Electronics > Open Source Hardware

Paul Carlson's Super Probe

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floobydust:
His capacitor leakage tester is not open-sourced that I know of.

I had done an LTSpice sim and the voltage gain is extremely high for the Superprobe alone (no audio amp gain), around 660 and it clips with 1mV input.
I find it's better to have less or controllable gain and higher input impedance from a JFET. Signal tracing I need to cope up to line-level and have an input gain pot, and I needed low distortion to hear problems with stages. The Superprobe has no local feedback and I think would be gritty. It's a different approach.

Kjo:
@floobydust

--- Quote ---His capacitor leakage tester is not open-sourced that I know of.
--- End quote ---

I think you are correct about the leak tester, but as I commented on his UT channel when he released it,
anyone with a good DMM that has a nS range, like the Fluke 87s, can do pretty much
the same thing for all practical needs.


--- Quote ---I find it's better to have less or controllable gain and higher input impedance from a JFET.
--- End quote ---
This would be an interesting mod, but my goal was just to try to satisfy all those Carlson DIYers who
cant, won't or don't know to build the probe from scratch and source the parts. Being 95% SMD a DIYer needs a lot of SMD
stuff in bins or needs to buy 100-200 pieces of everything to be cost effective. But they almost certainly only want one probe!

They will expect it to work like his also....

Kjo:
@floobydust

--- Quote ---I had done an LTSpice sim and the voltage gain is extremely high for the Superprobe alone (no audio amp gain), around 660 and it clips with 1mV input.
--- End quote ---

Yea that is about right, and the amp T1 adds Av=88 and the LM4871 Av=1.4 or almost 100dB!

tooki:

--- Quote from: Kjo on August 29, 2023, 01:23:02 am ---… They are available on eBay (a dirty word on screwtube) and on my website.

Screwtube would not let me add comments like these to Carlsons channel even though many of his viewers were looking
for sources of parts, kits or completely assembled probes. (My comments just got deleted after a few minutes...)

--- End quote ---
Youtube pretty much auto deletes any comment containing a URL (I have given up trying to link to eevblog forum posts, for example), too many numbers (!), or any text to the effect of “search the web for [relevant keywords, article title, etc]”. It makes it de facto impossible to provide sources to any information or product suppliers, even for people who ask for them.

I am convinced it’s their spam filters, which disallow all that while still allowing all manner of junk.

Kjo:
Carlson appears to follow the "give a man a fish and you feed him for a day, teach him to fish and you feed him for a lifetime". He has a large base of followers who are DIYers but it is hard to divine haw many actually follow through and complete his projects. Completing some of these as a one-off build requires quite an array of resources and components. So I often wonder what percentage of his followers go unsatisfied by not having the required skill set & resources.

I happen to like his Super Probe concept. But the original PCB design with 0602 SMD components was a daunting build. Others created more reasonable 0805 PCB designs opening the project to to more amateur kit builders. The design is 6-7 years old now, and he has a newer design in the works, but the old one is just really popular!

There is quite a pent up interest in assembling one of these probes based on the response to the kits I have put together. And designing, procuring and assembling quality kits for the DIY community is not a trivial project. I'd like to think that I have helped quite a few people accomplish something that would otherwise never have happened.

This thread is not intended to be an advertisement for these kits but rather a discussion area for anyone who has built them. But I also find that the rules in the Buy/Sell/Wanted section are vague, arbitrarily applied, and come without warnings. I have been a forum member for going on 10 years, but I have not posted there (B/S/W) for fear of being banned.

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