Author Topic: KX Reference  (Read 48103 times)

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Offline kj7e

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Re: KX Reference
« Reply #225 on: January 04, 2018, 02:34:45 pm »
Finally installed my first KX board in a proper enclosure, used a Hammond 1590B with some Pomona 3770 binding posts on the output and 3760's for the input.

Sorry, the photo orientation seems to be amiss.







The board is recessed in the foam, only the edge of the board makes contact with the foam surrounding;


The foam on the lid then compresses to gently sandwich in the board in the recessed area;


This seems to work very well and should not present any stress on the board as well as add some thermal insulation to minimize external temperature effects.
« Last Edit: January 05, 2018, 02:57:19 am by kj7e »
 
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Offline kj7e

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Re: KX Reference
« Reply #226 on: January 05, 2018, 06:10:38 am »
Using one of Pipelie's LNA noise meters, here are some noise measurements comparing the LTZ1000 KX #1 in the Hammond enclosure above, vs the PDVS2 (LM399 based) at 7.14150v.

The LNA has a gain of 10,000, all measurement @ 10mV/div for 1uV/div.

Baseline LNA + scope noise, 280nV p-p;


LTZ1000 over 14 seconds, 1.12uV p-p;


LTZ1000 over 140 seconds, 1.256uV p-p;


So right on the money with the data sheet spec of ~ 1.2uV p-p.

LM399 based PDVS2 over 14 seconds, 6.04uV p-p;


LM399 based PDVS2 over 140 seconds, 5.68uV p-p;


« Last Edit: January 05, 2018, 08:49:14 am by kj7e »
 
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Offline AG7CK

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Re: KX Reference
« Reply #227 on: January 05, 2018, 10:03:02 am »
A very telling post. Thanks.
 

Offline Pipelie

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Re: KX Reference
« Reply #228 on: January 05, 2018, 12:55:35 pm »
Thank you! kj7e

Finally , I find a supply for the  Hammond 1590B in local, Thanks for kj7e who provide the part number of the case.

nice work on the black Insulation materials,How did you do that? it looks perfect fit in the case.

use a Coaxial cable to connect the reference and LNA, will get a little better result.

here is some of my test result.
« Last Edit: January 05, 2018, 01:07:44 pm by Pipelie »
 
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Offline kj7e

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Re: KX Reference
« Reply #229 on: January 05, 2018, 01:04:38 pm »
Thank you! kj7e

Finally , I find a supply for the  Hammond 1590B in local, Thanks for kj7e who provide the part number of the case.

nice work on the black Insulation materials,How did you do that? it looks perfect fit in the case.

use a Coaxial cable to connect the reference and LNA, will get a little better result.

here is some of my test result.

Fresh razor blade, ruler, Dremel tool and a steady hand  :)

Those where taken with coaxial cables and a dual banana to BNC adapter on the LTZ1000 box.  The LM399 based reference is about where it should be as its much more than a bare reference, there is a 10v buffer, DAC and other circuitry and another output buffer, so lots of things going on there to add a bit of noise.  The LTZ1000A is about where it should be but I have two other KX boards to test.  Ill compare all three soon and see if how they stack up.
« Last Edit: January 05, 2018, 01:10:28 pm by kj7e »
 

Offline kj7e

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Re: KX Reference
« Reply #230 on: January 17, 2018, 03:03:01 pm »
Some additional noise measurements from my latest KX (#3 with LTZ1000A date code 1750).

The test setup;


Baseline LNA/scope noise, 260nV;


14 seconds, 960nV;


140 seconds, 1.3uV;


Found some very interesting things regarding ground loops and my gear with this noise meter, very handy indeed.

 
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Offline CalMachine

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Re: KX Reference
« Reply #231 on: March 04, 2018, 03:00:16 am »
I've got some measurement results of my 2 KX modules.  Dubbed 'KXBlue' and 'KXGreen' from the label TiN_MaN placed on them.

More tests will be run in the future.  KXBlue had a few ACAL incidents during its ramp, makes it not look so stable.  Here, the TC of the measurement system realllllly pokes through  :popcorn:
All your volts are belong to me
 
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Online Mr. Scram

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Re: KX Reference
« Reply #232 on: March 06, 2018, 07:55:29 pm »
Forgive me my ignorance, but I seem too see a lot of different references and I think most or all are based on the same reference IC. What is the idea behind these variations? Are they attempts to achieve the same thing or do they have differentiated purposes?
 

Offline hwj-d

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Re: KX Reference
« Reply #233 on: March 06, 2018, 09:59:15 pm »
...
Are they attempts to achieve the same thing ... ?

Yes, the ltz1000 and all around is fun!  ;D

 

Offline hwj-d

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Re: KX Reference
« Reply #234 on: March 07, 2018, 10:55:13 pm »
... and don't forget this little boy or girl inside all of us, who/she allows to be creative all over the lifetime ;)
 

Offline cellularmitosis

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Re: KX Reference
« Reply #235 on: April 10, 2018, 05:47:17 pm »
I jumped on the KX train!

I picked up a yard of 100% wool, and cut out a small piece to place between the LTZ and the board, to disrupt air drafts.  Hopefully the wool will be durable enough to be a long-term solution (it is a solid sheet of wool which I poked the leads through before soldering in the LTZ, so it is now permanently part of the build).

I went with hermetic resistors, as this ref will be (eventually) traveling to Taiwan to fetch the TiN Volt.  Hopefully they will minimize any travel-related offsets (e.g. regional humidity differences).

I threaded a 1N5819 schottky into the positive input, for reverse bias protection.

My surface mount soldering is pretty horrific, but it got the job done :)  C1, 2, 3, and 9 gave me particular trouble -- it felt like I was installing a 1206 part onto an 0805 pad.

Edit: wow, you can get an 8"x8" square of wool for $3 https://www.birdbraindesigns.net/wool-black
« Last Edit: April 10, 2018, 06:03:42 pm by cellularmitosis »
LTZs: KX FX MX CX PX Frank A9 QX
 
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Offline CalMachine

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Re: KX Reference
« Reply #236 on: January 30, 2019, 11:14:30 am »
It's been a little over a year since my 2 KX modules made the journey across the Pacific Ocean to TW. 

With the advent of surpassing the year mark, I'd like to share my current results  :-+

KX "Blue"




KX "Green"


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Online TiN

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Re: KX Reference
« Reply #237 on: March 02, 2019, 09:55:53 pm »
That moment, when you get YT ads showing your PCB design, while watching EEVBlog video...



Not to mention stolen video content from Marco Reps  :-- 
YouTube | Chat room | Live-cam | Have documentation to share? Upload here! No size limit, firmware dumps, photos.
 

Online syau

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Re: KX Reference
« Reply #238 on: March 03, 2019, 12:39:09 pm »
That moment, when you get YT ads showing your PCB design, while watching EEVBlog video...



Not to mention stolen video content from Marco Reps  :--

 :palm:
 

Online beanflying

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Re: KX Reference
« Reply #239 on: March 03, 2019, 01:16:09 pm »
Sux a lot. Have you and Marco tried to copyright strike them or get together with others who seem to have had their designs and videos 'borrowed' for their commercial gain? All us other viewers is give them a dislike or when they leave it available give them a serve in the comments section.

Not that they have a large youtube following but they do have a lot of paid and sponsored noise out there on youtube from content creators.

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