<azonenberg>
Random fun fact: The Vishay CH resistors I use on some of my probes, at $7.10 each (digikey qty 1 price) and an estimated 310 μg each, cost $3226/g
<azonenberg>
Which is more than gold ($57/g) or cocaine (average street price in the US $120/g)
<azonenberg>
and only 32x less than the Mona Lisa ($850M / 18 pounds, it's painted on a wood panel) at $104K/g
<sorear>
imagining if there was a competitive market for individual grams of the mona lisa
<bvernoux>
azonenberg, yes really crazy price ;)
someone-else has joined #scopehal
<azonenberg>
sorear: lol
<azonenberg>
Also... turns out the big difference feature wise between the D420 probe I got from ebay and the D420-A I already have is that the -A adds support for the QL-SI tip
<azonenberg>
which i find very curious
<azonenberg>
the two otherwise have the same performance
<azonenberg>
i assumed the tips were all essentially the same
<azonenberg>
and the only thing that was changed was flatness correction coefficients in the scope
massi has quit [Remote host closed the connection]
<azonenberg>
Also, update from Vishay
<azonenberg>
HML series are "made to order only"
<azonenberg>
i'm trying to get a) some samples and b) a MOQ
<azonenberg>
ok it seems MOQ is 100 units
<azonenberg>
But Vishay has a few contract overruns left over from a previous batch. They're going to hook me up with some samples
<azonenberg>
So I can test them against the old and new style LeCroy resistors and compare performance
<azonenberg>
Conveniently, that's three options and oshpark is giving me three boards... ;)
<d1b2>
<Uwe> What is that special about those HML resistors?
<azonenberg>
They're non inductive axial lead through hole resistors that are tiny, 0.5mm square x 1mm long body
<azonenberg>
which makes them great for use as probe tips
<azonenberg>
Assuming, of course, that the LeCroy resistors I'm looking at are indeed HML01s
<azonenberg>
i'm ~98% sure at this point, same dimensions and package markings
<d1b2>
<Uwe> Ah. 30 years ago that size was probably better available than now. Should I look if I find some 47/51 Ohm/0.063 Watt/THT somewhere in the backyard? But I can not guarantee non-induktive design.
<azonenberg>
These are 100 ohm
<azonenberg>
and i'
<azonenberg>
and i'm targeting high single to low double digit GHz
<azonenberg>
non-inductive is critical
<azonenberg>
i've been looking for these for months
<azonenberg>
and only a few weeks ago did i succeed in identifying them
<azonenberg>
I tried to buy some from distributors but they were backordered with no ETA
<azonenberg>
so i went straight to the manufacturer and am having some success, they're shipping me 5 samples
<azonenberg>
if i want more, i'll have to special order 100
<d1b2>
<Uwe> When i find 100 Ohm tomorrow, I will scratch the parts if the resistive layer has "turns".
<d1b2>
<Uwe> Are you in EU?
<azonenberg>
No, US
<azonenberg>
The other thing is, i'm not just looking for some random one-offs
<azonenberg>
I want to find something I can obtain a steady, consistent supply of
<azonenberg>
There's no point in putting a lot of design and engineering effort into building a probe around one 1980s resistor that's now unobtainium
<d1b2>
<Uwe> Okay.
<d1b2>
<Uwe> Minimelf 0102 is to big?
<azonenberg>
It has to be through hole that's the thing
<azonenberg>
for this design
<azonenberg>
you're relying on flex in the leads to absorb strain on the probe and make it less fragile than my previous design which used flip chip 0402s and castellated tips
<azonenberg>
the tip has a SMT resistor then the through hole resistor soldered on edge-launch style
<azonenberg>
the free end of the resistor gets soldered to the DUT
<d1b2>
<Uwe> If you get fed with me, please let me know 😉 Otherweise what about spot weld wires to Minimelfs ? Or perhaps use "high temperature" solder to attach a wire?
<azonenberg>
Spot welding wires to melfs is a nice idea. It's also been done