have not decided which one to start with.

Looking forward to seeing pictures of your front and rear panels.

Jim
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Old 12th October 2012, 05:29 PM   #24
rsavas is offline rsavas  Canada
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Quote:
I bought a small break to bend some aluminum for shielding the power supply
Fyi
You may want to consider steel rather than aluminum, as a material for magnetic field shielding!!
For plastic, you need a thread forming type screw, but tapping the plastic works, as you have done. A course thread is better to use than a fine thread, 4-20 UNC vs 4-40 UNF

Good Luck
Rick

Last edited by rsavas; 12th October 2012 at 05:31 PM.
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Old 12th October 2012, 05:48 PM   #25
redjr is offline redjr  United States
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I don't have any 2mm screws, but I can say that 3mm screws are too big for the mounting holes in the jacks. I tried. 2-2.5mm screws will be nearly impossible to find locally too.
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Old 13th October 2012, 12:22 AM   #26
redjr is offline redjr  United States
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I was able to use a 3mm tap on one of the holes. However the screw went in very tight - I suspect because of the binding with the plastic. Seems like 2.5mm, or 2mm may be a more workable solution. I need to try a few more combinations.
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Last edited by redjr; 13th October 2012 at 12:33 AM.
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Old 13th October 2012, 01:34 AM   #27
redjr is offline redjr  United States
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Here are a few pics of my panels. The front panel looks 'goldish', but it's really brushed silver. While the cutouts for the back panel connectors were near perfect, the way the back panel fits onto my case will present some challenges to get it all to fit right. Some metal work modifications will be required. The front turned out good too, but the cavity holes on the 4 large holes on the right turned out smaller than what they should have been. Maybe it was my mis-measuring and not allowing a wide enough cavity. I was planning on using the supplied 3/8" nut on the pots to secure it from the front since my panel is so thick (8mm). So now I'm trying to find some 3/8" knurl nuts that will fit down in the cavity and still allow me to tighten them up. My knobs are wide enough to cover the cavity holes so I was not to concerned with the nut being on the front. Oh the joys of doing it the DIY-way!

If I had to do all over again, I would opt for a bigger enclosure. This one will end up being too tight I'm afraid once all the modules are installed and wired up.
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Old 13th October 2012, 02:56 AM   #28
cbdb is offline cbdb  Canada
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Looks great. The only thing I would do is replace the ribbon cable (if nowhere else do the phono inputs) with shielded pairs.
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Old 13th October 2012, 03:06 AM   #29
redjr is offline redjr  United States
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Looks great. The only thing I would do is replace the ribbon cable (if nowhere else do the phono inputs) with shielded pairs.
I intend to use shielded cables to/from the phono board. After making some measurements tonight on my 4 cavity holes, I discovered they were milled to the wrong diameter! Smaller by .33mm than my file specified. I've contacted FPE, so will see what they say.
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Old 20th October 2012, 04:30 AM   #30
redjr is offline redjr  United States
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Update... My bad

A while ago I ordered a variety of spiffy brushed chrome knobs from vt4c.com. [BTW, this is a great website and has loads of stuff for the DIY'er.] I wanted the knobs so I would have a reference of the size perspective to the front panel I was laying out in FPE. After they arrived, I was so engrossed in seeing how they were looking on my mocked up front panel, I never thought to see if they actually fit the 4 main pots of the design. Well tonight I found out. They don't! Much to my dismay, I was sad to learn that it will be next to impossible making them fit without boring the center out by a mm or two. Which will be extra hard without a drill press. The shafts of the spec'ed pots are solid metal and are bigger than the holes in the knobs ordered from vt4c Studios. Urgh!

Now, call me naive, but I thought the shaft of most widely accepted pots and such have a standard diameter size. Sometimes they're groved, other ones have a a solid shaft made either of plastic or aluminum. SOme even have a flat side for proper orientation, etc. I used the standard expensive 1k Vishay pots as called out in the pre-amp design. So, is the reason they will not fit an issue between metric size holes and English standard pot shafts? What is the standard size pot shaft diameter? My bad for overlooking this in my design.

So what to do? I guess I'll now have to look for other knobs that will fit these pots, but after spending $100USD (I bought more for other projects too.) on some really nice looking solid aluminum knobs I'm bummed. Can anyone provide a link to a site that specializes in knobs.
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