MBSID 8580 output level

[malichos]

Hello there, I am novice in the forum, though I am not noob as regards electronics, nevermind. I started to build Midibox SID v3 (with Core v3) using 8580 chips. The project is still at prototyping stage, being performed in the "shoe box", so there is no control surface, just the CORE module, SID module, PSU (original C64 PSU adapted according to the http://www.ucapps.de/mbhp/mbhp_8xsid_c64_psu_optimized.pdf) and LCD.

My problem is very quiet (or silent) output. I have 3 chips, one of the them seems to be dead and the others just behave the same way - the output is barely audible. I measured it with oscilloscope and it shows something around 180mVpp, as I remember. So I decided to build a simple amplifier using the electronic parts I bought for the project (2 x BC547C in Darlington configuration) and it works but not as good as I wish, Reaper shows input level at about -40dB max, using VST compressor helps so the signal level rises up to -16dB, but hum and noise rise along. And I think that is not the way it should work. I think that the SID itself should be much louder.

I tried the sid_testtone application and the output was quite loud and clear. I also ran mbsid_interconnection_test and all voltages were OK.

Is it possible that if the 2 chips are damaged they behave the same way? Or, could it be a kind of SID chip damage or rather something else, such as damaged another electronic part in the SID module? Or maybe PSU? My first thought was the issue is caused by to low power voltage or to low current efficiency of the 78L09 or 78L05, so I replaced them with 1,5A ones. That did not change a thing. The Vdd for the SID is 8.97V but this is OK I think.

Does anyone encountered similar symptoms and succeed to resolve? Did onyone measure the 8580 SID output level and can tell what it is?

I will appreciate any help.

Thanks in advance

[malichos]

I originaly put the topic in the inappropriate category, so I post it again. Sorry for messing up.

Hello there, I am novice in the forum, though I am not noob as regards electronics, nevermind. I started to build Midibox SID v3 (with Core v3) using 8580 chips. The project is still at prototyping stage, being performed in the "shoe box", so there is no control surface, just the CORE module, SID module, PSU (original C64 PSU adapted according to the http://www.ucapps.de/mbhp/mbhp_8xsid_c64_psu_optimized.pdf) and LCD.

My problem is very quiet (or silent) output. I have 3 chips, one of the them seems to be dead and the others just behave the same way - the output is barely audible. I measured it with oscilloscope and it shows something around 180mVpp, as I remember. So I decided to build a simple amplifier using the electronic parts I bought for the project (2 x BC547C in Darlington configuration) and it works but not as good as I wish, Reaper shows input level at about -40dB max, using VST compressor helps so the signal level rises up to -16dB, but hum and noise rise along. And I think that is not the way it should work. I think that the SID itself should be much louder.

I tried the sid_testtone application and the output was quite loud and clear. I also ran mbsid_interconnection_test and all voltages were OK.

Is it possible that if the 2 chips are damaged they behave the same way? Or, could it be a kind of SID chip damage or rather something else, such as damaged another electronic part in the SID module? Or maybe PSU? My first thought was the issue is caused by to low power voltage or to low current efficiency of the 78L09 or 78L05, so I replaced them with 1,5A ones. That did not change a thing. The Vdd for the SID is 8.97V but this is OK I think.

Does anyone encountered similar symptoms and succeed to resolve? Did onyone measure the 8580 SID output level and can tell what it is?

I will appreciate any help.

Thanks in advance

[julienvoirin]

it is a bit more louder than a line level (on a bass sound for example)

there is no need to amp this usually

8,97V is ok. you should try with certified SID chip

Edited May 12, 2010 by julienvoirin