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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment.

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Old 10th Dec 2018, 5:53 pm   #1
pentoad
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Default Turning speakers off when headphones jack is inserted.

My Proton 520B amplifier does not disconnect the speaker output when the headphones jack is inserted so the speakers are still audible when i just want the headphones on.
Apart from adding a speaker switch between the amplifier output and speakers is there a modification to the amplifier which will do as i want.
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Old 10th Dec 2018, 6:14 pm   #2
Herald1360
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Default Re: turning speakers off when headphones jack is inserted

Depends whether the headphone jack could be replaced by one with DP switch contacts and where the headphone output originates from in the circuit. And whether you want to add a couple of potentially unreliable switch contacts into the audio path anywhere along with how happy you are to modify your amp......
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Old 10th Dec 2018, 6:18 pm   #3
vidjoman
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Default Re: turning speakers off when headphones jack is inserted

From memory there are speaker selector switches, just switch the speakers off.
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Old 10th Dec 2018, 9:50 pm   #4
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Default Re: Turning speakers off when headphones jack is inserted.

Quote:
Originally Posted by pentoad View Post
My Proton 520B amplifier does not disconnect the speaker output when the headphones jack is inserted so the speakers are still audible when i just want the headphones on.
Apart from adding a speaker switch between the amplifier output and speakers is there a modification to the amplifier which will do as i want.
You could wire in a new headphone jack socket, that will switch the speakers off when plugging the headphones in.
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Old 10th Dec 2018, 9:58 pm   #5
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Default Re: Turning speakers off when headphones jack is inserted.

Just looked at one in a Youtube video, and as vidjoman says, it has speaker A/B buttons on the front panel.

My guess is that both of those buttons have an independent latch in / latch out action, so just switch both speaker outputs off if you only want to use phones. My Yamaha RX-V396 works exactly the same way, plugging in phones doesn't cut off the speakers but the speaker A/B buttons can be both in, one in and one out, or both out.
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Old 10th Dec 2018, 10:38 pm   #6
teetoon
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Default Re: Turning speakers off when headphones jack is inserted.

Hi guy's, It's the 520B he has and I can't see any speaker switching.
The headphone socket wiring seems to go back to the speaker terminal board at the back (through some resistors no doubt).

See image.

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Old 10th Dec 2018, 10:45 pm   #7
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Default Re: Turning speakers off when headphones jack is inserted.

Apologies, it was a 520 (not B) that I was looking at on Youtube.
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Old 11th Dec 2018, 12:01 am   #8
mhennessy
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Default Re: Turning speakers off when headphones jack is inserted.

I've just downloaded the service manual from HiFi Engine, and it confirms that the speakers are unswitched. How utterly bizarre!

The headphone socket is mounted on a small PCB which includes the 220R series resistors. There is no provision on that PCB to replace that socket with a switched one - if you wanted to do that, you would have to hard-wire it in place. If so, do not omit those 220R resistors.

You need to find a headphone socket that has independent switches - that means a total of 7 or 9 connections (as the 2 switches are often double-throw). Here's an example - this one has 7 connections (single-throw switches), which is all you need to do the job:

https://cpc.farnell.com/unbranded/t-...swi/dp/AV19950

I'd ensure the metal bushing of the socket is insulated from the metalwork of the chassis if possible (to avoid earth loops) - assuming that's the case with the original. And it might be necessary to enlarge the hole on the facia, depending again on the original socket.

Finally, the service manual implies that there is a mains fuse on the same PCB as the headphone socket. If so, you'll need to accommodate that elsewhere - and there are obvious safety issues with that. I might have misunderstood the manual, but do check carefully with your actual amp that's in front of you.
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Old 11th Dec 2018, 12:57 am   #9
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Default Re: Turning speakers off when headphones jack is inserted.

Before we go any further - I've just noticed that it says that the OP has been 'banned' from the forum (under his/her username in the first post). What on earth has he/she done wrong? Could it be because he/she didn't type a capital "I" a couple of times in that post?
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Old 11th Dec 2018, 10:36 am   #10
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Default Re: Turning speakers off when headphones jack is inserted.

The ban is only a temporary one. Let's not discuss the reason here.
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Old 11th Dec 2018, 10:43 am   #11
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Default Re: Turning speakers off when headphones jack is inserted.

I will close this thread temporarily, until he is reinstated.
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