[Jeffrey]

I just have a simple question: Can I just put a mono plug into a stereo
jack, or do I need to use a mono/stereo adapter plug?

[Richard Crowley]

"Jeffrey" wrote ...
I just have a simple question: Can I just put a mono plug into a stereo
jack, or do I need to use a mono/stereo adapter plug?

Maybe it will work, and maybe it will blow up in your face.
Critical dependencies on the context here. What is the
equipment? Source and destination?

[William Sommerwerck]

I have a simple question: Can I just put a mono plug into a
stereo jack, or do I need to use a mono/stereo adapter plug?

You'll need an adapter.

Why?

Because the mono plug will give you only the left channel, _and_ the right
channel of the source will be shorted to ground.

Let's confuse this a bit further... Simply paralleling L and R might not
work, because the sources (whatever they are) might not like "looking into"
each other. So a series resistor on each channel might be needed.

[Laurence Payne]

On 24 Nov 2006 17:44:52 -0800, "Jeffrey"
wrote:

I just have a simple question: Can I just put a mono plug into a stereo
jack, or do I need to use a mono/stereo adapter plug?

The question was TOO simple :-)

Is this a stereo headphone output, a stereo line signal or a balanced
mono signal?

[Mike Rivers]

Jeffrey wrote:
I just have a simple question: Can I just put a mono plug into a stereo
jack, or do I need to use a mono/stereo adapter plug?

It depends on what's coming out of a jack. If it's a headphone jack and
you want to hear both channels, you'll need an adapter. If you're
content with hearing just the left channel, you can us a mono plug and
you'll probalby not blow up anything. Of you can stick it in half way
and hear just the right channel.

[David Satz]

Jeffrey wrote:

I just have a simple question: Can I just put a mono plug into a stereo
jack, or do I need to use a mono/stereo adapter plug?

There are ambiguities in your question. In most of the replies that
you've received already, the writers have tried to guess your
situation, and they didn't all guess the same way. The only way to give
you a reliable answer is to ask you first:

[1] Is the stereo jack [a] an input or is it [b] an output?

[2] Does the stereo jack carrying [c] a pair of signals (e.g. left and
right channels, as with stereo headphones or a stereo microphone) or
does it carry [d] a single balanced signal (as with a professional
microphone or line input)?

Depending on your answers, there are four possible situations to
consider:

[a] + [c]: Only one side or channel of the device will receive a
signal. That's not harmful but it may seem a little strange or
uncomfortable. You can use an adapter to feed both channels in parallel
if you prefer.

[a] + [d]: This will usually work, but the arrangement may be
vulnerable to hum and RFI pickup. To many people's surprise, you can
generally reduce the interference by using balanced cabling, even
though you're driving the cable in a single-ended manner.

[b] + [c]: For this case, use an adapter--otherwise you receive only
one channel while short-circuiting the other. You'll get acceptable
results in some cases, but in others the short circuit will cause
distortion in the channel that you receive--and sometimes damage may
even occur.

[b] + [d]: Similar to the preceding except that it's the two "legs" of
a single channel rather than two separate channels; same possible range
of outcomes if you don't use an adapter: Everything may work just fine
(there may be a reduction in output level), there may be distortion, or
the short circuit might break something.

--best regards

[Mike Rivers]

David Satz wrote:

There are ambiguities in your question. In most of the replies that
you've received already, the writers have tried to guess your
situation, and they didn't all guess the same way.

That's what makes life interesting. To most people who don't have the
perception to provide all the information, "jack" means a headphone
jack, so it's worth a guess.

But sometimes it means a plug. And sometimes they'll come back and tell
you that they work in IT and have a degree in computer science and just
had a simple question.

[Richard Kuschel]

Mike Rivers wrote:
David Satz wrote:

There are ambiguities in your question. In most of the replies that
you've received already, the writers have tried to guess your
situation, and they didn't all guess the same way.

That's what makes life interesting. To most people who don't have the
perception to provide all the information, "jack" means a headphone
jack, so it's worth a guess.

But sometimes it means a plug. And sometimes they'll come back and tell
you that they work in IT and have a degree in computer science and just
had a simple question.

Jacks are female recepticles for male plugs.
In this world, Jacks are really Jills.

[Chevdo]

In article . com,
says...


David Satz wrote:

There are ambiguities in your question. In most of the replies that
you've received already, the writers have tried to guess your
situation, and they didn't all guess the same way.

That's what makes life interesting. To most people who don't have the
perception to provide all the information, "jack" means a headphone
jack, so it's worth a guess.

But sometimes it means a plug. And sometimes they'll come back and tell
you that they work in IT and have a degree in computer science and just
had a simple question.


Which would be an understandable response after having been told twice by two
different people that something could possibly 'blow up', which is ridiculous.
Last time I checked neither jacks nor plugs are packed with explosives.

[WillStG]

Chevdo wrote:
In article . com,
says...


David Satz wrote:

There are ambiguities in your question. In most of the replies that
you've received already, the writers have tried to guess your
situation, and they didn't all guess the same way.

That's what makes life interesting. To most people who don't have the
perception to provide all the information, "jack" means a headphone
jack, so it's worth a guess.

But sometimes it means a plug. And sometimes they'll come back and tell
you that they work in IT and have a degree in computer science and just
had a simple question.


Which would be an understandable response after having been told twice by two
different people that something could possibly 'blow up', which is ridiculous.
Last time I checked neither jacks nor plugs are packed with explosives.

Some amps do not like being shorted to ground, which is what
happens when you have a male mono 1/4" headphone jack plugged into a
female stereo trs headphone output. These amps *will* start to crackle
after being run this way for a few minutes, shut down and finally will
fail - "blow up" so to speak - although perhaps not in as exciting a
manner as when you insert a capacitor into a circuit backward. I think
I had a Tascam 234 or something once upon a time that plainly warned
against doing this in the manual.

Modern amp design is more tolerant of this kind of treatment, but
older gear often isn't. Another example, when you plug in say floor
monitors, connected with 1/4" jacks. You momentarily short out the
amp inserting or pulling out the jacks (with neutrik or banana
connectors of course you wouldn't short anything out.) A lot of older
amps will blow up if you "hot plug" them - certain "Phase Linear"s come
to mind - but modern amps are a lot more tolerant of momentary abuse
like that. Still, using jacks that do not short out are the preferred,
better method of interfacing monitor speakers and amps.

Will Miho
NY TV/Audio Post/Music/Live Sound Guy
"The live sound giveth and the small print taketh away..." Tom Waits

[William Sommerwerck]

Which would be an understandable response after having been
told twice by two different people that something could possibly
"blow up", which is ridiculous. Last time I checked neither jacks
nor plugs are packed with explosives.

If you're trying to be funny, make jokes about something you know about.
It's not ridiculous.

Some amplifiers (both line-level and power) might be damaged if they're
shorted. This isn't common, but it's possible. Inserting a mono plug into a
stereo jack shorts the right channel to ground.

[Mike Rivers]

Chevdo wrote:

Which would be an understandable response after having been told twice by two
different people that something could possibly 'blow up', which is ridiculous.

An exaggeration, perhaps, but some outputs don't like to be driven, and
some outputs don't like being shorted. While the walls of the building
may not collapse, it's possible that after some abuse, the shorted
output might cease to be an output until it's repaired.

[Skler]

"Jeffrey" wrote in message
ps.com...
I just have a simple question: Can I just put a mono plug into a stereo
jack, or do I need to use a mono/stereo adapter plug?



If you plug a mono (Tip Sleeve) connector into a "stereo" (Tip Ring Sleeve)
jack it depends on a few factors as to what the result will be...

For a stereo output jack, like a headphone amp, a mono Tip-Sleeve connector
plugged in will short out one channel or "side" of the output. In such an
instance, you will certainly get signal through the un-shorted channel, but
may actually damage or at least put stress on the other output channel,
though this would depend on the circuit design and how hard you're driving
the headphone amplifier. I wouldn't recommend doing this, but instead would
advise using an adapter plug or cord.

On the other hand, there are cases where one might be using a mono Tip
Sleeve connector to take the output of some piece of gear and plug it into
the input of a mixer, say for example. If the input is balanced and uses a
Tip Ring Sleeve jack, you may end up with the problem of creating a
secondary signal path and picking up unwanted hum and noise, since plugging
the mono connector into the stereo jack in such an instance would serve to
short the negative side of the input to the shield. In most cases I've
encountered, using a mono plug to route signal into a balanced input jack
will work and not produce hum though. It's pretty safe to try.

Schuy

[Skler]

For a stereo output jack, like a headphone amp, a mono Tip-Sleeve
connector
plugged in will short out one channel or "side" of the output. In such an
instance, you will certainly get signal through the un-shorted channel,
but
may actually damage or at least put stress on the other output channel,
though this would depend on the circuit design and how hard you're driving
the headphone amplifier. I wouldn't recommend doing this, but instead
would
advise using an adapter plug or cord.

A proper adapter would involve the use of a stereo or Tip Ring Sleeve plug
in order to route one side of it to where ever you wanted to go with it.
Sometimes people will combine the left and right sides by simply shorting
them together or using a "Y" adapter, but this can result in unwanted
distortion. It's better to sum the outputs of a headphone amp for instance,
by using summing resistors for isolation or by going into a little mixer or
something with two input buffer stages. If all you need is one channel, it
would be generally safe to take signal from just one side though, either Tip
or Ring, with Sleeve as the common.

Schuy

[Chevdo]

In article ,
says...

Which would be an understandable response after having been
told twice by two different people that something could possibly
"blow up", which is ridiculous. Last time I checked neither jacks
nor plugs are packed with explosives.

If you're trying to be funny, make jokes about something you know about.
It's not ridiculous.

Some amplifiers (both line-level and power) might be damaged if they're
shorted. This isn't common, but it's possible.

Only if you're retarded, like you.

[WillStG]

Chevdo wrote:

says...
If you're trying to be funny, make jokes about something you know about.
It's not ridiculous.

Some amplifiers (both line-level and power) might be damaged if they're
shorted. This isn't common, but it's possible.

Only if you're retarded, like you.

If your advice to the orginal poster is don't worry about shorting
an amp to ground, it's very bad advice, the practice should be avoided.
And I don't know how much more gingerly we could have tried to expand
your lack of understanding on the subject.

If you can't deal gracefully with being wrong, maybe avoid the
situation by not offering opinions on subjects you don't really know
anything about.

Will Miho
NY TV/Audio Post/Music/Live Sound Guy
"The large print giveth and the small print taketh away..." Tom Waits

[William Sommerwerck]

Only if you're retarded, like you.

I don't know who you are, or what makes you think you're justified in
posting comments to this group, but all I can say is... Get a life. Find
something productive to do with your time.

I will no longer respond to any of Chevdo's comments, and I urge others in
this group not to respond, either.

[Richard Crowley]

"Jeffrey" wrote ...
I just have a simple question: Can I just put a mono plug into a stereo
jack, or do I need to use a mono/stereo adapter plug?

As you can see, this is anything but a "simple question".
Unless you reveal the details (what equipment, what you
are doing, etc.) you will never get a satisfactory answer.

[Meindert Sprang]

"Richard Crowley" wrote in message
...
"Jeffrey" wrote ...
I just have a simple question: Can I just put a mono plug into a stereo
jack, or do I need to use a mono/stereo adapter plug?

As you can see, this is anything but a "simple question".

I do like to see it as a simple question, with a simple answer: yes you can.
Why? Because of the fact that both plugs exist and are physically
interchangeable if feel that any equipment designed with jacks, should be
able to cope with a mono plug into a stereo (balanced) output. If that
equipment cannot cope with it, I consider the design as flawed. If it
breaks, I will return it to the supplier and tell him that the design is
flawed and claim a warrantee replacement with a better device. Simple.

Meindert

[WillStG]

Meindert Sprang wrote:
"Richard Crowley" wrote in message
...
"Jeffrey" wrote ...
I just have a simple question: Can I just put a mono plug into a stereo
jack, or do I need to use a mono/stereo adapter plug?

As you can see, this is anything but a "simple question".

I do like to see it as a simple question, with a simple answer: yes you can.
Why? Because of the fact that both plugs exist and are physically
interchangeable if feel that any equipment designed with jacks, should be
able to cope with a mono plug into a stereo (balanced) output. If that
equipment cannot cope with it, I consider the design as flawed. If it
breaks, I will return it to the supplier and tell him that the design is
flawed and claim a warrantee replacement with a better device. Simple.

Meindert

And if the gear is no longer covered by warrantee? What then?
Will *YOU* fix the gear for the orginal poster, at your own expense
because the guy was foolish enough to actually follow your bad advice?

Your advice is ill conceived and poorly reasoned. Better to learn
what the hell you're talking about, before you start issing opinions -
or at least learn to qualify your statements. Try wording your
statements as questions, that might help you keep your foot out of your
mouth. BTW, the sockpuppet thing is pretty lame.

Will Miho
NY TV/Audio Post/Music/Live Sound Guy
"The large print giveth and the small print taketh away..." Tom Waits

[Mike Rivers]

Meindert Sprang wrote:

I do like to see it as a simple question, with a simple answer: yes you can.
Why? Because of the fact that both plugs exist and are physically
interchangeable if feel that any equipment designed with jacks, should be
able to cope with a mono plug into a stereo (balanced) output.

You're mixing your metaphors here. Stereo and balanced are totally
different. As are gozintas and gozoutas.

Thanks mostly to Mackie, what have been called "impedance balanced" or
"balanced/unbalanced" outputs have become pretty common on studio
equipment (and not just cheap equipment) and are perfectly happy with
either a TRS or TS plug inserted. That's because there's only signal on
the tip. There's nothing but a resistor with only (negligably small)
common mode noise current flowing through it to short out if the ring
contact gets grounded.

There is also a differential output configuration that deals with
grounding the ring by essentially putting the two outputs in series and
no harm is done. And you can get the same results (with no harm) by
grounding the ring side of a transformer output.

But there's another output configuration, fortunately one that's not
often used any more, where both the tip and ring are driven by
independent ICs, and ICs don't always like being shorted out. While
it's rare that there will be enough power to damage the IC, because of
the way the ICs are interconnected (generally one is simply an inverter
connected to the output of the other) dragging down the output with a
short circuit causes the signal that manages to push through anyway to
be distorted, and since this is connected to the IC that you want to
use, distortion is added to what would be a perfectly usable unbalanced
output. So, while there's not likely to be smoke and fire, there's
likely to be distortion where there was none with a proper plug. The
way to connect to this output is to use a TRS plug and just not use the
ring contact (or a special plug that has an insulator where the ring
normally is - but I haven't seen one of those in a long time).

If the output has some power behind it, you might actually get smoke,
or at least electrical damage. Again, it's not very likely simply
because it's just not very common to put signal power greater than
headphone level on to both the tip and ring of a 1/4" TRS jack. But
people do all sorts of dumb things.

If that
equipment cannot cope with it, I consider the design as flawed. If it
breaks, I will return it to the supplier and tell him that the design is
flawed and claim a warrantee replacement with a better device. Simple.

If the user can't cope with it, I consider the user as flawed, and
perhaps he should return the equipment. Because of the way our commerce
works, you probably will get away with this once. But after you return
the second or third unit damaged in the same way, any dealer with any
smarts at all will ask you what you're doing with these things to
damage them?

[Meindert Sprang]

"WillStG" wrote in message
oups.com...
And if the gear is no longer covered by warrantee? What then?

One should then try that before the warranty expires.

Will *YOU* fix the gear for the orginal poster, at your own expense
because the guy was foolish enough to actually follow your bad advice?

Your advice is ill conceived and poorly reasoned.

I think not. Read below.

Better to learn what the hell you're talking about, before you start
issing opinions -
or at least learn to qualify your statements.

Ok, I do know what the hell I'm talking about, because I design an build
electronic equipment. albeit digital equipment, the problem is the same: I
have a balanced output which in many cases is shorted to ground because some
installer doesn't grasp the difference between balanced and single ended
outputs. So I therefore design all balanced outputs to be short-circuit
proof. That's why I think I have 'the right' to claim it a design flaw when
some equipment cannot stand grouding of one or both balanced output
terminals.

And I know that most modern mixers and other audio equipment is indeed short
circuit proof on the line outputs. I can read the schematics.....

Meindert
www.shipmodul.com
www.customware.nl

[Mike Rivers]

Meindert Sprang wrote:

I design an build
electronic equipment. albeit digital equipment, the problem is the same: I
have a balanced output which in many cases is shorted to ground because some
installer doesn't grasp the difference between balanced and single ended
outputs. So I therefore design all balanced outputs to be short-circuit
proof. That's why I think I have 'the right' to claim it a design flaw when
some equipment cannot stand grouding of one or both balanced output
terminals.

Yeah, but is the equipment that you design bottom-shelf,
cheap-so-people-who-have-
no-business-using-it-can-easily-afford-it cheap? When you want to cut
costs, idiot protection, as long as it doesn't compromise user safety,
is one of the first things to go. And most of the audio equipment that
we talk about here, sadly, is cost-cut designed.

And I know that most modern mixers and other audio equipment is indeed short
circuit proof on the line outputs. I can read the schematics.....

That's true, because the "low" side doesn't have any voltage on it. And
there isn't enough power behind the "high" side to do any permanent
damage. But you can't do that with a stereo headhpone jack which is
unbalanced. Short out one side of that and you're shorting out an
output that can deliver some power. Short it to the other side and
you'll be feeding an output with some power.

Instant descruction isn't guareanteed. It's just not a good idea to
stress equipment like that. It won't work right anyway, so why force it?

[Scott Dorsey]

Meindert Sprang wrote:

Ok, I do know what the hell I'm talking about, because I design an build
electronic equipment. albeit digital equipment, the problem is the same: I
have a balanced output which in many cases is shorted to ground because some
installer doesn't grasp the difference between balanced and single ended
outputs. So I therefore design all balanced outputs to be short-circuit
proof. That's why I think I have 'the right' to claim it a design flaw when
some equipment cannot stand grouding of one or both balanced output
terminals.

That's fine. Now, give me an output that can sink ten watts into a 50 ohm
headphone load and will behave that way. You can do it, but it's a pain
and nobody much does.

And I know that most modern mixers and other audio equipment is indeed short
circuit proof on the line outputs. I can read the schematics.....

Who ever said that we were dealing with line outputs?
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Meindert Sprang]

"Mike Rivers" wrote in message
oups.com...
Yeah, but is the equipment that you design bottom-shelf,
cheap-so-people-who-have-
no-business-using-it-can-easily-afford-it cheap? When you want to cut
costs, idiot protection, as long as it doesn't compromise user safety,
is one of the first things to go. And most of the audio equipment that
we talk about here, sadly, is cost-cut designed.

That might be true, but you forget one thing: a company could save a
fraction of a cent per resistor left out, but that would mean that much more
equipment will be sent back for repair, which is very bad for the
manufacturers' reputation. So what would you choose?

And I know that most modern mixers and other audio equipment is indeed
short
circuit proof on the line outputs. I can read the schematics.....

That's true, because the "low" side doesn't have any voltage on it. And
there isn't enough power behind the "high" side to do any permanent
damage.

Depends. The older Behringer mixers for example, had a single ended output
and a resistor to ground on the ring. But the newer ones (UB series) have
true balanced outputs, delivering a voltage on both + and - lines. I checked
that.

But you can't do that with a stereo headhpone jack which is
unbalanced. Short out one side of that and you're shorting out an
output that can deliver some power. Short it to the other side and
you'll be feeding an output with some power.

Really? You must know the famous trick of inserting a TRS first click into a
mixer insert socket. It works because the tip shorts both hot contacts of
the socket. The same happens if you insert a stereo headphone jack into the
heaphone output: left and right get shorted together. No damage done.

I can tell you it is much in the manufacturers interest to spend a few extra
cents when that prevents a massive return of damaged equipment.

Meindert

[Meindert Sprang]

"Scott Dorsey" wrote in message
...
Meindert Sprang wrote:

Ok, I do know what the hell I'm talking about, because I design an build
electronic equipment. albeit digital equipment, the problem is the same:
I
have a balanced output which in many cases is shorted to ground because
some
installer doesn't grasp the difference between balanced and single ended
outputs. So I therefore design all balanced outputs to be short-circuit
proof. That's why I think I have 'the right' to claim it a design flaw
when
some equipment cannot stand grouding of one or both balanced output
terminals.

That's fine. Now, give me an output that can sink ten watts into a 50 ohm
headphone load and will behave that way. You can do it, but it's a pain
and nobody much does.

You're not realistic here. No headphone output would need that much power.

And I know that most modern mixers and other audio equipment is indeed
short
circuit proof on the line outputs. I can read the schematics.....

Who ever said that we were dealing with line outputs?

See my reply to Mike about heaphone outputs getting shorted when you plug in
the stereo jack of a heaphone.

Meindert

[Mike Rivers]

Meindert Sprang wrote:

That might be true, but you forget one thing: a company could save a
fraction of a cent per resistor left out, but that would mean that much more
equipment will be sent back for repair, which is very bad for the
manufacturers' reputation. So what would you choose?

If I was selling 1,000 mixers a month, I'd take the chance and save the
couple of cents on the resistor. You can always tell the customer that
he shouldn't have done that. And besides, most people don't actually
send this stuff back for repair because it's too cheap. They sell it on
eBay and get something else. Or they ask if anyone has a schematic and
then you never hear from them again. Cheap gear doesn't last long
enough to worry about reputation.

Depends. The older Behringer mixers for example, had a single ended output
and a resistor to ground on the ring. But the newer ones (UB series) have
true balanced outputs, delivering a voltage on both + and - lines. I checked
that.

And how did they do that? If they used an inverter to get the - side,
that can be shorted out. And even if it doesn't fry, it can cause
distortion in the + side. The Mackie Onyx 1220 (as well as the VLZ/Pro
series) have the main outputs with that configuration. The Onyx 1620
and 1640 use a cross-coupled balanced stage that's perfectly happy
having one side grounded. They're kind of sleazy about it though and
the open circuit output levels aren't very accurately balanced. So with
one model, when connecting the output to an unbalanced input, you
should leave the low side floating, and on the other side, you should
ground it. Ya gotta read the instructions if you want to do it right.

But you can't do that with a stereo headhpone jack

Really? You must know the famous trick of inserting a TRS first click into a
mixer insert socket. It works because the tip shorts both hot contacts of
the socket.

Nope.

But first off, I was talking about a headphone jack (by which I meant a
jack fed from a headphone outpu, not a generic jack. I can see where a
digital designer can make that mistake. When all you have is on and
off, you don't need to worry about what's generating the voltage.

An insert jack has one output and one input, and normalling contacts
that connect the output to the input so the signal will flow through
the channel path. When you insert the plug all the way, you break that
normal connection. If you don't connect something to the insert input
(return) you don't hear whatever went into the channel input.

When you put the plug in halfway, it doesn't go in far enough to open
the normalling contacts, so, yes, the tip and ring contacts of the jack
are indeed "shorted" together, which is their normal state. The tip of
the plug actually connects to the ring contact of the jack, but since
there's signal on it, you can tap it off.

The same happens if you insert a stereo headphone jack into the
heaphone output: left and right get shorted together. No damage done.

Want to try that one again? If you insert a stereo headphone PLUG into
a stereo headphone JACK (output) you'll connect the left headphone to
one output and the right hedphone to the other output. No damage done,
because that's the way you're supposed to connect it.

Now if you plug in a TS (unbalanced) plug, you'll short one output. If
you have a 50 watt headphone amplifier, you probalby will damage it.
You probalby won't damage a 50 milliwatt amplifier.

I can tell you it is much in the manufacturers interest to spend a few extra
cents when that prevents a massive return of damaged equipment.

Don't tell me, tell the manufacturer. And ask how much damaged
equipment he gets back.

You don't see to understand that there's a difference between damage to
equipment and something not working right. because the user didn't hook
it up right.

[Scott Dorsey]

Meindert Sprang wrote:

That's fine. Now, give me an output that can sink ten watts into a 50 ohm
headphone load and will behave that way. You can do it, but it's a pain
and nobody much does.

You're not realistic here. No headphone output would need that much power.

My old Studio-Z console can throw about 20 watts out into the headphone jack,
using stacked 2N3055s on the headphone amp circuit. This USED to be pretty
common. It's starting to go the way of outputs capable of properly driving
600 ohm loads, though.

It's still fairly common for consumer receivers to power the headphones from
the power amplifier stage, usually through safety resistors. And usually
these safety resistors are not rated for enough dissipation to deal with
a dead short for too long, although they are usually overrated enough that
occasional momentary shorts won't kill them.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Richard Crowley]

"Meindert Sprang" wrote ...

Ok, I do know what the hell I'm talking about, because I design an
build
electronic equipment. albeit digital equipment, the problem is the
same: I
have a balanced output which in many cases is shorted to ground
because some
installer doesn't grasp the difference between balanced and single
ended
outputs. So I therefore design all balanced outputs to be
short-circuit
proof. That's why I think I have 'the right' to claim it a design flaw
when
some equipment cannot stand grouding of one or both balanced output
terminals.

Go ahead and do whatever you want.
Apparently Mr. Sprang is offering to fix it
if anything breaks. Riiiiiight.

[Meindert Sprang]

"Mike Rivers" wrote in message
oups.com...
If I was selling 1,000 mixers a month, I'd take the chance and save the
couple of cents on the resistor.

Seriously, you don't. If you sell 1000 mixers a month, these extra resistors
would cost you maybe 10 cents per mixer, so you'd save $100 a month. Two
warranty repairs would consume that profit.

You can always tell the customer that he shouldn't have done that.

That doesn't work. The customer is always right. If a plug fits into a
socket, it should not damage his equipment. That's how customers think.

And besides, most people don't actually send this stuff back for repair
because it's too cheap.

Not in my experience. The devices I sell start at $150 and they are sent
back when broken.

Depends. The older Behringer mixers for example, had a single ended
output
and a resistor to ground on the ring. But the newer ones (UB series)
have
true balanced outputs, delivering a voltage on both + and - lines. I
checked
that.

And how did they do that? If they used an inverter to get the - side,
that can be shorted out. And even if it doesn't fry, it can cause
distortion in the + side.

Why? If the inverter is protected with a resistor, it will just drive more
current into that resistor. The isolation from an op-amps' output to input
is huge.

Really? You must know the famous trick of inserting a TRS first click
into a
mixer insert socket. It works because the tip shorts both hot contacts
of
the socket.

Nope.

But first off, I was talking about a headphone jack (by which I meant a
jack fed from a headphone outpu, not a generic jack. I can see where a
digital designer can make that mistake. When all you have is on and
off, you don't need to worry about what's generating the voltage.

An insert jack has one output and one input, and normalling contacts
that connect the output to the input so the signal will flow through
the channel path. When you insert the plug all the way, you break that
normal connection. If you don't connect something to the insert input
(return) you don't hear whatever went into the channel input.

When you put the plug in halfway, it doesn't go in far enough to open
the normalling contacts, so, yes, the tip and ring contacts of the jack
are indeed "shorted" together, which is their normal state. The tip of
the plug actually connects to the ring contact of the jack, but since
there's signal on it, you can tap it off.

Indeed. I was pretty wrong there.... have to think before typing.....

The same happens if you insert a stereo headphone jack into the
heaphone output: left and right get shorted together. No damage done.

Want to try that one again? If you insert a stereo headphone PLUG into
a stereo headphone JACK (output) you'll connect the left headphone to
one output and the right hedphone to the other output. No damage done,
because that's the way you're supposed to connect it.

I always understood that inserting whatever jack into whatever socket (TRS
or TS), there's always a moment where contacts get shorted. but I never
actually measured that.

You don't see to understand that there's a difference between damage to
equipment and something not working right. because the user didn't hook
it up right.

Now, don't tell me that even professionals never hook something up wrong in
the heat of the moment and in tons of cables......

Meindert

[WillStG]

Meindert Sprang wrote:
"WillStG" wrote in message
oups.com...
And if the gear is no longer covered by warrantee? What then?

One should then try that before the warranty expires.

And again if it fails Sir, will YOU fix the gear for the man at
your own expense because he followed your operating advice? Will you
supply a replacement for his gear when it fails during a session with a
paying client? There is a much larger world out there where apparently
you have had little responsibility for, a world in which "the show must
go on..." is more than a slogan.

Ok, I do know what the hell I'm talking about, because I design an build
electronic equipment. albeit digital equipment, the problem is the same: I
have a balanced output which in many cases is shorted to ground because some
installer doesn't grasp the difference between balanced and single ended
outputs. So I therefore design all balanced outputs to be short-circuit
proof. That's why I think I have 'the right' to claim it a design flaw when
some equipment cannot stand grouding of one or both balanced output
terminals.


Your arrogance is self serving. If you give bad advice and gear
fails, it just shows your superiority as a designer, huh? But other
guys have to deal with the mess that's left behind, and that's the
actual audio operators, maintanance and installation engineers.

And I know that most modern mixers and other audio equipment is indeed short
circuit proof on the line outputs. I can read the schematics.....

Meindert
www.shipmodul.com
www.customware.nl

And you have no way of knowing whether the gear the original
poster was asking about was "modern", by your standards, or not. He may
own a large format late 80's mixing console for example. I know for a
fact from personal experience that that if you short stereo phone
outputs to ground on many of these, they start to sputter and will
fail. He may have been asking about a stereo jack on a studio
headphone box, driven by a power amp. You advice could well blow the
studio power amps, depending on the amps. This could cause downtime
during a tracking session - do YOU want to cover that cost for the
studio owner, for following your advice?

And you have no way of knowing if the manufacturer of his gear, even
if new, would accept responsibility for their gear having a "design
flaw" just because *you* said it was so. What you call bad design was
once pretty typical. Again, real woprld experience, in the 80's my
brother had to continually replace the transistors on the Phase Linear
amps that drove our band's monitors, because they got pulled during a
tear down while the amps were still hot, or the banana plugs got kicked
out during a show, which only shorted the amps to ground for an
instant.

What is obvious is you have never had to be responsible for other
people's property - or if you have, you are not very good at it or are
just not a very careful person. As a designer, this is "design flaw"
of your very own, to be theoretical and callous about the real world
impact this could have on other people.

Come down off your Ivory tower Dude.

Will Miho
NY TV/Audio Post/Music/Live Sound Guy
"The large print giveth and the small print taketh away..." Tom Waits

[WillStG]

WillStG wrote:
in the 80's my
brother had to continually replace the transistors on the Phase Linear
amps that drove our band's monitors, because they got pulled during a
tear down while the amps were still hot, or the banana plugs got kicked
out during a show, which only shorted the amps to ground for an
instant.

I meant 1/4' jacks of course. Bananas are easier to kick, but
don't short out when inserted or pulled out like 1/4" jacks do.
That's why they make Neutriks...

Will

[Laurence Payne]

On Wed, 29 Nov 2006 09:14:58 +0100, "Meindert Sprang"
wrote:

You can always tell the customer that he shouldn't have done that.

That doesn't work. The customer is always right. If a plug fits into a
socket, it should not damage his equipment. That's how customers think.

Indeed. I lent a small PA to a musician friend once. The mic inputs
were 1/4" jacks. So were the speaker outputs. (This used to be
common practice, oh Best Beloved.)

Yes, they tried to pump 100 watts through a SM58.

[William Sommerwerck]

Over 20 years ago, I reviewed a bunch of headphones for Stereophile. Because
headphones were (and still are) commonly used with portable equipment, I
auditioned them on a Sony Discman as well.

Why? Well, the schematics of a lot of portable electronics of that era
showed a resistor -- from 10 to 100 ohms -- at the output of the driver
chip. (The resistance would convert variations in headphone impedance into
variations in headphone respone.) The designer must have been worried about
the output being shorted, either because "too much" current for an extended
period, or even a brief short, would damage the chip. I can't think of any
other plausible reason.

[William Sommerwerck]

I lent a small PA to a musician friend once. The mic inputs
were 1/4" jacks. So were the speaker outputs.

Yes, they tried to pump 100 watts through a SM58.

Did he ask you to replace the mic because your amp damaged it?

[Meindert Sprang]

"Laurence Payne" lpayne1NOSPAM@dslDOTpipexDOTcom wrote in message
...
On Wed, 29 Nov 2006 09:14:58 +0100, "Meindert Sprang"
wrote:

You can always tell the customer that he shouldn't have done that.

That doesn't work. The customer is always right. If a plug fits into a
socket, it should not damage his equipment. That's how customers think.

Indeed. I lent a small PA to a musician friend once. The mic inputs
were 1/4" jacks. So were the speaker outputs. (This used to be
common practice, oh Best Beloved.)

Yes, they tried to pump 100 watts through a SM58.

"Smoke gets in your eyes...."

Meindert

[Meindert Sprang]

"WillStG" wrote in message
oups.com...
And again if it fails Sir, will YOU fix the gear for the man at
your own expense because he followed your operating advice? Will you
supply a replacement for his gear when it fails during a session with a
paying client?

Yeah yeah, next time your're gonna take me to court because what I said,
right?

Meindert

[Meindert Sprang]

"William Sommerwerck" wrote in message
. ..
Over 20 years ago, I reviewed a bunch of headphones for Stereophile.
Because
headphones were (and still are) commonly used with portable equipment, I
auditioned them on a Sony Discman as well.

Why? Well, the schematics of a lot of portable electronics of that era
showed a resistor -- from 10 to 100 ohms -- at the output of the driver
chip. (The resistance would convert variations in headphone impedance into
variations in headphone respone.) The designer must have been worried
about
the output being shorted, either because "too much" current for an
extended
period, or even a brief short, would damage the chip. I can't think of any
other plausible reason.

That's exactly the reason why this resistor is there.

Meindert

[Laurence Payne]

On Wed, 29 Nov 2006 03:11:13 -0800, "William Sommerwerck"
wrote:

I lent a small PA to a musician friend once. The mic inputs
were 1/4" jacks. So were the speaker outputs.

Yes, they tried to pump 100 watts through a SM58.

Did he ask you to replace the mic because your amp damaged it?

No. But I required HIM to replace the microphone because his
stupidity had damaged it. I'd given full instructions. No
wriggle-room :-)

[Mike Rivers]

Meindert Sprang wrote:

If you sell 1000 mixers a month, these extra resistors
would cost you maybe 10 cents per mixer, so you'd save $100 a month. Two
warranty repairs would consume that profit.

Unfortunately that's not really the way it works. The mixer isn't a
dime more expensive to the customer. And if it's $50 more expensive
(perhaps a more realistic figure), in a competitive market, they'll
lose a few dozen sales. That costs more than a warranty repair.

The devices I sell start at $150 and they are sent
back when broken.

Perhaps you design them to be repaired. Have you tried repairing a $150
Behringer mixer? And are your $150 devices as complex? Let's compare
apples to apples, not an unnamed digital device compared to a cheap
mixer.

If the inverter is protected with a resistor, it will just drive more
current into that resistor. The isolation from an op-amps' output to input
is huge.

Remember that an op-amp inverter has the output connected to the input,
usually through a 50 ohm resistor if they're not too cheap. Since the
input of the "low" op amp is tied directly to the input of the "high"
op amp, which is fed from something else, the shorted output is putting
a 50 ohm load across whatever is feeding the output stage. Again, not
likely to go up in flames, but quite likely to reduce the available
headroom, which leads to distortion.

I always understood that inserting whatever jack into whatever socket (TRS
or TS), there's always a moment where contacts get shorted. but I never
actually measured that.

The tip of the plug can contact the sleeve of the jack (and PLEASE -
the jack is the think with the hole in it, the plug is the thing that
goes into the hole) on the way in. It can also contact the sleeve. But
unless you stop and contemplate what you're doing, this "short" is
momentary and rarely does damage. And since you probably aren't going
to be listening to the audio during the brief time during which you're
inserting the plug, you probably won't notice distortion or a brief
mute.

One place where there has been trouble is when people use a TRS
patchbay for patching microphones, and have phantom power switched on.
Shorting out one side of a phantom powered input (like when the tip of
the plug momentarily touches the sleeve on the way in to the jack) can
put the full 48V on to one side of the mic input. ICs don't like that
and there were a few popular mixers that had their front end blown out
as a result of "hot plugging" mic inputs.

There's a pretty standard circuit that came out of that experience that
clamps the inputs with a pair of diodes and just about everyone does
that now. It's an example of where it's worth spending an extra dime a
channel - not to avoid making warranty repairs, but to improve the
reliability of the equipment. But this is a special case where there's
a pretty good chance of component damage rather than increased
distortion.

Now, don't tell me that even professionals never hook something up wrong in
the heat of the moment and in tons of cables......

Sure. But they don't buy equipment that breaks when it's hooked up
wrong. People hook S/PDIF outputs to phono inputs and blow out their
speakers, too. Whose problem is that?