General Forum

Re: White noise and how to minmise it.

DoubleU — Tue, 24 Aug 2010 13:46:11 GMT

Graham1982:

set it up with a freeview box and set of PC speakers connected to the projector's headphone socket - this is the only way to output sound

I'm not the familiar with the freeview box, but aren't there L/R RCA's to use?

Re: White noise and how to minmise it.

Graham1982 — Tue, 24 Aug 2010 12:49:22 GMT

Hi guys:

Thanks for the input - guess I will sit on it till I connect some speakers to it properly and see if it is actually a problem or if it is the headphone jack.

Thanks again

Graham

Re: White noise and how to minmise it.

Rich — Tue, 24 Aug 2010 10:58:52 GMT

Sounds like an impedance matching problem using the headphone jack like that. I'm no expert in fixing the issue, so I can't suggest a fix.

Re: White noise and how to minmise it.

cooldude — Tue, 24 Aug 2010 10:50:52 GMT

Also the headphone jack is just not the best output by default as mostly they are added as an after thought.
Noise like that is typical a grounding issue. A clean power unit between the wall socket and the projector should help the issue somewhat.

It might be better to use a better (rca?) output jacks on your projector as those circuits should be better designed.

If no other equipment has a symptoms like it, it is doubtfull that the mass of cables are creating the interference.

Re: White noise and how to minmise it.

Graham1982 — Tue, 24 Aug 2010 10:08:26 GMT

Hi:

Thanks for the information. Whilst I understand in theory what you mean (I think), I do not feel I am competent enough to open up the unit without blowing myself and the projector up.

I was thinking would the mass of cables in close proximety and connected to the projector unit such as roof antenna, freeview box and speakers be creating some kind of conducting loop which is making this worse?

Thanks

Graham

Re: White noise and how to minmise it.

cooldude — Tue, 24 Aug 2010 09:55:34 GMT

Graham1982:

Hi all:

I hope that the title of this thread is correct because I am guessing as a direct result of extensive research - wikipedia!

I have just got hold of a CRT projector for free from a friend and have set it up with a freeview box and set of PC speakers connected to the projector's headphone socket - this is the only way to output sound whilst I am waiting to move house and get all of my things out of storage.

When watching TV (or any source) where there are images with a lot of white on the screen I get a lot more background buzz than normal. Whilst I can ignore/live with this I would rather not. Thus is there a way to get rid of it? I guess that when connected to a proper amp and speakers the problem will be amplified (no pun intended).

Thoughts

Graham

I would check the power supply, or try a power filter.
More white means more energy drawn and if the PSU is getting tired this symptom might be coming from that.
I did have a similar issue with a computer monitor a while back.

White noise and how to minmise it.

Graham1982 — Tue, 24 Aug 2010 07:31:58 GMT

Hi all:

I hope that the title of this thread is correct because I am guessing as a direct result of extensive research - wikipedia!

I have just got hold of a CRT projector for free from a friend and have set it up with a freeview box and set of PC speakers connected to the projector's headphone socket - this is the only way to output sound whilst I am waiting to move house and get all of my things out of storage.

When watching TV (or any source) where there are images with a lot of white on the screen I get a lot more background buzz than normal. Whilst I can ignore/live with this I would rather not. Thus is there a way to get rid of it? I guess that when connected to a proper amp and speakers the problem will be amplified (no pun intended).

Thoughts

Graham