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[Super TWiT]

I have an amiga 500, and was transferring some files to it when I started hearing a strange noise. It was like a pulsating alarm clock. This noise happens whenever I do any sort of serial communication. Even when I just hit refresh on Amiga Explorer. It lasts the duration of the serial communication. It is output from the amiga via the rca jacks I am fairly certain as it comes into my computer via my line in. I have attached a sound recording. This is the amiga when I am transferring an adf to floppy over the serial port. The serial port seems to function normally.

Note that the static/noise is not from the Amiga but from my dirt-cheap Sabrent capture card

[Super TWiT]

Wow, I really thought I posted this in the Hardware Forum. Sorry...... It really should be moved.

[Karlos]

Originally Posted by Super TWiT

I have an amiga 500, and was transferring some files to it when I started hearing a strange noise. It was like a pulsating alarm clock. This noise happens whenever I do any sort of serial communication. Even when I just hit refresh on Amiga Explorer. It lasts the duration of the serial communication. It is output from the amiga via the rca jacks I am fairly certain as it comes into my computer via my line in. I have attached a sound recording. This is the amiga when I am transferring an adf to floppy over the serial port. The serial port seems to function normally.

Note that the static/noise is not from the Amiga but from my dirt-cheap Sabrent capture card

There's all sorts of crosstalk noise you get from the old hardware. I once started work on a joke glitch track in OctaMED called "Songs of the blitter" using samples of the strange audio background I got from just moving windows around and scrolling

I think the problem was always there but far less noticeable when the kit was new. More than likely various decoupling capacitors have dried out, allowing more interference through. Also, I guess that in my case, not having any RF shielding over the motherboard contributes to induced noise from other hardware too.

[Franko]

I made my own built in amp for my A1200 tower, at first I powered it using the main PSU but the this resulted in lots of strange noises coming through the amp. The simple cure was to place another small PSU in the tower from which to run the amp from...

It would seem that without adding extra filtering on the DC supply to any audio device that uses the main PSU results in all this crosstalk, anything from moving the mouse, windows being drawn or HD access all result in this 'interference' on most audio devices using the main PSU...

[Tension]

Possible dodgy cap. situation.

[Karlos]

Originally Posted by Tension

Possible dodgy cap. situation.

Yeah, you have to expect that by now, I mean you're talking about 20 year old kit.