SID Aftersound

Testing/Troubleshooting
1

I just got my SID working and I noticed that when I hit a note there is a sort of aftersound. It sounds like the last note I played only softer. Anybody know what this is and/or how to fix it?

Thanks

Dave

2

the sound is quite a bit softer but still noticable? I think that is one of the sids “bugs”; allthough i can live with this aftersound, i guess you

could build/buy a (noise)gate, this will turn down the volume completely (of the sid, or whatever you feed through the gate) if the volume goes under a predefined threshold.

cheers \

marcel

3

Yes, unless this is really loud, then it is normal. It is especially noticable on the wavetable sounds, because the wavetable keeps going and going…

Justin

4

It seems a little loud to me but I may just have my speakers turned up too loud.. i dunno.

You can here a sample here

5

yep, thats normal allright., i can understand that you don’t like the (after)sound but when you are making music together with other sounds/machines, the aftersound isn’t (that) noticable. If you find it still irritating you will have to use a (noise)gate or something similar.

cheers,

marcel  

6

Please correct me if I’m wrong, but the aftersound is a bug of the older 6581 type SID chip. If it really bothers you, you could change to the newer 8580 type chip, that doesn’t have the bug/effect (but the overall sound will be a bit different, too…).

7

Please correct me if I’m wrong, but the aftersound is a bug of the older 6581 type SID chip.

i think thats right, the later SID is a bit more “static” (cleaner) or so i’ve heard. depends on what you want; i like the little fluctuations in the sound of the good old 6581 (sounds “alive”).

cheerz,

m4rc31

8

Thanks for the info. I think I might try running it through a noise gate. Anyone know where I can get one cheap, possibly DIY?

9

The bug is downsized in the 8580, but not gone. It´s still there, if you push the volume you still hear it. The SNR (signal to noise ratio) is just better.

Anyhow: At first I didn´t like it, too. But with the time I realized it brings in some interesting “analog” type of background sound (which you don´t really hear anyhow). At first I killed it with noisegates, too. But with the time I threw the noisegates out again and just muted the track within passages where everything had to be turned off. It´s bringing in some (you might kill me for that word) “natural” behaviour of the sound.

Like alyways: Try it with, try it without and *then* do decide.  ;)

Greetz!

10

what I think I’m gonna do is add a switch to turn the noise gate on and off. That way i can go either way. Since I plan on using my SID with my band at live shows, it might be good to be able to get rid of the hum at the flick of a switch, and if I want it just switch it right back.

11

Thanks for the info. I think I might try running it through a noise gate. Anyone know where I can get one cheap, possibly DIY?

Here is a schematic:

http://www.tonepad.com/project.asp?id=18

this one looks easy

here’s the mouser partslist

http://www.lucyjordan.com/interest/noisegate.htm

Justin

12

Here is a schematic:

http://www.tonepad.com/project.asp?id=18

this one looks easy

here’s the mouser partslist

http://www.lucyjordan.com/interest/noisegate.htm

Justin

I just found that myself the other day. They’ve got alot of cool projects on that page. I may build one of the phaser pedals on there and maybe make a distrotion box for my guitar. Thanks for the partslist it’ll be a big help. ROCK \m/

13

You could probably replace some pots with digital pots so that your guitar pedals can be midi controllable… Or maybe build a midi controlled gate for the sid aftersound problem

;D

-S

14

How would I go about doing that? Rotary Encoders? I was thinking of adding a phaser from tonepad too so that’d be pretty sweet.

~Dave

15

Digital pots - digitally controlled resistor IC’s..

And I wouldn’t do that - Captain Hastings from the forum, reported a bad noise problems on a design with a digipot (Hmm.. and what was the gain factor of a BigMuff again.. ;))

The Ross phaser is a OTA based - Just droping the LFO section there and inserting control current thru resistor instead of a original LFO.. Instant SID mod matrix phasing fun :wink:

Bye, Moebius