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Old 2nd September 2012, 02:25 AM   #11
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redjr,
That is a super nice construction job from what I can see of the pictures. Looks like it would be a great project to build. Can you give us a running cost of production as you go, if you care to. I will definitely be following your build.

Steven

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Old 2nd September 2012, 03:50 AM   #12
redjr is offline redjr  United States
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Quote:
Originally Posted by Coconuts 500 View Post
This must be good. I certainly trust Doug Self. Looks expensive, though. How much have you spent on all these parts?
It is/will be expensive. I don't know the exact amount, but the PCBs alone with shipping from Europe were close to $180. The 1k pots from Newark/Element are ~$100 total, although I've since heard reported similar ones can be had for way less. Other components probably totaled another $200-300 dollars. But mind you... I bought all exactly spec'd parts as called out by Doug's design and implemented by Elektor - mostly from Newark/Element and some from Mouser. Many parts had to be back-ordered when I purchased most of them in the Spring. So that slowed things down. I just found I could navigate and lookup parts much easier on Newark than other supplier sites. So, all my parts were new. I didn't use any parts from my junk drawer! I know, not very DIY..ish. Plus I bought way more header pins, female header connectors and sockets, and other connector stuff like that, since I have some other projects going too. It's just kinda my approach. When I sit down at my bench to work, I like to have everything I need right there, and not have to go looking or scrounging around to find something! I'm sure many parts can be found a little cheaper if you want to take the time to visit multiple sites in the process.

I figured the enclosure will be another $100+ too. I'm a real stickler for how my projects look and this will be no exception. I generally like to mock-up my build on cardboard first to see how things will fit inside the case. This not only helps in the layout and construction phase of the traffo and PCB modules, but helps to determine the exact size enclosure I need to begin with.

I'll post updates as I go along, but for now my PCBs are all finished, and I'm making a final decision on the case. I have many more interconnects to put together too.

Edit: Elektor alluded to the idea of providing a custom enclosure at the end of the 3rd article in the June issue - if there was enough interest. I'd certainly be interested, but it's not certain they will and I haven't seen or heard anything about a case yet. So, I'll most likely see what I can come up with using some off the shelf enclosure.
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Old 2nd September 2012, 08:54 PM   #13
redjr is offline redjr  United States
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Here are a few pics where I've mocked-up the internal layout of the PCBs. This layout would fit a case with minimum internal dimensions of; 300mm W x 236mm D x 74mm H. As you can see, this size is very snug fitting for everything that's got to go inside for sure. I found an enclosure on eBay from a supplier I use, and it looks like it would fit the bill beautifully. Here's the link if interested. The price is very reasonable for a case that size. Too bad the shipping is almost the same! There is also another case that I used to build a power amp in earlier in the year that would work also. If I bought another one of those I would have a matching pair.

While these pics may not be of interest to the community at large, I find doing this layout exercise very useful in helping me determine the dimensions of enclosure I need, fabricating wire lengths, and ultimately how the wire routing may be done. Hope this helps.
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Old 2nd September 2012, 11:24 PM   #14
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Nice work redjr!

One suggestion: if you used a standard 430mm wide rack chassis or similar, you could space the transformer further away from the sensitive circuit areas. It looks close enough to potentially induce hum/buzz in your proposed layout.
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Old 3rd September 2012, 03:43 AM   #15
redjr is offline redjr  United States
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Originally Posted by owdeo View Post
Nice work redjr!

One suggestion: if you used a standard 430mm wide rack chassis or similar, you could space the transformer further away from the sensitive circuit areas. It looks close enough to potentially induce hum/buzz in your proposed layout.
Hi owdeo. That same concern crossed my mind too. Rack-mount size is just a little bigger than I need this project to be, but I understand the issue. Perhaps with some very well planned out wiring I can avoid that pesky induced hum if it raises it's ugly head. But, you really never know how much of an issue it will be. If I am faced with some induced hum I could try shielding the traffo with a metal cover, or worse case take all AC power outside and put the PSU in another, separate enclosure. Obviously that's not my first choice, so I'll have to wait and see what hum related issues (if any) I end up with.
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Old 3rd September 2012, 03:57 AM   #16
redjr is offline redjr  United States
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Default pre-amp Intra-connect Map

Since there are so many intra-connects required for this project I thought it would be useful to create a map. This not only provides a guide for the fabrication of the specific cable, but also serves to identify just how many I need. This is going to take awhile! Once I'm satisfied with the final layout of the PCBs, I'll have a better idea how long to make them, and where the routing should take place to avoid hum issues(if they occur).

This is my first pass at this map, so there may be some errors, or typos. If you've been following the articles in Elektor and notice a mistake, please feel free to post it here.
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Old 3rd September 2012, 09:36 AM   #17
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Hi All,

A few people have inquired about the cost of this pre-amp. I have kept a spread sheet on costs related to this project. As of now, I am right at $750.00. This does not include the rear panel (about $100.00) the power cord and a few odds and ends. Also, I did not include shipping costs or taxes. A few pictures of my project and one other can be found here.

I did not use shielded connections in my build and found the pre-amp to be dead quiet. However, I do not have the phono stage completed as of now and may have to use some shielded cable there. Saying that, I agree with Owdeo in that your power supply is to probably to close to some sensitive circuitry.

I ran the pre-amp in my system for about 2 hours and was very happy with the results. Cost and labor were well worth it. As of now I am working on the rear panel (what a bear) and will add some shielding around the power supply.

Good luck with your build!
Jim




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Old 3rd September 2012, 05:26 PM   #18
redjr is offline redjr  United States
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Originally Posted by muskyhuntr View Post
Hi All,

A few people have inquired about the cost of this pre-amp. I have kept a spread sheet on costs related to this project. As of now, I am right at $750.00. This does not include the rear panel (about $100.00) the power cord and a few odds and ends. Also, I did not include shipping costs or taxes. A few pictures of my project and one other can be found here.

I did not use shielded connections in my build and found the pre-amp to be dead quiet. However, I do not have the phono stage completed as of now and may have to use some shielded cable there. Saying that, I agree with Owdeo in that your power supply is to probably to close to some sensitive circuitry.

I ran the pre-amp in my system for about 2 hours and was very happy with the results. Cost and labor were well worth it. As of now I am working on the rear panel (what a bear) and will add some shielding around the power supply.

Good luck with your build!
Jim



I had a look at your pics. Great job on your front panel. That will give me some ideas. The back panel will be very challenging, as I've noticed some of the jack holes will need to be very close together. I might have to farm that one out! Good work. I'll be sure to follow the progress on your build as well. For now I think I'll leave my layout as it is, but pay very close attention to wiring in and and around the traffo. Hopefully it won't present a problem.
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Old 5th September 2012, 12:55 AM   #19
redjr is offline redjr  United States
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I had a change in strategy with the control intra-connects. I decided that the guage of wire I was trying use at first was too big and more difficult to twist. Enter... CAT5 wire that's (a) the proper gauge for the tiny connectors, (b) more flexible to work with, and most of all (c) plentiful - at least around my house! I've elected to fabricate various lengths and during final construction cut to exact length and solder on the other end.

For the shielded cables I will need to and from the input PCBs, phono board and the main board, I found some custom 9" lengths complete with the 4-pin connector on eBay. And you can't beat the price @ $1.00 each. Seems like a suitable solution if 9" will work with your build. I ordered a few of them, but I'm prepared to also make custom lengths - if I need to - during the final placement. PC sound-card cables work well and are generally 24" long. The 9" cable on eBay can be found here.
Attached Images
File Type: jpg P1080276.jpg (947.3 KB, 284 views)
File Type: jpg 9 Shielded Intra-connect.JPG (11.1 KB, 188 views)
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Old 12th October 2012, 01:57 PM   #20
redjr is offline redjr  United States
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I posted this over on the Elektor forum, but it's not near as active as this one, so I'm sure I can get an answer here.

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? Thx.

Rick

PS. My panels arrived today from FPE. They look fabulous, but I will have some issue getting everything mounted properly. Mostly design issues from my-end. FPE workmanship is superb - including packaging. Well done FPE! Being my first layout and use of FPE, I'd say it was a pretty good experience. Next time I won't tackle something as advanced. Pictures to follow.
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