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Old 19th March 2013, 09:21 PM   #36951
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Quote:
Originally Posted by vacuphile View Post
Nelson has a more obedient church, filled with true believers.
The reviewers say it's positively toe tapping, right up there with the MBL-6010D. What's that old eight legs still good for something?
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Old 19th March 2013, 09:26 PM   #36952
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Simon,
Glad we could agree on something. I assume you are using a turret press for production of sheet metal parts. Yes it is funny how people talk about tolerances on parts that long on one of these gantry milling machines. They often aren't in temperature controlled environments so the ambient temperature is going to change all the dimensions. I have had to argue when someone wanted to change the inspection method on tooling that was produced over 30 years ago and they want to change from a theodolite inspection to laser tracker. All of the tooling would have been rejected if we did that.
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Old 19th March 2013, 09:31 PM   #36953
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Originally Posted by simon7000 View Post
We were talking cases. As I said by hand .005", sheet metal finished about the same to .015". Machined (not ground) .001" on modern equipment, WWII era .005", Ground .0005"-.0002" are what I would call typical. Now with aluminum or a bit less as temperature really counts and quickly machined to size it will shrink a bit.

Now hobbiest milled .01" ! But what kind of tolerance can you get on a 100 foot long milled piece of 7075?

(We aren't really in disagreement!)
Try 3 meter long alum tubes where it's 98 degrees F room temperature, and the coolant fluid isn't temperature controlled.

jn
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Old 19th March 2013, 09:39 PM   #36954
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Isn't that device too analytical for toe tapping . I still think you only designed it to trick AD into building you a better phono pre-amp.I like it in that position btw.

New widget from TI

http://www.ti.com/general/docs/lit/g...0&fileType=pdf

Would be nice to have an adapter board for TTH.
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Old 19th March 2013, 09:54 PM   #36955
bcarso is offline bcarso  United States
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Quote:
Originally Posted by vacuphile View Post
Isn't that device too analytical for toe tapping . I still think you only designed it to trick AD into building you a better phono pre-amp.I like it in that position btw.

New widget from TI

http://www.ti.com/general/docs/lit/g...0&fileType=pdf

Would be nice to have an adapter board for TTH.
What a funny spec to trumpet: 4.17uV noise. And not 10 nV more! Still, happy to see it.
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Old 19th March 2013, 09:59 PM   #36956
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Originally Posted by Kindhornman View Post
Simon,
Glad we could agree on something. I assume you are using a turret press for production of sheet metal parts. Yes it is funny how people talk about tolerances on parts that long on one of these gantry milling machines. They often aren't in temperature controlled environments so the ambient temperature is going to change all the dimensions. I have had to argue when someone wanted to change the inspection method on tooling that was produced over 30 years ago and they want to change from a theodolite inspection to laser tracker. All of the tooling would have been rejected if we did that.
Actually I didn't think we disagreed on much. I got my first drill press before I was 10. I do have a "journeyman" machinist who works for me part time keeping the tooling sharp.

On the weekend, went to use a chisel and only found one undamaged. Need to have a chat with my guys about that. One fellow made a custom grill for his guitar amp with just the .159" punch doing graphics and letters!

So this week there is a lot to clean and sharpen!


George,

I reran the ripple test and got more of what I was expecting.

Attached is an FFT showing a CRC of 1000 uF 1 ohm 4700 uF and then reversed 4700 uF 1 ohm 1000 uF. Almost exactly the same.

The big Duh moment was when I tried a 4700 uF 1 ohm 4700 uf against a triple 4700 uF 1 ohm 4700 uF 1 ohm 4700 uF. Results that stood out.

The other issue was capacitor brand. The cheapies had the same results for the first few harmonics but were no where as good at the upper ranges! So now I have to order in samples of all the common brands!
Attached Images
File Type: jpg 4700 1 1000 v 1000 1 4700.JPG (84.4 KB, 160 views)
File Type: jpg 4700 1 4700 v 4700 1 4700 1 4700.JPG (95.6 KB, 166 views)

Last edited by simon7000; 19th March 2013 at 10:02 PM.
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Old 19th March 2013, 10:25 PM   #36957
SY is offline SY  United States
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Steve, we generally don't do prints, we submit dxf files. The CNC crew has no problem holding tolerances, and my engineers are pretty good at making one material fit another. Then again, we don't do fashion audio, we make stuff that has to perform in high end factories and top test labs, day in and day out, no excuses.

The real secret is the machining fluids, of course.
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Old 19th March 2013, 10:35 PM   #36958
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Quote:
Originally Posted by simon7000 View Post
I reran the ripple test and got more of what I was expecting.
Ed
What was the source of noise in your previous measurement?

Before start ordering bags with capacitors, try to test what happens with these 3 psu setups when the load is not a simple passive resistor.
Connect them to supply power to a small amplifier.
Feed a freq sweep to amplifier input.
Do this at 3 power levels low, medium, high. Probe the psu rails.
Then spell some #@%!! on me
(I am not in a good mood)

George
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Old 19th March 2013, 11:02 PM   #36959
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Sy,
I'm afraid if I give someone my Solidworks file I have to cut a mold with a dxf file that there are going to be some real problems as I haven't been able to get the part as one complete solid. I think the cutter path is going to be a mess when it tries to transition from one section to another. I haven't worked on trying to merge the sections lately, the error I get is that the two section are allowing a zero thickness section. Not easy to fix on a complex surface shape such as I have done. I haven't learned MasterCam yet but think I am going to have to do that to make the design CNC compatible. G-code is what I think most machinist are wanting these days.
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Old 19th March 2013, 11:08 PM   #36960
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Fortunately, we just generate the Autocad files, the machine shop translates them. The recursive irony is that the parts we make are for machine tools- if they're not perfect, machining fluid squirts around everywhere. It's CNC all the way down!
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