Clever telly and broken audio pre-amp

Jim Lesurf wrote:
In article , Bill Wright
wrote:
So I'm thinking that the telly must have sensed that the audio pre-amp
wasn't working. Maybe it looks for a sensible load, I dunno. Clever
though.

I'm curious to know how it would do that. What type of connection between
them? I can imagine that something like HDMI might allow a handshake to
tell the TV. But don't know any general protocol for something like a pair
of phono/coax audio leads.

Jim


It's a mystery to me. But some CCTV recorders won't send video out
unless there's roughly 75ohm at the end of the cable. Some modulators
don't present that load so I have to strap a 120ohm res across the feeder.

It IS sensing it because as it happens I used some gold plated phono
barrel connectors to bypass the pre-amp, forgetting that they were the
leftovers from some I had that were faulty (poor contact of the inner;
very unreliable. I chucked a dozen of the beastly things away but these
somehow found their way back onto the shelf.) Anyroadup I put the telly
on this avvy and there was the message, and there was no audio on the
left channel. I fiddled with the line connecvtor and the audio came back.

I'm taking the audio from the 3.5mm mini jack on the telly, BTW, and the
telly is set to mute its own speakers. It's worked really well so far.

I wish I could find a way to make the telly jump to HDMI 1 whenever I
switch the 28E HD sat box on though.

Another problem is that the said (Humax) box send a blast of 'screech
THUMP' through the audio system about 20 minutes after it's been put on
standby.

Bill

"Bill Wright" wrote in message
...
R. Mark Clayton wrote:
"Bill Wright" wrote in message
...
I switched on my lovely big Sony telly and a strange message appeared.
'Searching for external loudspeakers'. Never seen that before. When the
telly came on there was no sound. It's set up for its own speakers to be
muted. It turned out that the audio pre-amp (a Rotel RC850) had failed.
We've recently had two power cuts, plus the RCD firing due to a faulty
kettle. For the time being I've bypassed the preamp, taking the TV audio
straight to the power amp. So I'm thinking that the telly must have
sensed that the audio pre-amp wasn't working. Maybe it looks for a
sensible load, I dunno. Clever though. And what to do about the pre-amp?

Bill

Try power cycling it again.
And switching back and forth between internal and external sound.
The pre-amp is the same on all inputs. I have four things feeding into it
and they're all the same: very weak audio at the pre-amp output.

So is it semi-independent then?


Bill

R. Mark Clayton wrote:

So is it semi-independent then?

I don't understand the question.

Bill

On Wed, 11 Dec 2013 16:22:11 +0000, Bill Wright said...
It IS sensing it because as it happens I used some gold plated phono
barrel connectors to bypass the pre-amp, forgetting that they were the
leftovers from some I had that were faulty (poor contact of the inner;
very unreliable. I chucked a dozen of the beastly things away but these
somehow found their way back onto the shelf.) Anyroadup I put the telly
on this avvy and there was the message, and there was no audio on the
left channel. I fiddled with the line connecvtor and the audio came back.

I'm taking the audio from the 3.5mm mini jack on the telly, BTW, and the
telly is set to mute its own speakers. It's worked really well so far.

I've got a Sony Bravia 42" KDL-42W653A. I have one of the sets of inputs
on an Arcam Alpha integrated stereo amplifier connected to the 3.5mm
audio out jack on the back of the TV, and the TV is set to mute its own
speakers, and to vary the volume at the jack as with the TV remote
volume control.

With the amp on, I turn on the TV. I hear the TV sound through the
speakers connected to the amp, and I ALWAYS see the message 'checking
the connection with external speakers'. Mind you that's not quite the
same as the message you mentioned. But if I disconnect the 3.5mm jack,
on power up I still get the same message, 'checking the connection with
external speakers'.

Perhaps you've got different software.

Windy Miller wrote:

Perhaps you've got different software.

It's all very rum.

Bill

Windy Miller wrote:

With the amp on, I turn on the TV. I hear the TV sound through the
speakers connected to the amp, and I ALWAYS see the message 'checking
the connection with external speakers'. Mind you that's not quite the
same as the message you mentioned. But if I disconnect the 3.5mm jack,
on power up I still get the same message, 'checking the connection with
external speakers'.

Same with my Sony too. I use an optical interface to feed an amp.
Just tried pulling it out, the same message for a few seconds, then
no further information.


--
Mark
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