[nospam[_2_]]

Hello,

We recently had a heat wave on the East coast starting on Saturday. That
same day I turned on my home recording computer system and had a nasty hum.

I ripped apart the system and isolated the hum between the power amp and the
speakers. I have a Hafler TA1600 power amp. If I plugged one speaker into
the amp with no input signal, the hum was there.

I've been reading up on ground loops and such - but they all talk about
mismatched ground across electrical components. Can I have a ground loop
between an amp and "just" speakers"?

Does humidity in the air cause hum somehow? Can I get fancy speakers to
eliminate this? Or maybe my speaker wire shielding is bad?

The heat wave broke last night - humidity is back to normal for NJ. And the
hum is gone....

Thanks in advance,
bruce

[Don Pearce]

nospam wrote:
Hello,

We recently had a heat wave on the East coast starting on Saturday. That
same day I turned on my home recording computer system and had a nasty hum.

I ripped apart the system and isolated the hum between the power amp and the
speakers. I have a Hafler TA1600 power amp. If I plugged one speaker into
the amp with no input signal, the hum was there.

I've been reading up on ground loops and such - but they all talk about
mismatched ground across electrical components. Can I have a ground loop
between an amp and "just" speakers"?

Does humidity in the air cause hum somehow? Can I get fancy speakers to
eliminate this? Or maybe my speaker wire shielding is bad?

The heat wave broke last night - humidity is back to normal for NJ. And the
hum is gone....

Thanks in advance,
bruce



Probably the mains got upset by some huge and abnormal load it
encountered during the heat wave - air conditioners flat out or
something. Still, this would not normally be expected to affect an
amplifier, which should cope perfectly well.

Just to be sure, did you disconnect all the inputs from the amp - just
switching them off doesn't stop ground loops.

As for speaker wire it isn't shielded, and doesn't need to be.

d

[Scott Dorsey]

In article TOQ3k.583$ul.221@trndny08, nospam wrote:

We recently had a heat wave on the East coast starting on Saturday. That
same day I turned on my home recording computer system and had a nasty hum.

I ripped apart the system and isolated the hum between the power amp and the
speakers. I have a Hafler TA1600 power amp. If I plugged one speaker into
the amp with no input signal, the hum was there.

I've been reading up on ground loops and such - but they all talk about
mismatched ground across electrical components. Can I have a ground loop
between an amp and "just" speakers"?

No, because the speakers are not grounded. A ground loop is when there are
multiple ground paths from any given piece of equipment.

Does humidity in the air cause hum somehow? Can I get fancy speakers to
eliminate this? Or maybe my speaker wire shielding is bad?

No, you had a power supply capacitor fail in the Hafler. Get it fixed.
Or else you have an internal ground connection that has come loose.

The heat wave broke last night - humidity is back to normal for NJ. And the
hum is gone....

It'll be back.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Richard Crowley]

Bruce wrote ...
We recently had a heat wave on the East coast starting on Saturday.

Meanwhile, here on the west coast (at least where I am in southern
Oregon) we are unusually cold. We've been burning wood in the stove
to keep the house warm at night (and several days, as well).

That same day I turned on my home recording computer system and had a
nasty hum.

I ripped apart the system and isolated the hum between the power amp and
the speakers. I have a Hafler TA1600 power amp. If I plugged one speaker
into the amp with no input signal, the hum was there.

I've been reading up on ground loops and such - but they all talk about
mismatched ground across electrical components. Can I have a ground loop
between an amp and "just" speakers"?

If NOTHING was connected to the amp but the power cord
and the speaker(s), then you should have no ground loop(s).
This is assuming that you don't have your speaker wires
grounded anywhere (accidentally?)

Does humidity in the air cause hum somehow?

Not as you are describing.

Can I get fancy speakers to eliminate this?

No. Speakers only reproduce what the amp is putting out.

Or maybe my speaker wire shielding is bad?

Speaker wires do not require shielding unless you have an
unusually severe RFI problem.

The heat wave broke last night - humidity is back to normal for NJ. And
the hum is gone....

I would strongly suspect that something went wonky with your
power then. Most equipment doesn't like operating properly
when the power is much lower (or higher) than the nominal
mains voltage (120V in North America).

If the power is doing things that crazy, I would be concerned
about my electronic equipment. I would at least be monitoring
the power mains voltage to be sure I wasn't frying my stuff.

If the hum *had not* gone away, I would have suspected
the combined effects of age and extra heat to have dried out
one or more of the electrolytic capacitors in the amp.

[GregS[_3_]]

In article TOQ3k.583$ul.221@trndny08, "nospam" wrote:
Hello,

We recently had a heat wave on the East coast starting on Saturday. That
same day I turned on my home recording computer system and had a nasty hum.

I ripped apart the system and isolated the hum between the power amp and the
speakers. I have a Hafler TA1600 power amp. If I plugged one speaker into
the amp with no input signal, the hum was there.

I've been reading up on ground loops and such - but they all talk about
mismatched ground across electrical components. Can I have a ground loop
between an amp and "just" speakers"?

Does humidity in the air cause hum somehow? Can I get fancy speakers to
eliminate this? Or maybe my speaker wire shielding is bad?

The heat wave broke last night - humidity is back to normal for NJ. And the
hum is gone....

Thanks in advance,
bruce

You didn't specify exactly what you did. Were the inputs removed completly or just
shut off. You could try headphones or a local speaker. Does the amp have a ground
plug ? A speaker is sorta ground or the ground at its working position which may be different than
the amp ground. Most electrical components are isolated from a wood cabinet, but you never know.
Its not likely electrostatic noise can affect a speaker, but currents
through the signal chain can cause current noise.

greg

[nospam[_2_]]

"Don Pearce" wrote in message
et...
nospam wrote:
Hello,

We recently had a heat wave on the East coast starting on Saturday. That
same day I turned on my home recording computer system and had a nasty
hum.

I ripped apart the system and isolated the hum between the power amp and
the speakers. I have a Hafler TA1600 power amp. If I plugged one
speaker into the amp with no input signal, the hum was there.

I've been reading up on ground loops and such - but they all talk about
mismatched ground across electrical components. Can I have a ground loop
between an amp and "just" speakers"?

Does humidity in the air cause hum somehow? Can I get fancy speakers to
eliminate this? Or maybe my speaker wire shielding is bad?

The heat wave broke last night - humidity is back to normal for NJ. And
the hum is gone....

Thanks in advance,
bruce



Probably the mains got upset by some huge and abnormal load it encountered
during the heat wave - air conditioners flat out or something. Still, this
would not normally be expected to affect an amplifier, which should cope
perfectly well.

Just to be sure, did you disconnect all the inputs from the amp - just
switching them off doesn't stop ground loops.

As for speaker wire it isn't shielded, and doesn't need to be.

d

I disconnected everything - mixer, computer, amp.

I moved the Hafler amp to another room with 1 speaker attached and there was
still hum. There was not any input into the amp.

I read that humidity can cause resistance in ground and then thought. most
studios are usually pretty cool in the control room. So, I was thinking
that the humidity somehow resulted in this.

Thanks.

[Don Pearce]

nospam wrote:
"Don Pearce" wrote in message
et...
nospam wrote:
Hello,

We recently had a heat wave on the East coast starting on Saturday. That
same day I turned on my home recording computer system and had a nasty
hum.

I ripped apart the system and isolated the hum between the power amp and
the speakers. I have a Hafler TA1600 power amp. If I plugged one
speaker into the amp with no input signal, the hum was there.

I've been reading up on ground loops and such - but they all talk about
mismatched ground across electrical components. Can I have a ground loop
between an amp and "just" speakers"?

Does humidity in the air cause hum somehow? Can I get fancy speakers to
eliminate this? Or maybe my speaker wire shielding is bad?

The heat wave broke last night - humidity is back to normal for NJ. And
the hum is gone....

Thanks in advance,
bruce


Probably the mains got upset by some huge and abnormal load it encountered
during the heat wave - air conditioners flat out or something. Still, this
would not normally be expected to affect an amplifier, which should cope
perfectly well.

Just to be sure, did you disconnect all the inputs from the amp - just
switching them off doesn't stop ground loops.

As for speaker wire it isn't shielded, and doesn't need to be.

d

I disconnected everything - mixer, computer, amp.

I moved the Hafler amp to another room with 1 speaker attached and there was
still hum. There was not any input into the amp.

I read that humidity can cause resistance in ground and then thought. most
studios are usually pretty cool in the control room. So, I was thinking
that the humidity somehow resulted in this.

Thanks.


OK - that just shouldn't happen. The amplifier has some sort of problem
that is maybe made worse by humidity. It is certainly on its way out
though, and I would recommend you replace it.

d

[Mark]

On Jun 11, 11:35*am, Don Pearce wrote:
nospam wrote:
"Don Pearce" wrote in message
net...
nospam wrote:
Hello,

We recently had a heat wave on the East coast starting on Saturday. *That
same day I turned on my home recording computer system and had a nasty
hum.

I ripped apart the system and isolated the hum between the power amp and
the speakers. *I have a Hafler TA1600 power amp. *If I plugged one
speaker into the amp with no input signal, *the hum was there.

I've been reading up on ground loops and such - but they all talk about
mismatched ground across electrical components. *Can I have a ground loop
between an amp and "just" speakers"?

Does humidity in the air cause hum somehow? * Can I get fancy speakers to
eliminate this? *Or maybe my speaker wire shielding is bad?

The heat wave broke last night - humidity is back to normal for NJ. *And
the hum is gone....

Thanks in advance,
bruce

Probably the mains got upset by some huge and abnormal load it encountered
during the heat wave - air conditioners flat out or something. Still, this
would not normally be expected to affect an amplifier, which should cope
perfectly well.

Just to be sure, did you disconnect all the inputs from the amp - just
switching them off doesn't stop ground loops.

As for speaker wire it isn't shielded, and doesn't need to be.

d

I disconnected everything - mixer, computer, amp.

I moved the Hafler amp to another room with 1 speaker attached and there was
still hum. There was not any input into the amp.

I read that humidity can cause resistance in ground and then thought. most
studios are usually pretty cool in the control room. *So, I was thinking
that the humidity somehow resulted in this.

Thanks.

OK - that just shouldn't happen. The amplifier has some sort of problem
that is maybe made worse by humidity. It is certainly on its way out
though, and I would recommend you replace it.

d- Hide quoted text -

- Show quoted text -


low line voltage can cause hum in an amp with marginal power supply
regulation..

running lots of air conditioners can cause low line voltage

Mark

[jakdedert]

nospam wrote:
Hello,

We recently had a heat wave on the East coast starting on Saturday. That
same day I turned on my home recording computer system and had a nasty hum.

I ripped apart the system and isolated the hum between the power amp and the
speakers. I have a Hafler TA1600 power amp. If I plugged one speaker into
the amp with no input signal, the hum was there.

I've been reading up on ground loops and such - but they all talk about
mismatched ground across electrical components. Can I have a ground loop
between an amp and "just" speakers"?

Does humidity in the air cause hum somehow? Can I get fancy speakers to
eliminate this? Or maybe my speaker wire shielding is bad?

The heat wave broke last night - humidity is back to normal for NJ. And the
hum is gone....

Thanks in advance,
bruce


You've either, like Scott says, have a filter cap going out; or (I think
more likely), have something in the amp which is corroding. The excess
heat/humidity caused a temporary bridge between two things which should
not be connected...or caused something which should be connected to
become intermittent.

Check for dust or other contamination in the amp which could become
slightly conductive when moist. Clean all that out (if present) with a
vacuum or blower. Then check every mounting screw, especially ones
which hold down circuit boards. Finally clean every control/switch with
a good contact cleaner. Most people swear by Caig products. Expensive,
but worth it.

If it never comes back, it was one of the above. If it does, a clean
'operating field' will make further dx easier.

jak

[Eric B]

Quite likely if you checked your lines voltage you were under going a
brown-out.
Eric B

[Paul Stamler]

"Mark" wrote in message
...

I moved the Hafler amp to another room with 1 speaker attached and there
was
still hum. There was not any input into the amp.

I read that humidity can cause resistance in ground and then thought.
most
studios are usually pretty cool in the control room. So, I was thinking
that the humidity somehow resulted in this.

Thanks.

OK - that just shouldn't happen. The amplifier has some sort of problem
that is maybe made worse by humidity. It is certainly on its way out
though, and I would recommend you replace it.


low line voltage can cause hum in an amp with marginal power supply
regulation..

running lots of air conditioners can cause low line voltage

And that's usually the cause of hum during heat waves: the line voltage goes
low, the unregulated DC voltage drops, and there's no longer enough voltage
across the regulator for it to regulate properly.

This usually happens in equipment handling low-level signals, though, not
power amps. Most power amps have unregulated supplies, so the only result of
low line voltage is less output before it clips.

Some power amplifiers, though, have a regulator for the input sections. Does
the Hafler? If so, that'd explain the problem. And it would indicate that
the amp isn't broken, just not designed for extreme low-line conditions.

Peace,
Paul