8580 audio out problems,

[massimiliano]

i'm trying to build a new sid synth stuffed with an 8580 chip..

the powering of the core is ok (around 5,3v)

the lcd works correctly

the interconnection test is ok

the voltage of the sid is around 8,90v

when i play some notes i only ear small changes in the noise floor,

i think that there is no problem on the 8580 chips.. because i have meny ones and the problem is the same with all my chips...

and i can hear that the slight noisy sound is very similar to the sound of the patch i select

tryed to remove the crystal and connected to the j7 of the core... but the problem is the same

tryed to use a different powering but nothing...

thoug the voltages are ok the synth does not work.

tryed to substitute the protection transistor but nothing...

uff!

with some other 8580 chips what i hear is only 50hz hum and when i play notes that hum is "modulated" by something that i don't understand...

may be omething wrong in the core?

i noticed that the current to the sid was too low (ca. 4,5v) so i used the same 5vdc to power separately the core and the sid (74hc595 section)

used high quality cables for audio... nothing

it seem that i hear the only typical sid noise floor (with relative changing, tuning, regarding the played notes)  but not the sid sounds!!

any idea??

[th0mas]

The capacitors c1 and c2.. are they shorting against each other?

[Wilba]

Where did you get your SID chips? You cannot assume that all your chips aren't dead.

[TK.]

Have you already tried the mbsid_interconnection_test and the sid_testtone application?

Best Regards, Thorsten.