Trouble getting DAC to work on Taki's MiSTer Pi

[Weatherby]

Apologies if I'm asking a dumb question, but I am a newcomer to the whole FPGA scene and have been struggling to get past a very specific hurdle since receiving my MiSTer Pi. I'm trying to hook this up to a CRT with composite inputs, and while I am able to get video out using the VGA port on the I/O board, I am having a lot of trouble getting audio. I tried a 3.5mm jack to composite cable at first, which returned very muffled and low audio, and was then advised to grab a DAC and toslink-to-mini toslink cable. Unfortunately, I'm getting zero audio from the DAC. I've tested both 3.5mm ports and both are dead silent. I do get a slight buzz when hooking the cables up, but it's only momentary.

I've searched and searched and a lot of the guides and troubleshooting I'm finding online are for other boards. At this point I feel like I've exhausted everything I can think of. Both core and main audio is on and at max, I've checked for loose pins, I don't see anything in the ini that would seem to be related to DACs, and I'm hitting a wall. At this point I assume the products themselves are to blame and that I need a better DAC but I also don't know what DACs are known to work with something like Taki's I/O board. Any help would be appreciated...

[AngelicLiver]

I would first start by reading the MiSTer FPGA docs, thoroughly. Pay particular attention to the Using Your CRT With MiSTer section. Connecting via composite requires a few additional steps and some adapters.

Check your DIP switches are set correctly, give them a wiggle in case they are not making good contact. The audio jack should be outputting analogue audio just fine.

[Weatherby]

Advised by whom? When they are talking DAC, they probably mean an HDMI->VGA DAC for Direct Video? But that doesn't make sense with your setup.

I would first start by reading the MiSTer FPGA docs, thoroughly. Pay particular attention to the Using Your CRT With MiSTer section. Connecting via composite requires a few additional steps and some adapters.

I have read the documentation. I am using Taki's MiSTer Pi I/O board and an active Y/C adapter with the pins appropriately jumped on the I/O. Video signal is great, comparing it with actual hardware shows no discernable difference.

The problem here is the audio. The 3.5mm jack next to the VGA port will feed poor, muffled audio when connected to a 3.5mm-to-composite cable. From what I've gathered, this is normal. Digging around through forum posts, documentation, anything I can find, I keep coming back to the same thing: plug in a toslink and run that to a DAC which can then feed out using composite. Unfortunately, what I've bought doesn't seem to actually do that, it's silent on all cores even after confirming the audio is on. I don't know if it's the DAC or cable itself or if there's an extra step somewhere I'm missing or some part of this which just hasn't clicked into place for me.

[akeley]

I thought Taki's I/O board is new design and that they are have improved audio?

Also, it's a bit confusing when you mention "composite" CRT video and "composite" audio connections. Do you mean you're connecting the DAC to the TV to get audio?

Overall, yeah, a proper DAC + TOSLINK cable should work ok, at least it does on one of my old-style MiSTers. Unfortunately, this setup is elsewhere atm and I don't remember exactly which parts and connections I've used (although I definitely did connect to an external speaker rig, Logitech or some such). Maybe somebody else can advise.

[Weatherby]

I thought Taki's I/O board is new design and that they are have improved audio?

Also, it's a bit confusing when you mention "composite" CRT video and "composite" audio connections. Do you mean you're connecting the DAC to the TV to get audio?

Overall, yeah, a proper DAC + TOSLINK cable should work ok, at least it does on one of my old-style MiSTers. Unfortunately, this setup is elsewhere atm and I don't remember exactly which parts and connections I've used (although I definitely did connect to an external speaker rig, Logitech or some such). Maybe somebody else can advise.

My setup is a Toshiba CRT that only has your basic yellow/white/red inputs. I have multiple consoles connected to it using an 8-channel switcher, which all work fine. The MiSTer's audio is connected using a mini-toslink to toslink cable which feeds into a DAC, and then I have the red/white going out of the back of the DAC to the appropriate channel on the switcher. Using the 3.5mm-to-RCA does get audio but it's awful, I'm not sure if Taki's board did improve upon it over older models but to hear anything I have to put the TV up to nearly full-blast.

Because I've never used a DAC or done anything as advanced as a MiSTer yet - though I've not had any other issues really - I'm thinking I'm missing some very basic thing that would otherwise be overlooked because it's common knowledge.

[akeley]

I got this set up working going by following simple advice in some thread on this forum, so if you had a similar source, it's probably solid. For the sake of being thorough, try to skip the switcher and connect the DAC directly to some other speaker than your TV (even headphones). EDIT: another simple thing - you did power the DAC, right?

Taki's I/O board advertises as being the 9.2 version (the latest, improved design), and having a "Hi-Fi Analog Audio DAC". Which is similar to what "official" sellers state, eg Ultimatemister.com: "Hi-Fi Analog Audio DAC with crystal clear stereo audio, pop-free and better frequency response"

My understanding is that this is one of the things improved over the old (6.1) I/O board design, and so the whole DAC/TOSLINK shebang shouldn't really be needed. But I don't have the new board yet, so maybe somebody else can confirm whether this is really the case (for both Taki and other sellers).

[Weatherby]

I got this set up working going by following simple advice in some thread on this forum, so if you had a similar source, it's probably solid. For the sake of being thorough, try to skip the switcher and connect the DAC directly to some other speaker than your TV (even headphones). EDIT: another simple thing - you did power the DAC, right?

Taki's I/O board advertises as being the 9.2 version (the latest, improved design), and having a "Hi-Fi Analog Audio DAC". Which is similar to what "official" sellers state, eg Ultimatemister.com: "Hi-Fi Analog Audio DAC with crystal clear stereo audio, pop-free and better frequency response"

My understanding is that this is one of the things improved over the old (6.1) I/O board design, and so the whole DAC/TOSLINK shebang shouldn't really be needed. But I don't have the new board yet, so maybe somebody else can confirm whether this is really the case (for both Taki and other sellers).

Hooked a pair of headphones to the output port in the DAC and it looks like I'm not getting audio that way either. The DAC is receiving power and I'm using appropriate cables for its power rating.

Don't know if it's worth noting, but when I hook the white/red cables into the output end and then connect them into the switcher, I do get a brief buzz through the speaker like you would when plugging in a powered device.

[akeley]

Ok, not sure about your DAC (it should work...) but how about connecting audio directly from the I/O board mini jack to external speakers/headphone/etc? I mean, it really should be fine on the new-design I/O boards. The lower quality sound (which wasn't all that bad to start with) and subsequent DAC solutions were a thing with the 6.1 boards and I'm 95% sure the new ones should be fine.

Maybe you should reach out to Taki and ask him, in case it's just a faulty I/O board?

[Weatherby]

Ok, not sure about your DAC (it should work...) but how about connecting audio directly from the I/O board mini jack to external speakers/headphone/etc? I mean, it really should be fine on the new-design I/O boards. The lower quality sound (which wasn't all that bad to start with) and subsequent DAC solutions were a thing with the 6.1 boards and I'm 95% sure the new ones should be fine.

Maybe you should reach out to Taki and ask him, in case it's just a faulty I/O board?

I just tested with headphones. My headphones do get audio directly from the I/O board. Just like the 3.5mm jack to RCA, though more clear and less muffled (this might just be because it's right up against my ears, though...) I then took the DAC and tried to hook it up to my computer to see if I could get any audio out with the same headphones using the 3.5 port on the output end of the DAC. Nothing.

I take it since audio is coming through headphones when plugged into the I/O that the board itself is fine, but that the toslink cord or the DAC itself may be the issue. I checked on Reddit, which is where the DAC was originally linked, and I did find another user bought the same DAC and claims that it's working fine. However, they bought a mini-toslink adapter that I assume they're using with the cable that came with the DAC. I've bought the same adapter and it should get here tomorrow so, hopefully, the problem has to do with the cable.

[akeley]

My point is that Taki's I/O boards should output quality audio (because they are the new 9.2 design), without the need for a DAC solution. So even if you eventually get the DAC to work, and it outputs better quality audio, the question remains why is the 3.5mm port outputting lower quality audio, and whether it's something to do with your board/setup only or all Taki's boards. I suspect it's probably the former, or we would have heard about this problem already.

I'm interested in getting one of his rigs myself, hence I'd appreciate it if other owners could comment on that issue.

[rickdangerous]

The problem lies with Taki's board, which has the wrong capacitors in the low pass filter. If you compare it to the sound of UltimateMiSTer.com's A/V Pro 9.2 (TM), the difference in sound is striking. Not to mention the difference in the LEDs, the light isolators, the wrong size buttons, and some incorrectly populated parts. We just should use good brands like Connfly VGA connectors and others of recognized quality, among many others. If there's a fault with the AV board, it's his fault alone. If you pay low prices, you have to accept things as they are! For the caps on AV module he just used 22000 instead of 2200, that's why it filters out all high freqs. This was already reported and hope he gets this fixed on future builds.

About the ram failing that is other story: all Mister Pi's layout between the FPGA and the 40pin GPIO could be different than with the Terasic's de10. The CLK line length matching is crucial to be accurate, to guarantee a good compatibility with JT's JTFrame, which was fine tunned to the combo "Terasic's de10 + official_MiSTer_SDRAM". No fix for this, because DE10nano layout is owned by Terasic. Guys, deal with this before you go reporting problems everywhere.

[akeley]

Guys, deal with this before you go reporting problems everywhere.

Thanks for the explanation, Ricardo. But these forums are exactly for reporting this kind of stuff, how else are we going to know about them (not everyone is on Discord, Twitter, etc)? I haven't seen it mentioned in the main Pi thread on this board, hence my doubts when replying to Weatherby here.

[rickdangerous]

I know, and I'm sorry for being rude, but we've spent so much time optimizing the A/V Pro and new upgraded cores, that it makes me crazy when people say that the A/V Pro has bad quality sound.

[pbsk8]

Ok, not sure about your DAC (it should work...) but how about connecting audio directly from the I/O board mini jack to external speakers/headphone/etc? I mean, it really should be fine on the new-design I/O boards. The lower quality sound (which wasn't all that bad to start with) and subsequent DAC solutions were a thing with the 6.1 boards and I'm 95% sure the new ones should be fine.

Maybe you should reach out to Taki and ask him, in case it's just a faulty I/O board?

I just tested with headphones. My headphones do get audio directly from the I/O board. Just like the 3.5mm jack to RCA, though more clear and less muffled (this might just be because it's right up against my ears, though...) I then took the DAC and tried to hook it up to my computer to see if I could get any audio out with the same headphones using the 3.5 port on the output end of the DAC. Nothing.

I take it since audio is coming through headphones when plugged into the I/O that the board itself is fine, but that the toslink cord or the DAC itself may be the issue. I checked on Reddit, which is where the DAC was originally linked, and I did find another user bought the same DAC and claims that it's working fine. However, they bought a mini-toslink adapter that I assume they're using with the cable that came with the DAC. I've bought the same adapter and it should get here tomorrow so, hopefully, the problem has to do with the cable.

what dac model are you using? I have an old one dac aiyma a2

[Weatherby]

Guys, deal with this before you go reporting problems everywhere.

Thanks for the explanation, Ricardo. But these forums are exactly for reporting this kind of stuff, how else are we going to know about them (not everyone is on Discord, Twitter, etc)? I haven't seen it mentioned in the main Pi thread on this board, hence my doubts when replying to Weatherby here.

I'm not going to disqualify this as being a me thing, but I've seen others complain about it, too. I'm trying to work backwards before chalking this up to QA on the board, although based on what the other user said, it may very well be build quality... I don't know.

That said, I'm using a DAC that I've confirmed at least one other person to be using, and they're getting audio. I've now matched the cables they're using and, unfortunately, I'm still getting nothing. Headphones and a 3.5mm-to-RCA work but the audio quality is mediocre to poor respectively. It's possible the DAC itself is faulty, so I've now ordered another, this time directly from MiSTer Addons as I assume that'll be much more suitable. Unfortunately, it'll probably take a week to get here.

I know, and I'm sorry for being rude, but we've spent so much time optimizing the A/V Pro and new upgraded cores, that it makes me crazy when people say that the A/V Pro has bad quality sound.

Sorry. I'm lumping Taki's specific build in with the A/V Pro in general. The way you explained the specifics of Taki's build has helped clarify some things for me here, it sounds like I should be getting cleaner audio from that port but for the reasons you explained, it's probable that I might not.

[rickdangerous]

For those of you in Europe, there's no problem - I can correct the caps. Just pay for the shipping. No problem to help.

[akeley]

Awesome offer from Ricardo. Also, as per info in this thread, you can RMA the I/O board, if it's easier. That's in case your DAC setup still doesn't work (even if it does, it's a lot of extra cables hanging about).