Between replacing a cooling fan and moving into a place that
demanded a whole lot of other work, my audio system has been MIA
for many months. Thanks to the storm, between yesterday and today
I finally found the time to track down all the pieces and wire all
the pieces (amp, preamp, tuner, turntable and CD player) together.

I turned on Ampzilla first and promptly heard what I presume was a
ground hum. I turned Ampzilla off. My first thought was to rule
out any connection to any other link in the chain as the culprit.
I disconnected the preamp (Thaedra) from the amp, unplugged
everything else, and plugged 'zilla straight into the wall, then
turned it on again. The hum returned, accompanied by a couple of
fairly loud pops from the left channel speaker.

The system worked fine in the previous apartment, but for an
annoyance with the old cooling fan. After seeking some newsgroup
advice, I found a Papst fan to replace it, but did not find the
time to try the system with the new fan in the old location.

In short, it worked, I replaced the fan, I moved, and now it hums.

At the risk of sounding like some sort of electronics school exam:
How many possible hum sources are there in the above scenario, and
what can I do to troubleshoot them and/or rule some out?

Thanks in advance,
Phil

In article , Phil Anderson
wrote:

In short, it worked, I replaced the fan, I moved, and now it hums.

At the risk of sounding like some sort of electronics school exam:
How many possible hum sources are there in the above scenario, and
what can I do to troubleshoot them and/or rule some out?

It would be nice to rule the fan in or out right away. You can
probably run the amp for a short period of time without it. How
about disconnecting the fan, both wires, and see what happens.
If it still hums, then it wasn't the fan, and you likely have a
power or grounding issue.

-john-

--
================================================== ==================
John A. Weeks III 952-432-2708
Newave Communications http://www.johnweeks.com
================================================== ==================

Occasionally wire routing might induce hum, but this doesn't explain the
pops. I'm thinking the amp has an actual problem, such as a intermediate
level dc offset on that left channel.

Mark Z.



--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Phil Anderson" wrote in message
...
Between replacing a cooling fan and moving into a place that
demanded a whole lot of other work, my audio system has been MIA
for many months. Thanks to the storm, between yesterday and today
I finally found the time to track down all the pieces and wire all
the pieces (amp, preamp, tuner, turntable and CD player) together.

I turned on Ampzilla first and promptly heard what I presume was a
ground hum. I turned Ampzilla off. My first thought was to rule
out any connection to any other link in the chain as the culprit.
I disconnected the preamp (Thaedra) from the amp, unplugged
everything else, and plugged 'zilla straight into the wall, then
turned it on again. The hum returned, accompanied by a couple of
fairly loud pops from the left channel speaker.

The system worked fine in the previous apartment, but for an
annoyance with the old cooling fan. After seeking some newsgroup
advice, I found a Papst fan to replace it, but did not find the
time to try the system with the new fan in the old location.

In short, it worked, I replaced the fan, I moved, and now it hums.

At the risk of sounding like some sort of electronics school exam:
How many possible hum sources are there in the above scenario, and
what can I do to troubleshoot them and/or rule some out?

Thanks in advance,
Phil

P.S.

Does it hum on both channels?

mz

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Phil Anderson" wrote in message
...
Between replacing a cooling fan and moving into a place that
demanded a whole lot of other work, my audio system has been MIA
for many months. Thanks to the storm, between yesterday and today
I finally found the time to track down all the pieces and wire all
the pieces (amp, preamp, tuner, turntable and CD player) together.

I turned on Ampzilla first and promptly heard what I presume was a
ground hum. I turned Ampzilla off. My first thought was to rule
out any connection to any other link in the chain as the culprit.
I disconnected the preamp (Thaedra) from the amp, unplugged
everything else, and plugged 'zilla straight into the wall, then
turned it on again. The hum returned, accompanied by a couple of
fairly loud pops from the left channel speaker.

The system worked fine in the previous apartment, but for an
annoyance with the old cooling fan. After seeking some newsgroup
advice, I found a Papst fan to replace it, but did not find the
time to try the system with the new fan in the old location.

In short, it worked, I replaced the fan, I moved, and now it hums.

At the risk of sounding like some sort of electronics school exam:
How many possible hum sources are there in the above scenario, and
what can I do to troubleshoot them and/or rule some out?

Thanks in advance,
Phil

"John A. Weeks III" wrote in message
...
In article , Phil Anderson
wrote:

In short, it worked, I replaced the fan, I moved, and now it
hums.

At the risk of sounding like some sort of electronics school
exam:
How many possible hum sources are there in the above scenario,
and
what can I do to troubleshoot them and/or rule some out?

It would be nice to rule the fan in or out right away. You can
probably run the amp for a short period of time without it. How
about disconnecting the fan, both wires, and see what happens.
If it still hums, then it wasn't the fan, and you likely have a
power or grounding issue.

-john-

The amp will run for quite a while without the fan. I will try to
open it up tomorrow night and report back to the group. Thanks
for an excellent suggestion.

Phil

This turns out to be a little weirder than I thought. When I
heard the hum last night, it never occurred to me it might be from
one channel only. I figured this was a ground hum, and such
things always occur in both channels, do they not? The pop came
from the left channel, that I was sure of, but nothing more.

So, I turned it on again tonight, with a listener staged by the
right channel. She heard nothing. I heard another pop from the
left channel. I moved over to that speaker, and heard only a very
slight hiss. The hum is coming from the amp itself!

I am far from expert in any of this, but I've got to admit this
worries me a lot more than did the thought I had a ground hum to
diagnose. Also, my power meter lights no longer work. I am
certain that they worked in the old apartment, all those months
ago. I do not recall if they worked last night or not. I turned
it off pretty quick and do not recall noticing.

What is my next step?

Phil

"Mark D. Zacharias" wrote in message
...
P.S.

Does it hum on both channels?

mz

--
Please reply only to Group. I regret this is necessary. Viruses
and spam
have rendered my regular e-mail address useless.


"Phil Anderson" wrote in message
...
Between replacing a cooling fan and moving into a place that
demanded a whole lot of other work, my audio system has been
MIA
for many months. Thanks to the storm, between yesterday and
today
I finally found the time to track down all the pieces and wire
all
the pieces (amp, preamp, tuner, turntable and CD player)
together.

I turned on Ampzilla first and promptly heard what I presume
was a
ground hum. I turned Ampzilla off. My first thought was to
rule
out any connection to any other link in the chain as the
culprit.
I disconnected the preamp (Thaedra) from the amp, unplugged
everything else, and plugged 'zilla straight into the wall,
then
turned it on again. The hum returned, accompanied by a couple
of
fairly loud pops from the left channel speaker.

The system worked fine in the previous apartment, but for an
annoyance with the old cooling fan. After seeking some
newsgroup
advice, I found a Papst fan to replace it, but did not find
the
time to try the system with the new fan in the old location.

In short, it worked, I replaced the fan, I moved, and now it
hums.

At the risk of sounding like some sort of electronics school
exam:
How many possible hum sources are there in the above scenario,
and
what can I do to troubleshoot them and/or rule some out?

Thanks in advance,
Phil

"John A. Weeks III" wrote in message
...
In article , Phil Anderson
wrote:

In short, it worked, I replaced the fan, I moved, and now it
hums.

At the risk of sounding like some sort of electronics school
exam:
How many possible hum sources are there in the above scenario,
and
what can I do to troubleshoot them and/or rule some out?

It would be nice to rule the fan in or out right away. You can
probably run the amp for a short period of time without it. How
about disconnecting the fan, both wires, and see what happens.
If it still hums, then it wasn't the fan, and you likely have a
power or grounding issue.

Some followup before I disconnect the fan tomorrow night. Mark
Zacharias asked if the hum was in one or both channels. After
turning it back on to check, I wrote the following to him, and
wonder if it changes your fan suggestion at all:
quote:
This turns out to be a little weirder than I thought. When I
heard the hum last night, it never occurred to me it might be from
one channel only. I figured this was a ground hum, and such
things always occur in both channels, do they not? The pop came
from the left channel, that I was sure of, but nothing more.

So, I turned it on again tonight, with a listener staged by the
right channel. She heard nothing. I heard another pop from the
left channel. I moved over to that speaker, and heard only a very
slight hiss. The hum is coming from the amp itself!

I am far from expert in any of this, but I've got to admit this
worries me a lot more than did the thought I had a ground hum to
diagnose. Also, my power meter lights no longer work. I am
certain that they worked in the old apartment, all those months
ago. I do not recall if they worked last night or not. I turned
it off pretty quick and do not recall noticing.

What is my next step?
end quote

Phil

In article ,
"Phil Anderson" wrote:

This turns out to be a little weirder than I thought. When I
heard the hum last night, it never occurred to me it might be from
one channel only. I figured this was a ground hum, and such
things always occur in both channels, do they not? The pop came
from the left channel, that I was sure of, but nothing more.

So, I turned it on again tonight, with a listener staged by the
right channel. She heard nothing. I heard another pop from the
left channel. I moved over to that speaker, and heard only a very
slight hiss. The hum is coming from the amp itself!

I am far from expert in any of this, but I've got to admit this
worries me a lot more than did the thought I had a ground hum to
diagnose. Also, my power meter lights no longer work. I am
certain that they worked in the old apartment, all those months
ago. I do not recall if they worked last night or not. I turned
it off pretty quick and do not recall noticing.

What is my next step?

Phil


The pops could be a bad electrolytic capacitor or solder joint. As for
the hum, you probably caused that during repairs. Find the vibrating
panel and crease it, or check that the fan is mounted the right way.

Hi, Phil.

I'm still not sure from your response whether the hum is coming from one or
both speakers, or a mechanical noise from the amp chassis itself.
If it's a mechanical noise, one can use a listening instrument such as a
medium length screwdriver, and physically touch it to a part of the chassis
while holding the handle to your ear. Works like a stethoscope, and I find
this useful to help isolate mech noises.

To be truthful I'm not very familiar with the larger 'Zilla, but I'm pretty
sure I have a schematic somewhere.

It's not uncommon for lamps to fail after a piece is moved from one location
to another. The old filament is often very weak from age and the slightest
vibration is all it takes for it to die.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"Phil Anderson" wrote in message
...

"John A. Weeks III" wrote in message
...
In article , Phil Anderson
wrote:

In short, it worked, I replaced the fan, I moved, and now it
hums.

At the risk of sounding like some sort of electronics school
exam:
How many possible hum sources are there in the above scenario,
and
what can I do to troubleshoot them and/or rule some out?

It would be nice to rule the fan in or out right away. You can
probably run the amp for a short period of time without it. How
about disconnecting the fan, both wires, and see what happens.
If it still hums, then it wasn't the fan, and you likely have a
power or grounding issue.

Some followup before I disconnect the fan tomorrow night. Mark
Zacharias asked if the hum was in one or both channels. After
turning it back on to check, I wrote the following to him, and
wonder if it changes your fan suggestion at all:
quote:
This turns out to be a little weirder than I thought. When I
heard the hum last night, it never occurred to me it might be from
one channel only. I figured this was a ground hum, and such
things always occur in both channels, do they not? The pop came
from the left channel, that I was sure of, but nothing more.

So, I turned it on again tonight, with a listener staged by the
right channel. She heard nothing. I heard another pop from the
left channel. I moved over to that speaker, and heard only a very
slight hiss. The hum is coming from the amp itself!

I am far from expert in any of this, but I've got to admit this
worries me a lot more than did the thought I had a ground hum to
diagnose. Also, my power meter lights no longer work. I am
certain that they worked in the old apartment, all those months
ago. I do not recall if they worked last night or not. I turned
it off pretty quick and do not recall noticing.

What is my next step?
end quote

Phil

"Mark D. Zacharias" wrote in message
...
Hi, Phil.

I'm still not sure from your response whether the hum is coming
from one or
both speakers, or a mechanical noise from the amp chassis
itself.
If it's a mechanical noise, one can use a listening instrument
such as a
medium length screwdriver, and physically touch it to a part of
the chassis
while holding the handle to your ear. Works like a stethoscope,
and I find
this useful to help isolate mech noises.

I am sorry if I was unclear. The hum is from the amp itself.
Also, the meter lamps have stopped working.

"Phil Anderson" wrote in message

"Mark D. Zacharias" wrote in message
...

Hi, Phil.

I'm still not sure from your response whether the hum is coming from
one or both speakers, or a mechanical noise from the amp chassis
itself. If it's a mechanical noise, one can use a listening
instrument such as a medium length screwdriver, and physically touch
it to a part of the chassis while holding the handle to your ear.
Works like a stethoscope, and I find this useful to help isolate
mech noises.

I am sorry if I was unclear. The hum is from the amp itself.
Also, the meter lamps have stopped working.

You moved your abode, which means that the amp was shipped. Both of these
symptoms could be the result of severe shock, which is of course common when
things are shipped.

The hum could be due to something getting a little loose, mechanically. The
bulbs may have failed because their filaments were damaged by extreme shock.

I would also check the plug-in transistors at the input stage of the left
channel card. One or more of them might have come loose (there are four of
them).

Pete

"Kevin McMurtrie" wrote in message
...
In article ,
"Phil Anderson" wrote:

This turns out to be a little weirder than I thought. When I
heard the hum last night, it never occurred to me it might be from
one channel only. I figured this was a ground hum, and such
things always occur in both channels, do they not? The pop came
from the left channel, that I was sure of, but nothing more.

So, I turned it on again tonight, with a listener staged by the
right channel. She heard nothing. I heard another pop from the
left channel. I moved over to that speaker, and heard only a very
slight hiss. The hum is coming from the amp itself!

I am far from expert in any of this, but I've got to admit this
worries me a lot more than did the thought I had a ground hum to
diagnose. Also, my power meter lights no longer work. I am
certain that they worked in the old apartment, all those months
ago. I do not recall if they worked last night or not. I turned
it off pretty quick and do not recall noticing.

What is my next step?

Phil


The pops could be a bad electrolytic capacitor or solder joint. As for
the hum, you probably caused that during repairs. Find the vibrating
panel and crease it, or check that the fan is mounted the right way.

"Phil Anderson" wrote in message
...
Between replacing a cooling fan and moving into a place that
demanded a whole lot of other work, my audio system has been MIA
for many months. Thanks to the storm, between yesterday and today
I finally found the time to track down all the pieces and wire all
the pieces (amp, preamp, tuner, turntable and CD player) together.

I turned on Ampzilla first and promptly heard what I presume was a
ground hum. I turned Ampzilla off. My first thought was to rule
out any connection to any other link in the chain as the culprit.
I disconnected the preamp (Thaedra) from the amp, unplugged
everything else, and plugged 'zilla straight into the wall, then
turned it on again. The hum returned, accompanied by a couple of
fairly loud pops from the left channel speaker.

The system worked fine in the previous apartment, but for an
annoyance with the old cooling fan. After seeking some newsgroup
advice, I found a Papst fan to replace it, but did not find the
time to try the system with the new fan in the old location.

In short, it worked, I replaced the fan, I moved, and now it hums.

At the risk of sounding like some sort of electronics school exam:
How many possible hum sources are there in the above scenario, and
what can I do to troubleshoot them and/or rule some out?


**The Ampzilla is not a nice amp to work on. You may need to take it to a
specialist. Here's some answers, however:

* Lights: Old lamps are fragile. The move may have damaged the filaments. It
is possible that only a couple were working anyway.
* Noises: Could be due to a couple of thins: Most Ampzillas used plug in
front end transistors. Sometimes they fail intermittently, or go noisy. They
need to be replaced with matched sets. Sometimes the sockets get dirty.
The output and driver devices are coupled to the PCB via an array of
gold plated pins. These or the sockets may require replacement.
The output stage is biased by a transistor array (GAS100A). This may
need replacing.
Various other things.
* Hum: Since the noise appears to be mechanical, I suggest that the
transformer may have loose laminations.


--
Trevor Wilson
www.rageaudio.com.au

Thanks one and all for the responses. You've convinced me I am
over my head on this one, and that it is time to find someone with
a clue. Any recommendations in the DC-Baltimore area?

FWIW, this amp was substantially rebuilt by James Bongiorno a few
years back, so I do not think old age is the cause of the
problems. The list of other possibilities nonetheless exceeds my
ken, so it is time for me to seek a professional.

Phil Anderson

Phil Anderson wrote:

Thanks one and all for the responses. You've convinced me I am
over my head on this one, and that it is time to find someone with
a clue. Any recommendations in the DC-Baltimore area?

FWIW, this amp was substantially rebuilt by James Bongiorno a few
years back, so I do not think old age is the cause of the
problems. The list of other possibilities nonetheless exceeds my
ken, so it is time for me to seek a professional.

Phil Anderson



Perhaps the best place for GAS service is Gasworks, located in Idaho.
Mike Bettinger has been a GAS fanatic for over 25 years. Their web site
is www.gasaudio.com

Peter Hansen

I've seen one of Gasworks' mods. Not a pretty sight.

Mark Z.

--
Please reply only to Group. I regret this is necessary. Viruses and spam
have rendered my regular e-mail address useless.


"fronobulax" wrote in message
link.net...
Phil Anderson wrote:

Thanks one and all for the responses. You've convinced me I am
over my head on this one, and that it is time to find someone with
a clue. Any recommendations in the DC-Baltimore area?

FWIW, this amp was substantially rebuilt by James Bongiorno a few
years back, so I do not think old age is the cause of the
problems. The list of other possibilities nonetheless exceeds my
ken, so it is time for me to seek a professional.

Phil Anderson



Perhaps the best place for GAS service is Gasworks, located in Idaho.
Mike Bettinger has been a GAS fanatic for over 25 years. Their web site
is www.gasaudio.com

Peter Hansen