In article ,
Peter Larsen wrote:
Dave Plowman (News) wrote:

In article ,
Peter Larsen wrote:

DC offset? - shorting time too short? - anyway: first fix: stop
turning the x-over off, second fix: a 12 to 15 dB attenuator in
series with the x-over outputs.

I'm not a lover of leaving things on that don't need to be. ;-)

Leave your crossover on to reduce its failure-probability, it should not
use more than a single digit numbers of watts.

But the crossovers are inside the amps. Which would mean rewiring and
providing a second mains connector. And a second mains outlet on the wall
since the present ones are switched by the pre-amp. So rather an expensive
solution. ;-)

I suppose I could experiment with attenuation rather than a short.

Read what I actually wrote, there was no "rather". Run you x-over hotter
and it will sound better AND the probability of very loud noises caused
by any kind of failure will be drastically reduced.

At the moment it is unity gain running at a nominal zero level. Not sure
I'd be willing to re-engineer the whole thing just for what is a fairly
minor issue.

The noise the crossover makes at switch on isn't very nice - I've a
feeling it is a function of the type of filter, given the original BBC
one did much the same, and they are discrete transistors rather than
ICs.

Relays just as you have deployed them are known and described in the
literature to constitute The solution, not powering x-over off is also
known good.

I must admit to not having researched digital crossovers.
Other than seeing the price of commercial ones.

They use more power when they are on and are easy to get steep, those
are the two main differences and some of them create mayhem at
power-off and need to be run via an UPS.

Rather suspected that. ;-)

Thanks for your thoughts.

--
*Kill one man and you're a murderer, kill a million youand 're a conqueror.

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman = ****ing ****


** The "gentle plop" is coming from the Quad 405s at switch on.

The squeak form the xover would have masked it, so the DW fool never
noticed.

And just who said the noise was coming from a 405?


** No one needs to say it here, ****head - cos it is a KNOWN FACT
that 405s make a switch on thud.


** Snip retarded, ****wit OT reply.



FYI: relay contacts open instantly, so there is a sharp "click" when
any DC voltage is around.

Sigh. Which is why I was asking if there was a simple cure -


** But you do not have a sharp "click".

YOU ILLITERATE ****ING **** !!

YOU have the sound of a TURD drooping in a dunny.
-------------------------------------------------------------

FOAD - you stinking pile of psychotic pommy ****.


.... Phil

In article , Dave Plowman (News)
wrote:
Bit of a play on words. I used relays between the analogue crossover and
the power amps on my modified LS5/8 to prevent that annoying squeak at
power up. They simply short the amp inputs for a second after power op.
They do prevent the 'squeak', but replace it with a gentle plop. Any
easy way to make this totally silent?

I'm still puzzled by you calling this a 'squeak'. Is it a click/pop/crack,
or some kind of short burst of tone/noise?

And have you considered a mute of the kind used in, say, the Quad 34? Or
perhaps using a FET or two driven via an RC to slowly unmute?

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

In article ,
Phil Allison wrote:
Sigh. Which is why I was asking if there was a simple cure -


** But you do not have a sharp "click".

Sneak in when I wasn't looking and have a listen, did you?

For others the mute relay is delayed slightly after power up of the amps.

It's the noise it produces when removing the short I'd like to reduce.

Not any of the fantasies in Phil's diseased mind...

--
*You can't have everything, where would you put it?*

Dave Plowman London SW
To e-mail, change noise into sound.

One of the good and bad ideas seems to be a speaker relay delay, which from
what I can see on my elderly Denon, simply l allows the psus to stabilise
while running into a resistor inside and when all will be well, moving the
relay to the speakers position.
its good as you hear no plops, but is bad as the relays are a constant
source of poor connections and need cleaning every six months or so or
distortion and low or missing channels occur with no warning!

Brian

--
From the Sofa of Brian Gaff Reply address is active
"Dave Plowman (News)" wrote in message
...
Bit of a play on words. I used relays between the analogue crossover and
the power amps on my modified LS5/8 to prevent that annoying squeak at
power up. They simply short the amp inputs for a second after power op.
They do prevent the 'squeak', but replace it with a gentle plop. Any easy
way to make this totally silent?

--
*You know you're a redneck if your home has wheels and your car doesn't.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Brian Gaff wrote:
One of the good and bad ideas seems to be a speaker relay delay, which
from what I can see on my elderly Denon, simply l allows the psus to
stabilise while running into a resistor inside and when all will be
well, moving the relay to the speakers position.
its good as you hear no plops, but is bad as the relays are a constant
source of poor connections and need cleaning every six months or so or
distortion and low or missing channels occur with no warning!

Sounds like poor quality relays?

--
*Be nice to your kids. They'll choose your nursing home.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Jim Lesurf wrote:
In article , Dave Plowman (News)
wrote:
Bit of a play on words. I used relays between the analogue crossover and
the power amps on my modified LS5/8 to prevent that annoying squeak at
power up. They simply short the amp inputs for a second after power op.
They do prevent the 'squeak', but replace it with a gentle plop. Any
easy way to make this totally silent?

I'm still puzzled by you calling this a 'squeak'. Is it a
click/pop/crack, or some kind of short burst of tone/noise?

Without any muting, the crossover produces a sort of (loud) squeak when
powered up. As did the BBC one. Dunno what else to call it. Not a plop or
click. My guess is it's a function of the filter type.

And have you considered a mute of the kind used in, say, the Quad 34? Or
perhaps using a FET or two driven via an RC to slowly unmute?

I dunno what the Quad 34 uses.

The click I'm getting as the relays remove the short on the amp inputs is
much preferable to the 'squeak'. It isn't loud - just a rather unexpected
noise. I had lots of decent small signal relays lying around - hence using
them. But not any suitable FETs. Perhaps I'll have a play with that idea
in the future.

--
*Dance like nobody's watching.

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Dave Plowman (News)
wrote:
In article , Jim Lesurf
wrote:

I'm still puzzled by you calling this a 'squeak'. Is it a
click/pop/crack, or some kind of short burst of tone/noise?

Without any muting, the crossover produces a sort of (loud) squeak when
powered up. As did the BBC one. Dunno what else to call it. Not a plop
or click. My guess is it's a function of the filter type.

That sounds more like a short burst of oscillation rather than a switch-on
click. However I guess it may be something 'ringing' in the filter. Seems
odd, though.

And have you considered a mute of the kind used in, say, the Quad 34?
Or perhaps using a FET or two driven via an RC to slowly unmute?

I dunno what the Quad 34 uses.

Essentially it used a shunt transisor across each output. A circuit lets
these see a bias current at turnout, so mutes. Then an RC causes this bias
to be reduced as time passes, un-muting the output after a delay.

Jim

--
Please use the address on the audiomisc page if you wish to email me.
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Armstrong Audio http://www.audiomisc.co.uk/Armstrong/armstrong.html
Audio Misc http://www.audiomisc.co.uk/index.html

I'm just trying to recall which make of relay they use. Its one I've heard
of certainly, but the hardest bit is getting the bloody top off!
I now leave it off.
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Dave Plowman (News)" wrote in message
...
In article ,
Brian Gaff wrote:
One of the good and bad ideas seems to be a speaker relay delay, which
from what I can see on my elderly Denon, simply l allows the psus to
stabilise while running into a resistor inside and when all will be
well, moving the relay to the speakers position.
its good as you hear no plops, but is bad as the relays are a constant
source of poor connections and need cleaning every six months or so or
distortion and low or missing channels occur with no warning!

Sounds like poor quality relays?

--
*Be nice to your kids. They'll choose your nursing home.

Dave Plowman London SW
To e-mail, change noise into sound.

In article , Brian Gaff
wrote:
I'm just trying to recall which make of relay they use. Its one I've
heard of certainly, but the hardest bit is getting the bloody top off! I
now leave it off. Brian

Have you checked for DC offset on the amp output if the relay contacts are
suffering? With no signal input you should see only a few milli-volts.

--
*Why is it that doctors call what they do "practice"?

Dave Plowman London SW
To e-mail, change noise into sound.