<![CDATA[ChipMusic.org - Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/topic/13317/have-we-figured-out-what-causes-noisy-sample-playback-on-some-dmgs/ Fri, 31 Jan 2014 14:45:28 +0000 PunBB <![CDATA[Re: Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199513/#p199513 nonfinite says:
nitro2k01 wrote:

Actually, I realize I have a really old (and dirty) DMG that I bought cheaply on an auction for its low serial number, and it has this problem. Unfortunately, after a quick analysis, I don't think the particular problem is related to bad/low value capacitors, but how the sound circuit in the CPU chip is constructed. It seems like when you turn the wave channel off, (which has to be done to reload the sample buffer) it returns to a DC level way outside of the amplitude range of the wave channel. My antispike fix isn't of much help either. Unfortunately, I don't think the problem is fixable. I will try some things, but don't keep your hope up.

Oh, wow.  So each time you play a sample your DMG turns OFF a channel?  Does that cause...clicking?

On the topic of power spikes, Nitro.  Why does a DMG have that audible "pop" when you turn it on?  Why do you get the same when you pan L or R?  Are they related, or separate causes?  Can that L R pan pop be reduced somehow?

]]> Fri, 31 Jan 2014 14:45:28 +0000 https://chipmusic.org/forums/post/199513/#p199513 <![CDATA[Re: Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199510/#p199510 nitro2k01 says:

Actually, I realize I have a really old (and dirty) DMG that I bought cheaply on an auction for its low serial number, and it has this problem. Unfortunately, after a quick analysis, I don't think the particular problem is related to bad/low value capacitors, but how the sound circuit in the CPU chip is constructed. It seems like when you turn the wave channel off, (which has to be done to reload the sample buffer) it returns to a DC level way outside of the amplitude range of the wave channel. My antispike fix isn't of much help either. Unfortunately, I don't think the problem is fixable. I will try some things, but don't keep your hope up.

]]> Fri, 31 Jan 2014 13:18:40 +0000 https://chipmusic.org/forums/post/199510/#p199510 <![CDATA[Re: Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199509/#p199509 nitro2k01 says:

If you have a motherboard that does this, feel free to send it to me for analysis.

]]> Fri, 31 Jan 2014 12:49:59 +0000 https://chipmusic.org/forums/post/199509/#p199509 <![CDATA[Re: Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199507/#p199507 Zuberi says:

Im getting that noise when I try to play samples in a CPU-04, that is supposed to be working, even if I MUTE every channel, when the pointer gets to the part that should play the samples, I get that noise hmm

]]> Fri, 31 Jan 2014 12:37:26 +0000 https://chipmusic.org/forums/post/199507/#p199507 <![CDATA[Re: Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199481/#p199481 nonfinite says:

You're all legendary.  Thank you!

]]> Fri, 31 Jan 2014 01:38:34 +0000 https://chipmusic.org/forums/post/199481/#p199481 <![CDATA[Re: Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199479/#p199479 katsumbhong says:

http://chipmusic.org/forums/topic/11881 … revisited/

]]> Fri, 31 Jan 2014 01:09:39 +0000 https://chipmusic.org/forums/post/199479/#p199479 <![CDATA[Re: Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199478/#p199478 katsumbhong says:

The older cpus weren't up to snuff.

]]> Fri, 31 Jan 2014 01:04:40 +0000 https://chipmusic.org/forums/post/199478/#p199478 <![CDATA[Re: Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199477/#p199477 katsumbhong says:

This was addressed in my thread about DMG CPUs awhile back.

]]> Fri, 31 Jan 2014 01:03:47 +0000 https://chipmusic.org/forums/post/199477/#p199477 <![CDATA[Re: Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199475/#p199475 TSC says:

Examples comparing a noisy signal to a "clean" one?

]]> Fri, 31 Jan 2014 00:46:07 +0000 https://chipmusic.org/forums/post/199475/#p199475 <![CDATA[Re: Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199474/#p199474 herr_prof says:

Its a bug on dmg-02 rev mobos isnt it? Luckily you can see the number through the battery hole.

]]> Fri, 31 Jan 2014 00:39:38 +0000 https://chipmusic.org/forums/post/199474/#p199474 <![CDATA[Have we figured out what causes noisy sample playback on some DMGs?]]> https://chipmusic.org/forums/post/199473/#p199473 nonfinite says:

This has been an inherent issue ever since I got into modding.  Replacing the rear PCB fixes it.  It's isolated to WAV channel sample playback.  Any of you who've heard it know exactly what I'm talking about.  Samples have a noisy "whine" to them 100% of the time.


Any hypothesis on what causes this issue, and how to fix it?

]]> Fri, 31 Jan 2014 00:35:12 +0000 https://chipmusic.org/forums/post/199473/#p199473