I can see this being the solution to external mixer hunting for multiple soundcards/midi
very nicely done - can't wait to test mine 😁

dreamblaster wrote on 2024-12-30, 09:58:

Feel free to suggest improvements

This looks great! I'm just wondering, would it be possible to make an adapter which converts the standard IDE CD audio cable to 3.5mm input? Or maybe add the CD_IN pins as an alternative input on the mixer?

I wager a lot of people would prefer to have CD audio mixed in separately, so that it can only be used when needed (due to noise).

Oh my, finally! Been waiting for it for the last 15 years!
As an idea for improvement, would there be some possibility for integration with the WP32 Panel? 3,5" ideally.

And for the name - MixBlaster?..

If I understand correctly you have to wire the cable (for most sound cards) externally back inside the case to use it? As most sound cards (at least the ones I have) don't have an internal 3.5mm connector. In my case only one wave table card has an internal 3.5mm connector. If so it's a bit too messy for my taste to be honest but I'm sure that a lot of users with multiple sound cards in one retro pc will love it. Hope there will be a 8 port external version in the future. 😜

Yoghoo wrote on 2024-12-30, 11:17:

If I understand correctly you have to wire the cable (for most sound cards) externally back inside the case to use it? As most sound cards (at least the ones I have) don't have an internal 3.5mm connector. In my case only one wave table card has an internal 3.5mm connector. If so it's a bit too messy for my taste to be honest but I'm sure that a lot of users with multiple sound cards in one retro pc will love it. Hope there will be a 8 port external version in the future. 😜

Do you see a use for 8 ports ???

hard1k wrote on 2024-12-30, 10:53:

And for the name - MixBlaster?..

oh yes thats a good name

My immediate suggestion would be to replace the 3.5mm internal jacks with 4-pin headers instead.

dreamblaster wrote on 2024-12-30, 11:24:

Yoghoo wrote on 2024-12-30, 11:17:

If I understand correctly you have to wire the cable (for most sound cards) externally back inside the case to use it? As most sound cards (at least the ones I have) don't have an internal 3.5mm connector. In my case only one wave table card has an internal 3.5mm connector. If so it's a bit too messy for my taste to be honest but I'm sure that a lot of users with multiple sound cards in one retro pc will love it. Hope there will be a 8 port external version in the future. 😜

Do you see a use for 8 ports ???

For my use case yes. 😀 As I have a lot of retro pc's all using 1 speaker set. I now use a couple of cheap aliexpress 4 port ones but can't find an affordable 8 port (or more) one.

dreamblaster wrote on 2024-12-30, 09:58:

I made some first working prototypes of a new project : MixerBay This is an audio mixer for the 3.5" drive bay […]
Show full quote

I made some first working prototypes of a new project : MixerBay
This is an audio mixer for the 3.5" drive bay

Feel free to suggest improvements, and maybe also a better name

rear side :

• 4 x line in (3.5mm stereo connectors)
• 1 x line out (3.5mm stereo connector)
• 1 x floppy power connector

front panel :

• 4 x potentiometer for controlling input levels (1-4)
• 1 x potentiometer for controlling output level
• 1 x headphone out (3.5mm stereo connector)

The attachment mixerbay_front_wb.jpg is no longer available

The attachment mixerbay_rear_wb.jpg is no longer available

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awesome 😀 i dont think you can really improve on it, as for the inputs i think you should stick with 3.5 jacks over the 4pin headers others have suggested, i think the easier option would be to make up a cable, it will only require soldering a few wires from an old cd cable onto a 3.5 jack, i have an old external cd drive which has the same cable but goes to RCA's,

the 3.5 jack is more multifunctional since a lot of wavetable boards/midi devices use either a jack or RCA's it will be easier to connect up, but with 4pin headers people will have to make up a bunch of cables just to use the mixer

a 5.25 version would be good though since most cases only have one 3.5bay, and most will be using either a floppy/gotek or card reader, i was thinking a larger 3/4 jack on the front for instruments would be good, though i could just make up a cable.

Yoghoo wrote on 2024-12-30, 11:17:

If I understand correctly you have to wire the cable (for most sound cards) externally back inside the case to use it? As most sound cards (at least the ones I have) don't have an internal 3.5mm connector. In my case only one wave table card has an internal 3.5mm connector. If so it's a bit too messy for my taste to be honest but I'm sure that a lot of users with multiple sound cards in one retro pc will love it. Hope there will be a 8 port external version in the future. 😜

most sound cards dont have any output headers only inputs, so if you wanted to plug your sound card into the mixer you'd have to route a cable in through the case, ive got a cmedia 8738 that has an output header but its the only one ive seen that has one, i'd just have the mixer output everything in to the cd/aux in on my sound card.

also i think mixblaster is a good name, save Dreamixer for when you find a way for the mixer to take the place of a soundcard/windows mixer, old keyboards could adjust/mute volume, i wonder if something like that would be possible, if it could also work in dos and somehow amplify each channel that would be a dream.

appiah4 wrote on 2024-12-30, 11:27:

My immediate suggestion would be to replace the 3.5mm internal jacks with 4-pin headers instead.

Yep, it was quite hassle to create correct lenght cables for 3.5mm jacks. On the other hand i would not tottally replace 3.5 jacks but there should be both options on mixer board (some sound cards have no 4pin headers on board).
Also it would be nice if you could create passive mixer, at least i think this cheap aliexpress mixer unit picks up some noise there.
I would add an Line-in port to front panel next to headphones .
Most cases have only 2 3.5" bays, so i would suggest to create also an "high end" 5.25" version of mixer, maybe with eq and led graphic equalizer.
My project:

Pentium MMX DOS gaming build "Bright Star"

Edit, Dudeface was faster and had same ideas.

I would appreciate an option for flat pot-knobs because I have one of those PC cases with a door.

appiah4 wrote on 2024-12-30, 11:27:

My immediate suggestion would be to replace the 3.5mm internal jacks with 4-pin headers instead.

Pretty much my first though. Either that, or at least include the necessary footprints and offer a version with the jacks kept unpopulated.

Definitely gotta have a beige panel as an option. Or some other lighter color, something that's easily painted over.

Speaking of panels, you currently have a single mounting hole per side. Have you tried this design in a variety of cases yet? Maybe others need the screws in slightly different locations.

Optional ones:

- A choice in knobs might be nice, I don't like the ones pictured. Might imply a need for different pots with different length stems? Actually, come to think of it - probably easier to scratch my earlier "partially populated" idea and just offer all-loose-parts DIY kits for people wanting customization.

- Quick mute button

- LEDs (one per channel, with changing brightness) or some other way to easily see where signals are coming in, even when turned down. Basically el-cheapo VU meters. (If this gets picked up, please use the good old dim red/yellow ones though, not the modern bright blue "floodlight" type.)

- Maybe also offer a 5.25'' panel. With the same board behind it. Just in case all 3.5'' bays are taken.

Are your mixer solution based on an NE5532 preamp ? I heard they are quality stuff from high end system that are today's outdated so they provide cheap solution for great result and come aplenty as NOS. I cannot see on your pictures what chips you are using. I am using one of those on a similar solution I eventually came up with, your build is of course way better put together but I feel they might be similar under the hood.

If you check out my thread (mainly at the end) you can see that I struggled about providing input for the PC Beeper, it somehow fried the AC/DC rectifier, but I dont even understand what use case scenario would benefit an AC 10~17v power source. Into one computer case of course you use the DC 12v. With a 100ohm resistor and 1μF at least no more electronic fire and melting wire sheath, but the Beeper sound is way too strong and noisy. Maybe I should increase the resistor or start my own thread about it 😅 Oh well, I'm just here to ask if you considered it since you request improvement suggestion. (The Psychofox VU meter is soooo neat, I'm clearly jealous !). I think it make sense to add in the mix the pc beeper as some older games would put sound effects there and music on an FM or PSG chip. Being very crude you might want to tone it down, just think of the magnificent Xacalite speech in the Silpheed intro which sounded so bad that nobody noticed it was broken before a while 🤣

NE5532 and other "proper" audio opamps are not really usable at 5V supply rail (although 12V can be ok), they aren't having Rail to Rail Input/Output and clip far too early with limited supply voltage. They are meant to operate at +/15V or 30V, and on PC you only get the negative rail from ISA/PCI/PCIE slot, or AT(X) connector. But with a molex or floppy you'll be stuck with 12V and need a a DC-DC converter to go beyond. (virtual grounds are of course a thing and will help but they typically require far more parts than if you had a negative rail available to use).

Would it be possible to add other audio connectors in parallel with the Jack ports?
E.x:
Jack input no.1 having a PC Speaker port : 4-pin Molex KK connector, and maybe a resistor?
Jack input no.2 having a CD-ROM connector input - also a 4-pin Molex KK / 4-Pin MPC Connector, or sometimes another kind, that i dont know the name of. Maybe MPC-4?

And maybe an external jack line in - for an external synth?

And since we still are in Christmas mode, could we ask for a VU meter?

appiah4 wrote on 2024-12-30, 11:27:

My immediate suggestion would be to replace the 3.5mm internal jacks with 4-pin headers instead.

Good idea. We all have a bunch of those wires. Or better yet a combination, like a few at least with jack and 4pin, it would make it more universal.

Personally I'd also welcome a dedicated sub-out on something like this (even if it had no adjustment) as it opens up even more potential usefulness

Lot of sound cards also have spots for the 4 pin headers on their connectors, although often not populated. Then it is just matter of using plentifully available CD ROM audio cables to connect things to whatever is of interest.

That looks awesome and is exactly what I'm searching for.
I would also vote for a 5.25" sized one as well.
Both of my floppy bays are already used with HxC floppy emulator and WP32 McCake front panel.