8mm Forum: Line Level Output

This is topic Line Level Output in forum 16mm Forum at 8mm Forum.

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Posted by Maurice Leakey (Member # 916) on February 03, 2018, 03:55 AM:

A few projectors do not have a facility for a low level line sound output, so here's a cute accessory which will help. It connects to the projector's normal external loud speaker socket.

https://www.ebay.co.uk/itm/SPEAKER-TO-RCA-CONVERTER-HIGH-TO-LOW-LINE-LEVEL-CABLE/270662823340?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D49925%26meid%3Ddc45f6b046374fa 6b4053a471400caee%26pid%3D100005%26rk%3D2%26rkt%3D6%26mehot%3Des%26sd%3D361987845604%26itm%3D270662823340&_trksid=p2047675.c100005.m1851

Posted by Janice Glesser (Member # 2758) on February 03, 2018, 08:34 AM:

A very useful adapter. This "tiny URL" link might work better Maurice .

https://tinyurl.com/ybzxl92q

Posted by Steve Klare (Member # 12) on February 03, 2018, 09:41 AM:

Bummer!

(I wanted to build one!)

Can I pretend I didn’t see it? [Wink]

I got my first 16mm machine a few months ago and I need to plug it into my mixer.

The part of me that likes to solder was kind of glad there is no line out.

Posted by Janice Glesser (Member # 2758) on February 03, 2018, 11:11 AM:

I use a Direct Box.

Posted by Steve Klare (Member # 12) on February 03, 2018, 11:23 AM:

Do these typically have external power supplies or is it just input and output audio connections?

Posted by Janice Glesser (Member # 2758) on February 03, 2018, 04:00 PM:

Are you asking about the Direct Box or the line-level adapter Steve? DI boxes come in 2 varieties...active and passive.

Posted by Steve Klare (Member # 12) on February 03, 2018, 04:55 PM:

I guess it’s a general question. I‘ve never seen one of these and I’m curious how they are built.

I built a passive one years ago. If I do it again I’d go active: maybe add a little noise filtering and ground isolation if it made the sound nicer.

Posted by Janice Glesser (Member # 2758) on February 03, 2018, 05:39 PM:

The DI box does a lot more than just convert the line level. It will filter noise and ground loops especially if you have long cables. It's not a panacea for noise filtering...but definitely helps.

Posted by Mac Rebant (Member # 6156) on February 09, 2018, 06:24 PM:

Is this for connecting a projector to a stereo system? I didn't see a socket to insert a cable jack into.

I connect my projector to a guitar amp and it works pretty well but I've been interested in connecting it to my stereo system instead. Will this, or something similar, work for that?

Posted by Janice Glesser (Member # 2758) on February 09, 2018, 07:17 PM:

I use the DI Box to connect to a guitar amp...but I don't see whey you can't connect it to a stereo system. I would use a stereo splitter adapter to duplicate the mono output to left and right channels. Steve... do you see any reason this wouldn't work?

Posted by Steve Klare (Member # 12) on February 09, 2018, 08:01 PM:

Hi Janice,

A splitter should work just fine. That's what I used when I first started connecting my mono machines to my amp.

Worked great until I lost the thing! (Tooo many connectors and cables!)

Posted by Fred Achberger (Member # 6319) on February 10, 2018, 12:53 PM:

Following this thread, I purchased a level converter. I need to solder a 1/4" plug onto it so that it connects to my projector. I was thinking that I could solder both left and right channels from the converter to the tip of the 1/4" plug and both grounds to the ring. Since the projector is a mono output this would put the signal on both left and right output of the level converter.
Does that sound right?

Posted by Maurice Leakey (Member # 916) on February 10, 2018, 01:45 PM:

Fred
Not too sure of your speaker arrangement.
If you are using two separate speakers it is important that both are correctly phased, i.e., their cones go in and out together.

Posted by Fred Achberger (Member # 6319) on February 10, 2018, 03:12 PM:

I am trying to capture the sound from a film so I do not have any speakers.
If I connect both left and right channels into the level converter the phasing should be the same. And the signal and ground connections out should be the same.

Posted by Maurice Leakey (Member # 916) on February 11, 2018, 03:11 AM:

Fred
Phasing is important when using two loudspeakers, but I don't think there is any such problem with the set-up which you have described.

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