Keantoken's Aurum-X 300w Amp with LatFETs

I just got a new toy for debugging amps. I love this scope.
I like and really want one, it is like an electronic Swiss Army knife,
shaped like a multi-meter. The size (ability to hold and carry)
will lend to greater flexibility and use.

I can .almost. see choosing it over the multi-meter, in highly portable situation
(like air travel) or pulling an (extra) lens out out of my photo shooting bag...

The tease... that looks nice. How does it feel. Has it got some mass?
does it feel (of substance) like it is made well (for the price)?
 
I like and really want one, it is like an electronic Swiss Army knife,
shaped like a multi-meter. The size (ability to hold and carry)
will lend to greater flexibility and use.

I can .almost. see choosing it over the multi-meter, in highly portable situation
(like air travel) or pulling an (extra) lens out out of my photo shooting bag...

The tease... that looks nice. How does it feel. Has it got some mass?
does it feel (of substance) like it is made well (for the price)?
It feels very nice. Good solid professional feel to it. Buttons and layout are very intuitive. I have not had to look at instruction manual and I can use it. I have not checked it for accuracy yet. But given the ease of use, quality of the user interface, nice visual layout of screen, all the accessories and carry bag. For $154 it’s a no brainer - one of the handiest tools in my lab I would say. Many times I have avoided dragging out the bench scope because of the size and need for power cord. Many times, space is so tight there is no room for even a small bench scope. This one will literally sit on the same pile of 4 DMM’s I have in the middle of the lab. If the accuracy checks out, I would say that I can highly recommend this unit.
 
Looks to me that R118 has been left off the Build one jpg photos.

Is there a reason for this or not?

JT
 

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Working on the FE boards. Like to know a little more about R102 it's 470k/47K. Again, there is a call-out for R118, there is also a riser there, but it looks like the design calls for a 10k resistor in parallel with the lot.

Progress so far....
 

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Hi TT,
Maybe you are pulling Ozark’s chain here, but I’m not sure what you found offensive in his last post? I don’t think he was being patronizing or anything like that. Who doesn’t like talking about how they like to horde their favorite parts?

I’m guilty of buying a bag of 100 Murata 12v to +/-15v DCDC converters. The very last 100 Toshiba 2SA1837’s from Mouser. Or 4 bags 50 (fake) KOA BPR resistors. Or a roll of 600 (now verified genuine) LU1014D JFETs from Aliexpress. 🙂
 
The Macgyver way is to take a couple of circa 10k resistors (value is not important as long as it’s higher than impedance that the source can drive) and connect them in a Y split. Feed each leg with left or right. Connect the middle common to the amp input. This assumes the amp input doesn’t require much current (FET input). And the AurumX is JFET input so that’s all good.

Alternatively, you can build a summing junction with high impedance opamp buffer.

ESP website shows 10k resistors and add a “recovery”’buffer at the summing point to boost the output drive.

https://sound-au.com/articles/audio-mixing.htm
1644333903965.gif
 
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