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-   -   rca line level to heaphone mod? (https://www.dvinfo.net/forum/all-things-audio/80274-rca-line-level-heaphone-mod.html)

Brendan Sundry November 23rd, 2006 09:15 PM

rca line level to heaphone mod?
Hi all,

Just wondering.
Got a single chipper here with no headphone jack i want to use as a 2nd cam for a wedding.
Is it possible to convert the rca output line level from socket to headphone level?

with an rca to stereo mini female adapter?

do i need a pre amp?

Steve Leverich November 24th, 2006 01:57 AM

Most I've seen let you tell the cam in menu to treat it's AV jack as a headphone out - what model cam is it? Steve

Brendan Sundry November 24th, 2006 05:17 AM

Steve, its a PAL zr500 the mv920.
Mic input/widecreen. OK for a cutaway cam.

Any other ideas?

Steve Leverich November 24th, 2006 02:05 PM


PDF manual for the zr500 -

I went thru the entire manual and I'm afraid you're correct - this sucks. I have a couple of the Elura series for the same reasons you bought yours, a 65 and a newer 100, and both allow you to reprogram the AV jack to be a headphone out. Also both of mine are top loaders and have mic inputs (as does yours apparently- the mic input, I mean.)

Do you know if your ZR500 puts out line level audio while you're recording? I would hope so - if it does, all I can think to do is look for a small battery-powered amplifier that takes -10 dB in and outputs a headphone level.

Man, if they keep "dumbing down" DV cams for the public, even my wife is gonna want an XL2... Steve

Steve Leverich November 24th, 2006 02:24 PM


If you have a Radio Shack available, you should be able to find a couple of adapters - you'll need a stereo mini male/dual RCA female, and a double female stereo mini adapter. Use your AV cable's dual RCA audio into the first adapter, then couple its male mini to the headphone amp's male mini and bob's yer uncle... Steve

Brendan Sundry November 25th, 2006 06:18 AM


Appreciate your efforts.

I actually tried using the mini video/audio out terminal and adapter the audio rca's to accept my headphones and it worked!

I was stoked.

Im pretty damn happy with this cam, i does so much for so little

Also i think it does -10dbfs?

Also there is a thread on the lens for a filter but i cant see any info on the size. The canon website says n/a
Have you had any experience on this?

Steve Leverich November 26th, 2006 05:53 AM

Nope; B&H site also says "none" under filter - are you sure those are threads? I ran across another camera a while back that LOOKED like it had threads, turned out they were concentric RINGS instead.

If you're sure they're actual threads (try gently running the tip of a straight pin or needle in the groove, go around at least twice and see if you're any closer to the edge) - if they are indeed threads, take it to a camera shop and see what fits (don't tell 'em you're just looking :=)

One thing - yours has a "lens cover switch" same as my Elura 100 - mine also has threads (I keep a 0.7 WA adapter on it most of the time) but yours may, because of the SWITCH that covers the lens, not offer any threads. Try that check with the needle before you bother moseying on down to the nearest camera shop.

Also - just because your line output lets you hear your headphones, does NOT mean that this is "good" for your cam - its output is -10 dB, true, but that's with a 47kohm load - most headphones are under 600 ohms, some are down around 32 ohms. This could be nearly the same as shorting out your audio output, and may "let the smoke out" of your new friend - when this happens, it's pretty expensive to find someone to "put the smoke back in". In a lot of cases, the cost is the same as buying a new one (because that's what it takes :=)

One last thing - if you look at the front of your lens, usually around the front there will be a bunch of writing - something like "20x zoom 3.0-60mm 1:1.8", this may be followed by a zero with a vertical slash thru it, followed by a number like "27" - if so, this is your filter size in mm.

Good luck... Steve

Brendan Sundry November 27th, 2006 02:29 AM

Im afraid your right about the threading. They are just rings. And if you look close the rings taper off to become less than a perfect circle.
So imm still looking for a solution to that one, if there is one.

The manual states this about the av terminal.
Video: 1Vp=p/75ohms unbalanced
Audio: -10dbv(47kohm load) 3 ohms or less.

Lucky you suggested that about the terminal.. As i have only ued he headphones for an hour. What would you suggest i do?

Would any headphones work. What hardware would i need instead. Im already planning on buying one of those sign video beachtek type adapters. But ill still need the headphone out put. I do have a portable lcd tv about 2.5 inches. I could feed the A?V thru there and then plug headphones into that as a preamp. I dont think that would hurt.


Brendan Sundry November 27th, 2006 04:32 AM


Was reading this post again. Basically i just need one of these boostaroo's.
If i go from the rca's on the av out cable. To stereo mini, to female/female stereo mini, then this should work and not take any load and fry my lil cam?

Let me know, but i think this is my cheapest and best option.


Steve Leverich November 28th, 2006 12:20 AM

Exactly - I've not had experience with that specific company, it just popped up on a google; but that's the way I'd do it. I'm still unclear what the comment about "3 ohms or less" means, but the boostaroo is designed to take consumer line levels and drive up to three sets of phones so it should cause no problems whatever... Steve

Brendan Sundry November 28th, 2006 05:19 AM

A firend told me that i shold be able to attach a filter to the cam with some tape to hold it in place.

He's probably right. If i can match the outer ring of the lens i could glue a filter spacer with that same diameter onto the front of the lens.

Steve House November 28th, 2006 11:16 AM


Originally Posted by Brendan Sundry
A firend told me that i shold be able to attach a filter to the cam with some tape to hold it in place.

He's probably right. If i can match the outer ring of the lens i could glue a filter spacer with that same diameter onto the front of the lens.

Often what appear to be screw threads are actually serrations to reduce flare and reflections. Before resorting to glue, take a look at the Cokin filter system at your camera store - as I recall they have some bayonet adapters and even options to mount a filter holder via a clamp ring that fits to the outside of the lens barrel.

Phil Sherwood November 28th, 2006 12:22 PM

Could the 3 Ohms be referring to the camera's *input* impedance?

Brendan Sundry November 28th, 2006 02:00 PM

I'll look into Cokin, thanks Steve, as afar as the ohms ive got no idea. I did use headphones once with the cam with no probs. But im not feeling like risking it again. Ill get a headphone amplifier like the one Steve suggests.

Brendan Sundry November 29th, 2006 05:13 AM


This post doesnt mention a preamp. Does everyone agree i will short out my cam if i dont frst put the output into a line level device and then amplify it ? Rather than a plugs only

Steve Leverich November 29th, 2006 02:21 PM

Brendon, I don't know about "everybody", but I've been in electronics in one form or another since 1960 or so - I've taught electronics in the military, worked as an engineering tech in audio and video for several years, been a service manager for several audio and video companies both in California and Hawaii, designed and built audio, video and digital circuitry both for myself and as part of various jobs (did I mention I'm just a wee bit older than dirt??!?), run sound/lights for bands, played in same, and for the last 25+ years have been working as an industrial instrumentation tech in heavy manufacturing, all of which has taught me that it's NOT a good idea to ask more of an electronic circuit than it was designed to do...

Your cam's output is designed to run a relatively high impedance input, NOT a set of headphones - the fact that you "got away with it" briefly only shows that your cam is "beefier" than it needs to be in its output stage. Depending on just HOW much beefier it is, it MIGHT (key word, "might") continue to work that way without failure - but the ODDS are, it will (if run that way for longer periods of time) warm up enough to "toast" the output stage, at which time you'll have a non-functional camera (or at least, one that doesn't output sound when you use it for playback)

I only mentioned some of my experiences so you'll know what my qualifications/reasons are for saying what I did about your chances of getting away with NOT using a separate amplifier, NOT because I'm trying to "show off" or anything - I'd be really lax in my attempt to help if I let you do this to yourself without knowing the likelihood of ending up without a functional camera. That could really SUCK, compared to having to spend a few more $$ on something that will NOT cause you to lose a piece of gear.

Hope this helps you decide... Steve

Brendan Sundry November 29th, 2006 07:46 PM


Didnt mean to undermine your authority there. I was not aware of your expertise in the field. I was just looking for other people who might have the qualifications youve mentioned in this post, to comment. Seeing though this is you, thanks again.

Sometimes its hard to know, you know?

I owe ya a beer, if you ever over this side of the world

B. Sundry

Steve Leverich November 30th, 2006 11:35 AM

No prob, mate; actually, I have a partner in crime (designing recording studios) who lives in your neck of the woods (or at least on the same island) so might one day take you up on that beer :=) And I wouldn't exactly use the term "authority", more just experience. Hopefully SOME of that experience actually TAUGHT me a little :=))... Steve

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