How did you designed this blasterboard PCB to have quiet output vs the noisy original?

Cheers,

I need to save my pennies up so I can buy one of these kits. I had such a good time building all of the MPU cards that I got from here, a new project sounds like fun, and I know I need the practice when it comes to soldering. Thank you so much for offering a really interesting project like this!

pentiumspeed wrote on 2022-10-11, 00:00:

How did you designed this blasterboard PCB to have quiet output vs the noisy original?

Cheers,

I did not improve the original schematic, it is designed from scratch
How I designed it:
First - I build a prototype which was noisy as aphex twin's ventolin 😀
Then studied all I could find on power filtering and grounding etc, like:
https://andybrown.me.uk/2015/07/24/usb-filtering/
https://www.analog.com/en/analog-dialogue/art … l-grounded.html
Then lots of simulations in LTspice and tests on a breadboard, rearranging components and ground connections
After weeks I finally got what I needed for this exact card 😀

nathanieltolbert wrote on 2022-10-20, 20:02:

I need to save my pennies up so I can buy one of these kits. I had such a good time building all of the MPU cards that I got from here, a new project sounds like fun, and I know I need the practice when it comes to soldering. Thank you so much for offering a really interesting project like this!

You are very welcome, I can reserve one for you if you wish, drop me a message when you are ready

Hi everyone, quick question.

I was wondering if anyone had QA issues with their pre-made Blasterboard? I had one ordered and pre-made about 2 years ago and it stopped working, I wanted to used it on my NuXT Turbo XT as it seemed a perfect fit for it, and I noticed quite a bit of rust on the legs of some chips.

If I compare the chip legs of the Blasterboard they look dull and rusty/flaky in places compared with my ~30 year old SoundBlaster CT1350 where the chip legs look clean and shiny. I was wondering what could be the cause of this? Chip quality?

Thanks!

PS: The way I store all my hardware is in a tub, individually packed in an anti-static bag often with a slica gel pack.

Middle chip from the top:

Hi, sorry to hear about your issues.
Are you completely sure nothing was spilled on it?
IC13 and IC14 are rusty indeed, but IC15 is fine (the same 74HC138 chip).
And that IC12 - very strange.
Please pm, will try to figure out why it stopped working.

LABS wrote on 2022-12-29, 08:32:

Hi, sorry to hear about your issues. Are you completely sure nothing was spilled on it? IC13 and IC14 are rusty indeed, but IC15 […]
Show full quote

Hi, sorry to hear about your issues.
Are you completely sure nothing was spilled on it?
IC13 and IC14 are rusty indeed, but IC15 is fine (the same 74HC138 chip).
And that IC12 - very strange.
Please pm, will try to figure out why it stopped working.

Hi, thanks, I'll send a DM. I remembered I posted a photo of my Blasterboard here on Vogons shortly after I received it. It shows IC2 with a bit of corrosion on some of the legs, unfortunatly, the other ICs are to fuzzy in the photo but I did take another top-down photo back then and there is some corrossion visible there as well. I'll send you the photo in a DM.

Re: BLASTERBOARD : A new SB 2.0-compatible ISA sound card

Edit: To answer your question, nothing was spliited on it. I'm very careful with my hardware.

The rust looks like what you would get on old C64 MOS branded logic ICs. Bad or no passivation layer on the legs. When did NXP stop making 74 series logic? Maybe they did some crappy ones? The latest datasheet is from 2015:

https://media.digikey.com/pdf/Data%20Sheets/N … HCT138_Rev5.pdf

And at Digikey they are listed as obsolete:

https://www.digikey.de/en/products/detail/nxp … 138N-652/763002

My guess is that this is a bad batch and/or rebranded NOS pieces, that are actually not NXP, but some inferior brand.

root42 wrote on 2022-12-29, 13:45:

The rust looks like what you would get on old C64 MOS branded logic ICs. Bad or no passivation layer on the legs. When did NXP s […]
Show full quote

The rust looks like what you would get on old C64 MOS branded logic ICs. Bad or no passivation layer on the legs. When did NXP stop making 74 series logic? Maybe they did some crappy ones? The latest datasheet is from 2015:

https://media.digikey.com/pdf/Data%20Sheets/N … HCT138_Rev5.pdf

And at Digikey they are listed as obsolete:

https://www.digikey.de/en/products/detail/nxp … 138N-652/763002

My guess is that this is a bad batch and/or rebranded NOS pieces, that are actually not NXP, but some inferior brand.

Good point
Can you confirm that your bb doesn't have the same issue?

My board has TI chips exclusively. Some look a bit tarnished, but I have that with brand new Mouser TI chips as well. It's the passivation layer I think.

Checked mine: no corrosion / rust. But also no NXP ones used.

Thanks, root and mjay

Please, if anyone else ordered an assembled card and has NXP 74HC138 chips in it, let me know if you have the same issue as pan069

LABS wrote on 2022-10-28, 10:47:

I did not improve the original schematic, it is designed from scratch How I designed it: First - I build a prototype which was n […]
Show full quote

pentiumspeed wrote on 2022-10-11, 00:00:

How did you designed this blasterboard PCB to have quiet output vs the noisy original?

Cheers,

I did not improve the original schematic, it is designed from scratch
How I designed it:
First - I build a prototype which was noisy as aphex twin's ventolin 😀
Then studied all I could find on power filtering and grounding etc, like:
https://andybrown.me.uk/2015/07/24/usb-filtering/
https://www.analog.com/en/analog-dialogue/art … l-grounded.html
Then lots of simulations in LTspice and tests on a breadboard, rearranging components and ground connections
After weeks I finally got what I needed for this exact card 😀

nathanieltolbert wrote on 2022-10-20, 20:02:

I need to save my pennies up so I can buy one of these kits. I had such a good time building all of the MPU cards that I got from here, a new project sounds like fun, and I know I need the practice when it comes to soldering. Thank you so much for offering a really interesting project like this!

You are very welcome, I can reserve one for you if you wish, drop me a message when you are ready

Thank you, I'm glad you read the second link. The first link is good but doesn't go in depth how to calculate and do it correctly in rest of circuit like the second link is.

This part of this is similar to the book "The Art of Electronics". Highly recommended to get one if you are designing electronics and circuit board.

Cheers,

wil you release the gerber files ?

I found some time, ordered needed details and assembled the kit (kit 1 if I'm not mistaken).

Everything went pretty well, even with my soldering skills this thing is a medium complexity board among all through-the-hole kits I've been assembling so far. But I did a terrible mistake. In order to keep the precious and becoming more and more rare YM3812 chip available just in case I put it to the socket (just like DAC and opamps). And even though I soldered the socket correctly, I put the FM chip in the wrong direction and seems like killed it. It is not detected by all setups for games and produces garbage (resembling the original tunes) in Lotus. I ordered new ones from Ali and wait for proper testing of the whole card. And as for opamps - I just want to test replacement with OPA4134 and comparing - if it shows any difference at least on CD.

DSP part is working and my God - how silent it is. Comparing with ES1869 and Opti based ExpertColor card - I hear all the noise, every bus transaction, every CF access with a constant background noise. While the BlasterBoard is completely silent!

It definitely will become the part of my 386 build. Like, it's completely enough for all the games of the early 90's. I'm going to add MT-32 emulation via external intel NUC.

LABS, thank you for your work and fun and experience it gives!

Yay! I did it.

I've got new YM3812 chips (nasty old ones actually) but that didn't help. So I started checking the nearest ICs. There was 74HCT245N that decouples 2 8-bit buses as I understand. It had some resistance between 7 bits from both sides but bit eight wasn't connected. I checked all chips from that supplier (I bought 5) - all were faulty. Will use my TL866 next time for everything before soldering.

Hour of curses (hate desoldering chips, I still ruin boards, wig doesn't help) and replacing the chip - and everything works!

Also I replaced TL074 op-amps with OPA4134. Name it clinical audiophilia, but I like result much more. The sound is more distinctive and punchy as for my taste, sounds less 'noisy' or 'digital' for OPL. Also, I ordered several YM3014 DACs (just in case) - it seems like older version of YM3014B provided in kit. I cannot measure the result but to me it sounds better - the high frequencies are less pronounced and percussions blend better. So if you assemble this card like me - use sockets not only for DSP, but also for opamps and, probably, for DAC, just to have possibility to compare the sound.

I'm happy. Will try to test it on something more powerful than 386 with MOD music, poor old 386/40 doesn't feel well playing 66kHz music and starts freezing with interpolated sound. But even what I managed to hear is pretty impressive. Anyway, very nice device. Having it assembled by myself, even with difficulties that I treat as quest, was so fun. If somebody wants to repeat - buy the assembled one or at least check the ICs you've ordered yourself with logic tester. Seems like TL866 is required by any retro-hobbyist just like soldering skills even if you are not going to become the radio-engineer. 😀

Glad you made it, have fun! 😀

rkurbatov wrote on 2023-06-06, 20:15:

...Also I replaced TL074 op-amps with OPA4134...

It is nice that you experiment with the sound, OPA4134 is a good choice for this exact circuit without any modifications and it is not too expensive. Haven't seen them from any reliable supplier for a long time in DIP package though.

Hello @LABS, what is the current price for a Blasterboard kit?

Also, do you have any other projects in the works? 😀

appiah4 wrote on 2023-06-07, 08:22:

Hello @LABS, what is the current price for a Blasterboard kit?

Also, do you have any other projects in the works? 😀

Hi,
the prices are here BLASTERBOARD : A new SB 2.0-compatible ISA sound card if you want a THT-version,
but you better wait for an improved SMD version which is currently in the testing phase

LABS wrote on 2023-06-07, 10:18:

Hi, the prices are here BLASTERBOARD : A new SB 2.0-compatible ISA sound card if you want a THT-version, but you better wait for […]
Show full quote

appiah4 wrote on 2023-06-07, 08:22:

Hello @LABS, what is the current price for a Blasterboard kit?

Also, do you have any other projects in the works? 😀

Hi,
the prices are here BLASTERBOARD : A new SB 2.0-compatible ISA sound card if you want a THT-version,
but you better wait for an improved SMD version which is currently in the testing phase

Will the SMD version be any different price-wise? I'm a lot more confident with THT soldering than SMD 😀

appiah4 wrote on 2023-06-07, 10:31:

Will the SMD version be any different price-wise? I'm a lot more confident with THT soldering than SMD 😀

It also looks more supaplexy, unlike SMD 😀