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Lovoltech LU1014 Power Jfet Group Buy

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04dgmsilv

Member
Joined 2006
woofertester said:
The ZV9 manual has this section. Swap values of the source resistor to obtain 1.5A of idle current. Supply voltage somewhere in the range 3.0v to 3.5v. Ideally it will be the voltage in your amplifier circuit.

I do this measurement at room temp and quickly. You can let it cook and come to operating temperature and then take the measurement.
Click to expand...

I've been trying to complete this measurement per the ZV9 paper with one of the pairs of LU I've had sitting on the shelf for years. When you say 'quickly', how quick is that? When I start the test, I am right about 1.00V on both, but within 3-4 seconds that is up to 1.02V and still rising. I read somewhere else that Nelson said about 2 seconds. Just not sure what to read when it is not steady.

Thanks WT and everyone else for their efforts on this, will happily take another pair and build a LuDEF or LuFo with the other pair!
 
W

woofertester

Member
Joined 2011
It was a privilege to handle a pile of parts from the Pass Warehouse 13 stash. It allowed me to create a test and documentation methodology that was a germ of an idea for a long time. The pressure of people waiting for the outcome gave me some motivation to get it done. So, I benefited from this in a way that is valuable to me. I am looking forward to seeing builds from this group buy. My next effort is to use XRK's adapter boards to do in-circuit bench testing. Waiting on some missing Lego pieces to get the bench fully connected.
 
peppennino

peppennino

Member
Joined 2005
flickr.com/photos/194234898@N02/albums
Or maybe the Hangar 51 :D

400.jpg
 
W

woofertester

Member
Joined 2011
04dgmsilv said:
I've been trying to complete this measurement per the ZV9 paper with one of the pairs of LU I've had sitting on the shelf for years. When you say 'quickly', how quick is that? When I start the test, I am right about 1.00V on both, but within 3-4 seconds that is up to 1.02V and still rising. I read somewhere else that Nelson said about 2 seconds. Just not sure what to read when it is not steady.

Thanks WT and everyone else for their efforts on this, will happily take another pair and build a LuDEF or LuFo with the other pair!
Click to expand...

When I say fast, it is as fast as the automated equipment can execute.

Are your devices attached to a heatsink? These parts have a pronounced temperature dependence. My opinion is you either match them cold or you match them at final working temp.

If you have a very small stash, then I would have the parts come to working temp at the voltage and current of the intended circuit.
 
xrk971

xrk971

Founder of XSA-Labs
Joined 2012
etsy.com/shop/XRKAudio
Paid Member
Hi Folks,
Just to give you all a heads up - we are running into some logistical issues with how popular this GB for the adapter boards has been. We are at 700 adapter boards! It turns out that to get more than 700 of those SMT 0.20in pitch 3-pin headers is a 12 week lead time. 300 units is a 3 week lead time. We never expected this much interest. We are looking for alternatives...
 
T

tagheuer

Member
Joined 2003
xrk971 said:
Hi Folks,
Just to give you all a heads up - we are running into some logistical issues with how popular this GB for the adapter boards has been. We are at 700 adapter boards! It turns out that to get more than 700 of those SMT 0.20in pitch 3-pin headers is a 12 week lead time. 300 units is a 3 week lead time. We never expected this much interest. We are looking for alternatives...
Click to expand...

Can I get only adapter boards without those SMT 0.20in pitch 3-pin headers, since I have already got them in hands?
 
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