StriderTR wrote on 2025-08-15, 02:40:

dominusprog wrote on 2025-08-14, 22:30:

That purple board, is it an amplifier?

Stereo I2S DAC. 😀

https://www.amazon.com/dp/B09C5QX228?ref=ppx_ … _fed_asin_title

Got it. So is it necessary for the wavetable to function? Or it can work as any other wavetable?

dominusprog wrote on 2025-08-15, 19:47:

StriderTR wrote on 2025-08-15, 02:40:

dominusprog wrote on 2025-08-14, 22:30:

That purple board, is it an amplifier?

Stereo I2S DAC. 😀

https://www.amazon.com/dp/B09C5QX228?ref=ppx_ … _fed_asin_title

Got it. So is it necessary for the wavetable to function? Or it can work as any other wavetable?

I don't believe so, at least not in this case. I mean, you need a DAC somewhere to convert the emulated digital output from the Pi Zero into an analog output the card can send to your speakers. Though, I could be mistaken.

On here, the 3.5MM jack isn't used. The DAC does the conversion and sends it right out to the wavetable header.

Pi Zero GPIO21 to the DIN (Digital Input) on DAC, then to the DAC Analog L&R outputs, then to Wavetable Header Pins 20 & 24 through a couple 10uf caps.

I redid some old fragile battery fixes with sturdier "Not-a-varta" setups.

$20 for 50 PCBS, $20 for 20 SOT-23-5 hot exchange voltage controllers. That should keep me set for a while--

My First PCB Way order 0 the parts are so tiny, going to need the big magnifier to solder these....

Sturdier Solutions #1 You can see where I burned the board before.

Sturdier Solutions #2 I feel like I am not embarrassed by this board any more

I did some (de)soldering yesterday for the first time in many many years (like, thirty or so). A while ago I found an old motherboard in the garbage while on my daily walk. It had blown capacitors and I thought this might be a good opportunity to do some soldering. I had been gathering bits and pieces of equipment for a while now, like the iron [1], and yesterday was the day.

I live an apartment so I don't have a lot of space, so after I set up my gear I took a shot. Long story short, I started with the caps nearest the CPU as they were bulging the most. I took a while to get the hang of it (my eyes also aren't great as I have issues with depth perception due to a congenital cataract in my right eye). It took a while to get some movement of the first pin. I added some flux, that showed me that at least heat was being transferred.

Some issues I ran across:

1 - When I tried adding some solder to the pin I realized that I have bought shit solder as it didn't stick or flow very well, it often kinda turned into small balls or "crumbly towers".
2 - The solder wick I purchased also didn't seem to work well as it didn't seem to absorb solder. Maybe my iron just isn't powerful enough because placing the wick between the pin and iron, not much happens, even at 420c .
3 - In the end I managed to remove 6 caps, after the first two it became easier, the caps get quite hot as I have my thumb on it that I use to put some gentle pressure on it while heating up a pin. But now all the holes are closed and due to the shitty solder and wick, adding solder to clear the hole doesn't work. I might have to get a solder sucker for this after all. I have no room for a desoldering station.

Anyhow. I'll try to get some better solder. Any recommendations? I am in Australia so not everything might be as available as elsewhere in the world.

[1] https://www.fnirsi.com/products/hs-01?variant=45534131618010

Started unboxing and taking inventory of my huge stash from AVICC, which I had sent to my hotel when visiting Chicago earlier this week. If memory serves me right, there's 115 miscellaneous CPUs, 2 motherboards, at least one graphics card and some keychains too 😎

pan069 wrote on 2025-08-16, 20:22:

I did some (de)soldering yesterday for the first time in many many years (like, thirty or so). A while ago I found an old mother […]
Show full quote

I did some (de)soldering yesterday for the first time in many many years (like, thirty or so). A while ago I found an old motherboard in the garbage while on my daily walk. It had blown capacitors and I thought this might be a good opportunity to do some soldering. I had been gathering bits and pieces of equipment for a while now, like the iron [1], and yesterday was the day.

I live an apartment so I don't have a lot of space, so after I set up my gear I took a shot. Long story short, I started with the caps nearest the CPU as they were bulging the most. I took a while to get the hang of it (my eyes also aren't great as I have issues with depth perception due to a congenital cataract in my right eye). It took a while to get some movement of the first pin. I added some flux, that showed me that at least heat was being transferred.

Some issues I ran across:

1 - When I tried adding some solder to the pin I realized that I have bought shit solder as it didn't stick or flow very well, it often kinda turned into small balls or "crumbly towers".
2 - The solder wick I purchased also didn't seem to work well as it didn't seem to absorb solder. Maybe my iron just isn't powerful enough because placing the wick between the pin and iron, not much happens, even at 420c .
3 - In the end I managed to remove 6 caps, after the first two it became easier, the caps get quite hot as I have my thumb on it that I use to put some gentle pressure on it while heating up a pin. But now all the holes are closed and due to the shitty solder and wick, adding solder to clear the hole doesn't work. I might have to get a solder sucker for this after all. I have no room for a desoldering station.

Anyhow. I'll try to get some better solder. Any recommendations? I am in Australia so not everything might be as available as elsewhere in the world.

[1] https://www.fnirsi.com/products/hs-01?variant=45534131618010

Flux is your friend. If in doubt, add more flux. You can never add too much flux. Did I mention flux? Add flux. 😀

pan069 wrote on 2025-08-16, 20:22:

I did some (de)soldering yesterday for the first time in many many years (like, thirty or so). A while ago I found an old mother […]
Show full quote

I did some (de)soldering yesterday for the first time in many many years (like, thirty or so). A while ago I found an old motherboard in the garbage while on my daily walk. It had blown capacitors and I thought this might be a good opportunity to do some soldering. I had been gathering bits and pieces of equipment for a while now, like the iron [1], and yesterday was the day.

I live an apartment so I don't have a lot of space, so after I set up my gear I took a shot. Long story short, I started with the caps nearest the CPU as they were bulging the most. I took a while to get the hang of it (my eyes also aren't great as I have issues with depth perception due to a congenital cataract in my right eye). It took a while to get some movement of the first pin. I added some flux, that showed me that at least heat was being transferred.

Some issues I ran across:

1 - When I tried adding some solder to the pin I realized that I have bought shit solder as it didn't stick or flow very well, it often kinda turned into small balls or "crumbly towers".
2 - The solder wick I purchased also didn't seem to work well as it didn't seem to absorb solder. Maybe my iron just isn't powerful enough because placing the wick between the pin and iron, not much happens, even at 420c .
3 - In the end I managed to remove 6 caps, after the first two it became easier, the caps get quite hot as I have my thumb on it that I use to put some gentle pressure on it while heating up a pin. But now all the holes are closed and due to the shitty solder and wick, adding solder to clear the hole doesn't work. I might have to get a solder sucker for this after all. I have no room for a desoldering station.

Anyhow. I'll try to get some better solder. Any recommendations? I am in Australia so not everything might be as available as elsewhere in the world.

[1] https://www.fnirsi.com/products/hs-01?variant=45534131618010

I’ve been through many soldering stations. I wish started with this one and saved myself the money https://www.aliexpress.com/item/1005005820847973.html (choose T3A T245 Set B). It will handle anything you throw at it. Plus the auto switch off when the iron is placed in the holder is great. You’ll want to use some low melt solder https://www.aliexpress.com/item/1005009408608556.html with some flux https://www.aliexpress.com/item/32919126582.html when desoldering those caps. I apply heat to one leg at a time and then pull each side of the capacitor out bit by bit in a rocking motion. They should come out pretty easily without the capacity getting too hot to touch. As for solder I use this https://mektronics.com.au/products/multicore- … c-0-35mm-0-25kg and this https://mektronics.com.au/products/multicore- … 2-0-91mm-0-25kg. It’s more expensive than Aliexpress stuff but it’s high quality.

When using solder wick apply some flux to top of it but a good soldering iron with a tip that has a large surface area is key.

riplin wrote on 2025-08-16, 20:55:

Flux is your friend. If in doubt, add more flux. You can never add too much flux. Did I mention flux? Add flux. 😀

It's actually a fun drinking game. anytime you're watching a repair video and someone says flux, you take a shot. Butt seriously, you dont REALLY need much additional flux if its included in the solder, at least for thru-hole. if your doing SMD, you want to use the stuff like you're selling stock in the company...

I get my solder and wick from Aliexpress/temu. they will short change you, when you buy 100G that includes the weight of the spool, so plan accordingly. If I need something GOOD for preservation/restoration, i usually get some of the MG chemical stuff from Mouser. (i'm always ordering other parts so it just get tossed in the cart as needed)

riplin wrote on 2025-08-16, 20:55:

Flux is your friend. If in doubt, add more flux. You can never add too much flux. Did I mention flux? Add flux. 😀

This statement is fact! 😀

Been repairing electronics for over 35 years now. Flux flows freely in my work.

I often chuckle when I see people post on YT repair videos that the uploader is using too much flux... NO SUCH THING! 🤣

StriderTR wrote on 2025-08-16, 06:24:

I don't believe so, at least not in this case. I mean, you need a DAC somewhere to convert the emulated digital output from the […]
Show full quote

dominusprog wrote on 2025-08-15, 19:47:

StriderTR wrote on 2025-08-15, 02:40:

Stereo I2S DAC. 😀

https://www.amazon.com/dp/B09C5QX228?ref=ppx_ … _fed_asin_title

Got it. So is it necessary for the wavetable to function? Or it can work as any other wavetable?

I don't believe so, at least not in this case. I mean, you need a DAC somewhere to convert the emulated digital output from the Pi Zero into an analog output the card can send to your speakers. Though, I could be mistaken.

On here, the 3.5MM jack isn't used. The DAC does the conversion and sends it right out to the wavetable header.

Pi Zero GPIO21 to the DIN (Digital Input) on DAC, then to the DAC Analog L&R outputs, then to Wavetable Header Pins 20 & 24 through a couple 10uf caps.

Oh, okay. I always thought that the wavetable sends a digital signal to the sound card.

dominusprog wrote on 2025-08-16, 22:48:

StriderTR wrote on 2025-08-16, 06:24:

I don't believe so, at least not in this case. I mean, you need a DAC somewhere to convert the emulated digital output from the […]
Show full quote

dominusprog wrote on 2025-08-15, 19:47:

Got it. So is it necessary for the wavetable to function? Or it can work as any other wavetable?

I don't believe so, at least not in this case. I mean, you need a DAC somewhere to convert the emulated digital output from the Pi Zero into an analog output the card can send to your speakers. Though, I could be mistaken.

On here, the 3.5MM jack isn't used. The DAC does the conversion and sends it right out to the wavetable header.

Pi Zero GPIO21 to the DIN (Digital Input) on DAC, then to the DAC Analog L&R outputs, then to Wavetable Header Pins 20 & 24 through a couple 10uf caps.

Oh, okay. I always thought that the wavetable sends a digital signal to the sound card.

Actually... I stand corrected.

It will work without the DAC. It's labeled as "Optional but highly recommended".

It currently supports two modes of audio: using the raspberry pi's PWM audio out (which is noisy and sounds pretty bad), and an external Hi-Fi PCM5102A based DAC.

It seems the DAC is there for a higher quality audio output, better than straight PWM output on the Pi.

Edit: Forgot to add ... The current board version, 0.3 (the ones I ordered), added a low-pass filter to clean up PWN output should you chose to not use a DAC.

On a side note... it's done!

Might be a few days before I have time to play with it, but, it's assembled and setup. 😀