I built myself and audio amplifier circuit to play music from an old
phone through to a speaker.This worked fine for a while, then the phone
stopped playing to the amplifier. The sound was still coming from the
phone speaker even when a stereo audio lead was plugged into the phone's
socket. I tried 2 other leads but still the same result.

I then tried the same with another old phone , and the same thing
happened. The phone will play music but not out through the audio leads.

Anyone know why this happened and what I can do??.

Thanks

RobH wrote:

> I built myself and audio amplifier circuit to play music from an old
> phone through to a speaker.This worked fine for a while, then the phone
> stopped playing to the amplifier. The sound was still coming from the
> phone speaker even when a stereo audio lead was plugged into the phone's
> socket. I tried 2 other leads but still the same result.
>
> I then tried the same with another old phone , and the same thing
> happened. The phone will play music but not out through the audio leads.
>
> Anyone know why this happened and what I can do??.
>
> Thanks

You tried 2 different audio sources (2 phones), but neither played
through the external amplifier. Without using the amplifier, have you
plugged a headphone set into the same jack on the phone? Have you tried
a non-phone audio source, like plugging your stereo's headphone jack
(that you've check with headphones has the stereo configured to route
sound to the jack) into the amplifier?

You never mentioned how the amplifier gets its power. If batteries,
have you replaced them? If the external amplifier uses power adapter,
have you checked the voltage from the tips of the power plug (center to
barrel) going into the amplifier?

On 2022/03/09 1:52 pm, RobH wrote:

> I built myself and audio amplifier circuit

The sci.electronics.repair ng might be a good place to ask.
--
"Old pinballers never die, they just flip out."

On 09/03/2022 22:24, VanguardLH wrote:
> RobH wrote:
>
>> I built myself and audio amplifier circuit to play music from an old
>> phone through to a speaker.This worked fine for a while, then the phone
>> stopped playing to the amplifier. The sound was still coming from the
>> phone speaker even when a stereo audio lead was plugged into the phone's
>> socket. I tried 2 other leads but still the same result.
>>
>> I then tried the same with another old phone , and the same thing
>> happened. The phone will play music but not out through the audio leads.
>>
>> Anyone know why this happened and what I can do??.
>>
>> Thanks
>
> You tried 2 different audio sources (2 phones), but neither played
> through the external amplifier. Without using the amplifier, have you
> plugged a headphone set into the same jack on the phone? Have you tried
> a non-phone audio source, like plugging your stereo's headphone jack
> (that you've check with headphones has the stereo configured to route
> sound to the jack) into the amplifier?
>
> You never mentioned how the amplifier gets its power. If batteries,
> have you replaced them? If the external amplifier uses power adapter,
> have you checked the voltage from the tips of the power plug (center to
> barrel) going into the amplifier?

Apologies for being a bit lacking in details, doh!

I don't have a headphone set to plug in to the 2 different phones, as I
only used bluetooth headphones.

I haven't tried pluging into a stereo as I don't have one now but I
could plug in my Alexa device??

The amplifier is a home built one , nothing serious at the moment , more
just a try it and see, and is powered by a 9v DC power source from a
benchtop power supply.

I haven't done much else, as neither phone goes mute? when a stereo
audio lead is plugged in, but they did at first. That is what normally
happens , doesn't it.

Thanks

On 09/03/2022 23:44, John Robertson wrote:
> On 2022/03/09 1:52 pm, RobH wrote:
>
>> I built myself and audio amplifier circuit
>
> The sci.electronics.repair ng might be a good place to ask.

Thanks, I've posted there now.

RobH wrote:

> On 09/03/2022 22:24, VanguardLH wrote:
>> RobH wrote:
>>
>>> I built myself and audio amplifier circuit to play music from an old
>>> phone through to a speaker.This worked fine for a while, then the phone
>>> stopped playing to the amplifier. The sound was still coming from the
>>> phone speaker even when a stereo audio lead was plugged into the phone's
>>> socket. I tried 2 other leads but still the same result.
>>>
>>> I then tried the same with another old phone , and the same thing
>>> happened. The phone will play music but not out through the audio leads.
>>>
>>> Anyone know why this happened and what I can do??.
>>>
>>> Thanks
>>
>> You tried 2 different audio sources (2 phones), but neither played
>> through the external amplifier. Without using the amplifier, have you
>> plugged a headphone set into the same jack on the phone? Have you tried
>> a non-phone audio source, like plugging your stereo's headphone jack
>> (that you've check with headphones has the stereo configured to route
>> sound to the jack) into the amplifier?
>>
>> You never mentioned how the amplifier gets its power. If batteries,
>> have you replaced them? If the external amplifier uses power adapter,
>> have you checked the voltage from the tips of the power plug (center to
>> barrel) going into the amplifier?
>
> Apologies for being a bit lacking in details, doh!
>
> I don't have a headphone set to plug in to the 2 different phones, as I
> only used bluetooth headphones.
>
> I haven't tried pluging into a stereo as I don't have one now but I
> could plug in my Alexa device??
>
> The amplifier is a home built one , nothing serious at the moment , more
> just a try it and see, and is powered by a 9v DC power source from a
> benchtop power supply.
>
> I haven't done much else, as neither phone goes mute? when a stereo
> audio lead is plugged in, but they did at first. That is what normally
> happens , doesn't it.
>
> Thanks

I don't have an Alexa device to know if it has a line-level or variable
audio output jack.

https://customerdocumentation.s3-us-west-2.amazonaws.com/Alexa+Devices/Echo+4th+Generation/Echo_(4th_Gen)_QSG_US.pdf

That's the manual for the 4th gen Amazon Echo Dot with Alexa. It shows
there is a 3.5 mm in/out jack. Whether for line input or line output is
configurable in the Alexa app.

You don't have a line-in jack on the backpanel of your desktop PC, or in
a laptop, to run the headset jack on the phone to the line-in jack on a
PC or laptop? Some phones come bundled with ear buds. I probably have
some lying in drawers from getting them for movies on an airplane, but
I'd have to find them to check the size of the plug. You can get a set
of wired ear buds from $8 to $12 at Walmart or eBay depending on the
features you want (simple, noise cancelling, volume control, etc).

The normal wiring has the regular speakers disconnected when you insert
a plug into the headphone jack. I've also seen where the speakers still
work along with a plugged in headphone. For phones, I would assume they
disconnect the speakers to preserve power since you'll be listening to
the headphone, plus you might not want others to hear what your playing
(i.e., headphones give you privacy by not letting others hear the audio
of your phone, like for calls, although neighbors can still hear what
you say into the microphone). Plugging in just a 3.5 mm plug with no
wires attached to it should disconnect the phone's speakers. Although a
I have a 3-connector stereo 3.5 mm plug (just the part, nothing wired to
it), it won't work in my phone, because it cannot be fully seated with
the armor case I have on my phone. It's a part for soldering wires to
it, so it has a fat body and shoulder.

Ah, I found my ear bud headset in my travel gear. It has 4 connectors,
because there are the 2 ear buds, and a microphone. When I plug it into
the phone, any audio that was playing from the phone's speaker gets
squelched, and only heard in the ear buds. Because of the armor case,
and despite the headset jack was thin, I still had to push it in hard to
make sure the plug and jack connections were aligned. Hmm, you sure
your 3.5 mm plug on the cable for your amplifier is getting fully seated
in the headset jack on your phone?

How many connectors (top, rings, and sleeves) are on the plug you insert
into the phone's headset jack? Are there 3 connections (tip, ring,
sleeve), or 4 (tip, ring, ring, sleeve)? As I recall, the 4-connection
plugs are for headsets that also have a microphone, and a simple stereo
headphone-only setup should have 3 connections (top, ring, sleeve).
Just 2 connections on the plug means a mono headphone. Whether the
phone mixes L+R to create mono is up to its design, but I'm guessing
just 1 channel would get connected. If balance, if available on your
phone (look under Accessibility settings, Hearing for balance, and Audio
channel for mono or stereo), is configured to only output to, say, the
right channel (100% right), but the plug only connects to the left
channel (which gets 0% left) then there's no audio signal to the plug.

Odd that both phones do not mute their speakers when you plug in a
headphone (or the headset plug on the phone end of the cable to your
amplifier). However, the common factor for the 2 phones could be who
[ab]uses them.

One some phones, the USB port can be configured for power-only (to
charge the phone using a USB power adapter) or for data (to allow file
transfers). If configured for power-only, you can't do data transfers
via USB cable. Maybe your phone has something similar for the headset
jack.

Have you check Bluetooth devices on the phone to make sure it isn't
paired to an active Bluetooth speaker or headset?

Are you running an FM radio app? That uses the headset cord attached to
the headset jack in the phone as an antenna. I've never bothered to
listen to FM radio on my phone although the phone came bundled with an
FM Radio app, so I cannot attest if the FM radio app wants exclusive use
of the headset jack for an antenna connection (it's on my to-do list to
test the headset jack on the phone as an FM antenna, and experiment with
the FM Radio app). What I see described in my phone's manual is:

FM Radio
- To use this app, first connect a headset to the device. The headset
becomes the radio antenna.

It doesn't say you can still listen to the radio on the headset when it
is used as an antenna, but it also doesn't say the FM Radio app excludes
listening to the music on the headset that is being used as an antenna.

On 10/03/2022 10:44, VanguardLH wrote:
> RobH wrote:
>
>> On 09/03/2022 22:24, VanguardLH wrote:
>>> RobH wrote:
>>>
>>>> I built myself and audio amplifier circuit to play music from an old
>>>> phone through to a speaker.This worked fine for a while, then the phone
>>>> stopped playing to the amplifier. The sound was still coming from the
>>>> phone speaker even when a stereo audio lead was plugged into the phone's
>>>> socket. I tried 2 other leads but still the same result.
>>>>
>>>> I then tried the same with another old phone , and the same thing
>>>> happened. The phone will play music but not out through the audio leads.
>>>>
>>>> Anyone know why this happened and what I can do??.
>>>>
>>>> Thanks
>>>
>>> You tried 2 different audio sources (2 phones), but neither played
>>> through the external amplifier. Without using the amplifier, have you
>>> plugged a headphone set into the same jack on the phone? Have you tried
>>> a non-phone audio source, like plugging your stereo's headphone jack
>>> (that you've check with headphones has the stereo configured to route
>>> sound to the jack) into the amplifier?
>>>
>>> You never mentioned how the amplifier gets its power. If batteries,
>>> have you replaced them? If the external amplifier uses power adapter,
>>> have you checked the voltage from the tips of the power plug (center to
>>> barrel) going into the amplifier?
>>
>> Apologies for being a bit lacking in details, doh!
>>
>> I don't have a headphone set to plug in to the 2 different phones, as I
>> only used bluetooth headphones.
>>
>> I haven't tried pluging into a stereo as I don't have one now but I
>> could plug in my Alexa device??
>>
>> The amplifier is a home built one , nothing serious at the moment , more
>> just a try it and see, and is powered by a 9v DC power source from a
>> benchtop power supply.
>>
>> I haven't done much else, as neither phone goes mute? when a stereo
>> audio lead is plugged in, but they did at first. That is what normally
>> happens , doesn't it.
>>
>> Thanks
>
> I don't have an Alexa device to know if it has a line-level or variable
> audio output jack.
>
> https://customerdocumentation.s3-us-west-2.amazonaws.com/Alexa+Devices/Echo+4th+Generation/Echo_(4th_Gen)_QSG_US.pdf
>
> That's the manual for the 4th gen Amazon Echo Dot with Alexa. It shows
> there is a 3.5 mm in/out jack. Whether for line input or line output is
> configurable in the Alexa app.
>
> You don't have a line-in jack on the backpanel of your desktop PC, or in
> a laptop, to run the headset jack on the phone to the line-in jack on a
> PC or laptop? Some phones come bundled with ear buds. I probably have
> some lying in drawers from getting them for movies on an airplane, but
> I'd have to find them to check the size of the plug. You can get a set
> of wired ear buds from $8 to $12 at Walmart or eBay depending on the
> features you want (simple, noise cancelling, volume control, etc).
>
> The normal wiring has the regular speakers disconnected when you insert
> a plug into the headphone jack. I've also seen where the speakers still
> work along with a plugged in headphone. For phones, I would assume they
> disconnect the speakers to preserve power since you'll be listening to
> the headphone, plus you might not want others to hear what your playing
> (i.e., headphones give you privacy by not letting others hear the audio
> of your phone, like for calls, although neighbors can still hear what
> you say into the microphone). Plugging in just a 3.5 mm plug with no
> wires attached to it should disconnect the phone's speakers. Although a
> I have a 3-connector stereo 3.5 mm plug (just the part, nothing wired to
> it), it won't work in my phone, because it cannot be fully seated with
> the armor case I have on my phone. It's a part for soldering wires to
> it, so it has a fat body and shoulder.
>
> Ah, I found my ear bud headset in my travel gear. It has 4 connectors,
> because there are the 2 ear buds, and a microphone. When I plug it into
> the phone, any audio that was playing from the phone's speaker gets
> squelched, and only heard in the ear buds. Because of the armor case,
> and despite the headset jack was thin, I still had to push it in hard to
> make sure the plug and jack connections were aligned. Hmm, you sure
> your 3.5 mm plug on the cable for your amplifier is getting fully seated
> in the headset jack on your phone?
>
> How many connectors (top, rings, and sleeves) are on the plug you insert
> into the phone's headset jack? Are there 3 connections (tip, ring,
> sleeve), or 4 (tip, ring, ring, sleeve)? As I recall, the 4-connection
> plugs are for headsets that also have a microphone, and a simple stereo
> headphone-only setup should have 3 connections (top, ring, sleeve).
> Just 2 connections on the plug means a mono headphone. Whether the
> phone mixes L+R to create mono is up to its design, but I'm guessing
> just 1 channel would get connected. If balance, if available on your
> phone (look under Accessibility settings, Hearing for balance, and Audio
> channel for mono or stereo), is configured to only output to, say, the
> right channel (100% right), but the plug only connects to the left
> channel (which gets 0% left) then there's no audio signal to the plug.
>
> Odd that both phones do not mute their speakers when you plug in a
> headphone (or the headset plug on the phone end of the cable to your
> amplifier). However, the common factor for the 2 phones could be who
> [ab]uses them.
>
> One some phones, the USB port can be configured for power-only (to
> charge the phone using a USB power adapter) or for data (to allow file
> transfers). If configured for power-only, you can't do data transfers
> via USB cable. Maybe your phone has something similar for the headset
> jack.
>
> Have you check Bluetooth devices on the phone to make sure it isn't
> paired to an active Bluetooth speaker or headset?
>
> Are you running an FM radio app? That uses the headset cord attached to
> the headset jack in the phone as an antenna. I've never bothered to
> listen to FM radio on my phone although the phone came bundled with an
> FM Radio app, so I cannot attest if the FM radio app wants exclusive use
> of the headset jack for an antenna connection (it's on my to-do list to
> test the headset jack on the phone as an FM antenna, and experiment with
> the FM Radio app). What I see described in my phone's manual is:
>
> FM Radio
> - To use this app, first connect a headset to the device. The headset
> becomes the radio antenna.
>
> It doesn't say you can still listen to the radio on the headset when it
> is used as an antenna, but it also doesn't say the FM Radio app excludes
> listening to the music on the headset that is being used as an antenna.

The stereo jack plug or lead I have tried are all 3 rings , tip, middle
then sleeve.

I have reset both phones so no, there was nothing else paired with
either, and no FM radio either.

Thanks