Stupid question from my side - I have the card, with the pot and a 3D printed wheel (thanks Cyrix200+!), but what sort of axle should one use to stick the wheel in the pot?

dionb wrote on 2020-05-12, 19:33:

Stupid question from my side - I have the card, with the pot and a 3D printed wheel (thanks Cyrix200+!), but what sort of axle should one use to stick the wheel in the pot?

A very tiny screw. I quote:

Fasten it to the potentiometer using an M1.4x0.3mm thread, 6mm long screw (McMaster-Carr part number 91800A036 or equivalent).

I order micro screws from this shop:

https://www.microscrews-shop.nl/

Other shops specialized in model making might help as well.

Another night, more soldering..

I've reached out to Eric via email one more time for information on bypassing the potentiometer, and he has kindly responded. He's really a great guy. Anyway, apparently, this is how to set it up for around 85% volume rotation:

And the resistor divider formula is Vo = Vi * Rl / (Rl + Ru) where Rl is the output line resistor (2a/b - G) and Ru is the input line resistor (1a/b to 2a/b).

As for the potentiometer, this is the Vo/Vi vs Rotation graph:

So I settled on using 4.7KR for both Rl and Ru - this 50% divide will result in a roughly 75% rotation, pretty much what I wanted. 😀

This whould work until root42 helps me out with the Pot. Just dropping this here for future reference to anyone who needs it.

Note: I hope TubeTimeUS doesn't mind me sharing any of this but please let me know if it is a problem.

appiah4 wrote on 2020-05-13, 11:18:

Note: I hope TubeTimeUS doesn't mind me sharing any of this but please let me know if it is a problem.

No problem!

TubeTimeUS wrote on 2020-05-13, 22:48:

appiah4 wrote on 2020-05-13, 11:18:

Note: I hope TubeTimeUS doesn't mind me sharing any of this but please let me know if it is a problem.

No problem!

Cool, thank you 😀

In other news, another day of soldering done and I only have the sockets and connectors left to solder to the board. I will add a photo to this post soon 😀

Unfortunately I had to cut some corners.. I didn't have any 30pF caps so I used 33pF (I doubt it would make a difference) and instead of 47uF 16V electrolytics I used some pretty el-cheapo (Jwco branded) 47uF 25V electrolytics, which should be fine.. But we will see 😁

End of Day 5:

Only major mistake so far: Sodering the DIP-40 socket the wrong way around *facepalm*.. I socketed the IC the right way though.

Last parcel with remaining components arrived today. Opening it to find out that I forgot to order the voltage regulator was priceless.... 🙁

I actually inserted the MCU the wrong way first! Got really hot. Was fine though...

Yeah, on Day 6 we are all done. Aside from the voltage regulator I forgot to order *facepalm*.. Also lacks the SAA1090 chips (in the mail from China) and the Alps potentiometer (*sadface*) which I'm still not sure whether I want to bypass with ugly looking resistors or not.. It looks so beautiful.

Not bad for an amateur's follow up to the Adlib I would say.. (He said, not quite confident enough to show the back of the board 😁 )

appiah4 wrote on 2020-05-18, 07:20:

Yeah, on Day 6 we are all done. Aside from the voltage regulator I forgot to order *facepalm*.. Also lacks the SAA1090 chips ( […]
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Yeah, on Day 6 we are all done. Aside from the voltage regulator I forgot to order *facepalm*.. Also lacks the SAA1090 chips (in the mail from China) and the Alps potentiometer (*sadface*) which I'm still not sure whether I want to bypass with ugly looking resistors or not.. It looks so beautiful.

Not bad for an amateur's follow up to the Adlib I would say.. (He said, not quite confident enough to show the back of the board 😁 )

It's looking great! Show us the back, it might be better than mine haha.

Well.. Remember, you asked..

This is about as embarassing as dropping your pants to get in bed with someone for the first time 😁

one or two tiny scratch marks and only one pin that looks like bleeding a bit (near the connector). No burn marks. No opens. Pretty consistent soldering. 8 out of 10 I'd say.

Yeah it looks just fine! I found there were some tough spots on it to solder, especially everything on the large ground plane was harder to get up to proper temperature. Mine looks worse, I made some mistakes and the TEA2025 I had on it was not socketed and it died so I had to desolder it.

I hope you voltage regulator gets soon so you can enjoy the card!

evasive wrote on 2020-05-18, 08:08:

one or two tiny scratch marks and only one pin that looks like bleeding a bit (near the connector). No burn marks. No opens. Pretty consistent soldering. 8 out of 10 I'd say.

Thanks! Which joint is bleeding? And what does bleeding mean? I will fix it as soon as I identify the fault 😀

I used a simple 30w solder pen, it usually gets too hot for delicate soldering rather fast so I have to solder on and off. The extra heat helped with the ground plane I think..

I thought on the right side of the connector, the left of the two solder points had solder flowing too much crossing a trace, on second view, it is the pin sticking out so no worries there.

evasive wrote on 2020-05-18, 09:05:

I thought on the right side of the connector, the left of the two solder points had solder flowing too much crossing a trace, on second view, it is the pin sticking out so no worries there.

Does that upgrade my score to a 9 out of 10 then? 😁

appiah4 wrote on 2020-05-18, 09:43:

evasive wrote on 2020-05-18, 09:05:

I thought on the right side of the connector, the left of the two solder points had solder flowing too much crossing a trace, on second view, it is the pin sticking out so no worries there.

Does that upgrade my score to a 9 out of 10 then? 😁

9- because of the scratch 😉

A full 9 would be the maximum score I give, because in the 35 odd years I do stuff with circuit boards I have never seen a perfect 10. That means every solder blob is perfectly shaped, no bent pins anywhere, no residue, all of the board lacquer in pristine condition. Doesn't happen. Not even in high-end audio devices.

The voltage regulator finally came in the mail, so the only critical component I am left wanting is the potentiometer.. The CMS chips from China will probably take their sweet time, but I can wait.

I finally found a local supplier who has the Alps pot in stock so I ordered two. They will reach me in 2-3 weeks. It's a long wait, but I will finally have a working card, so I can't complain too much.

appiah4 wrote on 2020-06-05, 11:00:

I finally found a local supplier who has the Alps pot in stock so I ordered two. They will reach me in 2-3 weeks. It's a long wait, but I will finally have a working card, so I can't complain too much.

🤣. Sorry I forgot to mention, but I ordered two for you! They just arrived with the Renovation components. So if anyone needs two pots... Or I will have to build two more SnarkBarkers! 😁