[EADGBE]

I was looking at a receiver currently being offered for sale on eBay.
In the item description, the seller stated that the receiver powered
up fine but since he had no speakers, he didn't know what the receiver
sounded like. There are several photos of the receiver in the
auction, all showing the receiver's lights working.

I could imagine this nice receiver sitting there with no speaker load
connected to it whilst all these photos were being taken.

I decided to e-mail the seller. Here's what I said:

"Just a quick note to let you know... You should NEVER power up an
amplifier or receiver without speakers connected! You can blow the
output transformer, which is an expensive and hard-to-find part to
replace! I understand that you wanted to make sure it powers on, but
you can really do some damage that way."


The seller responded with this message:

"Actually I was informed by a technician that it is completely safe to
do so as long as you are not disconnecting or connecting anything
speaker wise or RCA wise but thank you for your concern"

Was I wrong? I have always been told that an amplfier MUST have a
speaker load connected to it when power is applied.

[Laurence Payne]

On 19 Apr 2007 06:29:09 -0700, EADGBE wrote:

I decided to e-mail the seller. Here's what I said:

"Just a quick note to let you know... You should NEVER power up an
amplifier or receiver without speakers connected! You can blow the
output transformer, which is an expensive and hard-to-find part to
replace! I understand that you wanted to make sure it powers on, but
you can really do some damage that way."


The seller responded with this message:

"Actually I was informed by a technician that it is completely safe to
do so as long as you are not disconnecting or connecting anything
speaker wise or RCA wise but thank you for your concern"

Was I wrong? I have always been told that an amplfier MUST have a
speaker load connected to it when power is applied.

You might want to look inside a modern amplifier and see if there IS
an output transformer :-)

[Serge Auckland]

EADGBE wrote:
I was looking at a receiver currently being offered for sale on eBay.
In the item description, the seller stated that the receiver powered
up fine but since he had no speakers, he didn't know what the receiver
sounded like. There are several photos of the receiver in the
auction, all showing the receiver's lights working.

I could imagine this nice receiver sitting there with no speaker load
connected to it whilst all these photos were being taken.

I decided to e-mail the seller. Here's what I said:

"Just a quick note to let you know... You should NEVER power up an
amplifier or receiver without speakers connected! You can blow the
output transformer, which is an expensive and hard-to-find part to
replace! I understand that you wanted to make sure it powers on, but
you can really do some damage that way."


The seller responded with this message:

"Actually I was informed by a technician that it is completely safe to
do so as long as you are not disconnecting or connecting anything
speaker wise or RCA wise but thank you for your concern"

Was I wrong? I have always been told that an amplfier MUST have a
speaker load connected to it when power is applied.


Yes and No! Some valved (tubed) amplifiers can be unstable without a
load, although well designed ones are fine. All Solid State amplifiers
worthy of the name are fine with no load.

So, unless we know whether the receiver in question was tubed or SS, we
can't say whether the question was right or wrong, and even then, it
depends on the tubed circuit. Most would be OK.

S.

--
http://audiopages.googlepages.com

[Eeyore]

EADGBE wrote:

I was looking at a receiver currently being offered for sale on eBay.
In the item description, the seller stated that the receiver powered
up fine but since he had no speakers, he didn't know what the receiver
sounded like. There are several photos of the receiver in the
auction, all showing the receiver's lights working.

I could imagine this nice receiver sitting there with no speaker load
connected to it whilst all these photos were being taken.

I decided to e-mail the seller. Here's what I said:

"Just a quick note to let you know... You should NEVER power up an
amplifier or receiver without speakers connected! You can blow the
output transformer, which is an expensive and hard-to-find part to
replace! I understand that you wanted to make sure it powers on, but
you can really do some damage that way."

The seller responded with this message:

"Actually I was informed by a technician that it is completely safe to
do so as long as you are not disconnecting or connecting anything
speaker wise or RCA wise but thank you for your concern"

Was I wrong? I have always been told that an amplfier MUST have a
speaker load connected to it when power is applied.

You're wrong.

Very few modern amplifiers (read solid state) have output transformers.

Graham

[EADGBE]

You see, that's where I went wrong. I am a longtime musician, with a
stack of vintage and modern tube amplifiers, and I was simply
transferring over to the stereo world what I had always heard in
musician circles. I added 2 and 2 and didn't get 4! I'll know better
next time! Thanks to everyone for setting me straight.

[Arny Krueger]

"EADGBE" wrote in message
oups.com...

I was looking at a receiver currently being offered for sale on eBay.
In the item description, the seller stated that the receiver powered
up fine but since he had no speakers, he didn't know what the receiver
sounded like.

BS alert! Think about it. This guy has no speakers to use to test a receiver
he wants you to buy?

There's a lot of fish in the sea, if you get my drift.

BTW please register my total agreement with others said about modern (not
tubed) receivers *not* having output transformers and absolutely positively
*not* being damaged by being played with no speakers connected.

[Eeyore]

Arny Krueger wrote:

"EADGBE" wrote

I was looking at a receiver currently being offered for sale on eBay.
In the item description, the seller stated that the receiver powered
up fine but since he had no speakers, he didn't know what the receiver
sounded like.

BS alert! Think about it. This guy has no speakers to use to test a receiver
he wants you to buy?

There's a lot of fish in the sea, if you get my drift.

BTW please register my total agreement with others said about modern (not
tubed) receivers *not* having output transformers and absolutely positively
*not* being damaged by being played with no speakers connected.

I said "very few".

Graham

"Arny Krueger" wrote in message
. ..

"EADGBE" wrote in message
oups.com...

I was looking at a receiver currently being offered for sale on eBay.
In the item description, the seller stated that the receiver powered
up fine but since he had no speakers, he didn't know what the receiver
sounded like.

BS alert! Think about it. This guy has no speakers to use to test a
receiver he wants you to buy?

There's a lot of fish in the sea, if you get my drift.

BTW please register my total agreement with others said about modern (not
tubed) receivers *not* having output transformers and absolutely
positively *not* being damaged by being played with no speakers connected.

cancel this post.

[[email protected]]

On Apr 19, 9:29 am, EADGBE wrote:

"Just a quick note to let you know... You should NEVER power up an
amplifier or receiver without speakers connected! You can blow the
output transformer,

Do you mean "output transformer," which the vast
majority of modern solid-state amplfiers and receivers
do NOT have, or "output transistor," which they DO
have and which are not only much more common and
less expensive than transformers, but in, again, the
vast majority of modern solid state units, do NOT fail
with no load?

which is an expensive and hard-to-find part to
replace! I understand that you wanted to make sure it powers on, but
you can really do some damage that way."

The seller responded with this message:

"Actually I was informed by a technician that it is completely safe to
do so as long as you are not disconnecting or connecting anything
speaker wise or RCA wise but thank you for your concern"

Was I wrong?

Basically, yes.

I have always been told that an amplfier MUST have a
speaker load connected to it when power is applied.

That might have been true with some amplifier topologies
common 40 years ago, certain less-than stable models
and some special-purpose units, but is is certainly
not ture of the vast moajority of consumer solid-state
audio equipment sold for the last 30+ years.

[Peter Larsen]

Arny Krueger wrote:

BTW please register my total agreement with others said about
modern (not tubed) receivers *not* having output transformers
and absolutely positively *not* being damaged by being played
with no speakers connected.

Sansui made a model with output trannies during the quality wars.
Products from the quality war era tend to outdate slowly. I vaguely
recall some advice to the effect that adding a suitable permanent load
resistor on the secondary is all that is required to address the
concerns by removing the possibility of the amplifier and output
transformer seeing no load conditions.


Kind regards

Peter Larsen

[Arny Krueger]

"Peter Larsen" wrote in message
...
Arny Krueger wrote:

BTW please register my total agreement with others said about
modern (not tubed) receivers *not* having output transformers
and absolutely positively *not* being damaged by being played
with no speakers connected.

Sansui made a model with output trannies during the quality wars.
Products from the quality war era tend to outdate slowly. I vaguely
recall some advice to the effect that adding a suitable permanent load
resistor on the secondary is all that is required to address the
concerns by removing the possibility of the amplifier and output
transformer seeing no load conditions.

Just because an amp has output transformers, doesn't mean that running it
without a speaker load is a problem.

A SS amp with OPTs is a considerably different animal than a tubed amp with
OPTs.

An OPT that is enclosed by a feedback loop lives in a different world than
one that is running outside any loop.

Back in the days of, I inadvertently ran a pair of Dyna ST70s without loads
from time to time. Sometimes the signal was cranked up pretty high. AFAIK
nothing bad happened.

[Eeyore]

Arny Krueger wrote:

"Peter Larsen" wrote in message
...
Arny Krueger wrote:

BTW please register my total agreement with others said about
modern (not tubed) receivers *not* having output transformers
and absolutely positively *not* being damaged by being played
with no speakers connected.

Sansui made a model with output trannies during the quality wars.
Products from the quality war era tend to outdate slowly. I vaguely
recall some advice to the effect that adding a suitable permanent load
resistor on the secondary is all that is required to address the
concerns by removing the possibility of the amplifier and output
transformer seeing no load conditions.

Just because an amp has output transformers, doesn't mean that running it
without a speaker load is a problem.

A SS amp with OPTs is a considerably different animal than a tubed amp with
OPTs.

Then again, that varies with amplifier topology ! With valves you're stuck with
only one realistically available, whereas a solid state amp might be classic
push-pull like a valve output or an emitter follower output with an impedance
'matching' transformer. The latter will barely be bothered about a no load
condition.

Graham

[Mr.T]

"Arny Krueger" wrote in message
. ..
"Peter Larsen" wrote in message
Sansui made a model with output trannies during the quality wars.
Products from the quality war era tend to outdate slowly. I vaguely
recall some advice to the effect that adding a suitable permanent load
resistor on the secondary is all that is required to address the
concerns by removing the possibility of the amplifier and output
transformer seeing no load conditions.

Then when you do add a speaker load, the amp not only sees the wrong load
impedance but wastes power in the dummy load.
Seems like a pretty silly idea to me.

Just because an amp has output transformers, doesn't mean that running it
without a speaker load is a problem.
A SS amp with OPTs is a considerably different animal than a tubed amp
with
OPTs.

Exactly.

MrT.

[west[_2_]]

wrote in message
...
cancel this post.

Damn! I been trying for almost 3 hours and still can't cancel this post.

west

[west[_2_]]

"EADGBE" wrote in message
oups.com...
I was looking at a receiver currently being offered for sale on eBay.
In the item description, the seller stated that the receiver powered
up fine but since he had no speakers, he didn't know what the receiver
sounded like. There are several photos of the receiver in the
auction, all showing the receiver's lights working.

I could imagine this nice receiver sitting there with no speaker load
connected to it whilst all these photos were being taken.

I decided to e-mail the seller. Here's what I said:

"Just a quick note to let you know... You should NEVER power up an
amplifier or receiver without speakers connected! You can blow the
output transformer, which is an expensive and hard-to-find part to
replace! I understand that you wanted to make sure it powers on, but
you can really do some damage that way."


The seller responded with this message:

"Actually I was informed by a technician that it is completely safe to
do so as long as you are not disconnecting or connecting anything
speaker wise or RCA wise but thank you for your concern"

Was I wrong? I have always been told that an amplfier MUST have a
speaker load connected to it when power is applied.

Any amp (SS or tube) can be turned on with no problem as long as the volume
control is all the way down. No signal ... no current flow!.

west

[Richard Crowley]

Damn! I been trying for almost 3 hours and still can't cancel this post.

It is virtually impossible to cancel a Usenet post. It may
have already gone halfway around the planet before
you get your finger off the keyboard. And many NNTP
servers don't honor cancel messages because of
abuse. In fact, the longer you wait, the more unlikely
it is to be effective.

[west[_2_]]

"Richard Crowley" wrote in message
...
Damn! I been trying for almost 3 hours and still can't cancel this post.

It is virtually impossible to cancel a Usenet post. It may
have already gone halfway around the planet before
you get your finger off the keyboard. And many NNTP
servers don't honor cancel messages because of
abuse. In fact, the longer you wait, the more unlikely
it is to be effective.

Just kidding to lighten things up a bit. However, I still appreciate the
advice.

west

[[email protected]]

On Apr 24, 10:07 am, "west" wrote:
"EADGBE" wrote in message
"Actually I was informed by a technician that it is completely safe to
do so as long as you are not disconnecting or connecting anything
speaker wise or RCA wise but thank you for your concern"

Was I wrong? I have always been told that an amplfier MUST have a
speaker load connected to it when power is applied.

Any amp (SS or tube) can be turned on with no problem
as long as the volume control is all the way down. No
signal ... no current flow!.

Not true of some older topologies. Imagine a case where the
load is used to set the feedback gain, and without the
load the feedback gain is such even small output (like
noise) can send the amp into instability.

That's extremely rare, especially with any reasonably modern
topology, but is the case with some older amplifiers and
some musical instrument stuff.