Cadet/Castle components sources and substitutions

Hi thank you! Good luck with the new castle! I also messed one up but hope these ones will work!
I will check all those replacements. that’s a great help!

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Can I ask what messed up?

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Hi Phil

Thanks for asking!!

mine was due to tiredness and inexperience - it was my fourth or fifth diy module ever - 2nd without a detailed build document - never soldered anything before - only learnt from youtube and dutch modular fest - which was semi-supervised - and everything else had worked fine first time

I had 2 packs of resistors (which looked almost identical) on the desk picked the wrong one up accidentally and stuffed and soldered them all in before noticing that they were the wrong ones + bad attempt at de-soldering with a cheap de-soldering pump and a later first attempt with braid => frustration and a slightly beat up board with some scorch marks and scratches

at the end of the day i learnt the obvious:

double check what you are placing where, and check again before you actually
solder 

don't build after midnight

it’ll have cost me less than 20€ - so annoying but not the end of the world - ordering a new pcb from thonk today to take advantage of the free shipping

I’ve built a further 4 or 5 modules since and they have all at least powered up ok - will be testing imminently once I’ve got my head fully round my new Visual Cortex - which I’m having a few issues syncing - but again most of that was late at night

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Definitely got to the same conclusion :wink: the Cadet is my first soldering project ever…
Was super late at night, over enthusiastic I placed the wrong part, and when pumped it out, lifted a pad … nothing to write home about but well yeah - work slow :slight_smile:

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Hi,
Are MLCC capacitors absolutely necessary ? Or can I use ceramic disc ones ?
Sorry if that’s a stupid question but I couldn’t find a simple answer and I’m relatively new to DIY.
Thanks !

I should think as long as the rest of the specs are the same - ie capacitance, tolerance, size, etc then you should be ok

just check the data sheets to confirm

Is sourcing some LM6172IN Op Amps on Ebay an especially bad idea?

They’re back-ordered at Mouser anyway right now, and about 1/3 as much from China.

In stock at https://www.digikey.com/product-detail/en/texas-instruments/LM6172IN%2FNOPB/LM6172IN%2FNOPB-ND/364218 without the worries.

I recently bought a testbatch on ebay - they worked fine.
yesterday I ordered more from them. hopefully they also work :slight_smile:

seller: (deleted link to avoid sadness) for reference: ‘allenlu1995’

update: I got some fakes with this seller. so avoid!

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Re: disc caps — I’m no expert by any means, but I’ve heard that ceramic discs can be microphonic at high frequencies. I always try to implement best practice with video stuff because of all the weird voodoo like that. It’s one of those things that’s probably fine, but I like to eliminate any possibility of letting the circuit act weird, however infinitesimal.

I should elaborate — a significant part of this has to do with troubleshooting, so if something’s gone wonky, I don’t have to think, “oh is it those goddamned capacitors I spent 1¢ on instead of 2¢ ?!” and then I can just simply focus on plugging the power connector in all the way, or whatever was the actual problem.

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Following up on this… I ended up trying some of the Chinese LM6172INs off of Ebay. And, as reverselandfill mentioned on another thread, there is some blurring (presumably because they aren’t actually as fast as they need to be?). Not recommended.

Figured this info could be helpful here if someone is searching in the future. It’s a shame because they are 1/3 the cost.

see here

I also filed a refund with that certain seller. so should you!
update: I just got the full amount in return via paypal.

Same. And (not surprisingly) no request to actually return them.

Going to just enjoy some glitchy/smudgy ICs until the bulk order of the real deal happens.

How critical is the 100ppm specification for the 100k resistors in the Cadet series? I’m currently working on the Cadet II and soldered normal 100k 1% resistors in place of the 100ppm ones. Will this cause problems?

No problems. Standard 1% resistors are fine.

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Can you write down any markings on those 6172s here? My fakeys say JR64AC. I’m wondering if they’re all the same marking.

Mine are M732F…

Hey guys,

LT1251 and LT1256 (DIP) seem to have nearly doubled in price in the past year or so, and the best price I can find now is USD$13.50 or more per each (Arrow, link above from Aug 2018).

I need a few for some Cadet builds - does anyone have a secret source they’re willing to share? No dodgy ebay seller links please, unless you vouch for them personally :-\

For reference, I tried soldering an SOIC LT1256 into a dip socket, using tiny wires, and it was no fun whatsoever and took over an hour… so not something I’d recommend :slight_smile:

Thanks!