PROPHET64 & MSSIAH Userforum

electriclifeform · 2010-09-30 23:42:32

hey everyone

i am trying to eliminate as much back ground noise as possible on my 64 breadbin but am having difficulties.

i have added a simple jump wire from the audio in point on the 8pin a/v connector to ground but still there is an awful amount of both high end and low end background noise.

i understand you can put a cap across points on the power input to eliminate further but am not sure on the details. i have looked on the forum and elswhere but want confirmation that simply soldering a 10uf cap across the 9v in + ground will be safe and work correctly.

any other ideas, i know some people call it character but when im planning on putting this badboy through 30,000watts + of sound system id like to at least reduce it ;-)

any info appreciated.

thanks, tom
www.handbakedarcade.co.uk

D Vibe · 2010-10-02 10:26:57

You can't get it to be 100% silent when no notes are played. Best shot is probably to use a noise gate when you've muffled it as much as you can..

Also, I think that the 6581 is more noisy than the 8580; at least my Sidstation is noisier than my both 8580 sid chips in my C64...

Spazi · 2010-10-06 00:44:06

I don't want to burst your bubble. But me being a musician and soundguy, I would really have to advice you to NOT use the C64 live.
There are other people using it live, for instance 8bit music bands. But I really think that there is noise in the live shows.
Gotta say, there is always a bit of noise when performing. I myself play guitar, and my amp always makes a bit noise.
Only advice I have to give you is to make as many noise removing mods as you can!
Ground the input on the sid chip. ground or replace the PSU.
6581 always makes more noise since it runs on 12 volts instead of 9 volts on the 8580.
Either way, camoflauge it with muting/gating it. People won't notice the noise if something else is playing in the meantime/before

Spazi

electriclifeform · 2010-10-06 11:03:23

Hi

I will be using the C64 live, but as you say making sure the noise is minimized. I have grounded the audio input via the a/v connecter but it doesn’t seem to have done a great deal.

When you say ground the psu how do you go about this?

A noise gate I am already using, I was hoping to find a 2 channel half rack or pedal gate though instead of having to lug round a 19” rack.

Any suggestions?

Cheers, tom

D Vibe · 2010-10-06 17:53:43

http://www.behringer.com/EN/Products/NR300.aspx

Actually called Noise Reducer but is a simple noise gate...

D Vibe · 2010-10-06 17:54:58

One thing to notice aswell, about noise from the SID chip is that the oscillators never close entirely, so you will always have some background hum even though you manage to mod away all other noises...

electriclifeform · 2010-10-06 17:57:09

D Vibe wrote:
http://www.behringer.com/EN/Products/NR300.aspx

Actually called Noise Reducer but is a simple noise gate...

i had been looking at this range of pedals, didnt realise this ahas addition send and return though, does that mean i could use this one pedal to gate both of my 1/4" outputs on my c64?

Spazi · 2010-10-06 19:26:23

When I was referring to the ground mod on the PSU, I was referring to adding a cap to the ground and either the negative or positive wire. (not sure)
My electronic skills are low, I just know that people do this.

electriclifeform · 2010-10-19 00:13:00

Spazi wrote:
When I was referring to the ground mod on the PSU, I was referring to adding a cap to the ground and either the negative or positive wire. (not sure)
My electronic skills are low, I just know that people do this.

anyone else shed any further light on this for me please?

i have grounded the audio input but it doesnt seem to have done anything in terms of reducing the noise..

Spazi · 2010-10-19 02:24:44

When I grounded my Audio input, I heard a great deal difference. Maybe something's wrong with your PSU or C64

AxiMaxi · 2010-10-25 22:23:23

Be sure that the audio output is correctly wired: ground to ground.
Another option would be to remove the TV modulator from your C64, but that's quite some hassle.

Are you using a SID2SID board?

And I wonder how you connected your C64 to the mixer.
I don't think it was ever discussed here: has anybody tried to put a DI box in the signal path?
If so, did that help because of ground lift and balancing the signal?

Ready. · 2010-11-17 09:22:44

Sometimes the noise is given by ground loops. A ground loop isolator between C64 and mixer/amp/whatever breaks the loop and can significantly reduce certain noise. Plus it protects the SID.

electriclifeform · 2010-11-17 10:06:15

can you suggest a ground loop isolator to buy?

Ready. · 2010-11-18 07:04:39

I think anything like this will do:

http://www.apex-audio.com/catalog/images/APNR160.JPG

just Google for "ground loop isolator", they are usually under $10.

electriclifeform · 2010-11-18 10:02:31

thanks!

slashviper64 · 2010-11-25 16:57:33

my solution are D.I. Boxes and a good power adaptor... most of the noise comes from there.

electriclifeform · 2010-11-25 16:59:37

D.I box, that's a good shout ad have one of those tucked away somewhere. thanks.

mike-with-the-bike · 2011-11-21 04:08:57

D Vibe wrote:
You can't get it to be 100% silent when no notes are played. Best shot is probably to use a noise gate when you've muffled it as much as you can..

Also, I think that the 6581 is more noisy than the 8580; at least my Sidstation is noisier than my both 8580 sid chips in my C64...

Actually you can, i discovered it by accident some years ago, i did a hideous monstrous mod on my backup c64 where i moved the rf modulator off the board and in the process i found that not attaching the luminance signal into the modulator removed ALL noise! ( atleast i think it was luminance ). No previous noise reduction mods done, though it is an incredibly scary mod, there is probably a trace that can be cut , but i will have to look into that tomorrow.

electriclifeform · 2011-11-21 10:49:57

mike-with-the-bike wrote:
D Vibe wrote:
You can't get it to be 100% silent when no notes are played. Best shot is probably to use a noise gate when you've muffled it as much as you can..

Also, I think that the 6581 is more noisy than the 8580; at least my Sidstation is noisier than my both 8580 sid chips in my C64...
Actually you can, i discovered it by accident some years ago, i did a hideous monstrous mod on my backup c64 where i moved the rf modulator off the board and in the process i found that not attaching the luminance signal into the modulator removed ALL noise! ( atleast i think it was luminance ). No previous noise reduction mods done, though it is an incredibly scary mod, there is probably a trace that can be cut , but i will have to look into that tomorrow.

This sounds interesting, was this on a 6581 or 8580 board? Look forward to hearing more about this mod...

www.handbakedarcade.co.uk

PROPHET64 & MSSIAH Userforum

#1 2010-09-30 23:42:32

damn noise...

#2 2010-10-02 10:26:57

Re: damn noise...

#3 2010-10-06 00:44:06

Re: damn noise...

#4 2010-10-06 11:03:23

Re: damn noise...

#5 2010-10-06 17:53:43

Re: damn noise...

#6 2010-10-06 17:54:58

Re: damn noise...

#7 2010-10-06 17:57:09

Re: damn noise...

D Vibe wrote:

#8 2010-10-06 19:26:23

Re: damn noise...

#9 2010-10-19 00:13:00

Re: damn noise...

Spazi wrote:

#10 2010-10-19 02:24:44

Re: damn noise...

#11 2010-10-25 22:23:23

Re: damn noise...

#12 2010-11-17 09:22:44

Re: damn noise...

#13 2010-11-17 10:06:15

Re: damn noise...

#14 2010-11-18 07:04:39

Re: damn noise...

#15 2010-11-18 10:02:31

Re: damn noise...

#16 2010-11-25 16:57:33

Re: damn noise...

#17 2010-11-25 16:59:37

Re: damn noise...

#18 2011-11-21 04:08:57

Re: damn noise...

D Vibe wrote:

#19 2011-11-21 10:49:57

Re: damn noise...

mike-with-the-bike wrote:

D Vibe wrote:

Board footer