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sid problems


kriz
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hi, i finally finished the core and sid module, and the voltages are ok (i used a different schematic for the powering from the c64 psu), because of the problem with the voltages on the sid module (ac + dc), see picture below.

sidpower.gif

next i programmed the mios and the program from the sid (step c). When i play a midi note, the sound gets interupted, listen to the mp3 file http://members.home.nl/degrotebozewolf/sid/sid.mp3

also after about 1 minute the sound go's into a high frequency sound, and i have to reset the sid

Is this a problem with the sid module or with the sid program software?

i used the mios 1.4 and the midibox_sid_v1_5c_18f_stepC main.syx

i have a 8580

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I'm not sure about that, but: Put that Recitifer in there! That prob can come from the fact, that on the core the recitifer is still there (and so getting the gnd up by 0,7 V) and on the SID it isn't. There was a problem like that before.

And: Do use MIOS 1.5b. Always use the latest MIOS & app version (working one) if possible or if any probs are there.

Greets

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i have put the rectifier after the ac but before the dc, zo that the 9 volt dc and the 5 volt dc come together, than there is nu need for the rectifier of the sid because the voltage is then dc not ac + dc.

I see your point, but i do not see the difference because on the power schematic the other pin is not even connected

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After a lot of testing, i have solved a bit of my problem.

After reading the problems of wilba, i tried some of my own. I have put the rectifier back on the sid board.

Then i disconnected the additional ground from the power supply.

Now i have a good level sound, and the voltages are ok.

But my main problem still is the same. The sound gets interupted, just like in the audio file, i tried mios 1.4, 1.5b, and sid software 1.5c and 1.6 alpha, but nothing helps. I just have sid step A, no lcd or controller, could this be the problem, and what can i do about it?

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Sounds like a pulse waveform whose pulsewidth is modulated by one or more LFOs. Once the PW reaches the maximum value, you won't hear a sound - in this case reduce the depth value.

Could you please record some of the presets so that I can hear the difference?

Best Regards, Thorsten.

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I finally found the problem !!!

I uploaded the new 1.6 alpha and started messing with the controller values.

how i found the problem:

It seems that when i lower the volume to about 60 a nice tone appeares, but above 64 not.

I singeled out the ocs's, and separate of eachother they work fine, but when i combine more then one osc you hear a sort of phase cancelation between the osc's.

when i transpose 1 osc you hear a sort of lfo sound becomming faster when i transpose the osc even more.

I think my problem has something to do with the synchronization of the ocs's.

I changed the cc# 124 but nothing happened (Oscillator Phase synchronization ).

Could this be the problem of the osc's cancelling eachother out?, and is this most likely a software problem, or a problem with my sid chip?

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Hi,

I think that this is neither a software, nor a hardware problem, but maybe only an understanding problem how the SID oscillators are working.

When all oscillators are in sync and playing the same wave, you will hear the sound 3 times louder than with the single oscillator.

When you detune or transpose the oscillators slightly, you will hear some kind of LFO effect, and the oscilltors sometimes cancel itself.

When you disable the phase synchronisation, the oscillator phases are still in sync so long as the frequencies are not changing.

These are the great features of the SID chip, with common wavetable or polyphonic synths such an effect mostly can't be realized - so maybe this is the reason why it confuses you.

Could you please try the presets first?

You can upload the presets with the jsynth editor, and it allows you also to tweak the parameters on a more induitive way.

Best Regards, Thorsten.

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thanx for the advice, i tried some patches and still the same problem, BUT..... when i disable the filter ( unchecking all the filter modes, and the osc's) the sid works lovely!!!!the hole problem is in the filter, and after 2 weeks of testing, i am glad that the problem is lokalised. When i enable the filter the background noise rises dramaticly, and the sounds stop playing.

and the band pass filter works a little bit after checking, but the high and low pass give no sound.

should i try to replace the filter caps, and check again, or is this a problem of the software?

greetz

kriz

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Alright.

Why are you thinking about a software bug? Did anybody else notice a similar problem?

So, if the filters are not working, then it would make sense to replace the caps. If it still doesn't work, then there is possibly an internal defect in your SID.

Best Regards, Thorsten.

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